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Date:   Mon, 7 Aug 2023 09:29:55 +0000
From:   Sakari Ailus <sakari.ailus@linux.intel.com>
To:     Hugues Fruchet <hugues.fruchet@foss.st.com>
Cc:     Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Hans Verkuil <hverkuil@xs4all.nl>,
        Rob Herring <robh+dt@kernel.org>, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org,
        linux-stm32@st-md-mailman.stormreply.com,
        Alain Volmat <alain.volmat@foss.st.com>,
        Philippe CORNU <philippe.cornu@foss.st.com>
Subject: Re: [PATCH v1 3/5] media: stm32-dcmipp: STM32 DCMIPP camera
 interface driver
Message-ID: <ZNC5k3PynnEWL/ou@kekkonen.localdomain>
References: <20220910144010.34272-1-hugues.fruchet@foss.st.com>
 <20220910144010.34272-4-hugues.fruchet@foss.st.com>
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In-Reply-To: <20220910144010.34272-4-hugues.fruchet@foss.st.com>
Precedence: bulk

Hi Hugues,

Sorry for the late review. Please ping if you don't get replies! I noticed
this as you replied Dan...

There are multiple drivers here and I haven't commented on similar
constructs on all of them but the comments do still apply.

There have been some API changes, in particular sub-device state. See e.g.
<URL:https://git.linuxtv.org/sailus/media_tree.git/commit/?id=3f516e053ae8e25bc673b8549a8a2bc4bbbd2e9d>.

On Sat, Sep 10, 2022 at 04:40:08PM +0200, Hugues Fruchet wrote:
> This V4L2 subdev driver enables Digital Camera Memory Interface
> Pixel Processor(DCMIPP) of STMicroelectronics STM32 SoC series.
> 
> Signed-off-by: Hugues Fruchet <hugues.fruchet@foss.st.com>
> ---
>  drivers/media/platform/st/stm32/Kconfig       |   15 +
>  drivers/media/platform/st/stm32/Makefile      |    1 +
>  .../platform/st/stm32/stm32-dcmipp/Makefile   |    5 +
>  .../st/stm32/stm32-dcmipp/dcmipp-bytecap.c    | 1112 +++++++++++++++++
>  .../st/stm32/stm32-dcmipp/dcmipp-byteproc.c   |  790 ++++++++++++
>  .../st/stm32/stm32-dcmipp/dcmipp-common.c     |  116 ++
>  .../st/stm32/stm32-dcmipp/dcmipp-common.h     |  240 ++++
>  .../st/stm32/stm32-dcmipp/dcmipp-core.c       |  682 ++++++++++
>  .../st/stm32/stm32-dcmipp/dcmipp-parallel.c   |  497 ++++++++
>  9 files changed, 3458 insertions(+)
>  create mode 100644 drivers/media/platform/st/stm32/stm32-dcmipp/Makefile
>  create mode 100644 drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-bytecap.c
>  create mode 100644 drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-byteproc.c
>  create mode 100644 drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-common.c
>  create mode 100644 drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-common.h
>  create mode 100644 drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-core.c
>  create mode 100644 drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-parallel.c
> 
> diff --git a/drivers/media/platform/st/stm32/Kconfig b/drivers/media/platform/st/stm32/Kconfig
> index b22dd4753496..fab531866941 100644
> --- a/drivers/media/platform/st/stm32/Kconfig
> +++ b/drivers/media/platform/st/stm32/Kconfig
> @@ -16,6 +16,21 @@ config VIDEO_STM32_DCMI
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called stm32-dcmi.
>  
> +config VIDEO_STM32_DCMIPP
> +	tristate "STM32 Digital Camera Memory Interface Pixel Processor (DCMIPP) support"
> +	depends on V4L_PLATFORM_DRIVERS
> +	depends on VIDEO_DEV && OF
> +	depends on MEDIA_CONTROLLER
> +	depends on ARCH_STM32 || COMPILE_TEST
> +	select VIDEOBUF2_DMA_CONTIG
> +	select V4L2_FWNODE
> +	help
> +	  This module makes the STM32 Digital Camera Memory Interface
> +	  Pixel Processor (DCMIPP) available as a v4l2 device.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called stm32-dcmipp.
> +
>  # Mem2mem drivers
>  config VIDEO_STM32_DMA2D
>  	tristate "STM32 Chrom-Art Accelerator (DMA2D)"
> diff --git a/drivers/media/platform/st/stm32/Makefile b/drivers/media/platform/st/stm32/Makefile
> index 896ef98a73ab..7ed8297b9b19 100644
> --- a/drivers/media/platform/st/stm32/Makefile
> +++ b/drivers/media/platform/st/stm32/Makefile
> @@ -1,4 +1,5 @@
>  # SPDX-License-Identifier: GPL-2.0-only
>  obj-$(CONFIG_VIDEO_STM32_DCMI) += stm32-dcmi.o
> +obj-$(CONFIG_VIDEO_STM32_DCMIPP) += stm32-dcmipp/
>  stm32-dma2d-objs := dma2d/dma2d.o dma2d/dma2d-hw.o
>  obj-$(CONFIG_VIDEO_STM32_DMA2D) += stm32-dma2d.o
> diff --git a/drivers/media/platform/st/stm32/stm32-dcmipp/Makefile b/drivers/media/platform/st/stm32/stm32-dcmipp/Makefile
> new file mode 100644
> index 000000000000..cbddc98141a4
> --- /dev/null
> +++ b/drivers/media/platform/st/stm32/stm32-dcmipp/Makefile
> @@ -0,0 +1,5 @@
> +# SPDX-License-Identifier: GPL-2.0
> +stm32-dcmipp-y := dcmipp-core.o dcmipp-common.o
> +
> +obj-$(CONFIG_VIDEO_STM32_DCMIPP) += stm32-dcmipp.o
> +obj-$(CONFIG_VIDEO_STM32_DCMIPP) += dcmipp-parallel.o dcmipp-byteproc.o dcmipp-bytecap.o
> diff --git a/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-bytecap.c b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-bytecap.c
> new file mode 100644
> index 000000000000..ae7841913000
> --- /dev/null
> +++ b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-bytecap.c
> @@ -0,0 +1,1112 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for STM32 Digital Camera Memory Interface Pixel Processor
> + *
> + * Copyright (C) STMicroelectronics SA 2022
> + * Authors: Hugues Fruchet <hugues.fruchet@foss.st.com>
> + *          Alain Volmat <alain.volmat@foss.st.com>
> + *          for STMicroelectronics.
> + */
> +
> +#include <linux/component.h>
> +#include <linux/delay.h>
> +#include <linux/iopoll.h>
> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/reset.h>
> +#include <media/v4l2-ioctl.h>
> +#include <media/v4l2-mc.h>
> +#include <media/videobuf2-core.h>
> +#include <media/videobuf2-dma-contig.h>
> +
> +#include "dcmipp-common.h"
> +
> +#define DCMIPP_BYTECAP_DRV_NAME "dcmipp-bytecap"
> +
> +#define DCMIPP_PRSR (0x1F8)
> +#define DCMIPP_CMIER (0x3F0)
> +#define DCMIPP_CMIER_P0FRAMEIE BIT(9)
> +#define DCMIPP_CMIER_P0VSYNCIE BIT(10)
> +#define DCMIPP_CMIER_P0OVRIE BIT(15)
> +#define DCMIPP_CMIER_P0ALL (DCMIPP_CMIER_P0VSYNCIE |\
> +			    DCMIPP_CMIER_P0FRAMEIE |\
> +			    DCMIPP_CMIER_P0OVRIE)
> +#define DCMIPP_CMSR1 (0x3F4)
> +#define DCMIPP_CMSR2 (0x3F8)
> +#define DCMIPP_CMSR2_P0FRAMEF BIT(9)
> +#define DCMIPP_CMSR2_P0VSYNCF BIT(10)
> +#define DCMIPP_CMSR2_P0OVRF BIT(15)
> +#define DCMIPP_CMFCR (0x3FC)
> +#define DCMIPP_P0FSCR (0x404)
> +#define DCMIPP_P0FSCR_PIPEN BIT(31)
> +#define DCMIPP_P0FCTCR (0x500)
> +#define DCMIPP_P0FCTCR_CPTREQ BIT(3)
> +#define DCMIPP_P0DCCNTR (0x5B0)
> +#define DCMIPP_P0DCLMTR (0x5B4)
> +#define DCMIPP_P0DCLMTR_ENABLE BIT(31)
> +#define DCMIPP_P0DCLMTR_LIMIT_MASK GENMASK(23, 0)
> +#define DCMIPP_P0PPM0AR1 (0x5C4)
> +#define DCMIPP_P0SR (0x5F8)
> +#define DCMIPP_P0SR_CPTACT BIT(23)
> +
> +struct dcmipp_bytecap_pix_map {
> +	unsigned int code;
> +	u32 pixelformat;
> +};
> +
> +#define PIXMAP_MBUS_PFMT(mbus, fmt)				\
> +		{						\
> +			.code = MEDIA_BUS_FMT_##mbus,		\
> +			.pixelformat = V4L2_PIX_FMT_##fmt	\
> +		}
> +
> +static const struct dcmipp_bytecap_pix_map dcmipp_bytecap_pix_map_list[] = {
> +	PIXMAP_MBUS_PFMT(RGB565_2X8_LE, RGB565),
> +	PIXMAP_MBUS_PFMT(YUYV8_2X8, YUYV),
> +	PIXMAP_MBUS_PFMT(YVYU8_2X8, YVYU),
> +	PIXMAP_MBUS_PFMT(UYVY8_2X8, UYVY),
> +	PIXMAP_MBUS_PFMT(VYUY8_2X8, VYUY),
> +	PIXMAP_MBUS_PFMT(Y8_1X8, GREY),
> +	PIXMAP_MBUS_PFMT(SBGGR8_1X8, SBGGR8),
> +	PIXMAP_MBUS_PFMT(SGBRG8_1X8, SGBRG8),
> +	PIXMAP_MBUS_PFMT(SGRBG8_1X8, SGRBG8),
> +	PIXMAP_MBUS_PFMT(SRGGB8_1X8, SRGGB8),
> +	PIXMAP_MBUS_PFMT(JPEG_1X8, JPEG),
> +};
> +
> +static const struct dcmipp_bytecap_pix_map *dcmipp_bytecap_pix_map_by_pixelformat
> +						(u32 pixelformat)
> +{
> +	const struct dcmipp_bytecap_pix_map *l = dcmipp_bytecap_pix_map_list;
> +	unsigned int size = ARRAY_SIZE(dcmipp_bytecap_pix_map_list);
> +	unsigned int i;
> +
> +	for (i = 0; i < size; i++) {
> +		if (l[i].pixelformat == pixelformat)
> +			return &l[i];
> +	}
> +
> +	return NULL;
> +}
> +
> +static const struct dcmipp_bytecap_pix_map *dcmipp_bytecap_pix_map_by_index(unsigned int i)
> +{
> +	const struct dcmipp_bytecap_pix_map *l = dcmipp_bytecap_pix_map_list;
> +	unsigned int size = ARRAY_SIZE(dcmipp_bytecap_pix_map_list);
> +
> +	if (i >= size)
> +		return NULL;
> +
> +	return &l[i];
> +}
> +
> +struct dcmipp_buf {
> +	struct vb2_v4l2_buffer	vb;
> +	bool			prepared;
> +	dma_addr_t		paddr;
> +	size_t			size;
> +	struct list_head	list;
> +};
> +
> +enum state {
> +	STOPPED = 0,
> +	WAIT_FOR_BUFFER,
> +	RUNNING,
> +};
> +
> +struct dcmipp_bytecap_device {
> +	struct dcmipp_ent_device ved;
> +	struct video_device vdev;
> +	struct device *dev;
> +	struct device *cdev;
> +	struct v4l2_pix_format format;
> +	struct vb2_queue queue;
> +	struct list_head buffers;
> +	/* Protects the access of variables shared within the interrupt */
> +	spinlock_t irqlock;
> +	/* Protect this data structure */
> +	struct mutex lock;
> +	u32 sequence;
> +	struct media_pipeline pipe;
> +
> +	enum state state;
> +
> +	/*
> +	 * DCMIPP driver is handling 2 buffers
> +	 * active: buffer into which DCMIPP is currently writing into
> +	 * next: buffer given to the DCMIPP and which will become
> +	 *       automatically active on next VSYNC
> +	 */
> +	struct dcmipp_buf *active, *next;
> +
> +	void __iomem *regs;
> +	struct reset_control *rstc;
> +
> +	u32 cmier;
> +	u32 cmsr2;
> +
> +	int errors_count;
> +	int limit_count;
> +	int overrun_count;
> +	int buffers_count;
> +	int vsync_count;
> +	int frame_count;
> +	int it_count;
> +	int underrun_count;
> +	int nactive_count;

These would probably be better unsigned.

> +};
> +
> +static const struct v4l2_pix_format fmt_default = {
> +	.width = DCMIPP_FMT_WIDTH_DEFAULT,
> +	.height = DCMIPP_FMT_HEIGHT_DEFAULT,
> +	.pixelformat = V4L2_PIX_FMT_RGB565,
> +	.field = V4L2_FIELD_NONE,
> +	.colorspace = DCMIPP_COLORSPACE_DEFAULT,
> +	.ycbcr_enc = DCMIPP_YCBCR_ENC_DEFAULT,
> +	.quantization = DCMIPP_QUANTIZATION_DEFAULT,
> +	.xfer_func = DCMIPP_XFER_FUNC_DEFAULT,
> +};
> +
> +static inline int frame_size(u32 width, u32 height, u32 format)
> +{
> +	switch (format) {
> +	case V4L2_PIX_FMT_SBGGR8:
> +	case V4L2_PIX_FMT_SGBRG8:
> +	case V4L2_PIX_FMT_SGRBG8:
> +	case V4L2_PIX_FMT_SRGGB8:
> +	case V4L2_PIX_FMT_GREY:
> +		return (width * height);
> +	case V4L2_PIX_FMT_RGB565:
> +	case V4L2_PIX_FMT_YUYV:
> +	case V4L2_PIX_FMT_YVYU:
> +	case V4L2_PIX_FMT_UYVY:
> +	case V4L2_PIX_FMT_VYUY:
> +		return (width * height * 2);
> +	case V4L2_PIX_FMT_JPEG:
> +		return (width * height);

No need for the parentheses.

> +	default:
> +		return 0;
> +	}
> +}
> +
> +static inline int frame_stride(u32 width, u32 format)
> +{
> +	switch (format) {
> +	case V4L2_PIX_FMT_SBGGR8:
> +	case V4L2_PIX_FMT_SGBRG8:
> +	case V4L2_PIX_FMT_SGRBG8:
> +	case V4L2_PIX_FMT_SRGGB8:
> +	case V4L2_PIX_FMT_GREY:
> +	case V4L2_PIX_FMT_JPEG:
> +		return width;
> +	case V4L2_PIX_FMT_RGB565:
> +	case V4L2_PIX_FMT_YUYV:
> +	case V4L2_PIX_FMT_YVYU:
> +	case V4L2_PIX_FMT_UYVY:
> +	case V4L2_PIX_FMT_VYUY:
> +		return (width * 2);
> +	default:
> +		return 0;
> +	}
> +}
> +
> +static inline int hdw_pixel_alignment(u32 format)
> +{
> +	/* 16 bytes alignment required by hardware */
> +	switch (format) {
> +	case V4L2_PIX_FMT_SBGGR8:
> +	case V4L2_PIX_FMT_SGBRG8:
> +	case V4L2_PIX_FMT_SGRBG8:
> +	case V4L2_PIX_FMT_SRGGB8:
> +	case V4L2_PIX_FMT_GREY:
> +	case V4L2_PIX_FMT_JPEG:
> +		return 4;/* 2^4 = 16 pixels = 16 bytes */
> +	case V4L2_PIX_FMT_RGB565:
> +	case V4L2_PIX_FMT_YUYV:
> +	case V4L2_PIX_FMT_YVYU:
> +	case V4L2_PIX_FMT_UYVY:
> +	case V4L2_PIX_FMT_VYUY:
> +		return 3;/* 2^3  = 8 pixels = 16 bytes */

A space after the semicolon? Same above.

> +	default:
> +		return 0;
> +	}
> +}
> +
> +static int dcmipp_bytecap_querycap(struct file *file, void *priv,
> +				   struct v4l2_capability *cap)
> +{
> +	strscpy(cap->driver, DCMIPP_PDEV_NAME, sizeof(cap->driver));
> +	strscpy(cap->card, KBUILD_MODNAME, sizeof(cap->card));
> +	snprintf(cap->bus_info, sizeof(cap->bus_info),
> +		 "platform:%s", DCMIPP_PDEV_NAME);

This isn't necessary anymore --- it's handled by v4l_querycap() directly.

> +
> +	return 0;
> +}
> +
> +static void dcmipp_bytecap_get_format(struct dcmipp_ent_device *ved,
> +				      struct v4l2_pix_format *fmt)
> +{
> +	struct dcmipp_bytecap_device *vcap = container_of(ved, struct dcmipp_bytecap_device,
> +						    ved);
> +
> +	*fmt = vcap->format;
> +}
> +
> +static int dcmipp_bytecap_g_fmt_vid_cap(struct file *file, void *priv,
> +					struct v4l2_format *f)
> +{
> +	struct dcmipp_bytecap_device *vcap = video_drvdata(file);
> +
> +	f->fmt.pix = vcap->format;
> +
> +	return 0;
> +}
> +
> +static int dcmipp_bytecap_try_fmt_vid_cap(struct file *file, void *priv,
> +					  struct v4l2_format *f)
> +{
> +	struct dcmipp_bytecap_device *vcap = video_drvdata(file);
> +	struct v4l2_pix_format *format = &f->fmt.pix;
> +	const struct dcmipp_bytecap_pix_map *vpix;
> +	u32 in_w, in_h;
> +
> +	/* Don't accept a pixelformat that is not on the table */
> +	vpix = dcmipp_bytecap_pix_map_by_pixelformat(format->pixelformat);
> +	if (!vpix)
> +		format->pixelformat = fmt_default.pixelformat;
> +
> +	/* Adjust width & height */
> +	in_w = format->width;
> +	in_h = format->height;
> +	v4l_bound_align_image(&format->width,
> +			      DCMIPP_FRAME_MIN_WIDTH, DCMIPP_FRAME_MAX_WIDTH,
> +			      hdw_pixel_alignment(format->pixelformat),
> +			      &format->height,
> +			      DCMIPP_FRAME_MIN_HEIGHT, DCMIPP_FRAME_MAX_HEIGHT,
> +			      hdw_pixel_alignment(format->pixelformat),
> +			      0);
> +	if (format->width != in_w || format->height != in_h)
> +		dev_dbg(vcap->dev,
> +			"resolution updated: %dx%d -> %dx%d\n",
> +			in_w, in_h, format->width, format->height);
> +
> +	format->bytesperline = frame_stride(format->width, format->pixelformat);
> +	format->sizeimage = frame_size(format->width, format->height, format->pixelformat);

Please run:

	./scripts/checkpatch.pl --strict --max-line-length=80

> +
> +	if (format->field == V4L2_FIELD_ANY)
> +		format->field = fmt_default.field;
> +
> +	dcmipp_colorimetry_clamp(format);
> +
> +	return 0;
> +}
> +
> +static int dcmipp_bytecap_s_fmt_vid_cap(struct file *file, void *priv,
> +					struct v4l2_format *f)
> +{
> +	struct dcmipp_bytecap_device *vcap = video_drvdata(file);
> +	int ret;
> +
> +	/* Do not change the format while stream is on */
> +	if (vb2_is_busy(&vcap->queue))
> +		return -EBUSY;
> +
> +	ret = dcmipp_bytecap_try_fmt_vid_cap(file, priv, f);
> +	if (ret)
> +		return ret;
> +
> +	dev_dbg(vcap->dev, "%s: format update: old:%dx%d (0x%x, %d, %d, %d, %d) new:%dx%d (0x%x, %d, %d, %d, %d)\n",
> +		vcap->vdev.name,
> +		/* old */
> +		vcap->format.width, vcap->format.height,
> +		vcap->format.pixelformat, vcap->format.colorspace,
> +		vcap->format.quantization, vcap->format.xfer_func,
> +		vcap->format.ycbcr_enc,
> +		/* new */
> +		f->fmt.pix.width, f->fmt.pix.height,
> +		f->fmt.pix.pixelformat, f->fmt.pix.colorspace,
> +		f->fmt.pix.quantization, f->fmt.pix.xfer_func,
> +		f->fmt.pix.ycbcr_enc);
> +
> +	vcap->format = f->fmt.pix;
> +
> +	return 0;
> +}
> +
> +static int dcmipp_bytecap_enum_fmt_vid_cap(struct file *file, void *priv,
> +					   struct v4l2_fmtdesc *f)
> +{
> +	const struct dcmipp_bytecap_pix_map *vpix = dcmipp_bytecap_pix_map_by_index(f->index);

This function is used only once, please move the code here.

> +
> +	if (!vpix)
> +		return -EINVAL;
> +
> +	f->pixelformat = vpix->pixelformat;
> +
> +	return 0;
> +}
> +
> +static int dcmipp_bytecap_enum_framesizes(struct file *file, void *fh,
> +					  struct v4l2_frmsizeenum *fsize)
> +{
> +	const struct dcmipp_bytecap_pix_map *vpix;
> +
> +	if (fsize->index)
> +		return -EINVAL;
> +
> +	/* Only accept code in the pix map table */
> +	vpix = dcmipp_bytecap_pix_map_by_pixelformat(fsize->pixel_format);
> +	if (!vpix)
> +		return -EINVAL;
> +
> +	fsize->type = V4L2_FRMSIZE_TYPE_CONTINUOUS;
> +	fsize->stepwise.min_width = DCMIPP_FRAME_MIN_WIDTH;
> +	fsize->stepwise.max_width = DCMIPP_FRAME_MAX_WIDTH;
> +	fsize->stepwise.min_height = DCMIPP_FRAME_MIN_HEIGHT;
> +	fsize->stepwise.max_height = DCMIPP_FRAME_MAX_HEIGHT;
> +	fsize->stepwise.step_width = 1;
> +	fsize->stepwise.step_height = 1;
> +
> +	return 0;
> +}
> +
> +/* TODO - based on the explanation text, should also use v4l2_pipeline_link_notify */
> +static int dcmipp_bytecap_open(struct file *file)
> +{
> +	struct dcmipp_bytecap_device *vcap = video_drvdata(file);
> +	int ret;
> +
> +	ret = mutex_lock_interruptible(&vcap->lock);
> +	if (ret)
> +		return ret;
> +
> +	ret = v4l2_fh_open(file);
> +	if (ret)
> +		goto err_unlock;
> +
> +	ret = v4l2_pipeline_pm_get(&vcap->vdev.entity);

You shouldn't do this anymore, instead please change any sensor driver you
need to use runtime PM.

> +	if (ret)
> +		goto err_close;
> +
> +	mutex_unlock(&vcap->lock);
> +
> +	return 0;
> +
> +err_close:
> +	v4l2_fh_release(file);
> +err_unlock:
> +	mutex_unlock(&vcap->lock);
> +
> +	return ret;
> +}
> +
> +static int dcmipp_bytecap_close(struct file *file)
> +{
> +	struct dcmipp_bytecap_device *vcap = video_drvdata(file);
> +
> +	vb2_fop_release(file);
> +
> +	v4l2_pipeline_pm_put(&vcap->vdev.entity);
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_file_operations dcmipp_bytecap_fops = {
> +	.owner		= THIS_MODULE,
> +	.open		= dcmipp_bytecap_open,
> +	.release	= dcmipp_bytecap_close,
> +	.read           = vb2_fop_read,
> +	.poll		= vb2_fop_poll,
> +	.unlocked_ioctl = video_ioctl2,
> +	.mmap           = vb2_fop_mmap,
> +};
> +
> +static const struct v4l2_ioctl_ops dcmipp_bytecap_ioctl_ops = {
> +	.vidioc_querycap = dcmipp_bytecap_querycap,
> +
> +	.vidioc_g_fmt_vid_cap = dcmipp_bytecap_g_fmt_vid_cap,
> +	.vidioc_s_fmt_vid_cap = dcmipp_bytecap_s_fmt_vid_cap,
> +	.vidioc_try_fmt_vid_cap = dcmipp_bytecap_try_fmt_vid_cap,
> +	.vidioc_enum_fmt_vid_cap = dcmipp_bytecap_enum_fmt_vid_cap,
> +	.vidioc_enum_framesizes = dcmipp_bytecap_enum_framesizes,
> +
> +	.vidioc_reqbufs = vb2_ioctl_reqbufs,
> +	.vidioc_create_bufs = vb2_ioctl_create_bufs,
> +	.vidioc_prepare_buf = vb2_ioctl_prepare_buf,
> +	.vidioc_querybuf = vb2_ioctl_querybuf,
> +	.vidioc_qbuf = vb2_ioctl_qbuf,
> +	.vidioc_dqbuf = vb2_ioctl_dqbuf,
> +	.vidioc_expbuf = vb2_ioctl_expbuf,
> +	.vidioc_streamon = vb2_ioctl_streamon,
> +	.vidioc_streamoff = vb2_ioctl_streamoff,
> +};
> +
> +static int dcmipp_pipeline_s_stream(struct dcmipp_bytecap_device *vcap,
> +				    int state)
> +{
> +	struct media_entity *entity = &vcap->vdev.entity;
> +	struct v4l2_subdev *subdev;
> +	struct media_pad *pad;
> +	int ret;
> +
> +	/* Start/stop all entities within pipeline */
> +	while (1) {
> +		pad = &entity->pads[0];
> +		if (!(pad->flags & MEDIA_PAD_FL_SINK))
> +			break;
> +
> +		pad = media_pad_remote_pad_first(pad);
> +		if (!pad || !is_media_entity_v4l2_subdev(pad->entity))
> +			break;
> +
> +		entity = pad->entity;
> +		subdev = media_entity_to_v4l2_subdev(entity);
> +
> +		ret = v4l2_subdev_call(subdev, video, s_stream, state);

Does this driver handle multiple sub-devices in the same pipeline?

If not, then you don't need a loop here.

> +		if (ret < 0 && ret != -ENOIOCTLCMD) {
> +			dev_err(vcap->dev, "%s: \"%s\" failed to %s streaming (%d)\n",
> +				__func__, subdev->name,
> +				state ? "start" : "stop", ret);
> +
> +			if (!state)
> +				v4l2_subdev_call(subdev, core, s_power, state);
> +
> +			return ret;
> +		}
> +
> +		dev_dbg(vcap->dev, "\"%s\" is %s\n",
> +			subdev->name, state ? "started" : "stopped");
> +	}
> +
> +	return 0;
> +}
> +
> +static void dcmipp_start_capture(struct dcmipp_bytecap_device *vcap,
> +				 struct dcmipp_buf *buf)
> +{
> +	/* Set buffer address */
> +	reg_write(vcap, DCMIPP_P0PPM0AR1, buf->paddr);
> +	dev_dbg(vcap->dev, "Write [%d] %p phy=%pad\n", buf->vb.vb2_buf.index, buf, &buf->paddr);
> +
> +	/* Set buffer size */
> +	reg_write(vcap, DCMIPP_P0DCLMTR, DCMIPP_P0DCLMTR_ENABLE |
> +		  ((buf->size / 4) & DCMIPP_P0DCLMTR_LIMIT_MASK));
> +
> +	/* Capture request */
> +	reg_set(vcap, DCMIPP_P0FCTCR, DCMIPP_P0FCTCR_CPTREQ);
> +}
> +
> +static int dcmipp_bytecap_start_streaming(struct vb2_queue *vq,
> +					  unsigned int count)
> +{
> +	struct dcmipp_bytecap_device *vcap = vb2_get_drv_priv(vq);
> +	struct media_entity *entity = &vcap->vdev.entity;
> +	struct dcmipp_buf *buf, *node;
> +	int ret;
> +
> +	vcap->sequence = 0;
> +	vcap->errors_count = 0;
> +	vcap->limit_count = 0;
> +	vcap->overrun_count = 0;
> +	vcap->buffers_count = 0;
> +	vcap->vsync_count = 0;
> +	vcap->frame_count = 0;
> +	vcap->it_count = 0;
> +	vcap->underrun_count = 0;
> +	vcap->nactive_count = 0;

What if you put these into a struct? You could also use memset() on it.

> +
> +	ret = pm_runtime_get_sync(vcap->cdev);
> +	if (ret < 0) {
> +		dev_err(vcap->dev, "%s: Failed to start streaming, cannot get sync (%d)\n",
> +			__func__, ret);
> +		goto err_pm_put;
> +	}
> +
> +	/* Start the media pipeline */
> +	ret = media_pipeline_start(entity, &vcap->pipe);
> +	if (ret) {
> +		dev_err(vcap->dev, "%s: Failed to start streaming, media pipeline start error (%d)\n",
> +			__func__, ret);
> +		goto err_pm_put;
> +	}
> +
> +	/* Start all the elements within pipeline */
> +	ret = dcmipp_pipeline_s_stream(vcap, 1);
> +	if (ret)
> +		goto err_media_pipeline_stop;
> +
> +	spin_lock_irq(&vcap->irqlock);
> +
> +	/* Enable pipe at the end of programming */
> +	reg_set(vcap, DCMIPP_P0FSCR, DCMIPP_P0FSCR_PIPEN);
> +
> +	/*
> +	 * Start capture if at least one buffer has been queued,
> +	 * otherwise start is deferred at next buffer queueing
> +	 */
> +	buf = list_first_entry_or_null(&vcap->buffers, typeof(*buf), list);
> +	if (!buf) {
> +		dev_dbg(vcap->dev, "Start streaming is deferred to next buffer queueing\n");
> +		vcap->next = NULL;
> +		vcap->state = WAIT_FOR_BUFFER;
> +		spin_unlock_irq(&vcap->irqlock);
> +		return 0;
> +	}
> +	vcap->next = buf;
> +	dev_dbg(vcap->dev, "Start with next [%d] %p phy=%pad\n",
> +		buf->vb.vb2_buf.index, buf, &buf->paddr);
> +
> +	/* Start capture */
> +	dcmipp_start_capture(vcap, buf);
> +
> +	/* Enable interruptions */
> +	vcap->cmier |= DCMIPP_CMIER_P0ALL;
> +	reg_set(vcap, DCMIPP_CMIER, vcap->cmier);
> +
> +	vcap->state = RUNNING;
> +
> +	spin_unlock_irq(&vcap->irqlock);
> +
> +	return 0;
> +
> +err_media_pipeline_stop:
> +	media_pipeline_stop(entity);
> +err_pm_put:
> +	pm_runtime_put(vcap->cdev);
> +	spin_lock_irq(&vcap->irqlock);
> +	/*
> +	 * Return all buffers to vb2 in QUEUED state.
> +	 * This will give ownership back to userspace
> +	 */
> +	list_for_each_entry_safe(buf, node, &vcap->buffers, list) {
> +		list_del_init(&buf->list);
> +		vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_QUEUED);
> +	}
> +	vcap->active = NULL;
> +	spin_unlock_irq(&vcap->irqlock);
> +
> +	return ret;
> +}
> +
> +static void dcmipp_dump_status(struct dcmipp_bytecap_device *vcap)
> +{
> +	struct device *dev = vcap->dev;
> +
> +	dev_dbg(dev, "[DCMIPP_PRSR]  =%#10.8x\n", reg_read(vcap, DCMIPP_PRSR));
> +	dev_dbg(dev, "[DCMIPP_P0SR] =%#10.8x\n", reg_read(vcap, DCMIPP_P0SR));
> +	dev_dbg(dev, "[DCMIPP_P0DCCNTR]=%#10.8x\n",
> +		reg_read(vcap, DCMIPP_P0DCCNTR));
> +	dev_dbg(dev, "[DCMIPP_CMSR1] =%#10.8x\n", reg_read(vcap, DCMIPP_CMSR1));
> +	dev_dbg(dev, "[DCMIPP_CMSR2] =%#10.8x\n", reg_read(vcap, DCMIPP_CMSR2));
> +}
> +
> +/*
> + * Stop the stream engine. Any remaining buffers in the stream queue are
> + * dequeued and passed on to the vb2 framework marked as STATE_ERROR.
> + */
> +static void dcmipp_bytecap_stop_streaming(struct vb2_queue *vq)
> +{
> +	struct dcmipp_bytecap_device *vcap = vb2_get_drv_priv(vq);
> +	struct dcmipp_buf *buf, *node;
> +	int ret;
> +	u32 status;
> +
> +	dcmipp_pipeline_s_stream(vcap, 0);
> +
> +	/* Stop the media pipeline */
> +	media_pipeline_stop(&vcap->vdev.entity);
> +
> +	/* Disable interruptions */
> +	reg_clear(vcap, DCMIPP_CMIER, vcap->cmier);
> +
> +	/* Stop capture */
> +	reg_clear(vcap, DCMIPP_P0FCTCR, DCMIPP_P0FCTCR_CPTREQ);
> +
> +	/* Wait until CPTACT become 0 */
> +	ret = readl_relaxed_poll_timeout(vcap->regs + DCMIPP_P0SR,
> +					 status,
> +					 !(status & DCMIPP_P0SR_CPTACT),
> +					 20, 1000);
> +	if (ret)
> +		dev_warn(vcap->dev, "Timeout when stopping\n");
> +
> +	/* Disable pipe */
> +	reg_clear(vcap, DCMIPP_P0FSCR, DCMIPP_P0FSCR_PIPEN);
> +
> +	spin_lock_irq(&vcap->irqlock);
> +
> +	/* Return all queued buffers to vb2 in ERROR state */
> +	list_for_each_entry_safe(buf, node, &vcap->buffers, list) {
> +		list_del_init(&buf->list);
> +		vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
> +	}
> +	INIT_LIST_HEAD(&vcap->buffers);
> +
> +	vcap->active = NULL;
> +	vcap->state = STOPPED;
> +
> +	dcmipp_dump_status(vcap);
> +
> +	spin_unlock_irq(&vcap->irqlock);
> +
> +	pm_runtime_put(vcap->cdev);
> +
> +	if (ret) {
> +		/* Reset IP on timeout */
> +		if (reset_control_assert(vcap->rstc))
> +			dev_warn(vcap->dev, "Failed to assert the reset line\n");
> +
> +		usleep_range(3000, 5000);
> +
> +		if (reset_control_deassert(vcap->rstc))
> +			dev_warn(vcap->dev, "Failed to deassert the reset line\n");
> +	}
> +
> +	if (vcap->errors_count)
> +		dev_warn(vcap->dev, "Some errors found while streaming: errors=%d (overrun=%d, limit=%d, nactive=%d), underrun=%d, buffers=%d\n",
> +			 vcap->errors_count, vcap->overrun_count, vcap->limit_count,
> +			 vcap->nactive_count, vcap->underrun_count, vcap->buffers_count);
> +	dev_dbg(vcap->dev, "Stop streaming, errors=%d (overrun=%d, limit=%d, nactive=%d), underrun=%d, vsync=%d, frame=%d, buffers=%d, it=%d\n",
> +		vcap->errors_count, vcap->overrun_count, vcap->limit_count,
> +		vcap->nactive_count, vcap->underrun_count, vcap->vsync_count,
> +		vcap->frame_count, vcap->buffers_count, vcap->it_count);
> +}
> +
> +static int dcmipp_bytecap_buf_prepare(struct vb2_buffer *vb)
> +{
> +	struct dcmipp_bytecap_device *vcap =  vb2_get_drv_priv(vb->vb2_queue);
> +	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
> +	struct dcmipp_buf *buf = container_of(vbuf, struct dcmipp_buf, vb);
> +	unsigned long size;
> +
> +	size = vcap->format.sizeimage;
> +
> +	if (vb2_plane_size(vb, 0) < size) {
> +		dev_err(vcap->dev, "%s data will not fit into plane (%lu < %lu)\n",
> +			__func__, vb2_plane_size(vb, 0), size);
> +		return -EINVAL;
> +	}
> +
> +	vb2_set_plane_payload(vb, 0, size);
> +
> +	if (!buf->prepared) {
> +		/* Get memory addresses */
> +		buf->paddr =
> +			vb2_dma_contig_plane_dma_addr(&buf->vb.vb2_buf, 0);
> +		buf->size = vb2_plane_size(&buf->vb.vb2_buf, 0);
> +		buf->prepared = true;
> +
> +		vb2_set_plane_payload(&buf->vb.vb2_buf, 0, buf->size);
> +
> +		dev_dbg(vcap->dev, "Setup [%d] phy=%pad size=%zu\n",
> +			vb->index, &buf->paddr, buf->size);
> +	}
> +
> +	return 0;
> +}
> +
> +static void dcmipp_bytecap_buf_queue(struct vb2_buffer *vb2_buf)
> +{
> +	struct dcmipp_bytecap_device *vcap =
> +		vb2_get_drv_priv(vb2_buf->vb2_queue);
> +	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb2_buf);
> +	struct dcmipp_buf *buf = container_of(vbuf, struct dcmipp_buf, vb);
> +
> +	spin_lock_irq(&vcap->irqlock);
> +	list_add_tail(&buf->list, &vcap->buffers);
> +
> +	dev_dbg(vcap->dev, "Queue [%d] %p phy=%pad\n", buf->vb.vb2_buf.index, buf, &buf->paddr);
> +
> +	if (vcap->state == WAIT_FOR_BUFFER) {
> +		vcap->next = buf;
> +		dev_dbg(vcap->dev, "Restart with next [%d] %p phy=%pad\n",
> +			buf->vb.vb2_buf.index, buf, &buf->paddr);
> +
> +		dcmipp_start_capture(vcap, buf);
> +
> +		vcap->state = RUNNING;
> +
> +		spin_unlock_irq(&vcap->irqlock);
> +
> +		return;
> +	}
> +
> +	spin_unlock_irq(&vcap->irqlock);
> +}
> +
> +static int dcmipp_bytecap_queue_setup(struct vb2_queue *vq,
> +				      unsigned int *nbuffers,
> +				      unsigned int *nplanes,
> +				      unsigned int sizes[],
> +				      struct device *alloc_devs[])
> +{
> +	struct dcmipp_bytecap_device *vcap = vb2_get_drv_priv(vq);
> +	unsigned int size;
> +
> +	size = vcap->format.sizeimage;
> +
> +	/* Make sure the image size is large enough */
> +	if (*nplanes)
> +		return sizes[0] < vcap->format.sizeimage ? -EINVAL : 0;
> +
> +	*nplanes = 1;
> +	sizes[0] = vcap->format.sizeimage;
> +
> +	dev_dbg(vcap->dev, "Setup queue, count=%d, size=%d\n",
> +		*nbuffers, size);
> +
> +	return 0;
> +}
> +
> +static int dcmipp_bytecap_buf_init(struct vb2_buffer *vb)
> +{
> +	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
> +	struct dcmipp_buf *buf = container_of(vbuf, struct dcmipp_buf, vb);
> +
> +	INIT_LIST_HEAD(&buf->list);
> +
> +	return 0;
> +}
> +
> +static const struct vb2_ops dcmipp_bytecap_qops = {
> +	.start_streaming	= dcmipp_bytecap_start_streaming,
> +	.stop_streaming		= dcmipp_bytecap_stop_streaming,
> +	.buf_init		= dcmipp_bytecap_buf_init,
> +	.buf_prepare		= dcmipp_bytecap_buf_prepare,
> +	.buf_queue		= dcmipp_bytecap_buf_queue,
> +	.queue_setup		= dcmipp_bytecap_queue_setup,
> +	/*
> +	 * Since q->lock is set we can use the standard
> +	 * vb2_ops_wait_prepare/finish helper functions.
> +	 */
> +	.wait_prepare		= vb2_ops_wait_prepare,
> +	.wait_finish		= vb2_ops_wait_finish,
> +};
> +
> +static const struct media_entity_operations dcmipp_bytecap_mops = {
> +	.link_validate		= dcmipp_link_validate,
> +};
> +
> +static void dcmipp_bytecap_release(struct video_device *vdev)
> +{
> +	struct dcmipp_bytecap_device *vcap =
> +		container_of(vdev, struct dcmipp_bytecap_device, vdev);
> +
> +	dcmipp_pads_cleanup(vcap->ved.pads);
> +	kfree(vcap);
> +}
> +
> +static void dcmipp_bytecap_comp_unbind(struct device *comp,
> +				       struct device *master,
> +				       void *master_data)
> +{
> +	struct dcmipp_ent_device *ved = dev_get_drvdata(comp);
> +	struct dcmipp_bytecap_device *vcap =
> +		container_of(ved, struct dcmipp_bytecap_device, ved);
> +
> +	media_entity_cleanup(ved->ent);
> +	vb2_video_unregister_device(&vcap->vdev);
> +}
> +
> +static void dcmipp_buffer_done(struct dcmipp_bytecap_device *vcap,
> +			       struct dcmipp_buf *buf,
> +			       size_t bytesused,
> +			       int err)
> +{
> +	struct vb2_v4l2_buffer *vbuf;
> +
> +	list_del_init(&buf->list);
> +
> +	vbuf = &buf->vb;
> +
> +	vbuf->sequence = vcap->sequence++;
> +	vbuf->field = V4L2_FIELD_NONE;
> +	vbuf->vb2_buf.timestamp = ktime_get_ns();
> +	vb2_set_plane_payload(&vbuf->vb2_buf, 0, bytesused);
> +	vb2_buffer_done(&vbuf->vb2_buf,
> +			err ? VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
> +	dev_dbg(vcap->dev, "Done  [%d] %p phy=%pad\n", buf->vb.vb2_buf.index, buf, &buf->paddr);
> +	vcap->buffers_count++;
> +}
> +
> +/* irqlock must be held */
> +static void dcmipp_bytecap_set_next_frame_or_stop(struct dcmipp_bytecap_device *vcap)
> +{
> +	if (!vcap->next && list_is_singular(&vcap->buffers)) {
> +		/*
> +		 * If there is no available buffer (none or a single one in the list while two
> +		 * are expected), stop the capture (effective for next frame). On-going frame
> +		 * capture will continue till FRAME END but no further capture will be done.
> +		 */
> +		reg_clear(vcap, DCMIPP_P0FCTCR, DCMIPP_P0FCTCR_CPTREQ);
> +
> +		dev_dbg(vcap->dev, "Capture restart is deferred to next buffer queueing\n");
> +		vcap->next = NULL;
> +		vcap->state = WAIT_FOR_BUFFER;
> +		return;
> +	}
> +
> +	/* If we don't have buffer yet, pick the one after active */
> +	if (!vcap->next)
> +		vcap->next = list_next_entry(vcap->active, list);
> +
> +	/*
> +	 * Set buffer address
> +	 * This register is shadowed and will be taken into
> +	 * account on next VSYNC (start of next frame)
> +	 */
> +	reg_write(vcap, DCMIPP_P0PPM0AR1, vcap->next->paddr);
> +	dev_dbg(vcap->dev, "Write [%d] %p phy=%pad\n",
> +		vcap->next->vb.vb2_buf.index, vcap->next, &vcap->next->paddr);
> +}
> +
> +/* irqlock must be held */
> +static void dcmipp_bytecap_process_frame(struct dcmipp_bytecap_device *vcap,
> +					 size_t bytesused)
> +{
> +	int err = 0;
> +	struct dcmipp_buf *buf = vcap->active;
> +
> +	if (!buf) {
> +		vcap->nactive_count++;
> +		vcap->errors_count++;
> +		return;
> +	}
> +
> +	if (bytesused > buf->size) {
> +		dev_dbg(vcap->dev, "frame larger than expected (%zu > %zu)\n",
> +			bytesused, buf->size);
> +		/* Clip to buffer size and return buffer to V4L2 in error */
> +		bytesused = buf->size;
> +		vcap->limit_count++;
> +		vcap->errors_count++;
> +		err = -EOVERFLOW;
> +	}
> +
> +	dcmipp_buffer_done(vcap, buf, bytesused, err);
> +	vcap->active = NULL;
> +}
> +
> +static irqreturn_t dcmipp_bytecap_irq_thread(int irq, void *arg)
> +{
> +	struct dcmipp_bytecap_device *vcap =
> +			container_of(arg, struct dcmipp_bytecap_device, ved);
> +	size_t bytesused = 0;
> +	u32 cmsr2;
> +
> +	spin_lock_irq(&vcap->irqlock);
> +
> +	cmsr2 = vcap->cmsr2 & vcap->cmier;
> +
> +	/*
> +	 * If we have an overrun, a frame-end will probably not be generated, in that
> +	 * case the active buffer will be recycled as next buffer by the VSYNC handler
> +	 */
> +	if (cmsr2 & DCMIPP_CMSR2_P0OVRF) {
> +		vcap->errors_count++;
> +		vcap->overrun_count++;
> +	}
> +
> +	if (cmsr2 & DCMIPP_CMSR2_P0FRAMEF) {
> +		vcap->frame_count++;
> +
> +		/* Read captured buffer size */
> +		bytesused = reg_read(vcap, DCMIPP_P0DCCNTR);
> +		dcmipp_bytecap_process_frame(vcap, bytesused);
> +	}
> +
> +	if (cmsr2 & DCMIPP_CMSR2_P0VSYNCF) {
> +		vcap->vsync_count++;
> +		if (vcap->state == WAIT_FOR_BUFFER) {
> +			vcap->underrun_count++;
> +			goto out;
> +		}
> +
> +		/*
> +		 * On VSYNC, the previously set next buffer is going to become active thanks to
> +		 * the shadowing mechanism of the DCMIPP. In most of the cases, since a FRAMEEND
> +		 * has already come, pointer next is NULL since active is reset during the
> +		 * FRAMEEND handling. However, in case of framerate adjustment, there are more
> +		 * VSYNC than FRAMEEND. Thus we recycle the active (but not used) buffer and put it
> +		 * back into next.
> +		 */
> +		swap(vcap->active, vcap->next);
> +		dcmipp_bytecap_set_next_frame_or_stop(vcap);
> +	}
> +
> +out:
> +	spin_unlock_irq(&vcap->irqlock);
> +	return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t dcmipp_bytecap_irq_callback(int irq, void *arg)
> +{
> +	struct dcmipp_bytecap_device *vcap =
> +			container_of(arg, struct dcmipp_bytecap_device, ved);
> +
> +	/* Store interrupt status register */
> +	vcap->cmsr2 = reg_read(vcap, DCMIPP_CMSR2) & vcap->cmier;
> +	vcap->it_count++;
> +
> +	/* Clear interrupt */
> +	reg_write(vcap, DCMIPP_CMFCR, vcap->cmsr2);
> +
> +	return IRQ_WAKE_THREAD;
> +}
> +
> +static int dcmipp_bytecap_comp_bind(struct device *comp, struct device *master,
> +				    void *master_data)
> +{
> +	struct dcmipp_bind_data *bind_data = master_data;
> +	struct dcmipp_platform_data *pdata = comp->platform_data;
> +	struct dcmipp_bytecap_device *vcap;
> +	struct v4l2_pix_format *format;
> +	struct video_device *vdev;
> +	struct vb2_queue *q;
> +	int ret = 0;
> +
> +	/* Allocate the dcmipp_bytecap_device struct */
> +	vcap = kzalloc(sizeof(*vcap), GFP_KERNEL);
> +	if (!vcap)
> +		return -ENOMEM;
> +
> +	/* Allocate the pads */
> +	vcap->ved.pads =
> +		dcmipp_pads_init(1,
> +				 (const unsigned long[1]) {MEDIA_PAD_FL_SINK});
> +	if (IS_ERR(vcap->ved.pads)) {
> +		ret = PTR_ERR(vcap->ved.pads);
> +		goto err_free_vcap;
> +	}
> +
> +	/* Initialize the media entity */
> +	vcap->vdev.entity.name = pdata->entity_name;
> +	vcap->vdev.entity.function = MEDIA_ENT_F_IO_V4L;
> +	ret = media_entity_pads_init(&vcap->vdev.entity,
> +				     1, vcap->ved.pads);

Fits on the same line.

> +	if (ret)
> +		goto err_clean_pads;
> +
> +	/* Initialize the lock */
> +	mutex_init(&vcap->lock);
> +
> +	/* Initialize the vb2 queue */
> +	q = &vcap->queue;
> +	q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> +	q->io_modes = VB2_MMAP | VB2_READ | VB2_DMABUF;
> +	q->lock = &vcap->lock;
> +	q->drv_priv = vcap;
> +	q->buf_struct_size = sizeof(struct dcmipp_buf);
> +	q->ops = &dcmipp_bytecap_qops;
> +	q->mem_ops = &vb2_dma_contig_memops;
> +	q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
> +	q->min_buffers_needed = 1;
> +	q->dev = comp;
> +
> +	ret = vb2_queue_init(q);
> +	if (ret) {
> +		dev_err(comp, "%s: vb2 queue init failed (err=%d)\n",
> +			pdata->entity_name, ret);
> +		goto err_clean_m_ent;
> +	}
> +
> +	/* Initialize buffer list and its lock */
> +	INIT_LIST_HEAD(&vcap->buffers);
> +	spin_lock_init(&vcap->irqlock);
> +
> +	/* Set default frame format */
> +	vcap->format = fmt_default;
> +	format = &vcap->format;
> +	format->bytesperline = frame_stride(format->width, format->pixelformat);
> +	format->sizeimage = frame_size(format->width,
> +				       format->height,

Fits on the same line.

> +				       format->pixelformat);
> +
> +	/* Fill the dcmipp_ent_device struct */
> +	vcap->ved.ent = &vcap->vdev.entity;
> +	vcap->ved.vdev_get_format = dcmipp_bytecap_get_format;
> +	vcap->ved.handler = dcmipp_bytecap_irq_callback;
> +	vcap->ved.thread_fn = dcmipp_bytecap_irq_thread;
> +	dev_set_drvdata(comp, &vcap->ved);
> +	vcap->dev = comp;
> +	vcap->regs = bind_data->regs;
> +	vcap->rstc = bind_data->rstc;
> +	vcap->cdev = master;
> +
> +	/* Initialize the video_device struct */
> +	vdev = &vcap->vdev;
> +	vdev->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING |
> +			    V4L2_CAP_READWRITE;
> +	vdev->entity.ops = &dcmipp_bytecap_mops;
> +	vdev->release = dcmipp_bytecap_release;
> +	vdev->fops = &dcmipp_bytecap_fops;
> +	vdev->ioctl_ops = &dcmipp_bytecap_ioctl_ops;
> +	vdev->lock = &vcap->lock;
> +	vdev->queue = q;
> +	vdev->v4l2_dev = bind_data->v4l2_dev;
> +	strscpy(vdev->name, pdata->entity_name, sizeof(vdev->name));
> +	video_set_drvdata(vdev, &vcap->ved);
> +
> +	/* Register the video_device with the v4l2 and the media framework */
> +	ret = video_register_device(vdev, VFL_TYPE_VIDEO, -1);
> +	if (ret) {
> +		dev_err(comp, "%s: video register failed (err=%d)\n",
> +			vcap->vdev.name, ret);
> +		goto err_clean_m_ent;
> +	}
> +
> +	return 0;
> +
> +err_clean_m_ent:
> +	media_entity_cleanup(&vcap->vdev.entity);
> +err_clean_pads:
> +	dcmipp_pads_cleanup(vcap->ved.pads);
> +err_free_vcap:
> +	kfree(vcap);
> +
> +	return ret;
> +}
> +
> +static const struct component_ops dcmipp_bytecap_comp_ops = {
> +	.bind = dcmipp_bytecap_comp_bind,
> +	.unbind = dcmipp_bytecap_comp_unbind,
> +};
> +
> +static int dcmipp_bytecap_probe(struct platform_device *pdev)
> +{
> +	return component_add(&pdev->dev, &dcmipp_bytecap_comp_ops);
> +}
> +
> +static int dcmipp_bytecap_remove(struct platform_device *pdev)
> +{
> +	component_del(&pdev->dev, &dcmipp_bytecap_comp_ops);
> +
> +	return 0;
> +}
> +
> +static const struct platform_device_id dcmipp_bytecap_driver_ids[] = {
> +	{
> +		.name	= DCMIPP_BYTECAP_DRV_NAME,
> +	},
> +	{ }
> +};
> +
> +static struct platform_driver dcmipp_bytecap_pdrv = {
> +	.probe		= dcmipp_bytecap_probe,
> +	.remove		= dcmipp_bytecap_remove,
> +	.id_table	= dcmipp_bytecap_driver_ids,
> +	.driver		= {
> +		.name	= DCMIPP_BYTECAP_DRV_NAME,
> +	},
> +};
> +
> +module_platform_driver(dcmipp_bytecap_pdrv);
> +
> +MODULE_DEVICE_TABLE(platform, dcmipp_bytecap_driver_ids);
> +
> +MODULE_AUTHOR("Hugues Fruchet <hugues.fruchet@foss.st.com>");
> +MODULE_AUTHOR("Alain Volmat <alain.volmat@foss.st.com>");
> +MODULE_DESCRIPTION("STMicroelectronics STM32 Digital Camera Memory Interface with Pixel Processor driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-byteproc.c b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-byteproc.c
> new file mode 100644
> index 000000000000..5458162a36bf
> --- /dev/null
> +++ b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-byteproc.c
> @@ -0,0 +1,790 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for STM32 Digital Camera Memory Interface Pixel Processor
> + *
> + * Copyright (C) STMicroelectronics SA 2022
> + * Authors: Hugues Fruchet <hugues.fruchet@foss.st.com>
> + *          Alain Volmat <alain.volmat@foss.st.com>
> + *          for STMicroelectronics.
> + */
> +
> +#include <linux/component.h>
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/platform_device.h>
> +#include <linux/vmalloc.h>
> +#include <linux/v4l2-mediabus.h>
> +#include <media/v4l2-rect.h>
> +#include <media/v4l2-subdev.h>
> +
> +#include "dcmipp-common.h"
> +
> +#define DCMIPP_BYTEPROC_DRV_NAME "dcmipp-byteproc"
> +
> +#define DCMIPP_FMT_WIDTH_DEFAULT  640
> +#define DCMIPP_FMT_HEIGHT_DEFAULT 480
> +
> +#define DCMIPP_P0FCTCR (0x500)
> +#define DCMIPP_P0FCTCR_FRATE_MASK GENMASK(1, 0)
> +#define DCMIPP_P0SCSTR (0x504)
> +#define DCMIPP_P0SCSTR_HSTART_SHIFT	0
> +#define DCMIPP_P0SCSTR_VSTART_SHIFT	16
> +#define DCMIPP_P0SCSZR (0x508)
> +#define DCMIPP_P0SCSZR_ENABLE BIT(31)
> +#define DCMIPP_P0SCSZR_HSIZE_SHIFT	0
> +#define DCMIPP_P0SCSZR_VSIZE_SHIFT	16
> +#define DCMIPP_P0PPCR (0x5C0)
> +#define DCMIPP_P0PPCR_BSM_1_2 0x1
> +#define DCMIPP_P0PPCR_BSM_1_4 0x2
> +#define DCMIPP_P0PPCR_BSM_2_4 0x3
> +#define DCMIPP_P0PPCR_BSM_MASK GENMASK(8, 7)
> +#define DCMIPP_P0PPCR_BSM_SHIFT 0x7
> +#define DCMIPP_P0PPCR_LSM BIT(10)
> +#define DCMIPP_P0PPCR_OELS BIT(11)

It'd be nice to align the macro values.

> +
> +#define IS_SINK(pad) (!(pad))
> +#define IS_SRC(pad)  ((pad))

It'd be nicer to have macros for the pads, e.g. DCIMPP_PAD_SINK, and use
them instead of opaque IS_SRC and IS_SINK.

> +#define PAD_STR(pad) (IS_SRC((pad))) ? "src" : "sink"

PAD_STR is unused.

> +
> +#define BYTEPROC_MEDIA_BUS_FMT_DEFAULT MEDIA_BUS_FMT_RGB565_2X8_LE

It'd be better to use plain MEDIA_BUS_FMT_RGB565_2X8_LE instead.

> +
> +struct dcmipp_byteproc_pix_map {
> +	unsigned int code;
> +	unsigned int bpp;
> +};
> +
> +#define PIXMAP_MBUS_BPP(mbus, byteperpixel)	\
> +		{						\
> +			.code = MEDIA_BUS_FMT_##mbus,		\
> +			.bpp = byteperpixel,	\
> +		}
> +static const struct dcmipp_byteproc_pix_map dcmipp_byteproc_pix_map_list[] = {
> +	PIXMAP_MBUS_BPP(RGB565_2X8_LE, 2),
> +	PIXMAP_MBUS_BPP(YUYV8_2X8, 2),
> +	PIXMAP_MBUS_BPP(YVYU8_2X8, 2),
> +	PIXMAP_MBUS_BPP(UYVY8_2X8, 2),
> +	PIXMAP_MBUS_BPP(VYUY8_2X8, 2),
> +	PIXMAP_MBUS_BPP(Y8_1X8, 1),
> +	PIXMAP_MBUS_BPP(SBGGR8_1X8, 1),
> +	PIXMAP_MBUS_BPP(SGBRG8_1X8, 1),
> +	PIXMAP_MBUS_BPP(SGRBG8_1X8, 1),
> +	PIXMAP_MBUS_BPP(SRGGB8_1X8, 1),
> +	PIXMAP_MBUS_BPP(JPEG_1X8, 1),
> +};
> +
> +static const struct dcmipp_byteproc_pix_map *dcmipp_byteproc_pix_map_by_index(unsigned int i)

This has one use only, please move it to where it is called.

> +{
> +	const struct dcmipp_byteproc_pix_map *l = dcmipp_byteproc_pix_map_list;
> +	unsigned int size = ARRAY_SIZE(dcmipp_byteproc_pix_map_list);

size is redundant, please use ARRAY_SIZE() below instead.

Same for l.

> +
> +	if (i >= size)
> +		return NULL;
> +
> +	return &l[i];
> +}
> +
> +static const struct dcmipp_byteproc_pix_map *dcmipp_byteproc_pix_map_by_code(u32 code)
> +{
> +	const struct dcmipp_byteproc_pix_map *l = dcmipp_byteproc_pix_map_list;
> +	unsigned int size = ARRAY_SIZE(dcmipp_byteproc_pix_map_list);
> +	unsigned int i;
> +
> +	for (i = 0; i < size; i++) {
> +		if (l[i].code == code)
> +			return &l[i];
> +	}
> +
> +	return NULL;
> +}
> +
> +struct dcmipp_byteproc_device {
> +	struct dcmipp_ent_device ved;
> +	struct v4l2_subdev sd;
> +	struct device *dev;
> +	struct v4l2_mbus_framefmt sink_fmt;
> +	bool streaming;
> +	/* Protect this data structure */
> +	struct mutex lock;
> +
> +	void __iomem *regs;
> +
> +	struct v4l2_fract sink_interval;
> +	struct v4l2_fract src_interval;
> +	unsigned int frate;
> +	u32 src_code;
> +	struct v4l2_rect crop;
> +	struct v4l2_rect compose;
> +};
> +
> +static const struct v4l2_mbus_framefmt fmt_default = {
> +	.width = DCMIPP_FMT_WIDTH_DEFAULT,
> +	.height = DCMIPP_FMT_HEIGHT_DEFAULT,
> +	.code = BYTEPROC_MEDIA_BUS_FMT_DEFAULT,
> +	.field = V4L2_FIELD_NONE,
> +	.colorspace = DCMIPP_COLORSPACE_DEFAULT,
> +	.ycbcr_enc = DCMIPP_YCBCR_ENC_DEFAULT,
> +	.quantization = DCMIPP_QUANTIZATION_DEFAULT,
> +	.xfer_func = DCMIPP_XFER_FUNC_DEFAULT,
> +};
> +
> +static const struct v4l2_rect crop_min = {
> +	.width = DCMIPP_FRAME_MIN_WIDTH,
> +	.height = DCMIPP_FRAME_MIN_HEIGHT,
> +	.top = 0,
> +	.left = 0,
> +};
> +
> +static struct v4l2_rect
> +dcmipp_byteproc_get_compose_bound(const struct v4l2_mbus_framefmt *fmt)

One user only, please move the code to the call site.

> +{
> +	/* Get the crop bounds to clamp the crop rectangle correctly */
> +	struct v4l2_rect r = {
> +		.left = 0,
> +		.top = 0,
> +		.width = fmt->width,
> +		.height = fmt->height,
> +	};
> +
> +	return r;
> +}
> +
> +static void dcmipp_byteproc_adjust_crop(struct v4l2_rect *r, struct v4l2_rect *compose)
> +{
> +	/* Disallow rectangles smaller than the minimal one. */
> +	v4l2_rect_set_min_size(r, &crop_min);
> +	v4l2_rect_map_inside(r, compose);
> +}
> +
> +static void dcmipp_byteproc_adjust_compose(struct v4l2_rect *r,
> +					   const struct v4l2_mbus_framefmt *fmt)
> +{
> +	r->top = 0;
> +	r->left = 0;
> +
> +	/* Compose is not possible for JPEG or Bayer formats */
> +	if (fmt->code == MEDIA_BUS_FMT_JPEG_1X8 ||
> +	    fmt->code == MEDIA_BUS_FMT_SBGGR8_1X8 || fmt->code == MEDIA_BUS_FMT_SGBRG8_1X8 ||
> +	    fmt->code == MEDIA_BUS_FMT_SGRBG8_1X8 || fmt->code == MEDIA_BUS_FMT_SRGGB8_1X8) {
> +		r->width = fmt->width;
> +		r->height = fmt->height;
> +		return;
> +	}
> +
> +	/* Adjust height - we can only perform 1/2 decimation */
> +	if (r->height <= (fmt->height / 2))
> +		r->height = fmt->height / 2;
> +	else
> +		r->height = fmt->height;
> +
> +	/* Adjust width - /2 or /4 for 8bits formats and /2 for 16bits formats */
> +	if (fmt->code == MEDIA_BUS_FMT_Y8_1X8 && r->width <= (fmt->width / 4))
> +		r->width = fmt->width / 4;
> +	else if (r->width <= (fmt->width / 2))
> +		r->width = fmt->width / 2;
> +	else
> +		r->width = fmt->width;
> +}
> +
> +static void dcmipp_byteproc_adjust_fmt(struct v4l2_mbus_framefmt *fmt)
> +{
> +	const struct dcmipp_byteproc_pix_map *vpix;
> +
> +	/* Only accept code in the pix map table */
> +	vpix = dcmipp_byteproc_pix_map_by_code(fmt->code);
> +	if (!vpix)
> +		fmt->code = fmt_default.code;
> +
> +	fmt->width = clamp_t(u32, fmt->width, DCMIPP_FRAME_MIN_WIDTH,
> +			     DCMIPP_FRAME_MAX_WIDTH) & ~1;
> +	fmt->height = clamp_t(u32, fmt->height, DCMIPP_FRAME_MIN_HEIGHT,
> +			      DCMIPP_FRAME_MAX_HEIGHT) & ~1;
> +
> +	if (fmt->field == V4L2_FIELD_ANY || fmt->field == V4L2_FIELD_ALTERNATE)
> +		fmt->field = fmt_default.field;
> +
> +	dcmipp_colorimetry_clamp(fmt);
> +}
> +
> +static int dcmipp_byteproc_init_cfg(struct v4l2_subdev *sd,
> +				    struct v4l2_subdev_state *sd_state)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < sd->entity.num_pads; i++) {
> +		struct v4l2_mbus_framefmt *mf;
> +		struct v4l2_rect *r;
> +
> +		mf = v4l2_subdev_get_try_format(sd, sd_state, i);
> +		*mf = fmt_default;
> +
> +		if (IS_SINK(i))
> +			r = v4l2_subdev_get_try_compose(sd, sd_state, i);
> +		else
> +			r = v4l2_subdev_get_try_crop(sd, sd_state, i);
> +
> +		r->top = 0;
> +		r->left = 0;
> +		r->width = DCMIPP_FMT_WIDTH_DEFAULT;
> +		r->height = DCMIPP_FMT_HEIGHT_DEFAULT;
> +	}
> +
> +	return 0;
> +}
> +
> +static int dcmipp_byteproc_enum_mbus_code(struct v4l2_subdev *sd,
> +					  struct v4l2_subdev_state *sd_state,
> +					  struct v4l2_subdev_mbus_code_enum *code)
> +{
> +	const struct dcmipp_byteproc_pix_map *vpix;
> +
> +	vpix = dcmipp_byteproc_pix_map_by_index(code->index);
> +	if (!vpix)
> +		return -EINVAL;
> +
> +	code->code = vpix->code;
> +
> +	return 0;
> +}
> +
> +static int dcmipp_byteproc_enum_frame_size(struct v4l2_subdev *sd,
> +					   struct v4l2_subdev_state *sd_state,
> +					   struct v4l2_subdev_frame_size_enum *fse)
> +{
> +	const struct dcmipp_byteproc_pix_map *vpix;
> +
> +	if (fse->index)
> +		return -EINVAL;
> +
> +	/* Only accept code in the pix map table */
> +	vpix = dcmipp_byteproc_pix_map_by_code(fse->code);
> +	if (!vpix)
> +		return -EINVAL;
> +
> +	fse->min_width = DCMIPP_FRAME_MIN_WIDTH;
> +	fse->max_width = DCMIPP_FRAME_MAX_WIDTH;
> +	fse->min_height = DCMIPP_FRAME_MIN_HEIGHT;
> +	fse->max_height = DCMIPP_FRAME_MAX_HEIGHT;
> +
> +	return 0;
> +}
> +
> +static int dcmipp_byteproc_get_fmt(struct v4l2_subdev *sd,
> +				   struct v4l2_subdev_state *sd_state,
> +				   struct v4l2_subdev_format *fmt)
> +{
> +	struct dcmipp_byteproc_device *byteproc = v4l2_get_subdevdata(sd);
> +	struct v4l2_rect *crop_rect;
> +
> +	mutex_lock(&byteproc->lock);
> +
> +	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY) {
> +		fmt->format = *v4l2_subdev_get_try_format(sd, sd_state, 0);
> +		crop_rect = v4l2_subdev_get_try_crop(sd, sd_state, 1);
> +	} else {
> +		fmt->format = byteproc->sink_fmt;
> +		crop_rect = &byteproc->crop;
> +	}
> +
> +	if (IS_SRC(fmt->pad)) {
> +		fmt->format.width = crop_rect->width;
> +		fmt->format.height = crop_rect->height;
> +	}
> +
> +	mutex_unlock(&byteproc->lock);
> +
> +	return 0;
> +}
> +
> +static int dcmipp_byteproc_set_fmt(struct v4l2_subdev *sd,
> +				   struct v4l2_subdev_state *sd_state,
> +				   struct v4l2_subdev_format *fmt)
> +{
> +	struct dcmipp_byteproc_device *byteproc = v4l2_get_subdevdata(sd);
> +	struct v4l2_mbus_framefmt *sink_fmt;
> +	struct v4l2_rect *crop, *compose;
> +	int ret = 0;
> +
> +	mutex_lock(&byteproc->lock);
> +
> +	if (fmt->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> +		if (byteproc->streaming) {
> +			ret = -EBUSY;
> +			goto out;
> +		}
> +
> +		sink_fmt = &byteproc->sink_fmt;
> +		crop = &byteproc->crop;
> +		compose = &byteproc->compose;
> +	} else {
> +		sink_fmt = v4l2_subdev_get_try_format(sd, sd_state, 0);
> +		crop = v4l2_subdev_get_try_crop(sd, sd_state, 1);
> +		compose = v4l2_subdev_get_try_compose(sd, sd_state, 0);
> +	}
> +
> +	if (IS_SRC(fmt->pad)) {
> +		fmt->format = *sink_fmt;
> +		fmt->format.width = crop->width;
> +		fmt->format.height = crop->height;
> +	} else {
> +		dcmipp_byteproc_adjust_fmt(&fmt->format);
> +		crop->top = 0;
> +		crop->left = 0;
> +		crop->width = fmt->format.width;
> +		crop->height = fmt->format.height;
> +		*compose = *crop;
> +		*sink_fmt = fmt->format;
> +	}
> +
> +out:
> +	mutex_unlock(&byteproc->lock);
> +
> +	return ret;
> +}
> +
> +static int dcmipp_byteproc_get_selection(struct v4l2_subdev *sd,
> +					 struct v4l2_subdev_state *sd_state,
> +					 struct v4l2_subdev_selection *s)
> +{
> +	struct dcmipp_byteproc_device *byteproc = v4l2_get_subdevdata(sd);
> +	struct v4l2_mbus_framefmt *sink_fmt;
> +	struct v4l2_rect *crop, *compose;
> +
> +	/*
> +	 * In the HW, the decimation block is located prior to the crop hence:
> +	 * Compose is done on the sink pad
> +	 * Crop is done on the src pad
> +	 */
> +	if ((s->target == V4L2_SEL_TGT_CROP ||
> +	     s->target == V4L2_SEL_TGT_CROP_BOUNDS ||
> +	     s->target == V4L2_SEL_TGT_CROP_DEFAULT) && IS_SINK(s->pad))

Check the pad first, not the target. Same below.

> +		return -EINVAL;
> +
> +	if ((s->target == V4L2_SEL_TGT_COMPOSE ||
> +	     s->target == V4L2_SEL_TGT_COMPOSE_BOUNDS ||
> +	     s->target == V4L2_SEL_TGT_COMPOSE_DEFAULT) && IS_SRC(s->pad))
> +		return -EINVAL;
> +
> +	if (s->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> +		sink_fmt = &byteproc->sink_fmt;
> +		crop = &byteproc->crop;
> +		compose = &byteproc->compose;
> +	} else {
> +		sink_fmt = v4l2_subdev_get_try_format(sd, sd_state, 0);
> +		crop = v4l2_subdev_get_try_crop(sd, sd_state, 1);
> +		compose = v4l2_subdev_get_try_compose(sd, sd_state, 0);
> +	}
> +
> +	switch (s->target) {
> +	case V4L2_SEL_TGT_CROP:
> +		s->r = *crop;
> +		break;
> +	case V4L2_SEL_TGT_CROP_BOUNDS:
> +	case V4L2_SEL_TGT_CROP_DEFAULT:
> +		s->r = *compose;
> +		break;
> +	case V4L2_SEL_TGT_COMPOSE:
> +		s->r = *compose;
> +		break;
> +	case V4L2_SEL_TGT_COMPOSE_BOUNDS:
> +		s->r = dcmipp_byteproc_get_compose_bound(sink_fmt);
> +		break;
> +	case V4L2_SEL_TGT_COMPOSE_DEFAULT:
> +		s->r.top = 0;
> +		s->r.left = 0;
> +		s->r.width = sink_fmt->width;
> +		s->r.height = sink_fmt->height;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int dcmipp_byteproc_set_selection(struct v4l2_subdev *sd,
> +					 struct v4l2_subdev_state *sd_state,
> +					 struct v4l2_subdev_selection *s)
> +{
> +	struct dcmipp_byteproc_device *byteproc = v4l2_get_subdevdata(sd);
> +	struct v4l2_mbus_framefmt *sink_fmt;
> +	struct v4l2_rect *crop, *compose;
> +
> +	/*
> +	 * In the HW, the decimation block is located prior to the crop hence:
> +	 * Compose is done on the sink pad
> +	 * Crop is done on the src pad
> +	 */
> +	if ((s->target == V4L2_SEL_TGT_CROP ||
> +	     s->target == V4L2_SEL_TGT_CROP_BOUNDS ||
> +	     s->target == V4L2_SEL_TGT_CROP_DEFAULT) && IS_SINK(s->pad))
> +		return -EINVAL;
> +
> +	if ((s->target == V4L2_SEL_TGT_COMPOSE ||
> +	     s->target == V4L2_SEL_TGT_COMPOSE_BOUNDS ||
> +	     s->target == V4L2_SEL_TGT_COMPOSE_DEFAULT) && IS_SRC(s->pad))
> +		return -EINVAL;
> +
> +	if (s->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> +		sink_fmt = &byteproc->sink_fmt;
> +		crop = &byteproc->crop;
> +		compose = &byteproc->compose;
> +	} else {
> +		sink_fmt = v4l2_subdev_get_try_format(sd, sd_state, 0);
> +		crop = v4l2_subdev_get_try_crop(sd, sd_state, 1);
> +		compose = v4l2_subdev_get_try_compose(sd, sd_state, 0);
> +	}
> +
> +	switch (s->target) {
> +	case V4L2_SEL_TGT_CROP:
> +		dcmipp_byteproc_adjust_crop(&s->r, compose);
> +
> +		*crop = s->r;
> +
> +		dev_dbg(byteproc->dev, "s_selection: crop %ux%u@(%u,%u)\n",
> +			crop->width, crop->height, crop->left, crop->top);
> +		break;
> +	case V4L2_SEL_TGT_COMPOSE:
> +		dcmipp_byteproc_adjust_compose(&s->r, sink_fmt);
> +		*compose = s->r;
> +		*crop = s->r;
> +
> +		dev_dbg(byteproc->dev, "s_selection: compose %ux%u@(%u,%u)\n",
> +			compose->width, compose->height, compose->left, compose->top);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static const unsigned int dcmipp_frates[] = {1, 2, 4, 8};
> +
> +static int dcmipp_byteproc_enum_frame_interval
> +				(struct v4l2_subdev *sd,
> +				 struct v4l2_subdev_state *sd_state,
> +				 struct v4l2_subdev_frame_interval_enum *fie)
> +{
> +	struct dcmipp_byteproc_device *byteproc = v4l2_get_subdevdata(sd);
> +	struct v4l2_fract *sink_interval = &byteproc->sink_interval;
> +	unsigned int ratio;
> +	int ret = 0;
> +
> +	if (fie->pad > 1 ||
> +	    fie->index >= (IS_SRC(fie->pad) ? ARRAY_SIZE(dcmipp_frates) : 1) ||
> +	    fie->width > DCMIPP_FRAME_MAX_WIDTH ||
> +	    fie->height > DCMIPP_FRAME_MAX_HEIGHT)
> +		return -EINVAL;
> +
> +	mutex_lock(&byteproc->lock);
> +
> +	if (IS_SINK(fie->pad)) {
> +		fie->interval = *sink_interval;
> +		goto out;
> +	}
> +
> +	ratio = dcmipp_frates[fie->index];

How does ratio work? Drop every n'th frame?

> +
> +	fie->interval.numerator = sink_interval->numerator * ratio;
> +	fie->interval.denominator = sink_interval->denominator;
> +
> +out:
> +	mutex_unlock(&byteproc->lock);
> +	return ret;
> +}
> +
> +static const struct v4l2_subdev_pad_ops dcmipp_byteproc_pad_ops = {
> +	.init_cfg		= dcmipp_byteproc_init_cfg,
> +	.enum_mbus_code		= dcmipp_byteproc_enum_mbus_code,
> +	.enum_frame_size	= dcmipp_byteproc_enum_frame_size,
> +	.enum_frame_interval	= dcmipp_byteproc_enum_frame_interval,
> +	.get_fmt		= dcmipp_byteproc_get_fmt,
> +	.set_fmt		= dcmipp_byteproc_set_fmt,
> +	.get_selection		= dcmipp_byteproc_get_selection,
> +	.set_selection		= dcmipp_byteproc_set_selection,
> +};
> +
> +static int dcmipp_byteproc_configure_scale_crop
> +			(struct dcmipp_byteproc_device *byteproc)
> +{
> +	const struct dcmipp_byteproc_pix_map *vpix;
> +	u32 hprediv, vprediv;
> +	struct v4l2_rect *crop = &byteproc->crop;
> +	u32 val = 0;
> +
> +	/* find output format bpp */
> +	vpix = dcmipp_byteproc_pix_map_by_code(byteproc->sink_fmt.code);
> +	if (!vpix)
> +		return -EINVAL;
> +
> +	/* clear decimation/crop */
> +	reg_clear(byteproc, DCMIPP_P0PPCR, DCMIPP_P0PPCR_BSM_MASK);
> +	reg_clear(byteproc, DCMIPP_P0PPCR, DCMIPP_P0PPCR_LSM);
> +	reg_write(byteproc, DCMIPP_P0SCSTR, 0);
> +	reg_write(byteproc, DCMIPP_P0SCSZR, 0);
> +
> +	/* Ignore decimation/crop with JPEG */
> +	if (vpix->code == MEDIA_BUS_FMT_JPEG_1X8)
> +		return 0;
> +
> +	/* decimation */
> +	hprediv = byteproc->sink_fmt.width / byteproc->compose.width;
> +	if (hprediv == 4)
> +		val |= DCMIPP_P0PPCR_BSM_1_4 << DCMIPP_P0PPCR_BSM_SHIFT;
> +	else if ((vpix->code == MEDIA_BUS_FMT_Y8_1X8) && (hprediv == 2))
> +		val |= DCMIPP_P0PPCR_BSM_1_2 << DCMIPP_P0PPCR_BSM_SHIFT;
> +	else if (hprediv == 2)
> +		val |= DCMIPP_P0PPCR_BSM_2_4 << DCMIPP_P0PPCR_BSM_SHIFT;
> +
> +	vprediv = byteproc->sink_fmt.height / byteproc->compose.height;
> +	if (vprediv == 2)
> +		val |= DCMIPP_P0PPCR_LSM | DCMIPP_P0PPCR_OELS;
> +
> +	/* decimate using bytes and lines skipping */
> +	if (val) {
> +		reg_set(byteproc, DCMIPP_P0PPCR, val);
> +
> +		dev_dbg(byteproc->dev, "decimate to %dx%d [prediv=%dx%d]\n",
> +			byteproc->compose.width, byteproc->compose.height, hprediv, vprediv);
> +	}
> +
> +	dev_dbg(byteproc->dev, "crop to %dx%d\n", crop->width, crop->height);
> +
> +	/* expressed in 32-bits words on X axis, lines on Y axis */
> +	reg_write(byteproc, DCMIPP_P0SCSTR,
> +		  (((crop->left * vpix->bpp) / 4) << DCMIPP_P0SCSTR_HSTART_SHIFT) |
> +		  (crop->top << DCMIPP_P0SCSTR_VSTART_SHIFT));
> +	reg_write(byteproc, DCMIPP_P0SCSZR,
> +		  DCMIPP_P0SCSZR_ENABLE |
> +		  (((crop->width * vpix->bpp) / 4) << DCMIPP_P0SCSZR_HSIZE_SHIFT) |
> +		  (crop->height << DCMIPP_P0SCSZR_VSIZE_SHIFT));
> +
> +	return 0;
> +}
> +
> +static void dcmipp_byteproc_configure_framerate
> +			(struct dcmipp_byteproc_device *byteproc)
> +{
> +	/* Frame skipping */
> +	reg_clear(byteproc, DCMIPP_P0FCTCR, DCMIPP_P0FCTCR_FRATE_MASK);
> +	reg_set(byteproc, DCMIPP_P0FCTCR, byteproc->frate);
> +}
> +
> +static int dcmipp_byteproc_g_frame_interval(struct v4l2_subdev *sd,
> +					    struct v4l2_subdev_frame_interval *fi)
> +{
> +	struct dcmipp_byteproc_device *byteproc = v4l2_get_subdevdata(sd);
> +
> +	if (IS_SINK(fi->pad))
> +		fi->interval = byteproc->sink_interval;
> +	else
> +		fi->interval = byteproc->src_interval;
> +
> +	return 0;
> +}
> +
> +static int dcmipp_byteproc_s_frame_interval(struct v4l2_subdev *sd,
> +					    struct v4l2_subdev_frame_interval *fi)
> +{
> +	struct dcmipp_byteproc_device *byteproc = v4l2_get_subdevdata(sd);
> +
> +	mutex_lock(&byteproc->lock);
> +
> +	if (byteproc->streaming) {
> +		mutex_unlock(&byteproc->lock);
> +		return -EBUSY;
> +	}
> +
> +	if (fi->interval.numerator == 0 || fi->interval.denominator == 0)
> +		fi->interval = byteproc->sink_interval;
> +
> +	if (IS_SINK(fi->pad)) {
> +		/*
> +		 * Setting sink frame interval resets frame skipping.
> +		 * Sink frame interval is propagated to src.
> +		 */
> +		byteproc->frate = 0;
> +		byteproc->sink_interval = fi->interval;
> +		byteproc->src_interval = byteproc->sink_interval;

Is this used for anything else than configure skipping?

I think I'd just have a control for it in that case.

I don't think exposing frame interval configuration is necessarily even
meaningful for a device that just processes data but does not produce it.

> +	} else {
> +		unsigned int ratio;
> +
> +		/* Normalize ratio */
> +		ratio = (byteproc->sink_interval.denominator *
> +			 fi->interval.numerator) /
> +			(byteproc->sink_interval.numerator *
> +			 fi->interval.denominator);
> +
> +		/* Hardware can skip 1 frame over 2, 4 or 8 */
> +		byteproc->frate = ratio >= 8 ? 3 :
> +				  ratio >= 4 ? 2 :
> +				  ratio >= 2 ? 1 : 0;
> +
> +		/* Adjust src frame interval to what hardware can really do */
> +		byteproc->src_interval.numerator =
> +			byteproc->sink_interval.numerator * ratio;
> +		byteproc->src_interval.denominator =
> +			byteproc->sink_interval.denominator;
> +	}
> +
> +	mutex_unlock(&byteproc->lock);
> +
> +	return 0;
> +}
> +
> +#define STOP_TIMEOUT_US 1000
> +#define POLL_INTERVAL_US  50
> +static int dcmipp_byteproc_s_stream(struct v4l2_subdev *sd, int enable)
> +{
> +	struct dcmipp_byteproc_device *byteproc = v4l2_get_subdevdata(sd);
> +	int ret = 0;
> +
> +	mutex_lock(&byteproc->lock);
> +	if (enable) {
> +		dcmipp_byteproc_configure_framerate(byteproc);
> +
> +		ret = dcmipp_byteproc_configure_scale_crop(byteproc);
> +		if (ret)
> +			goto err;

This does nothing.

> +	}
> +
> +err:
> +	mutex_unlock(&byteproc->lock);
> +
> +	return ret;
> +}
> +
> +static const struct v4l2_subdev_video_ops dcmipp_byteproc_video_ops = {
> +	.g_frame_interval = dcmipp_byteproc_g_frame_interval,
> +	.s_frame_interval = dcmipp_byteproc_s_frame_interval,
> +	.s_stream = dcmipp_byteproc_s_stream,
> +};
> +
> +static const struct v4l2_subdev_ops dcmipp_byteproc_ops = {
> +	.pad = &dcmipp_byteproc_pad_ops,
> +	.video = &dcmipp_byteproc_video_ops,
> +};
> +
> +/* FIXME */
> +static void dcmipp_byteproc_release(struct v4l2_subdev *sd)
> +{
> +	struct dcmipp_byteproc_device *byteproc = v4l2_get_subdevdata(sd);
> +
> +	kfree(byteproc);
> +}
> +
> +static const struct v4l2_subdev_internal_ops dcmipp_byteproc_int_ops = {
> +	.release = dcmipp_byteproc_release,
> +};
> +
> +static void dcmipp_byteproc_comp_unbind(struct device *comp,
> +					struct device *master,
> +					void *master_data)
> +{
> +	struct dcmipp_ent_device *ved = dev_get_drvdata(comp);
> +	struct dcmipp_byteproc_device *byteproc =
> +			container_of(ved, struct dcmipp_byteproc_device, ved);
> +
> +	dcmipp_ent_sd_unregister(ved, &byteproc->sd);
> +}
> +
> +static int dcmipp_byteproc_comp_bind(struct device *comp, struct device *master,
> +				     void *master_data)
> +{
> +	struct dcmipp_bind_data *bind_data = master_data;
> +	struct dcmipp_platform_data *pdata = comp->platform_data;
> +	struct dcmipp_byteproc_device *byteproc;
> +	struct v4l2_rect r = {
> +		.top = 0,
> +		.left = 0,
> +		.width = DCMIPP_FMT_WIDTH_DEFAULT,
> +		.height = DCMIPP_FMT_HEIGHT_DEFAULT,
> +	};
> +	struct v4l2_fract interval = {
> +		.numerator = 1,
> +		.denominator = 30,
> +	};
> +	int ret;
> +
> +	/* Allocate the byteproc struct */
> +	byteproc = kzalloc(sizeof(*byteproc), GFP_KERNEL);
> +	if (!byteproc)
> +		return -ENOMEM;
> +
> +	byteproc->regs = bind_data->regs;
> +
> +	/* Initialize the lock */
> +	mutex_init(&byteproc->lock);
> +
> +	/* Initialize ved and sd */
> +	ret = dcmipp_ent_sd_register(&byteproc->ved, &byteproc->sd,
> +				     bind_data->v4l2_dev,
> +				     pdata->entity_name,
> +				     MEDIA_ENT_F_PROC_VIDEO_PIXEL_FORMATTER, 2,
> +				     (const unsigned long[2]) {
> +				     MEDIA_PAD_FL_SINK,
> +				     MEDIA_PAD_FL_SOURCE,
> +				     },
> +				     &dcmipp_byteproc_int_ops,
> +				     &dcmipp_byteproc_ops,
> +				     NULL, NULL);
> +	if (ret) {
> +		kfree(byteproc);
> +		return ret;
> +	}
> +
> +	dev_set_drvdata(comp, &byteproc->ved);
> +	byteproc->dev = comp;
> +
> +	/* Initialize the frame format */
> +	byteproc->sink_fmt = fmt_default;
> +	byteproc->crop = r;
> +	byteproc->compose = r;
> +	byteproc->src_interval = interval;
> +	byteproc->sink_interval = interval;
> +
> +	return 0;
> +}
> +
> +static const struct component_ops dcmipp_byteproc_comp_ops = {
> +	.bind = dcmipp_byteproc_comp_bind,
> +	.unbind = dcmipp_byteproc_comp_unbind,
> +};
> +
> +static int dcmipp_byteproc_probe(struct platform_device *pdev)
> +{
> +	return component_add(&pdev->dev, &dcmipp_byteproc_comp_ops);
> +}
> +
> +static int dcmipp_byteproc_remove(struct platform_device *pdev)
> +{
> +	component_del(&pdev->dev, &dcmipp_byteproc_comp_ops);
> +
> +	return 0;
> +}
> +
> +static const struct platform_device_id dcmipp_byteproc_driver_ids[] = {
> +	{
> +		.name           = DCMIPP_BYTEPROC_DRV_NAME,
> +	},
> +	{ }
> +};
> +
> +static struct platform_driver dcmipp_byteproc_pdrv = {
> +	.probe		= dcmipp_byteproc_probe,
> +	.remove		= dcmipp_byteproc_remove,
> +	.id_table	= dcmipp_byteproc_driver_ids,
> +	.driver		= {
> +		.name	= DCMIPP_BYTEPROC_DRV_NAME,
> +	},
> +};
> +
> +module_platform_driver(dcmipp_byteproc_pdrv);
> +
> +MODULE_DEVICE_TABLE(platform, dcmipp_byteproc_driver_ids);
> +
> +MODULE_AUTHOR("Hugues Fruchet <hugues.fruchet@foss.st.com>");
> +MODULE_AUTHOR("Alain Volmat <alain.volmat@foss.st.com>");
> +MODULE_DESCRIPTION("STMicroelectronics STM32 Digital Camera Memory Interface with Pixel Processor driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-common.c b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-common.c
> new file mode 100644
> index 000000000000..f070690ccbb1
> --- /dev/null
> +++ b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-common.c
> @@ -0,0 +1,116 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for STM32 Digital Camera Memory Interface Pixel Processor
> + *
> + * Copyright (C) STMicroelectronics SA 2022
> + * Authors: Hugues Fruchet <hugues.fruchet@foss.st.com>
> + *          Alain Volmat <alain.volmat@foss.st.com>
> + *          for STMicroelectronics.
> + */
> +
> +#include <linux/init.h>
> +#include <linux/module.h>
> +
> +#include "dcmipp-common.h"
> +
> +/* Helper function to allocate and initialize pads */
> +struct media_pad *dcmipp_pads_init(u16 num_pads, const unsigned long *pads_flag)
> +{
> +	struct media_pad *pads;
> +	unsigned int i;
> +
> +	/* Allocate memory for the pads */
> +	pads = kcalloc(num_pads, sizeof(*pads), GFP_KERNEL);
> +	if (!pads)
> +		return ERR_PTR(-ENOMEM);
> +
> +	/* Initialize the pads */
> +	for (i = 0; i < num_pads; i++) {
> +		pads[i].index = i;
> +		pads[i].flags = pads_flag[i];
> +	}
> +
> +	return pads;
> +}
> +EXPORT_SYMBOL_GPL(dcmipp_pads_init);
> +
> +int dcmipp_link_validate(struct media_link *link)
> +{
> +	/* TODO */
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(dcmipp_link_validate);
> +
> +static const struct media_entity_operations dcmipp_ent_sd_mops = {
> +	.link_validate = dcmipp_link_validate,
> +};
> +
> +int dcmipp_ent_sd_register(struct dcmipp_ent_device *ved,
> +			   struct v4l2_subdev *sd,
> +			   struct v4l2_device *v4l2_dev,
> +			   const char *const name,
> +			   u32 function,
> +			   u16 num_pads,
> +			   const unsigned long *pads_flag,
> +			   const struct v4l2_subdev_internal_ops *sd_int_ops,
> +			   const struct v4l2_subdev_ops *sd_ops,
> +			   irq_handler_t handler,
> +			   irq_handler_t thread_fn)
> +{
> +	int ret;
> +
> +	/* Allocate the pads. Should be released from the sd_int_op release */
> +	ved->pads = dcmipp_pads_init(num_pads, pads_flag);
> +	if (IS_ERR(ved->pads))
> +		return PTR_ERR(ved->pads);
> +
> +	/* Fill the dcmipp_ent_device struct */
> +	ved->ent = &sd->entity;
> +
> +	/* Initialize the subdev */
> +	v4l2_subdev_init(sd, sd_ops);
> +	sd->internal_ops = sd_int_ops;
> +	sd->entity.function = function;
> +	sd->entity.ops = &dcmipp_ent_sd_mops;
> +	sd->owner = THIS_MODULE;
> +	strscpy(sd->name, name, sizeof(sd->name));
> +	v4l2_set_subdevdata(sd, ved);
> +
> +	/* Expose this subdev to user space */
> +	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	if (sd->ctrl_handler)
> +		sd->flags |= V4L2_SUBDEV_FL_HAS_EVENTS;
> +
> +	/* Initialize the media entity */
> +	ret = media_entity_pads_init(&sd->entity, num_pads, ved->pads);
> +	if (ret)
> +		goto err_clean_pads;
> +
> +	/* Register the subdev with the v4l2 and the media framework */
> +	ret = v4l2_device_register_subdev(v4l2_dev, sd);
> +	if (ret) {
> +		dev_err(v4l2_dev->dev,
> +			"%s: subdev register failed (err=%d)\n",
> +			name, ret);
> +		goto err_clean_m_ent;
> +	}
> +
> +	ved->handler = handler;
> +	ved->thread_fn = thread_fn;
> +
> +	return 0;
> +
> +err_clean_m_ent:
> +	media_entity_cleanup(&sd->entity);
> +err_clean_pads:
> +	dcmipp_pads_cleanup(ved->pads);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(dcmipp_ent_sd_register);
> +
> +void dcmipp_ent_sd_unregister(struct dcmipp_ent_device *ved, struct v4l2_subdev *sd)
> +{
> +	media_entity_cleanup(ved->ent);
> +	v4l2_device_unregister_subdev(sd);
> +}
> +EXPORT_SYMBOL_GPL(dcmipp_ent_sd_unregister);
> diff --git a/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-common.h b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-common.h
> new file mode 100644
> index 000000000000..a8c162193de6
> --- /dev/null
> +++ b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-common.h
> @@ -0,0 +1,240 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Driver for STM32 Digital Camera Memory Interface Pixel Processor
> + *
> + * Copyright (C) STMicroelectronics SA 2022
> + * Authors: Hugues Fruchet <hugues.fruchet@foss.st.com>
> + *          Alain Volmat <alain.volmat@foss.st.com>
> + *          for STMicroelectronics.
> + */
> +
> +#ifndef _DCMIPP_COMMON_H_
> +#define _DCMIPP_COMMON_H_
> +
> +#include <linux/interrupt.h>
> +#include <linux/slab.h>
> +#include <media/media-device.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-fwnode.h>
> +
> +#define DCMIPP_PDEV_NAME "dcmipp"
> +
> +/* DCMIPP-specific controls */
> +#define DCMIPP_CID_DCMIPP_BASE		(0x00f00000 | 0xf000)
> +#define DCMIPP_CID_DCMIPP_CLASS		(0x00f00000 | 1)
> +#define DCMIPP_CID_TEST_PATTERN		(DCMIPP_CID_DCMIPP_BASE + 0)
> +
> +#define DCMIPP_FRAME_MAX_WIDTH 4096
> +#define DCMIPP_FRAME_MAX_HEIGHT 2160
> +#define DCMIPP_FRAME_MIN_WIDTH 16
> +#define DCMIPP_FRAME_MIN_HEIGHT 16
> +
> +#define DCMIPP_FMT_WIDTH_DEFAULT  640
> +#define DCMIPP_FMT_HEIGHT_DEFAULT 480
> +
> +#define DCMIPP_FRAME_INDEX(lin, col, width, bpp) \
> +	(((lin) * (width) + (col)) * (bpp))
> +
> +#define DCMIPP_COLORSPACE_DEFAULT	V4L2_COLORSPACE_REC709
> +#define DCMIPP_YCBCR_ENC_DEFAULT	V4L2_YCBCR_ENC_DEFAULT
> +#define DCMIPP_QUANTIZATION_DEFAULT	V4L2_QUANTIZATION_DEFAULT
> +#define DCMIPP_XFER_FUNC_DEFAULT	V4L2_XFER_FUNC_DEFAULT
> +
> +/**
> + * struct dcmipp_colorimetry_clamp - Adjust colorimetry parameters
> + *
> + * @fmt:		the pointer to struct v4l2_pix_format or
> + *			struct v4l2_mbus_framefmt
> + *
> + * Entities must check if colorimetry given by the userspace is valid, if not
> + * then set them as DEFAULT
> + */
> +#define dcmipp_colorimetry_clamp(fmt)					\
> +do {									\
> +	if ((fmt)->colorspace == V4L2_COLORSPACE_DEFAULT ||		\
> +	    (fmt)->colorspace > V4L2_COLORSPACE_DCI_P3) {		\
> +		(fmt)->colorspace = DCMIPP_COLORSPACE_DEFAULT;		\
> +		(fmt)->ycbcr_enc = DCMIPP_YCBCR_ENC_DEFAULT;		\
> +		(fmt)->quantization = DCMIPP_QUANTIZATION_DEFAULT;	\
> +		(fmt)->xfer_func = DCMIPP_XFER_FUNC_DEFAULT;		\
> +	}								\
> +	if ((fmt)->ycbcr_enc > V4L2_YCBCR_ENC_SMPTE240M)		\
> +		(fmt)->ycbcr_enc = DCMIPP_YCBCR_ENC_DEFAULT;		\
> +	if ((fmt)->quantization > V4L2_QUANTIZATION_LIM_RANGE)		\
> +		(fmt)->quantization = DCMIPP_QUANTIZATION_DEFAULT;	\
> +	if ((fmt)->xfer_func > V4L2_XFER_FUNC_SMPTE2084)		\
> +		(fmt)->xfer_func = DCMIPP_XFER_FUNC_DEFAULT;		\
> +} while (0)
> +
> +/**
> + * struct dcmipp_platform_data - platform data to components
> + *
> + * @entity_name:	The name of the entity to be created
> + *
> + * Board setup code will often provide additional information using the device's
> + * platform_data field to hold additional information.
> + * When injecting a new platform_device in the component system the core needs
> + * to provide to the corresponding submodules the name of the entity that should
> + * be used when registering the subdevice in the Media Controller system.
> + */
> +struct dcmipp_platform_data {
> +	char entity_name[32];
> +};
> +
> +struct dcmipp_bind_data {
> +	/* Internal v4l2 parent device*/
> +	struct v4l2_device		*v4l2_dev;
> +
> +	/* Hardware resources */
> +	struct reset_control		*rstc;
> +	void __iomem			*regs;
> +};
> +
> +/**
> + * struct dcmipp_ent_device - core struct that represents a node in the topology
> + *
> + * @ent:		the pointer to struct media_entity for the node
> + * @pads:		the list of pads of the node
> + * @process_frame:	callback send a frame to that node
> + * @vdev_get_format:	callback that returns the current format a pad, used
> + *			only when is_media_entity_v4l2_video_device(ent) returns
> + *			true
> + *
> + * Each node of the topology must create a dcmipp_ent_device struct. Depending on
> + * the node it will be of an instance of v4l2_subdev or video_device struct
> + * where both contains a struct media_entity.
> + * Those structures should embedded the dcmipp_ent_device struct through
> + * v4l2_set_subdevdata() and video_set_drvdata() respectivaly, allowing the
> + * dcmipp_ent_device struct to be retrieved from the corresponding struct
> + * media_entity
> + */
> +struct dcmipp_ent_device {
> +	struct media_entity *ent;
> +	struct media_pad *pads;
> +	void * (*process_frame)(struct dcmipp_ent_device *ved,
> +				const void *frame);
> +	void (*vdev_get_format)(struct dcmipp_ent_device *ved,
> +				struct v4l2_pix_format *fmt);
> +
> +	/* Parallel input device */
> +	struct v4l2_mbus_config_parallel bus;
> +	enum v4l2_mbus_type bus_type;
> +	irq_handler_t handler;
> +	irqreturn_t handler_ret;
> +	irq_handler_t thread_fn;
> +};
> +
> +/**
> + * dcmipp_pads_init - initialize pads
> + *
> + * @num_pads:	number of pads to initialize
> + * @pads_flags:	flags to use in each pad
> + *
> + * Helper functions to allocate/initialize pads
> + */
> +struct media_pad *dcmipp_pads_init(u16 num_pads,
> +				   const unsigned long *pads_flag);
> +
> +/**
> + * dcmipp_pads_cleanup - free pads
> + *
> + * @pads: pointer to the pads
> + *
> + * Helper function to free the pads initialized with dcmipp_pads_init
> + */
> +static inline void dcmipp_pads_cleanup(struct media_pad *pads)
> +{
> +	kfree(pads);
> +}
> +
> +/**
> + * dcmipp_ent_sd_register - initialize and register a subdev node
> + *
> + * @ved:	the dcmipp_ent_device struct to be initialize
> + * @sd:		the v4l2_subdev struct to be initialize and registered
> + * @v4l2_dev:	the v4l2 device to register the v4l2_subdev
> + * @name:	name of the sub-device. Please notice that the name must be
> + *		unique.
> + * @function:	media entity function defined by MEDIA_ENT_F_* macros
> + * @num_pads:	number of pads to initialize
> + * @pads_flag:	flags to use in each pad
> + * @sd_int_ops:	pointer to &struct v4l2_subdev_internal_ops
> + * @sd_ops:	pointer to &struct v4l2_subdev_ops.
> + *
> + * Helper function initialize and register the struct dcmipp_ent_device and struct
> + * v4l2_subdev which represents a subdev node in the topology
> + */
> +int dcmipp_ent_sd_register(struct dcmipp_ent_device *ved,
> +			   struct v4l2_subdev *sd,
> +			   struct v4l2_device *v4l2_dev,
> +			   const char *const name,
> +			   u32 function,
> +			   u16 num_pads,
> +			   const unsigned long *pads_flag,
> +			   const struct v4l2_subdev_internal_ops *sd_int_ops,
> +			   const struct v4l2_subdev_ops *sd_ops,
> +			   irq_handler_t handler,
> +			   irq_handler_t thread_fn);
> +
> +/**
> + * dcmipp_ent_sd_unregister - cleanup and unregister a subdev node
> + *
> + * @ved:	the dcmipp_ent_device struct to be cleaned up
> + * @sd:		the v4l2_subdev struct to be unregistered
> + *
> + * Helper function cleanup and unregister the struct dcmipp_ent_device and struct
> + * v4l2_subdev which represents a subdev node in the topology
> + */
> +void dcmipp_ent_sd_unregister(struct dcmipp_ent_device *ved,
> +			      struct v4l2_subdev *sd);
> +
> +/**
> + * dcmipp_link_validate - validates a media link
> + *
> + * @link: pointer to &struct media_link
> + *
> + * This function call validates if a media link is valid for streaming.
> + */
> +int dcmipp_link_validate(struct media_link *link);
> +
> +#define reg_write(device, reg, val) \
> +	(reg_write_dbg((device)->dev, #reg, (device)->regs, (reg), (val)))
> +#define reg_read(device, reg) \
> +	 (reg_read_dbg((device)->dev, #reg, (device)->regs, (reg)))
> +#define reg_set(device, reg, mask) \
> +	 (reg_set_dbg((device)->dev, #reg, (device)->regs, (reg), (mask)))
> +#define reg_clear(device, reg, mask) \
> +	 (reg_clear_dbg((device)->dev, #reg, (device)->regs, (reg), (mask)))
> +
> +static inline u32 reg_read_dbg(struct device *dev, const char *regname,
> +			       void __iomem *base, u32 reg)
> +{
> +	u32 val = readl_relaxed(base + reg);
> +
> +	dev_dbg(dev, "RD  %s %#10.8x\n", regname, val);
> +	return val;
> +}
> +
> +static inline void reg_write_dbg(struct device *dev, const char *regname,
> +				 void __iomem *base, u32 reg, u32 val)
> +{
> +	dev_dbg(dev, "WR  %s %#10.8x\n", regname, val);
> +	writel_relaxed(val, base + reg);
> +}
> +
> +static inline void reg_set_dbg(struct device *dev, const char *regname,
> +			       void __iomem *base, u32 reg, u32 mask)
> +{
> +	dev_dbg(dev, "SET %s %#10.8x\n", regname, mask);
> +	reg_write_dbg(dev, regname, base, reg, readl_relaxed(base + reg) | mask);
> +}
> +
> +static inline void reg_clear_dbg(struct device *dev, const char *regname,
> +				 void __iomem *base, u32 reg, u32 mask)
> +{
> +	dev_dbg(dev, "CLR %s %#10.8x\n", regname, mask);
> +	reg_write_dbg(dev, regname, base, reg, readl_relaxed(base + reg) & ~mask);
> +}
> +
> +#endif
> +
> diff --git a/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-core.c b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-core.c
> new file mode 100644
> index 000000000000..aa7ae9a5b1a8
> --- /dev/null
> +++ b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-core.c
> @@ -0,0 +1,682 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for STM32 Digital Camera Memory Interface Pixel Processor
> + *
> + * Copyright (C) STMicroelectronics SA 2022
> + * Authors: Hugues Fruchet <hugues.fruchet@foss.st.com>
> + *          Alain Volmat <alain.volmat@foss.st.com>
> + *          for STMicroelectronics.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/component.h>
> +#include <linux/delay.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_graph.h>

#include <linux/property.h> instead of these three.

> +#include <linux/pinctrl/consumer.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/reset.h>
> +#include <media/media-device.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-fwnode.h>
> +
> +#include "dcmipp-common.h"
> +
> +#define DCMIPP_MDEV_MODEL_NAME "DCMIPP MDEV"
> +
> +#define DCMIPP_ENT_LINK(src, srcpad, sink, sinkpad, link_flags) {	\
> +	.src_ent = src,						\
> +	.src_pad = srcpad,					\
> +	.sink_ent = sink,					\
> +	.sink_pad = sinkpad,					\
> +	.flags = link_flags,					\
> +}
> +
> +#define DCMIPP_CMHWCFGR (0x200)
> +#define DCMIPP_P0HWCFGR (0x400)
> +#define DCMIPP_VERR (0xFF4)
> +
> +struct dcmipp_device {
> +	/* The platform device */
> +	struct platform_device		pdev;
> +	struct device			*dev;
> +
> +	/* Hardware resources */
> +	struct reset_control		*rstc;
> +	void __iomem			*regs;
> +	struct clk			*kclk;
> +
> +	/* The pipeline configuration */
> +	const struct dcmipp_pipeline_config	*pipe_cfg;
> +
> +	/* The Associated media_device parent */
> +	struct media_device		mdev;
> +
> +	/* Internal v4l2 parent device*/
> +	struct v4l2_device		v4l2_dev;
> +
> +	/* Subdevices */
> +	struct platform_device		**subdevs;
> +
> +	struct v4l2_async_notifier	notifier;
> +};
> +
> +static inline struct dcmipp_device *notifier_to_dcmipp(struct v4l2_async_notifier *n)
> +{
> +	return container_of(n, struct dcmipp_device, notifier);
> +}
> +
> +/* Structure which describes individual configuration for each entity */
> +struct dcmipp_ent_config {
> +	const char *name;
> +	const char *drv;
> +};
> +
> +/* Structure which describes links between entities */
> +struct dcmipp_ent_link {
> +	unsigned int src_ent;
> +	u16 src_pad;
> +	unsigned int sink_ent;
> +	u16 sink_pad;
> +	u32 flags;
> +};
> +
> +/* Structure which describes the whole topology */
> +struct dcmipp_pipeline_config {
> +	const struct dcmipp_ent_config *ents;
> +	size_t num_ents;
> +	const struct dcmipp_ent_link *links;
> +	size_t num_links;
> +};
> +
> +/* --------------------------------------------------------------------------
> + * Topology Configuration
> + */
> +
> +static const struct dcmipp_ent_config stm32mp13_ent_config[] = {
> +	{
> +		.name = "dcmipp_parallel",
> +		.drv = "dcmipp-parallel",
> +	},
> +	{
> +		.name = "dcmipp_dump_postproc",
> +		.drv = "dcmipp-byteproc",
> +	},
> +	{
> +		.name = "dcmipp_dump_capture",
> +		.drv = "dcmipp-bytecap",
> +	},
> +};
> +
> +#define ID_PARALLEL 0
> +#define ID_DUMP_BYTEPROC 1
> +#define ID_DUMP_CAPTURE 2
> +
> +static const struct dcmipp_ent_link stm32mp13_ent_links[] = {
> +	DCMIPP_ENT_LINK(ID_PARALLEL,      1, ID_DUMP_BYTEPROC, 0,
> +			MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
> +	DCMIPP_ENT_LINK(ID_DUMP_BYTEPROC, 1, ID_DUMP_CAPTURE,  0,
> +			MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
> +};
> +
> +static const struct dcmipp_pipeline_config stm32mp13_pipe_cfg = {
> +	.ents		= stm32mp13_ent_config,
> +	.num_ents	= ARRAY_SIZE(stm32mp13_ent_config),
> +	.links		= stm32mp13_ent_links,
> +	.num_links	= ARRAY_SIZE(stm32mp13_ent_links)
> +};
> +
> +/* -------------------------------------------------------------------------- */
> +#define LINK_FLAG_TO_STR(f) ((f) == 0 ? "" :\
> +			     (f) == MEDIA_LNK_FL_ENABLED ? "ENABLED" :\
> +			     (f) == MEDIA_LNK_FL_IMMUTABLE ? "IMMUTABLE" :\
> +			     (f) == (MEDIA_LNK_FL_ENABLED |\
> +				     MEDIA_LNK_FL_IMMUTABLE) ?\
> +					"ENABLED, IMMUTABLE" :\
> +			     "UNKNOWN")
> +
> +static int dcmipp_create_links(struct dcmipp_device *dcmipp)
> +{
> +	unsigned int i;
> +	int ret;
> +
> +	/* Initialize the links between entities */
> +	for (i = 0; i < dcmipp->pipe_cfg->num_links; i++) {
> +		const struct dcmipp_ent_link *link = &dcmipp->pipe_cfg->links[i];
> +		/*
> +		 * TODO: Check another way of retrieving ved struct without
> +		 * relying on platform_get_drvdata
> +		 */
> +		struct dcmipp_ent_device *ved_src =
> +			platform_get_drvdata(dcmipp->subdevs[link->src_ent]);
> +		struct dcmipp_ent_device *ved_sink =
> +			platform_get_drvdata(dcmipp->subdevs[link->sink_ent]);
> +
> +		dev_dbg(dcmipp->dev, "Create link \"%s\":%d -> %d:\"%s\" [%s]\n",
> +			dcmipp->pipe_cfg->ents[link->src_ent].name,
> +			link->src_pad,
> +			link->sink_pad,
> +			dcmipp->pipe_cfg->ents[link->sink_ent].name,
> +			LINK_FLAG_TO_STR(link->flags));
> +
> +		ret = media_create_pad_link(ved_src->ent, link->src_pad,
> +					    ved_sink->ent, link->sink_pad,
> +					    link->flags);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int dcmipp_graph_init(struct dcmipp_device *dcmipp);
> +
> +static int dcmipp_comp_bind(struct device *master)
> +{
> +	struct dcmipp_device *dcmipp = platform_get_drvdata(to_platform_device(master));
> +	struct dcmipp_bind_data bind_data;
> +	int ret;
> +
> +	/* Register the v4l2 struct */
> +	ret = v4l2_device_register(dcmipp->mdev.dev, &dcmipp->v4l2_dev);
> +	if (ret) {
> +		dev_err(dcmipp->mdev.dev,
> +			"v4l2 device register failed (err=%d)\n", ret);
> +		return ret;
> +	}
> +
> +	/* Bind subdevices */
> +	bind_data.v4l2_dev = &dcmipp->v4l2_dev;
> +	bind_data.rstc = dcmipp->rstc;
> +	bind_data.regs = dcmipp->regs;
> +	ret = component_bind_all(master, &bind_data);
> +	if (ret)
> +		goto err_v4l2_unregister;
> +
> +	/* Initialize links */
> +	ret = dcmipp_create_links(dcmipp);
> +	if (ret)
> +		goto err_comp_unbind_all;
> +
> +	ret = dcmipp_graph_init(dcmipp);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +
> +	media_device_unregister(&dcmipp->mdev);
> +	media_device_cleanup(&dcmipp->mdev);
> +err_comp_unbind_all:
> +	component_unbind_all(master, NULL);
> +err_v4l2_unregister:
> +	v4l2_device_unregister(&dcmipp->v4l2_dev);
> +
> +	return ret;
> +}
> +
> +static void dcmipp_comp_unbind(struct device *master)
> +{
> +	struct dcmipp_device *dcmipp = platform_get_drvdata(to_platform_device(master));
> +
> +	v4l2_async_nf_unregister(&dcmipp->notifier);
> +	v4l2_async_nf_cleanup(&dcmipp->notifier);
> +
> +	media_device_unregister(&dcmipp->mdev);
> +	media_device_cleanup(&dcmipp->mdev);
> +	component_unbind_all(master, NULL);
> +	v4l2_device_unregister(&dcmipp->v4l2_dev);
> +}
> +
> +static int dcmipp_comp_compare(struct device *comp, void *data)
> +{
> +	return comp == data;
> +}
> +
> +static struct component_match *dcmipp_add_subdevs(struct dcmipp_device *dcmipp)
> +{
> +	struct component_match *match = NULL;
> +	struct dcmipp_platform_data pdata;
> +	int i;
> +
> +	for (i = 0; i < dcmipp->pipe_cfg->num_ents; i++) {
> +		dev_dbg(dcmipp->dev, "new pdev for %s (%s)\n",
> +			dcmipp->pipe_cfg->ents[i].drv,
> +			dcmipp->pipe_cfg->ents[i].name);
> +
> +		strscpy(pdata.entity_name, dcmipp->pipe_cfg->ents[i].name,
> +			sizeof(pdata.entity_name));
> +
> +		dcmipp->subdevs[i] =
> +			platform_device_register_data
> +				(dcmipp->dev,
> +				 dcmipp->pipe_cfg->ents[i].drv,
> +				 PLATFORM_DEVID_AUTO,
> +				 &pdata,
> +				 sizeof(pdata));
> +		if (IS_ERR(dcmipp->subdevs[i])) {
> +			match = ERR_CAST(dcmipp->subdevs[i]);
> +			while (--i >= 0)
> +				platform_device_unregister(dcmipp->subdevs[i]);
> +
> +			dev_err(dcmipp->mdev.dev,
> +				"%s error (err=%ld)\n", __func__,
> +				PTR_ERR(match));
> +			return match;
> +		}
> +
> +		component_match_add(dcmipp->dev, &match, dcmipp_comp_compare,
> +				    &dcmipp->subdevs[i]->dev);
> +	}
> +
> +	return match;
> +}
> +
> +static void dcmipp_rm_subdevs(struct dcmipp_device *dcmipp)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < dcmipp->pipe_cfg->num_ents; i++)
> +		platform_device_unregister(dcmipp->subdevs[i]);
> +}
> +
> +static const struct component_master_ops dcmipp_comp_ops = {
> +	.bind = dcmipp_comp_bind,
> +	.unbind = dcmipp_comp_unbind,
> +};
> +
> +static const struct of_device_id dcmipp_of_match[] = {
> +	{ .compatible = "st,stm32mp13-dcmipp", .data = &stm32mp13_pipe_cfg},

Space before '}'.

> +	{ /* end node */ },
> +};
> +MODULE_DEVICE_TABLE(of, dcmipp_of_match);
> +
> +static int dcmipp_graph_notify_complete(struct v4l2_async_notifier *notifier)
> +{
> +	struct dcmipp_device *dcmipp = notifier_to_dcmipp(notifier);
> +	int ret;
> +
> +	/* Register the media device */
> +	ret = media_device_register(&dcmipp->mdev);
> +	if (ret) {
> +		dev_err(dcmipp->mdev.dev,
> +			"media device register failed (err=%d)\n", ret);
> +		return ret;
> +	}
> +
> +	/* Expose all subdev's nodes*/
> +	ret = v4l2_device_register_subdev_nodes(&dcmipp->v4l2_dev);
> +	if (ret) {
> +		dev_err(dcmipp->mdev.dev,
> +			"dcmipp subdev nodes registration failed (err=%d)\n",
> +			ret);
> +		media_device_unregister(&dcmipp->mdev);
> +		return ret;
> +	}
> +
> +	dev_dbg(dcmipp->dev, "Notify complete !\n");
> +
> +	return 0;
> +}
> +
> +static void dcmipp_graph_notify_unbind(struct v4l2_async_notifier *notifier,
> +				       struct v4l2_subdev *sd,
> +				       struct v4l2_async_subdev *asd)
> +{
> +	struct dcmipp_device *dcmipp = notifier_to_dcmipp(notifier);
> +
> +	dev_dbg(dcmipp->dev, "Removing %s\n", sd->name);
> +}
> +
> +static irqreturn_t dcmipp_irq_thread(int irq, void *arg)
> +{
> +	struct dcmipp_device *dcmipp = arg;
> +	struct dcmipp_ent_device *ved;
> +	unsigned int i;
> +
> +	/* Call irq thread of each entities of pipeline */
> +	for (i = 0; i < dcmipp->pipe_cfg->num_ents; i++) {
> +		ved = platform_get_drvdata(dcmipp->subdevs[i]);
> +		if (ved->thread_fn && ved->handler_ret == IRQ_WAKE_THREAD)
> +			ved->thread_fn(irq, ved);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t dcmipp_irq_callback(int irq, void *arg)
> +{
> +	struct dcmipp_device *dcmipp = arg;
> +	struct dcmipp_ent_device *ved;
> +	irqreturn_t ret = IRQ_HANDLED;
> +	unsigned int i;
> +
> +	/* Call irq handler of each entities of pipeline */
> +	for (i = 0; i < dcmipp->pipe_cfg->num_ents; i++) {
> +		ved = platform_get_drvdata(dcmipp->subdevs[i]);
> +		if (ved->handler)
> +			ved->handler_ret = ved->handler(irq, ved);
> +		else if (ved->thread_fn)
> +			ved->handler_ret = IRQ_WAKE_THREAD;
> +		else
> +			ved->handler_ret = IRQ_HANDLED;

Does this need to be serialised somehow (access to ved->handler_ret, that
is)?

> +		if (ved->handler_ret != IRQ_HANDLED)
> +			ret = ved->handler_ret;
> +	}
> +
> +	return ret;
> +}
> +
> +static int dcmipp_graph_notify_bound(struct v4l2_async_notifier *notifier,
> +				     struct v4l2_subdev *subdev,
> +				     struct v4l2_async_subdev *asd)
> +{
> +	struct dcmipp_device *dcmipp = notifier_to_dcmipp(notifier);
> +	unsigned int ret;
> +	int src_pad;
> +	struct dcmipp_ent_device *sink;
> +	struct device_node *np = dcmipp->dev->of_node;
> +	struct v4l2_fwnode_endpoint ep = { .bus_type = 0 };

Please set bus_type explicitly (DPHY)?

> +
> +	dev_dbg(dcmipp->dev, "Subdev \"%s\" bound\n", subdev->name);
> +
> +	/*
> +	 * Link this sub-device to DCMIPP, it could be
> +	 * a parallel camera sensor or a CSI-2 to parallel bridge
> +	 */
> +

No need for a newline.

> +	src_pad = media_entity_get_fwnode_pad(&subdev->entity,
> +					      subdev->fwnode,
> +					      MEDIA_PAD_FL_SOURCE);
> +
> +	/* Get bus characteristics from devicetree */
> +	np = of_graph_get_next_endpoint(np, NULL);
> +	if (!np) {
> +		dev_err(dcmipp->dev, "Could not find the endpoint\n");
> +		of_node_put(np);
> +		return -ENODEV;
> +	}
> +
> +	ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(np), &ep);
> +	of_node_put(np);
> +	if (ret) {
> +		dev_err(dcmipp->dev, "Could not parse the endpoint\n");
> +		return ret;
> +	}
> +
> +	if ((ep.bus_type == V4L2_MBUS_PARALLEL ||
> +	     ep.bus_type == V4L2_MBUS_BT656) &&
> +	     ep.bus.parallel.bus_width > 0) {
> +		/* Only 8 bits bus width supported with BT656 bus */
> +		if (ep.bus_type == V4L2_MBUS_BT656 &&
> +		    ep.bus.parallel.bus_width != 8) {
> +			dev_err(dcmipp->dev, "BT656 bus conflicts with %u bits bus width (8 bits required)\n",
> +				ep.bus.parallel.bus_width);
> +			return -ENODEV;
> +		}
> +
> +		/*
> +		 * Parallel input device detected
> +		 * Connect it to parallel subdev
> +		 */
> +		sink = platform_get_drvdata(dcmipp->subdevs[ID_PARALLEL]);
> +		sink->bus.flags = ep.bus.parallel.flags;
> +		sink->bus.bus_width = ep.bus.parallel.bus_width;
> +		sink->bus.data_shift = ep.bus.parallel.data_shift;
> +		sink->bus_type = ep.bus_type;
> +		ret = media_create_pad_link(&subdev->entity, src_pad,
> +					    sink->ent, 0,
> +					    MEDIA_LNK_FL_IMMUTABLE |
> +					    MEDIA_LNK_FL_ENABLED);
> +		if (ret)
> +			dev_err(dcmipp->dev, "Failed to create media pad link with subdev \"%s\"\n",
> +				subdev->name);
> +		else
> +			dev_dbg(dcmipp->dev, "DCMIPP is now linked to \"%s\"\n",
> +				subdev->name);
> +
> +		return 0;
> +	}
> +
> +	return ret;
> +}
> +
> +static const struct v4l2_async_notifier_operations dcmipp_graph_notify_ops = {
> +	.bound = dcmipp_graph_notify_bound,
> +	.unbind = dcmipp_graph_notify_unbind,
> +	.complete = dcmipp_graph_notify_complete,
> +};
> +
> +static int dcmipp_graph_init(struct dcmipp_device *dcmipp)
> +{
> +	struct v4l2_async_subdev *asd;
> +	struct device_node *ep;
> +	int ret;
> +
> +	ep = of_graph_get_next_endpoint(dcmipp->dev->of_node, NULL);

You could switch to device property API:

struct fwnode_handle *ep;

ep = fwnode_graph_get_next_endpoint(dev_fwnode(dcmipp->dev), NULL);

> +	if (!ep) {
> +		dev_err(dcmipp->dev, "Failed to get next endpoint\n");
> +		return -EINVAL;
> +	}
> +
> +	v4l2_async_nf_init(&dcmipp->notifier);

V4L2 async API has just changed slightly: you'd call
v4l2_async_nf_init(&dcmipp->notifier, &dcmipp->v4l2_dev) here. The notifier
registration just takes the notifier.

Be sure to register the v4l2_device first (probably already done but I
didn't check).

> +
> +	asd = v4l2_async_nf_add_fwnode_remote

Don't wrap just before or after '('.

> +		(&dcmipp->notifier, of_fwnode_handle(ep),
> +		 struct v4l2_async_subdev);

struct v4l2_async_subdev is now struct v4l2_async_connection.

> +
> +	of_node_put(ep);

fwnode_handle_put(ep);

> +
> +	if (IS_ERR(asd)) {
> +		dev_err(dcmipp->dev, "Failed to add fwnode remote subdev\n");
> +		return PTR_ERR(asd);
> +	}
> +
> +	dcmipp->notifier.ops = &dcmipp_graph_notify_ops;
> +
> +	ret = v4l2_async_nf_register(&dcmipp->v4l2_dev, &dcmipp->notifier);
> +	if (ret < 0) {
> +		dev_err(dcmipp->dev, "Failed to register notifier\n");
> +		v4l2_async_nf_cleanup(&dcmipp->notifier);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int dcmipp_probe(struct platform_device *pdev)
> +{
> +	struct dcmipp_device *dcmipp;
> +	struct component_match *comp_match = NULL;
> +	struct resource *res;
> +	struct clk *kclk;
> +	const struct dcmipp_pipeline_config *pipe_cfg;
> +	int irq;
> +	int ret;
> +
> +	dcmipp = devm_kzalloc(&pdev->dev, sizeof(struct dcmipp_device), GFP_KERNEL);

..., sizeof(*dcmipp), ...

> +	if (!dcmipp)
> +		return -ENOMEM;
> +
> +	dcmipp->dev = &pdev->dev;
> +
> +	pipe_cfg = of_device_get_match_data(&pdev->dev);
> +	if (!pipe_cfg) {
> +		dev_err(&pdev->dev, "Can't get device data\n");
> +		return -ENODEV;
> +	}
> +	dcmipp->pipe_cfg = pipe_cfg;
> +
> +	platform_set_drvdata(pdev, dcmipp);
> +
> +	/* Get hardware resources from devicetree */
> +	dcmipp->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
> +	if (IS_ERR(dcmipp->rstc))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(dcmipp->rstc),
> +				     "Could not get reset control\n");
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq <= 0) {
> +		if (irq != -EPROBE_DEFER)
> +			dev_err(&pdev->dev, "Could not get irq\n");
> +		return irq ? irq : -ENXIO;
> +	}
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res) {
> +		dev_err(&pdev->dev, "Could not get resource\n");
> +		return -ENODEV;
> +	}
> +
> +	dcmipp->regs = devm_ioremap_resource(&pdev->dev, res);

devm_platform_get_and_ioremap_resource()?

> +	if (IS_ERR(dcmipp->regs)) {
> +		dev_err(&pdev->dev, "Could not map registers\n");
> +		return PTR_ERR(dcmipp->regs);
> +	}
> +
> +	ret = devm_request_threaded_irq(&pdev->dev, irq, dcmipp_irq_callback,
> +					dcmipp_irq_thread, IRQF_ONESHOT,
> +					dev_name(&pdev->dev), dcmipp);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Unable to request irq %d\n", irq);
> +		return ret;
> +	}
> +
> +	/* Reset device */
> +	ret = reset_control_assert(dcmipp->rstc);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed to assert the reset line\n");
> +		return ret;
> +	}
> +
> +	usleep_range(3000, 5000);
> +
> +	ret = reset_control_deassert(dcmipp->rstc);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed to deassert the reset line\n");
> +		return ret;
> +	}
> +
> +	kclk = devm_clk_get(&pdev->dev, "kclk");
> +	if (IS_ERR(kclk))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(kclk),
> +				     "Unable to get kclk\n");
> +	dcmipp->kclk = kclk;
> +
> +	/* Create platform_device for each entity in the topology */
> +	dcmipp->subdevs = devm_kcalloc(&pdev->dev, dcmipp->pipe_cfg->num_ents,
> +				       sizeof(*dcmipp->subdevs), GFP_KERNEL);
> +	if (!dcmipp->subdevs)
> +		return -ENOMEM;
> +
> +	comp_match = dcmipp_add_subdevs(dcmipp);
> +	if (IS_ERR(comp_match))
> +		return PTR_ERR(comp_match);
> +
> +	/* Link the media device within the v4l2_device */
> +	dcmipp->v4l2_dev.mdev = &dcmipp->mdev;
> +
> +	/* Initialize media device */
> +	strscpy(dcmipp->mdev.model, DCMIPP_MDEV_MODEL_NAME,
> +		sizeof(dcmipp->mdev.model));
> +	snprintf(dcmipp->mdev.bus_info, sizeof(dcmipp->mdev.bus_info),
> +		 "platform:%s", DCMIPP_PDEV_NAME);

bus_info is set by media_device_init() nowadays.

> +	dcmipp->mdev.dev = &pdev->dev;
> +	media_device_init(&dcmipp->mdev);
> +
> +	/* Add self to the component system */
> +	ret = component_master_add_with_match(&pdev->dev, &dcmipp_comp_ops,
> +					      comp_match);
> +	if (ret) {
> +		media_device_cleanup(&dcmipp->mdev);
> +		dcmipp_rm_subdevs(dcmipp);
> +		return ret;
> +	}
> +
> +	pm_runtime_enable(dcmipp->dev);
> +
> +	dev_info(&pdev->dev, "Probe done");
> +
> +	return 0;
> +}
> +
> +static int dcmipp_remove(struct platform_device *pdev)
> +{
> +	struct dcmipp_device *dcmipp = platform_get_drvdata(pdev);
> +
> +	pm_runtime_disable(&pdev->dev);
> +
> +	component_master_del(&pdev->dev, &dcmipp_comp_ops);
> +	dcmipp_rm_subdevs(dcmipp);
> +
> +	return 0;
> +}
> +
> +static __maybe_unused int dcmipp_runtime_suspend(struct device *dev)
> +{
> +	struct dcmipp_device *dcmipp = dev_get_drvdata(dev);
> +
> +	clk_disable_unprepare(dcmipp->kclk);
> +
> +	return 0;
> +}
> +
> +static __maybe_unused int dcmipp_runtime_resume(struct device *dev)
> +{
> +	struct dcmipp_device *dcmipp = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = clk_prepare_enable(dcmipp->kclk);
> +	if (ret)
> +		dev_err(dev, "%s: Failed to prepare_enable k clock\n", __func__);
> +
> +	return ret;
> +}
> +
> +static __maybe_unused int dcmipp_suspend(struct device *dev)
> +{
> +	/* disable clock */
> +	pm_runtime_force_suspend(dev);
> +
> +	/* change pinctrl state */
> +	pinctrl_pm_select_sleep_state(dev);
> +
> +	return 0;
> +}
> +
> +static __maybe_unused int dcmipp_resume(struct device *dev)
> +{
> +	/* restore pinctl default state */
> +	pinctrl_pm_select_default_state(dev);
> +
> +	/* clock enable */
> +	pm_runtime_force_resume(dev);
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops dcmipp_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(dcmipp_suspend, dcmipp_resume)
> +	SET_RUNTIME_PM_OPS(dcmipp_runtime_suspend,
> +			   dcmipp_runtime_resume, NULL)
> +};
> +
> +static struct platform_driver dcmipp_pdrv = {
> +	.probe		= dcmipp_probe,
> +	.remove		= dcmipp_remove,
> +	.driver		= {
> +		.name	= DCMIPP_PDEV_NAME,
> +		.of_match_table = of_match_ptr(dcmipp_of_match),

Please don't use of_match_ptr().

> +		.pm = &dcmipp_pm_ops,
> +	},
> +};
> +
> +module_platform_driver(dcmipp_pdrv);
> +
> +MODULE_AUTHOR("Hugues Fruchet <hugues.fruchet@foss.st.com>");
> +MODULE_AUTHOR("Alain Volmat <alain.volmat@foss.st.com>");
> +MODULE_DESCRIPTION("STMicroelectronics STM32 Digital Camera Memory Interface with Pixel Processor driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-parallel.c b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-parallel.c
> new file mode 100644
> index 000000000000..37215791c01c
> --- /dev/null
> +++ b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-parallel.c
> @@ -0,0 +1,497 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for STM32 Digital Camera Memory Interface Pixel Processor
> + *
> + * Copyright (C) STMicroelectronics SA 2022
> + * Authors: Hugues Fruchet <hugues.fruchet@foss.st.com>
> + *          Alain Volmat <alain.volmat@foss.st.com>
> + *          for STMicroelectronics.
> + */
> +
> +#include <linux/component.h>
> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/platform_device.h>
> +#include <linux/v4l2-mediabus.h>
> +#include <linux/vmalloc.h>
> +#include <media/v4l2-event.h>
> +#include <media/v4l2-subdev.h>
> +
> +#include "dcmipp-common.h"
> +
> +#define DCMIPP_PAR_DRV_NAME "dcmipp-parallel"
> +
> +#define DCMIPP_PRCR (0x104)
> +#define DCMIPP_PRCR_FORMAT_SHIFT 16
> +#define DCMIPP_PRCR_FORMAT_YUV422 0x1E
> +#define DCMIPP_PRCR_FORMAT_RGB565 0x22
> +#define DCMIPP_PRCR_FORMAT_RAW8 0x2A
> +#define DCMIPP_PRCR_FORMAT_G8 0x4A
> +#define DCMIPP_PRCR_FORMAT_BYTE_STREAM 0x5A
> +#define DCMIPP_PRCR_ESS BIT(4)
> +#define DCMIPP_PRCR_PCKPOL BIT(5)
> +#define DCMIPP_PRCR_HSPOL BIT(6)
> +#define DCMIPP_PRCR_VSPOL BIT(7)
> +#define DCMIPP_PRCR_ENABLE BIT(14)
> +#define DCMIPP_PRCR_SWAPCYCLES BIT(25)
> +#define DCMIPP_PRCR_SWAPBITS BIT(26)
> +
> +#define DCMIPP_PRESCR (0x108)
> +#define DCMIPP_PRESUR (0x10c)
> +
> +#define IS_SINK(pad) (!(pad))
> +#define IS_SRC(pad)  ((pad))
> +
> +#define PAR_MEDIA_BUS_FMT_DEFAULT MEDIA_BUS_FMT_RGB565_2X8_LE
> +
> +struct dcmipp_par_pix_map {
> +	unsigned int code_sink;
> +	unsigned int code_src;
> +	u8 prcr_format;
> +	u8 prcr_swapbits;
> +	u8 prcr_swapcycles;
> +};
> +
> +#define PIXMAP_SINK_SRC_PRCR_SWAP(sink, src, prcr, swap)	\
> +		{						\
> +			.code_sink = MEDIA_BUS_FMT_##sink,		\
> +			.code_src = MEDIA_BUS_FMT_##src,		\
> +			.prcr_format = DCMIPP_PRCR_FORMAT_##prcr,	\
> +			.prcr_swapcycles = swap,		\
> +		}
> +static const struct dcmipp_par_pix_map dcmipp_par_pix_map_list[] = {
> +	/* RGB565 */
> +	PIXMAP_SINK_SRC_PRCR_SWAP(RGB565_2X8_LE, RGB565_2X8_LE, RGB565, 1),
> +	PIXMAP_SINK_SRC_PRCR_SWAP(RGB565_2X8_BE, RGB565_2X8_LE, RGB565, 0),
> +	/* YUV422 */
> +	PIXMAP_SINK_SRC_PRCR_SWAP(YUYV8_2X8, YUYV8_2X8, YUV422, 1),
> +	PIXMAP_SINK_SRC_PRCR_SWAP(YUYV8_2X8, UYVY8_2X8, YUV422, 0),
> +	PIXMAP_SINK_SRC_PRCR_SWAP(UYVY8_2X8, UYVY8_2X8, YUV422, 1),
> +	PIXMAP_SINK_SRC_PRCR_SWAP(UYVY8_2X8, YUYV8_2X8, YUV422, 0),
> +	PIXMAP_SINK_SRC_PRCR_SWAP(YVYU8_2X8, YVYU8_2X8, YUV422, 1),
> +	PIXMAP_SINK_SRC_PRCR_SWAP(VYUY8_2X8, VYUY8_2X8, YUV422, 1),
> +	/* GREY */
> +	PIXMAP_SINK_SRC_PRCR_SWAP(Y8_1X8, Y8_1X8, G8, 0),
> +	/* Raw Bayer */
> +	PIXMAP_SINK_SRC_PRCR_SWAP(SBGGR8_1X8, SBGGR8_1X8, RAW8, 0),
> +	PIXMAP_SINK_SRC_PRCR_SWAP(SGBRG8_1X8, SGBRG8_1X8, RAW8, 0),
> +	PIXMAP_SINK_SRC_PRCR_SWAP(SGRBG8_1X8, SGRBG8_1X8, RAW8, 0),
> +	PIXMAP_SINK_SRC_PRCR_SWAP(SRGGB8_1X8, SRGGB8_1X8, RAW8, 0),
> +	/* JPEG */
> +	PIXMAP_SINK_SRC_PRCR_SWAP(JPEG_1X8, JPEG_1X8, BYTE_STREAM, 0),
> +};
> +
> +/*
> + * Search through the pix_map table, skipping two consecutive entry with the
> + * same code
> + */
> +static inline const struct dcmipp_par_pix_map *dcmipp_par_pix_map_by_index
> +						(unsigned int index,
> +						 unsigned int pad)
> +{
> +	const struct dcmipp_par_pix_map *l = dcmipp_par_pix_map_list;
> +	unsigned int size = ARRAY_SIZE(dcmipp_par_pix_map_list);
> +	unsigned int i = 0;
> +	u32 prev_code = 0, cur_code;
> +
> +	while (i < size) {
> +		if (IS_SRC(pad))
> +			cur_code = l[i].code_src;
> +		else
> +			cur_code = l[i].code_sink;
> +
> +		if (cur_code == prev_code) {
> +			i++;
> +			continue;
> +		} else {

Else is useless.

> +			prev_code = cur_code;
> +		}
> +
> +		if (index == 0)
> +			break;
> +		i++;
> +		index--;
> +	}
> +
> +	if (i >= size)
> +		return NULL;
> +
> +	return &l[i];
> +}
> +
> +static inline const struct dcmipp_par_pix_map *dcmipp_par_pix_map_by_code
> +					(u32 code_sink, u32 code_src)
> +{
> +	const struct dcmipp_par_pix_map *l = dcmipp_par_pix_map_list;
> +	unsigned int size = ARRAY_SIZE(dcmipp_par_pix_map_list);
> +	unsigned int i;
> +
> +	for (i = 0; i < size; i++) {
> +		if ((l[i].code_sink == code_sink && l[i].code_src == code_src) ||
> +		    (l[i].code_sink == code_src && l[i].code_src == code_sink) ||
> +		    (l[i].code_sink == code_sink && code_src == 0) ||
> +		    (code_sink == 0 && l[i].code_src == code_src))
> +			return &l[i];
> +	}
> +	return NULL;
> +}
> +
> +struct dcmipp_par_device {
> +	struct dcmipp_ent_device ved;
> +	struct v4l2_subdev sd;
> +	struct device *dev;
> +	/* The active format */
> +	struct v4l2_mbus_framefmt sink_format;
> +	struct v4l2_mbus_framefmt src_format;
> +	bool streaming;
> +	void __iomem			*regs;
> +};
> +
> +static const struct v4l2_mbus_framefmt fmt_default = {
> +	.width = DCMIPP_FMT_WIDTH_DEFAULT,
> +	.height = DCMIPP_FMT_HEIGHT_DEFAULT,
> +	.code = PAR_MEDIA_BUS_FMT_DEFAULT,
> +	.field = V4L2_FIELD_NONE,
> +	.colorspace = DCMIPP_COLORSPACE_DEFAULT,
> +	.ycbcr_enc = DCMIPP_YCBCR_ENC_DEFAULT,
> +	.quantization = DCMIPP_QUANTIZATION_DEFAULT,
> +	.xfer_func = DCMIPP_XFER_FUNC_DEFAULT,
> +};
> +
> +static int dcmipp_par_init_cfg(struct v4l2_subdev *sd,
> +			       struct v4l2_subdev_state *sd_state)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < sd->entity.num_pads; i++) {
> +		struct v4l2_mbus_framefmt *mf;
> +
> +		mf = v4l2_subdev_get_try_format(sd, sd_state, i);
> +		*mf = fmt_default;
> +	}
> +
> +	return 0;
> +}
> +
> +static int dcmipp_par_enum_mbus_code(struct v4l2_subdev *sd,
> +				     struct v4l2_subdev_state *sd_state,
> +				     struct v4l2_subdev_mbus_code_enum *code)
> +{
> +	const struct dcmipp_par_pix_map *vpix =
> +		dcmipp_par_pix_map_by_index(code->index, code->pad);
> +
> +	if (!vpix)
> +		return -EINVAL;
> +
> +	code->code = IS_SRC(code->pad) ? vpix->code_src : vpix->code_sink;
> +
> +	return 0;
> +}
> +
> +static int dcmipp_par_enum_frame_size(struct v4l2_subdev *sd,
> +				      struct v4l2_subdev_state *sd_state,
> +				      struct v4l2_subdev_frame_size_enum *fse)
> +{
> +	const struct dcmipp_par_pix_map *vpix;
> +
> +	if (fse->index)
> +		return -EINVAL;
> +
> +	/* Only accept code in the pix map table */
> +	vpix = dcmipp_par_pix_map_by_code(IS_SINK(fse->pad) ? fse->code : 0,
> +					  IS_SRC(fse->pad) ? fse->code : 0);
> +	if (!vpix)
> +		return -EINVAL;
> +
> +	fse->min_width = DCMIPP_FRAME_MIN_WIDTH;
> +	fse->max_width = DCMIPP_FRAME_MAX_WIDTH;
> +	fse->min_height = DCMIPP_FRAME_MIN_HEIGHT;
> +	fse->max_height = DCMIPP_FRAME_MAX_HEIGHT;
> +
> +	return 0;
> +}
> +
> +static int dcmipp_par_get_fmt(struct v4l2_subdev *sd,
> +			      struct v4l2_subdev_state *sd_state,
> +			      struct v4l2_subdev_format *fmt)
> +{
> +	struct dcmipp_par_device *par =
> +				container_of(sd, struct dcmipp_par_device, sd);
> +
> +	fmt->format = fmt->which == V4L2_SUBDEV_FORMAT_TRY ?
> +		      *v4l2_subdev_get_try_format(sd, sd_state, fmt->pad) :
> +		      (IS_SRC(fmt->pad) ? par->src_format : par->sink_format);
> +
> +	return 0;
> +}
> +
> +static void dcmipp_par_adjust_fmt(struct dcmipp_par_device *par,
> +				  struct v4l2_mbus_framefmt *fmt, __u32 pad)
> +{
> +	const struct dcmipp_par_pix_map *vpix;
> +
> +	/* Only accept code in the pix map table */
> +	vpix = dcmipp_par_pix_map_by_code(IS_SINK(pad) ? fmt->code : 0,
> +					  IS_SRC(pad) ? fmt->code : 0);
> +	if (!vpix)
> +		fmt->code = fmt_default.code;
> +
> +	/* Exclude JPEG if BT656 bus is selected */
> +	if (vpix && vpix->code_sink == MEDIA_BUS_FMT_JPEG_1X8 &&
> +	    par->ved.bus_type == V4L2_MBUS_BT656)
> +		fmt->code = fmt_default.code;
> +
> +	fmt->width = clamp_t(u32, fmt->width, DCMIPP_FRAME_MIN_WIDTH,
> +			     DCMIPP_FRAME_MAX_WIDTH) & ~1;
> +	fmt->height = clamp_t(u32, fmt->height, DCMIPP_FRAME_MIN_HEIGHT,
> +			      DCMIPP_FRAME_MAX_HEIGHT) & ~1;
> +
> +	if (fmt->field == V4L2_FIELD_ANY || fmt->field == V4L2_FIELD_ALTERNATE)
> +		fmt->field = fmt_default.field;
> +
> +	dcmipp_colorimetry_clamp(fmt);
> +}
> +
> +static int dcmipp_par_set_fmt(struct v4l2_subdev *sd,
> +			      struct v4l2_subdev_state *sd_state,
> +			      struct v4l2_subdev_format *fmt)
> +{
> +	struct dcmipp_par_device *par = v4l2_get_subdevdata(sd);
> +	struct v4l2_mbus_framefmt *mf;
> +
> +	if (fmt->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> +		/* Do not change the format while stream is on */
> +		if (par->streaming)
> +			return -EBUSY;
> +
> +		mf = IS_SRC(fmt->pad) ? &par->src_format : &par->sink_format;
> +	} else {
> +		mf = v4l2_subdev_get_try_format(sd, sd_state, fmt->pad);
> +	}
> +
> +	/* Set the new format */
> +	dcmipp_par_adjust_fmt(par, &fmt->format, fmt->pad);
> +
> +	dev_dbg(par->dev, "%s: format update: old:%dx%d (0x%x, %d, %d, %d, %d) new:%dx%d (0x%x, %d, %d, %d, %d)\n",
> +		par->sd.name,
> +		/* old */
> +		mf->width, mf->height, mf->code,
> +		mf->colorspace,	mf->quantization,
> +		mf->xfer_func, mf->ycbcr_enc,
> +		/* new */
> +		fmt->format.width, fmt->format.height, fmt->format.code,
> +		fmt->format.colorspace, fmt->format.quantization,
> +		fmt->format.xfer_func, fmt->format.ycbcr_enc);
> +
> +	*mf = fmt->format;
> +
> +	/* When setting the sink format, report that format on the src pad as well */
> +	if (IS_SINK(fmt->pad))
> +		par->src_format = fmt->format;
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_subdev_pad_ops dcmipp_par_pad_ops = {
> +	.init_cfg		= dcmipp_par_init_cfg,
> +	.enum_mbus_code		= dcmipp_par_enum_mbus_code,
> +	.enum_frame_size	= dcmipp_par_enum_frame_size,
> +	.get_fmt		= dcmipp_par_get_fmt,
> +	.set_fmt		= dcmipp_par_set_fmt,
> +};
> +
> +static int dcmipp_par_configure(struct dcmipp_par_device *par)
> +{
> +	u32 val = 0;
> +	const struct dcmipp_par_pix_map *vpix;
> +
> +	/* Set vertical synchronization polarity */
> +	if (par->ved.bus.flags & V4L2_MBUS_VSYNC_ACTIVE_HIGH)
> +		val |= DCMIPP_PRCR_VSPOL;
> +
> +	/* Set horizontal synchronization polarity */
> +	if (par->ved.bus.flags & V4L2_MBUS_HSYNC_ACTIVE_HIGH)
> +		val |= DCMIPP_PRCR_HSPOL;
> +
> +	/* Set pixel clock polarity */
> +	if (par->ved.bus.flags & V4L2_MBUS_PCLK_SAMPLE_RISING)
> +		val |= DCMIPP_PRCR_PCKPOL;
> +
> +	/*
> +	 * BT656 embedded synchronisation bus mode.
> +	 *
> +	 * Default SAV/EAV mode is supported here with default codes
> +	 * SAV=0xff000080 & EAV=0xff00009d.
> +	 * With DCMIPP this means LSC=SAV=0x80 & LEC=EAV=0x9d.
> +	 */
> +	if (par->ved.bus_type == V4L2_MBUS_BT656) {
> +		val |= DCMIPP_PRCR_ESS;
> +
> +		/* Unmask all codes */
> +		reg_write(par, DCMIPP_PRESUR, 0xffffffff);/* FEC:LEC:LSC:FSC */
> +
> +		/* Trig on LSC=0x80 & LEC=0x9d codes, ignore FSC and FEC */
> +		reg_write(par, DCMIPP_PRESCR, 0xff9d80ff);/* FEC:LEC:LSC:FSC */
> +	}
> +
> +	/* Set format */
> +	vpix = dcmipp_par_pix_map_by_code(par->sink_format.code,
> +					  par->src_format.code);
> +	if (!vpix) {
> +		dev_err(par->dev, "Invalid sink/src format configuration\n");
> +		return -EINVAL;
> +	}
> +
> +	val |= vpix->prcr_format << DCMIPP_PRCR_FORMAT_SHIFT;
> +
> +	/* swap LSB vs MSB within one cycle */
> +	if (vpix->prcr_swapbits)
> +		val |= DCMIPP_PRCR_SWAPBITS;
> +
> +	/* swap cycles */
> +	if (vpix->prcr_swapcycles)
> +		val |= DCMIPP_PRCR_SWAPCYCLES;
> +
> +	reg_write(par, DCMIPP_PRCR, val);
> +
> +	return 0;
> +}
> +
> +static int dcmipp_par_s_stream(struct v4l2_subdev *sd, int enable)
> +{
> +	struct dcmipp_par_device *par =
> +				container_of(sd, struct dcmipp_par_device, sd);
> +	int ret = 0;
> +
> +	if (enable) {
> +		ret = dcmipp_par_configure(par);
> +		if (ret)
> +			return ret;
> +
> +		/* Enable parallel interface */
> +		reg_set(par, DCMIPP_PRCR, DCMIPP_PRCR_ENABLE);
> +	} else {
> +		/* Disable parallel interface */
> +		reg_clear(par, DCMIPP_PRCR, DCMIPP_PRCR_ENABLE);
> +	}
> +
> +	par->streaming = enable;
> +	return ret;
> +}
> +
> +static const struct v4l2_subdev_video_ops dcmipp_par_video_ops = {
> +	.s_stream = dcmipp_par_s_stream,
> +};
> +
> +static const struct v4l2_subdev_ops dcmipp_par_ops = {
> +	.pad = &dcmipp_par_pad_ops,
> +	.video = &dcmipp_par_video_ops,
> +};
> +
> +static void dcmipp_par_release(struct v4l2_subdev *sd)
> +{
> +	struct dcmipp_par_device *par =
> +				container_of(sd, struct dcmipp_par_device, sd);
> +
> +	kfree(par);
> +}
> +
> +static const struct v4l2_subdev_internal_ops dcmipp_par_int_ops = {
> +	.release = dcmipp_par_release,
> +};
> +
> +static void dcmipp_par_comp_unbind(struct device *comp, struct device *master,
> +				   void *master_data)
> +{
> +	struct dcmipp_ent_device *ved = dev_get_drvdata(comp);
> +	struct dcmipp_par_device *par =
> +			container_of(ved, struct dcmipp_par_device, ved);
> +
> +	dcmipp_ent_sd_unregister(ved, &par->sd);
> +}
> +
> +static int dcmipp_par_comp_bind(struct device *comp, struct device *master,
> +				void *master_data)
> +{
> +	struct dcmipp_bind_data *bind_data = master_data;
> +	struct dcmipp_platform_data *pdata = comp->platform_data;
> +	struct dcmipp_par_device *par;
> +	int ret;
> +
> +	/* Allocate the par struct */
> +	par = kzalloc(sizeof(*par), GFP_KERNEL);
> +	if (!par)
> +		return -ENOMEM;
> +
> +	par->regs = bind_data->regs;
> +
> +	/* Initialize ved and sd */
> +	ret = dcmipp_ent_sd_register
> +		(&par->ved, &par->sd, bind_data->v4l2_dev,
> +		 pdata->entity_name,
> +		 MEDIA_ENT_F_VID_IF_BRIDGE, 2,
> +		 (const unsigned long[2]) {
> +		  MEDIA_PAD_FL_SINK,
> +		  MEDIA_PAD_FL_SOURCE,
> +		  },
> +		 &dcmipp_par_int_ops, &dcmipp_par_ops,
> +		 NULL, NULL);
> +	if (ret)
> +		goto err_free_hdl;
> +
> +	dev_set_drvdata(comp, &par->ved);
> +	par->dev = comp;
> +
> +	/* Initialize the frame format */
> +	par->sink_format = fmt_default;
> +	par->src_format = fmt_default;
> +
> +	return 0;
> +
> +err_free_hdl:
> +	kfree(par);
> +
> +	return ret;
> +}
> +
> +static const struct component_ops dcmipp_par_comp_ops = {
> +	.bind = dcmipp_par_comp_bind,
> +	.unbind = dcmipp_par_comp_unbind,
> +};
> +
> +static int dcmipp_par_probe(struct platform_device *pdev)
> +{
> +	return component_add(&pdev->dev, &dcmipp_par_comp_ops);
> +}
> +
> +static int dcmipp_par_remove(struct platform_device *pdev)
> +{
> +	component_del(&pdev->dev, &dcmipp_par_comp_ops);
> +
> +	return 0;
> +}
> +
> +static const struct platform_device_id dcmipp_par_driver_ids[] = {
> +	{
> +		.name           = DCMIPP_PAR_DRV_NAME,
> +	},
> +	{ }
> +};
> +
> +static struct platform_driver dcmipp_par_pdrv = {
> +	.probe		= dcmipp_par_probe,
> +	.remove		= dcmipp_par_remove,
> +	.id_table	= dcmipp_par_driver_ids,
> +	.driver		= {
> +		.name	= DCMIPP_PAR_DRV_NAME,
> +	},
> +};
> +
> +module_platform_driver(dcmipp_par_pdrv);
> +
> +MODULE_DEVICE_TABLE(platform, dcmipp_par_driver_ids);
> +
> +MODULE_AUTHOR("Hugues Fruchet <hugues.fruchet@foss.st.com>");
> +MODULE_AUTHOR("Alain Volmat <hugues.fruchet@foss.st.com>");
> +MODULE_DESCRIPTION("STMicroelectronics STM32 Digital Camera Memory Interface with Pixel Processor driver");
> +MODULE_LICENSE("GPL");

-- 
Kind regards,

Sakari Ailus