Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Message-ID: <33f9ab8ea253c01d3311346bc871d7f62213215f.camel@puri.sm>
Subject: Re: [PATCH v6 2/3] media: imx: add a driver for i.MX8MQ mipi csi rx
 phy and controller
From:   Martin Kepplinger <martin.kepplinger@puri.sm>
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc:     festevam@gmail.com, krzk@kernel.org, devicetree@vger.kernel.org,
        kernel@pengutronix.de, kernel@puri.sm,
        linux-arm-kernel@lists.infradead.org, linux-imx@nxp.com,
        linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
        linux-staging@lists.linux.dev, m.felsch@pengutronix.de,
        mchehab@kernel.org, phone-devel@vger.kernel.org, robh@kernel.org,
        shawnguo@kernel.org, slongerbeam@gmail.com
Date:   Thu, 15 Jul 2021 08:49:51 +0200
In-Reply-To: <YO8r6pZAduu1ZMK4@pendragon.ideasonboard.com>
References: <20210714111931.324485-1-martin.kepplinger@puri.sm>
         <20210714111931.324485-3-martin.kepplinger@puri.sm>
         <YO8r6pZAduu1ZMK4@pendragon.ideasonboard.com>
Content-Type: text/plain; charset="UTF-8"
User-Agent: Evolution 3.38.3-1 
Content-Transfer-Encoding: 8bit
Precedence: bulk

Am Mittwoch, dem 14.07.2021 um 21:24 +0300 schrieb Laurent Pinchart:
> Hi Martin,
> 
> Thank you for the patch.

thank you for reviewing.

> 
> On Wed, Jul 14, 2021 at 01:19:30PM +0200, Martin Kepplinger wrote:
> > Add a driver to support the i.MX8MQ MIPI CSI receiver. The hardware
> > side
> > is based on
> >  
> > https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/media/platform/imx8/mxc-mipi-csi2_yav.c?h=imx_5.4.70_2.3.0
> > 
> > It's built as part of VIDEO_IMX7_CSI because that's documented to
> > support
> > i.MX8M platforms. This driver adds i.MX8MQ support where currently
> > only the
> > i.MX8MM platform has been supported.
> > 
> > Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
> > ---
> >  drivers/staging/media/imx/Makefile           |   1 +
> >  drivers/staging/media/imx/imx8mq-mipi-csi2.c | 949
> > +++++++++++++++++++
> >  2 files changed, 950 insertions(+)
> >  create mode 100644 drivers/staging/media/imx/imx8mq-mipi-csi2.c
> > 
> > diff --git a/drivers/staging/media/imx/Makefile
> > b/drivers/staging/media/imx/Makefile
> > index 6ac33275cc97..19c2fc54d424 100644
> > --- a/drivers/staging/media/imx/Makefile
> > +++ b/drivers/staging/media/imx/Makefile
> > @@ -16,3 +16,4 @@ obj-$(CONFIG_VIDEO_IMX_CSI) += imx6-mipi-csi2.o
> >  
> >  obj-$(CONFIG_VIDEO_IMX7_CSI) += imx7-media-csi.o
> >  obj-$(CONFIG_VIDEO_IMX7_CSI) += imx7-mipi-csis.o
> > +obj-$(CONFIG_VIDEO_IMX7_CSI) += imx8mq-mipi-csi2.o
> > diff --git a/drivers/staging/media/imx/imx8mq-mipi-csi2.c
> > b/drivers/staging/media/imx/imx8mq-mipi-csi2.c
> > new file mode 100644
> > index 000000000000..949b3ef7a20a
> > --- /dev/null
> > +++ b/drivers/staging/media/imx/imx8mq-mipi-csi2.c
> > @@ -0,0 +1,949 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Freescale i.MX8MQ SoC series MIPI-CSI2 receiver driver
> 
> Maybe they should be called NXP these days :-)
> 
> > + *
> > + * Copyright (C) 2021 Purism SPC
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/delay.h>
> > +#include <linux/errno.h>
> > +#include <linux/interconnect.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/kernel.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/pm_runtime.h>
> > +#include <linux/regmap.h>
> > +#include <linux/regulator/consumer.h>
> > +#include <linux/reset.h>
> > +#include <linux/spinlock.h>
> > +
> > +#include <media/v4l2-common.h>
> > +#include <media/v4l2-device.h>
> > +#include <media/v4l2-fwnode.h>
> > +#include <media/v4l2-mc.h>
> > +#include <media/v4l2-subdev.h>
> > +
> > +#define MIPI_CSI2_DRIVER_NAME                  "imx8mq-mipi-csi2"
> > +#define
> > MIPI_CSI2_SUBDEV_NAME                  MIPI_CSI2_DRIVER_NAME
> > +
> > +#define MIPI_CSI2_PAD_SINK                     0
> > +#define MIPI_CSI2_PAD_SOURCE                   1
> > +#define MIPI_CSI2_PADS_NUM                     2
> > +
> > +#define MIPI_CSI2_DEF_PIX_WIDTH                        640
> > +#define MIPI_CSI2_DEF_PIX_HEIGHT               480
> > +
> > +/* Register map definition */
> > +
> > +/* i.MX8MQ CSI-2 controller CSR */
> > +#define CSI2RX_CFG_NUM_LANES                   0x100
> > +#define CSI2RX_CFG_DISABLE_DATA_LANES          0x104
> > +#define CSI2RX_BIT_ERR                         0x108
> > +#define CSI2RX_IRQ_STATUS                      0x10c
> > +#define CSI2RX_IRQ_MASK                                0x110
> > +#define CSI2RX_IRQ_MASK_ALL                    0x1ff
> > +#define CSI2RX_IRQ_MASK_ULPS_STATUS_CHANGE     0x8
> > +#define CSI2RX_ULPS_STATUS                     0x114
> > +#define CSI2RX_PPI_ERRSOT_HS                   0x118
> > +#define CSI2RX_PPI_ERRSOTSYNC_HS               0x11c
> > +#define CSI2RX_PPI_ERRESC                      0x120
> > +#define CSI2RX_PPI_ERRSYNCESC                  0x124
> > +#define CSI2RX_PPI_ERRCONTROL                  0x128
> > +#define CSI2RX_CFG_DISABLE_PAYLOAD_0           0x12c
> > +#define CSI2RX_CFG_VID_P_FIFO_SEND_LEVEL       0x188
> > +#define CSI2RX_CFG_DISABLE_PAYLOAD_1           0x130
> > +
> > +enum {
> > +       ST_POWERED      = 1,
> > +       ST_STREAMING    = 2,
> > +       ST_SUSPENDED    = 4,
> > +};
> > +
> > +static const char * const imx8mq_mipi_csi_clk_id[] = {
> > +       "core",
> > +       "esc",
> > +       "ui",
> > +};
> > +
> > +#define CSI2_NUM_CLKS  ARRAY_SIZE(imx8mq_mipi_csi_clk_id)
> > +
> > +#define        GPR_CSI2_1_RX_ENABLE            BIT(13)
> > +#define        GPR_CSI2_1_VID_INTFC_ENB        BIT(12)
> > +#define        GPR_CSI2_1_HSEL                 BIT(10)
> > +#define        GPR_CSI2_1_CONT_CLK_MODE        BIT(8)
> > +#define        GPR_CSI2_1_S_PRG_RXHS_SETTLE(x) (((x) & 0x3f) << 2)
> > +
> > +/*
> > + * The send level configures the number of entries that must
> > accumulate in
> > + * the Pixel FIFO before the data will be transferred to the video
> > output.
> > + * See  
> > https://community.nxp.com/t5/i-MX-Processors/IMX8M-MIPI-CSI-Host-Controller-send-level/m-p/864005/highlight/true#M131704
> > + */
> > +#define CSI2RX_SEND_LEVEL                      64
> > +
> > +struct csi_state {
> > +       struct device *dev;
> > +       void __iomem *regs;
> > +       struct clk_bulk_data clks[CSI2_NUM_CLKS];
> > +       struct reset_control *rst;
> > +       struct regulator *mipi_phy_regulator;
> > +
> > +       struct v4l2_subdev sd;
> > +       struct media_pad pads[MIPI_CSI2_PADS_NUM];
> > +       struct v4l2_async_notifier notifier;
> > +       struct v4l2_subdev *src_sd;
> > +
> > +       struct v4l2_fwnode_bus_mipi_csi2 bus;
> > +
> > +       struct mutex lock; /* Protect csi2_fmt, format_mbus, state,
> > hs_settle*/
> 
> Missing space before */
> 
> > +       const struct csi2_pix_format *csi2_fmt;
> > +       struct v4l2_mbus_framefmt format_mbus[MIPI_CSI2_PADS_NUM];
> > +       u32 state;
> > +       u32 hs_settle;
> > +
> > +       struct regmap *phy_gpr;
> > +       u8 phy_gpr_reg;
> > +
> > +       struct icc_path                 *icc_path;
> > +       s32                             icc_path_bw;
> > +};
> > +
> > +/* ---------------------------------------------------------------
> > --------------
> > + * Format helpers
> > + */
> > +
> > +struct csi2_pix_format {
> > +       u32 code;
> > +       u8 width;
> > +};
> > +
> > +static const struct csi2_pix_format imx8mq_mipi_csi_formats[] = {
> > +       /* RAW (Bayer and greyscale) formats. */
> > +       {
> > +               .code = MEDIA_BUS_FMT_SBGGR8_1X8,
> > +               .width = 8,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_SGBRG8_1X8,
> > +               .width = 8,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_SGRBG8_1X8,
> > +               .width = 8,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_SRGGB8_1X8,
> > +               .width = 8,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_Y8_1X8,
> > +               .width = 8,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_SBGGR10_1X10,
> > +               .width = 10,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_SGBRG10_1X10,
> > +               .width = 10,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_SGRBG10_1X10,
> > +               .width = 10,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_SRGGB10_1X10,
> > +               .width = 10,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_Y10_1X10,
> > +               .width = 10,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_SBGGR12_1X12,
> > +               .width = 12,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_SGBRG12_1X12,
> > +               .width = 12,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_SGRBG12_1X12,
> > +               .width = 12,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_SRGGB12_1X12,
> > +               .width = 12,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_Y12_1X12,
> > +               .width = 12,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_SBGGR14_1X14,
> > +               .width = 14,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_SGBRG14_1X14,
> > +               .width = 14,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_SGRBG14_1X14,
> > +               .width = 14,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_SRGGB14_1X14,
> > +               .width = 14,
> > +       }, {
> > +       /* YUV formats */
> > +               .code = MEDIA_BUS_FMT_YUYV8_2X8,
> > +               .width = 16,
> > +       }, {
> > +               .code = MEDIA_BUS_FMT_YUYV8_1X16,
> > +               .width = 16,
> > +       }
> > +};
> > +
> > +static const struct csi2_pix_format *find_csi2_format(u32 code)
> > +{
> > +       unsigned int i;
> > +
> > +       for (i = 0; i < ARRAY_SIZE(imx8mq_mipi_csi_formats); i++)
> > +               if (code == imx8mq_mipi_csi_formats[i].code)
> > +                       return &imx8mq_mipi_csi_formats[i];
> > +       return NULL;
> > +}
> > +
> > +/* ---------------------------------------------------------------
> > --------------
> > + * Hardware configuration
> > + */
> > +
> > +static inline void imx8mq_mipi_csi_write(struct csi_state *state,
> > u32 reg, u32 val)
> > +{
> > +       writel(val, state->regs + reg);
> > +}
> > +
> > +static int imx8mq_mipi_csi_sw_reset(struct csi_state *state)
> > +{
> > +       int ret;
> > +
> > +       ret = reset_control_assert(state->rst);
> 
> That's peculiar, is there no need to deassert reset ?

I tried different things here that would look more intuitive, but in
the end only this worked, which is directly taken from
https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/media/platform/imx8/mxc-mipi-csi2_yav.c?h=imx_5.4.70_2.3.0#n105
(actual register value read from DT) that results in exactly the same
register bits set like this assertation.