Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Wed, 14 Sep 2022 17:51:22 +0200
From:   Tommaso Merciai <tommaso.merciai@amarulasolutions.com>
To:     Mikhail Rudenko <mike.rudenko@gmail.com>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Jacopo Mondi <jacopo@jmondi.org>,
        Shawn Tu <shawnx.tu@intel.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Daniel Scally <djrscally@gmail.com>,
        Christian Hemp <c.hemp@phytec.de>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Marek Vasut <marex@denx.de>, linux-media@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] media: i2c: add support for ov4689
Message-ID: <20220914155122.GA9874@tom-ThinkPad-T14s-Gen-2i>
References: <20220911200147.375198-1-mike.rudenko@gmail.com>
 <20220911200147.375198-3-mike.rudenko@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20220911200147.375198-3-mike.rudenko@gmail.com>
Precedence: bulk

Hi Mikhail,
I do a first round on reviewing your driver :)

On Sun, Sep 11, 2022 at 11:01:35PM +0300, Mikhail Rudenko wrote:
> Add a V4L2 sub-device driver for OmniVision OV4689 image sensor. This
> is a 4 Mpx image sensor using the I2C bus for control and the CSI-2
> bus for data.
> 
> This driver supports following features:
> - manual exposure and analog gain control support
> - test pattern support
> - media controller support
> - runtime PM support
> - support following resolutions:
>   + 2688x1520 at 30 fps
> 
> The driver provides all mandatory V4L2 controls for compatibility with
> libcamera. The sensor supports 1/2/4-lane CSI-2 modes, but the driver
> implements 4 lane mode only at this moment.
> 
> Signed-off-by: Mikhail Rudenko <mike.rudenko@gmail.com>
> ---
>  MAINTAINERS                |   1 +
>  drivers/media/i2c/Kconfig  |  14 +
>  drivers/media/i2c/Makefile |   1 +
>  drivers/media/i2c/ov4689.c | 951 +++++++++++++++++++++++++++++++++++++
>  4 files changed, 967 insertions(+)
>  create mode 100644 drivers/media/i2c/ov4689.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 63c4844f26e6..1857f3864e1b 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -14529,6 +14529,7 @@ L:	linux-media@vger.kernel.org
>  S:	Maintained
>  T:	git git://linuxtv.org/media_tree.git
>  F:	Documentation/devicetree/bindings/media/i2c/ovti,ov4689.yaml
> +F:	drivers/media/i2c/ov5647.c
>  
>  OMNIVISION OV5640 SENSOR DRIVER
>  M:	Steve Longerbeam <slongerbeam@gmail.com>
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index fae2baabb773..4993e1ae2ea8 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -429,6 +429,20 @@ config VIDEO_OV2740
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called ov2740.
>  
> +config VIDEO_OV4689
> +	tristate "OmniVision OV4689 sensor support"
> +	depends on OF
> +	depends on GPIOLIB && VIDEO_DEV && I2C
> +	select MEDIA_CONTROLLER
> +	select VIDEO_V4L2_SUBDEV_API
> +	select V4L2_FWNODE
> +	help
> +	  This is a Video4Linux2 sensor-level driver for the OmniVision
> +	  OV4689 camera.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called ov4689.
> +
>  config VIDEO_OV5640
>  	tristate "OmniVision OV5640 sensor support"
>  	depends on OF
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index 3e1696963e7f..7446c0a1eed0 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -78,6 +78,7 @@ obj-$(CONFIG_VIDEO_OV2659) += ov2659.o
>  obj-$(CONFIG_VIDEO_OV2680) += ov2680.o
>  obj-$(CONFIG_VIDEO_OV2685) += ov2685.o
>  obj-$(CONFIG_VIDEO_OV2740) += ov2740.o
> +obj-$(CONFIG_VIDEO_OV4689) += ov4689.o
>  obj-$(CONFIG_VIDEO_OV5640) += ov5640.o
>  obj-$(CONFIG_VIDEO_OV5645) += ov5645.o
>  obj-$(CONFIG_VIDEO_OV5647) += ov5647.o
> diff --git a/drivers/media/i2c/ov4689.c b/drivers/media/i2c/ov4689.c
> new file mode 100644
> index 000000000000..9f05e812acf8
> --- /dev/null
> +++ b/drivers/media/i2c/ov4689.c
> @@ -0,0 +1,951 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ov4689 driver
> + *
> + * Copyright (C) 2017 Fuzhou Rockchip Electronics Co., Ltd.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/device.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regulator/consumer.h>
> +#include <media/media-entity.h>
> +#include <media/v4l2-async.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-subdev.h>
> +#include <media/v4l2-fwnode.h>
> +
> +#define CHIP_ID				0x004688
> +#define OV4689_REG_CHIP_ID		0x300a
> +
> +#define OV4689_XVCLK_FREQ		24000000
> +
> +#define OV4689_REG_CTRL_MODE		0x0100
> +#define OV4689_MODE_SW_STANDBY		0x0
> +#define OV4689_MODE_STREAMING		BIT(0)
> +
> +#define OV4689_REG_EXPOSURE		0x3500
> +#define OV4689_EXPOSURE_MIN		4
> +#define OV4689_EXPOSURE_STEP		1
> +#define OV4689_VTS_MAX			0x7fff
> +
> +#define OV4689_REG_GAIN_H		0x3508
> +#define OV4689_REG_GAIN_L		0x3509
> +#define OV4689_GAIN_H_MASK		0x07
> +#define OV4689_GAIN_H_SHIFT		8
> +#define OV4689_GAIN_L_MASK		0xff
> +#define OV4689_GAIN_MIN			0x10
> +#define OV4689_GAIN_MAX			0xf8
> +#define OV4689_GAIN_STEP		1
> +#define OV4689_GAIN_DEFAULT		0x10
> +
> +#define OV4689_REG_TEST_PATTERN		0x5040
> +#define OV4689_TEST_PATTERN_ENABLE	0x80
> +#define OV4689_TEST_PATTERN_DISABLE	0x0
> +
> +#define OV4689_REG_VTS			0x380e
> +
> +#define REG_NULL			0xFFFF
> +
> +#define OV4689_REG_VALUE_08BIT		1
> +#define OV4689_REG_VALUE_16BIT		2
> +#define OV4689_REG_VALUE_24BIT		3
> +
> +#define OV4689_LANES			4
> +#define OV4689_BITS_PER_SAMPLE		10
> +
> +static const char *const ov4689_supply_names[] = {
> +	"avdd", /* Analog power */
> +	"dovdd", /* Digital I/O power */
> +	"dvdd", /* Digital core power */
> +};
> +
> +#define OV4689_NUM_SUPPLIES ARRAY_SIZE(ov4689_supply_names)
> +
> +struct regval {
> +	u16 addr;
> +	u8 val;
> +};

What about use ov4689_mode_id? I think could be usefull for the future:

+ enum ov4689_mode_id {
+	OV4689_MODE_2688_1520 = 0,
+	OV4689_NUM_MODES,
+	};


> +
> +struct ov4689_mode {
+	enum ov4689_mode_id id;
> +	u32 width;
> +	u32 height;
> +	u32 max_fps;
> +	u32 hts_def;
> +	u32 vts_def;
> +	u32 exp_def;
> +	const struct regval *reg_list;
> +};
> +
> +struct ov4689 {
> +	struct i2c_client *client;
> +	struct clk *xvclk;
> +	struct gpio_desc *reset_gpio;
> +	struct gpio_desc *pwdn_gpio;
> +	struct regulator_bulk_data supplies[OV4689_NUM_SUPPLIES];
> +
> +	struct v4l2_subdev subdev;
> +	struct media_pad pad;
> +
> +	struct mutex mutex; /* lock to protect streaming, ctrls and cur_mode */
> +	bool streaming;
> +	struct v4l2_ctrl_handler ctrl_handler;
> +	struct v4l2_ctrl *exposure;
> +	struct v4l2_ctrl *anal_gain;
> +	struct v4l2_ctrl *digi_gain;
> +	struct v4l2_ctrl *hblank;
> +	struct v4l2_ctrl *vblank;
> +	struct v4l2_ctrl *test_pattern;
> +
> +	const struct ov4689_mode *cur_mode;
> +};
> +
> +#define to_ov4689(sd) container_of(sd, struct ov4689, subdev)
> +
> +/*
> + * Xclk 24Mhz
> + */
> +static const struct regval ov4689_global_regs[] = {
> +	{ REG_NULL, 0x00 },
> +};
> +
> +/*
> + * Xclk 24Mhz
> + * max_framerate 30fps
> + * mipi_datarate per lane 1008Mbps
> + */
> +static const struct regval ov4689_2688x1520_regs[] = {
> +	{0x0103, 0x01}, {0x3638, 0x00}, {0x0300, 0x00},
> +	{0x0302, 0x2a}, {0x0303, 0x00}, {0x0304, 0x03},
> +	{0x030b, 0x00}, {0x030d, 0x1e}, {0x030e, 0x04},
> +	{0x030f, 0x01}, {0x0312, 0x01}, {0x031e, 0x00},
> +	{0x3000, 0x20}, {0x3002, 0x00}, {0x3018, 0x72},
> +	{0x3020, 0x93}, {0x3021, 0x03}, {0x3022, 0x01},
> +	{0x3031, 0x0a}, {0x303f, 0x0c}, {0x3305, 0xf1},
> +	{0x3307, 0x04}, {0x3309, 0x29}, {0x3500, 0x00},
> +	{0x3501, 0x60}, {0x3502, 0x00}, {0x3503, 0x04},
> +	{0x3504, 0x00}, {0x3505, 0x00}, {0x3506, 0x00},
> +	{0x3507, 0x00}, {0x3508, 0x00}, {0x3509, 0x80},
> +	{0x350a, 0x00}, {0x350b, 0x00}, {0x350c, 0x00},
> +	{0x350d, 0x00}, {0x350e, 0x00}, {0x350f, 0x80},
> +	{0x3510, 0x00}, {0x3511, 0x00}, {0x3512, 0x00},
> +	{0x3513, 0x00}, {0x3514, 0x00}, {0x3515, 0x80},
> +	{0x3516, 0x00}, {0x3517, 0x00}, {0x3518, 0x00},
> +	{0x3519, 0x00}, {0x351a, 0x00}, {0x351b, 0x80},
> +	{0x351c, 0x00}, {0x351d, 0x00}, {0x351e, 0x00},
> +	{0x351f, 0x00}, {0x3520, 0x00}, {0x3521, 0x80},
> +	{0x3522, 0x08}, {0x3524, 0x08}, {0x3526, 0x08},
> +	{0x3528, 0x08}, {0x352a, 0x08}, {0x3602, 0x00},
> +	{0x3603, 0x40}, {0x3604, 0x02}, {0x3605, 0x00},
> +	{0x3606, 0x00}, {0x3607, 0x00}, {0x3609, 0x12},
> +	{0x360a, 0x40}, {0x360c, 0x08}, {0x360f, 0xe5},
> +	{0x3608, 0x8f}, {0x3611, 0x00}, {0x3613, 0xf7},
> +	{0x3616, 0x58}, {0x3619, 0x99}, {0x361b, 0x60},
> +	{0x361c, 0x7a}, {0x361e, 0x79}, {0x361f, 0x02},
> +	{0x3632, 0x00}, {0x3633, 0x10}, {0x3634, 0x10},
> +	{0x3635, 0x10}, {0x3636, 0x15}, {0x3646, 0x86},
> +	{0x364a, 0x0b}, {0x3700, 0x17}, {0x3701, 0x22},
> +	{0x3703, 0x10}, {0x370a, 0x37}, {0x3705, 0x00},
> +	{0x3706, 0x63}, {0x3709, 0x3c}, {0x370b, 0x01},
> +	{0x370c, 0x30}, {0x3710, 0x24}, {0x3711, 0x0c},
> +	{0x3716, 0x00}, {0x3720, 0x28}, {0x3729, 0x7b},
> +	{0x372a, 0x84}, {0x372b, 0xbd}, {0x372c, 0xbc},
> +	{0x372e, 0x52}, {0x373c, 0x0e}, {0x373e, 0x33},
> +	{0x3743, 0x10}, {0x3744, 0x88}, {0x3745, 0xc0},
> +	{0x374a, 0x43}, {0x374c, 0x00}, {0x374e, 0x23},
> +	{0x3751, 0x7b}, {0x3752, 0x84}, {0x3753, 0xbd},
> +	{0x3754, 0xbc}, {0x3756, 0x52}, {0x375c, 0x00},
> +	{0x3760, 0x00}, {0x3761, 0x00}, {0x3762, 0x00},
> +	{0x3763, 0x00}, {0x3764, 0x00}, {0x3767, 0x04},
> +	{0x3768, 0x04}, {0x3769, 0x08}, {0x376a, 0x08},
> +	{0x376b, 0x20}, {0x376c, 0x00}, {0x376d, 0x00},
> +	{0x376e, 0x00}, {0x3773, 0x00}, {0x3774, 0x51},
> +	{0x3776, 0xbd}, {0x3777, 0xbd}, {0x3781, 0x18},
> +	{0x3783, 0x25}, {0x3798, 0x1b}, {0x3800, 0x00},
> +	{0x3801, 0x08}, {0x3802, 0x00}, {0x3803, 0x04},
> +	{0x3804, 0x0a}, {0x3805, 0x97}, {0x3806, 0x05},
> +	{0x3807, 0xfb}, {0x3808, 0x0a}, {0x3809, 0x80},
> +	{0x380a, 0x05}, {0x380b, 0xf0}, {0x380c, 0x0a},
> +	{0x380d, 0x80}, {0x380e, 0x06}, {0x380f, 0x12},
> +	{0x3810, 0x00}, {0x3811, 0x08}, {0x3812, 0x00},
> +	{0x3813, 0x04}, {0x3814, 0x01}, {0x3815, 0x01},
> +	{0x3819, 0x01}, {0x3820, 0x00}, {0x3821, 0x06},
> +	{0x3829, 0x00}, {0x382a, 0x01}, {0x382b, 0x01},
> +	{0x382d, 0x7f}, {0x3830, 0x04}, {0x3836, 0x01},
> +	{0x3837, 0x00}, {0x3841, 0x02}, {0x3846, 0x08},
> +	{0x3847, 0x07}, {0x3d85, 0x36}, {0x3d8c, 0x71},
> +	{0x3d8d, 0xcb}, {0x3f0a, 0x00}, {0x4000, 0xf1},
> +	{0x4001, 0x40}, {0x4002, 0x04}, {0x4003, 0x14},
> +	{0x400e, 0x00}, {0x4011, 0x00}, {0x401a, 0x00},
> +	{0x401b, 0x00}, {0x401c, 0x00}, {0x401d, 0x00},
> +	{0x401f, 0x00}, {0x4020, 0x00}, {0x4021, 0x10},
> +	{0x4022, 0x07}, {0x4023, 0xcf}, {0x4024, 0x09},
> +	{0x4025, 0x60}, {0x4026, 0x09}, {0x4027, 0x6f},
> +	{0x4028, 0x00}, {0x4029, 0x02}, {0x402a, 0x06},
> +	{0x402b, 0x04}, {0x402c, 0x02}, {0x402d, 0x02},
> +	{0x402e, 0x0e}, {0x402f, 0x04}, {0x4302, 0xff},
> +	{0x4303, 0xff}, {0x4304, 0x00}, {0x4305, 0x00},
> +	{0x4306, 0x00}, {0x4308, 0x02}, {0x4500, 0x6c},
> +	{0x4501, 0xc4}, {0x4502, 0x40}, {0x4503, 0x01},
> +	{0x4601, 0xa7}, {0x4800, 0x04}, {0x4813, 0x08},
> +	{0x481f, 0x40}, {0x4829, 0x78}, {0x4837, 0x10},
> +	{0x4b00, 0x2a}, {0x4b0d, 0x00}, {0x4d00, 0x04},
> +	{0x4d01, 0x42}, {0x4d02, 0xd1}, {0x4d03, 0x93},
> +	{0x4d04, 0xf5}, {0x4d05, 0xc1}, {0x5000, 0xf3},
> +	{0x5001, 0x11}, {0x5004, 0x00}, {0x500a, 0x00},
> +	{0x500b, 0x00}, {0x5032, 0x00}, {0x5040, 0x00},
> +	{0x5050, 0x0c}, {0x5500, 0x00}, {0x5501, 0x10},
> +	{0x5502, 0x01}, {0x5503, 0x0f}, {0x8000, 0x00},
> +	{0x8001, 0x00}, {0x8002, 0x00}, {0x8003, 0x00},
> +	{0x8004, 0x00}, {0x8005, 0x00}, {0x8006, 0x00},
> +	{0x8007, 0x00}, {0x8008, 0x00}, {0x3638, 0x00},
> +	{REG_NULL, 0x00},
> +};
> +
> +static const struct ov4689_mode supported_modes[] = {
> +	{
+		.id = OV4689_MODE_2688_1520,
> +		.width = 2688,
> +		.height = 1520,
> +		.max_fps = 30,
> +		.exp_def = 0x0600,
> +		.hts_def = 0x0a80,
> +		.vts_def = 0x0612,
> +		.reg_list = ov4689_2688x1520_regs,
> +	},
> +};
> +
> +#define OV4689_LINK_FREQ_500MHZ 500000000
> +static const s64 link_freq_menu_items[] = { OV4689_LINK_FREQ_500MHZ };
> +
> +static const char *const ov4689_test_pattern_menu[] = {
> +	"Disabled",
> +	"Vertical Color Bar Type 1",
> +	"Vertical Color Bar Type 2",
> +	"Vertical Color Bar Type 3",
> +	"Vertical Color Bar Type 4"
> +};
> +
> +/* Write registers up to 4 at a time */
> +static int ov4689_write_reg(struct i2c_client *client, u16 reg, u32 len,
> +			    u32 val)
> +{
> +	u32 buf_i, val_i;
> +	__be32 val_be;
> +	u8 *val_p;
> +	u8 buf[6];
> +
> +	if (len > 4)
> +		return -EINVAL;
> +
> +	buf[0] = reg >> 8;
> +	buf[1] = reg & 0xff;
> +
> +	val_be = cpu_to_be32(val);
> +	val_p = (u8 *)&val_be;
> +	buf_i = 2;
> +	val_i = 4 - len;
> +
> +	while (val_i < 4)
> +		buf[buf_i++] = val_p[val_i++];
> +
> +	if (i2c_master_send(client, buf, len + 2) != len + 2)
> +		return -EIO;
> +
> +	return 0;
> +}
> +
> +static int ov4689_write_array(struct i2c_client *client,
> +			      const struct regval *regs)
> +{
> +	int ret = 0;
> +	u32 i;
> +
> +	for (i = 0; ret == 0 && regs[i].addr != REG_NULL; i++)
> +		ret = ov4689_write_reg(client, regs[i].addr,
> +				       OV4689_REG_VALUE_08BIT, regs[i].val);
> +
> +	return ret;
> +}
> +
> +/* Read registers up to 4 at a time */
> +static int ov4689_read_reg(struct i2c_client *client, u16 reg, unsigned int len,
> +			   u32 *val)
> +{
> +	__be16 reg_addr_be = cpu_to_be16(reg);
> +	struct i2c_msg msgs[2];
> +	__be32 data_be = 0;
> +	u8 *data_be_p;
> +	int ret;
> +
> +	if (len > 4 || !len)
> +		return -EINVAL;
> +
> +	data_be_p = (u8 *)&data_be;
> +	/* Write register address */
> +	msgs[0].addr = client->addr;
> +	msgs[0].flags = 0;
> +	msgs[0].len = 2;
> +	msgs[0].buf = (u8 *)&reg_addr_be;
> +
> +	/* Read data from register */
> +	msgs[1].addr = client->addr;
> +	msgs[1].flags = I2C_M_RD;
> +	msgs[1].len = len;
> +	msgs[1].buf = &data_be_p[4 - len];
> +
> +	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
> +	if (ret != ARRAY_SIZE(msgs))
> +		return -EIO;
> +
> +	*val = be32_to_cpu(data_be);
> +
> +	return 0;
> +}
> +
> +static void ov4689_fill_fmt(const struct ov4689_mode *mode,
> +			    struct v4l2_mbus_framefmt *fmt)
> +{
> +	fmt->code = MEDIA_BUS_FMT_SBGGR10_1X10;
> +	fmt->width = mode->width;
> +	fmt->height = mode->height;
> +	fmt->field = V4L2_FIELD_NONE;
> +}
> +
> +static int ov4689_set_fmt(struct v4l2_subdev *sd,
> +			  struct v4l2_subdev_state *sd_state,
> +			  struct v4l2_subdev_format *fmt)
> +{
> +	struct v4l2_mbus_framefmt *mbus_fmt = &fmt->format;
> +	struct ov4689 *ov4689 = to_ov4689(sd);
> +
> +	/* only one mode supported for now */
> +	ov4689_fill_fmt(ov4689->cur_mode, mbus_fmt);
> +
> +	return 0;
> +}
> +
> +static int ov4689_get_fmt(struct v4l2_subdev *sd,
> +			  struct v4l2_subdev_state *sd_state,
> +			  struct v4l2_subdev_format *fmt)
> +{
> +	struct v4l2_mbus_framefmt *mbus_fmt = &fmt->format;
> +	struct ov4689 *ov4689 = to_ov4689(sd);
> +
> +	/* only one mode supported for now */
> +	ov4689_fill_fmt(ov4689->cur_mode, mbus_fmt);
> +
> +	return 0;
> +}
> +
> +static int ov4689_enum_mbus_code(struct v4l2_subdev *sd,
> +				 struct v4l2_subdev_state *sd_state,
> +				 struct v4l2_subdev_mbus_code_enum *code)
> +{
> +	if (code->index != 0)
> +		return -EINVAL;
> +	code->code = MEDIA_BUS_FMT_SBGGR10_1X10;
> +
> +	return 0;
> +}
> +
> +static int ov4689_enum_frame_sizes(struct v4l2_subdev *sd,
> +				   struct v4l2_subdev_state *sd_state,
> +				   struct v4l2_subdev_frame_size_enum *fse)
> +{
> +	if (fse->index >= ARRAY_SIZE(supported_modes))
> +		return -EINVAL;
> +
> +	if (fse->code != MEDIA_BUS_FMT_SBGGR10_1X10)
> +		return -EINVAL;
> +
> +	fse->min_width = supported_modes[fse->index].width;
> +	fse->max_width = supported_modes[fse->index].width;
> +	fse->max_height = supported_modes[fse->index].height;
> +	fse->min_height = supported_modes[fse->index].height;
> +
> +	return 0;
> +}
> +
> +static int ov4689_enable_test_pattern(struct ov4689 *ov4689, u32 pattern)
> +{
> +	u32 val;
> +
> +	if (pattern)
> +		val = (pattern - 1) | OV4689_TEST_PATTERN_ENABLE;
> +	else
> +		val = OV4689_TEST_PATTERN_DISABLE;
> +
> +	return ov4689_write_reg(ov4689->client, OV4689_REG_TEST_PATTERN,
> +				OV4689_REG_VALUE_08BIT, val);
> +}
> +
> +static int ov4689_get_selection(struct v4l2_subdev *sd,
> +				struct v4l2_subdev_state *state,
> +				struct v4l2_subdev_selection *sel)
> +{
> +	if (sel->which != V4L2_SUBDEV_FORMAT_ACTIVE)
> +		return -EINVAL;
> +
> +	switch (sel->target) {
> +	case V4L2_SEL_TGT_CROP_BOUNDS:
> +		sel->r.top = 0;
> +		sel->r.left = 0;
> +		sel->r.width = 2720;
> +		sel->r.height = 1536;
> +		return 0;
> +	case V4L2_SEL_TGT_CROP:
> +	case V4L2_SEL_TGT_CROP_DEFAULT:
> +		sel->r.top = 8;
> +		sel->r.left = 16;
> +		sel->r.width = 2688;
> +		sel->r.height = 1520;
> +		return 0;
> +	}
> +	return -EINVAL;
> +}
> +
> +static int ov4689_s_stream(struct v4l2_subdev *sd, int on)
> +{
> +	struct ov4689 *ov4689 = to_ov4689(sd);
> +	struct i2c_client *client = ov4689->client;
> +	int ret = 0;
> +
> +	mutex_lock(&ov4689->mutex);
> +
> +	on = !!on;
> +	if (on == ov4689->streaming)
> +		goto unlock_and_return;
> +
> +	if (on) {
> +		ret = pm_runtime_resume_and_get(&client->dev);
> +		if (ret < 0)
> +			goto unlock_and_return;
> +
> +		ret = __v4l2_ctrl_handler_setup(&ov4689->ctrl_handler);
> +		if (ret) {
> +			pm_runtime_put(&client->dev);
> +			goto unlock_and_return;
> +		}
> +
> +		ret = ov4689_write_array(ov4689->client,
> +					 ov4689->cur_mode->reg_list);
> +		if (ret) {
> +			pm_runtime_put(&client->dev);
> +			goto unlock_and_return;
> +		}
> +
> +		ret = ov4689_write_reg(ov4689->client, OV4689_REG_CTRL_MODE,
> +				       OV4689_REG_VALUE_08BIT,
> +				       OV4689_MODE_STREAMING);
> +		if (ret) {
> +			pm_runtime_put(&client->dev);
> +			goto unlock_and_return;
> +		}
> +	} else {
> +		ov4689_write_reg(ov4689->client, OV4689_REG_CTRL_MODE,
> +				 OV4689_REG_VALUE_08BIT,
> +				 OV4689_MODE_SW_STANDBY);
> +		pm_runtime_put(&client->dev);
> +	}
> +
> +	ov4689->streaming = on;
> +
> +unlock_and_return:
> +	mutex_unlock(&ov4689->mutex);
> +
> +	return ret;
> +}
> +
> +/* Calculate the delay in us by clock rate and clock cycles */
> +static inline u32 ov4689_cal_delay(u32 cycles)
> +{
> +	return DIV_ROUND_UP(cycles, OV4689_XVCLK_FREQ / 1000 / 1000);
> +}
> +
> +static int __ov4689_power_on(struct ov4689 *ov4689)

Just a doubt on this name function. Why __ ? Is this name reserved for?

> +{
> +	struct device *dev = &ov4689->client->dev;
> +	u32 delay_us;
> +	int ret;
> +
> +	ret = clk_prepare_enable(ov4689->xvclk);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to enable xvclk\n");
> +		return ret;
> +	}
> +
> +	gpiod_set_value_cansleep(ov4689->reset_gpio, 1);
> +
> +	ret = regulator_bulk_enable(OV4689_NUM_SUPPLIES, ov4689->supplies);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to enable regulators\n");
> +		goto disable_clk;
> +	}
> +
> +	gpiod_set_value_cansleep(ov4689->reset_gpio, 0);
> +	usleep_range(500, 1000);
> +	gpiod_set_value_cansleep(ov4689->pwdn_gpio, 0);
> +
> +	/* 8192 cycles prior to first SCCB transaction */
> +	delay_us = ov4689_cal_delay(8192);
> +	usleep_range(delay_us, delay_us * 2);
> +
> +	return 0;
> +
> +disable_clk:
> +	clk_disable_unprepare(ov4689->xvclk);
> +
> +	return ret;
> +}
> +
> +static void __ov4689_power_off(struct ov4689 *ov4689)
> +{
> +	gpiod_set_value_cansleep(ov4689->pwdn_gpio, 1);
> +	clk_disable_unprepare(ov4689->xvclk);
> +	gpiod_set_value_cansleep(ov4689->reset_gpio, 1);
> +	regulator_bulk_disable(OV4689_NUM_SUPPLIES, ov4689->supplies);
> +}
> +
> +static int __maybe_unused ov4689_runtime_resume(struct device *dev)
> +{
> +	struct v4l2_subdev *sd = dev_get_drvdata(dev);
> +	struct ov4689 *ov4689 = to_ov4689(sd);
> +
> +	return __ov4689_power_on(ov4689);
> +}
> +
> +static int __maybe_unused ov4689_runtime_suspend(struct device *dev)
> +{
> +	struct v4l2_subdev *sd = dev_get_drvdata(dev);
> +	struct ov4689 *ov4689 = to_ov4689(sd);
> +
> +	__ov4689_power_off(ov4689);
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_VIDEO_V4L2_SUBDEV_API
> +static int ov4689_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> +	struct ov4689 *ov4689 = to_ov4689(sd);
> +	struct v4l2_mbus_framefmt *try_fmt;
> +
> +	mutex_lock(&ov4689->mutex);
> +
> +	try_fmt = v4l2_subdev_get_try_format(sd, fh->state, 0);
> +	/* Initialize try_fmt */
> +	ov4689_fill_fmt(&supported_modes[0], try_fmt);

In this way instead of use magic number we can use this:

	ov4689_fill_fmt(&supported_modes[OV4689_MODE_2688_1520], try_fmt);

> +
> +	mutex_unlock(&ov4689->mutex);
> +
> +	return 0;
> +}
> +#endif
> +
> +static const struct dev_pm_ops ov4689_pm_ops = {
> +	SET_RUNTIME_PM_OPS(ov4689_runtime_suspend, ov4689_runtime_resume, NULL)
> +};
> +
> +#ifdef CONFIG_VIDEO_V4L2_SUBDEV_API
> +static const struct v4l2_subdev_internal_ops ov4689_internal_ops = {
> +	.open = ov4689_open,
> +};
> +#endif
> +
> +static const struct v4l2_subdev_video_ops ov4689_video_ops = {
> +	.s_stream = ov4689_s_stream,
> +};
> +
> +static const struct v4l2_subdev_pad_ops ov4689_pad_ops = {
> +	.enum_mbus_code = ov4689_enum_mbus_code,
> +	.enum_frame_size = ov4689_enum_frame_sizes,
> +	.get_fmt = ov4689_get_fmt,
> +	.set_fmt = ov4689_set_fmt,
> +	.get_selection = ov4689_get_selection,
> +};
> +
> +static const struct v4l2_subdev_ops ov4689_subdev_ops = {
> +	.video = &ov4689_video_ops,
> +	.pad = &ov4689_pad_ops,
> +};
> +
> +static int ov4689_set_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +	struct ov4689 *ov4689 =
> +		container_of(ctrl->handler, struct ov4689, ctrl_handler);
> +	struct i2c_client *client = ov4689->client;
> +	s64 max_expo;
> +	int ret;
> +
> +	/* Propagate change of current control to all related controls */
> +	switch (ctrl->id) {
> +	case V4L2_CID_VBLANK:
> +		/* Update max exposure while meeting expected vblanking */
> +		max_expo = ov4689->cur_mode->height + ctrl->val - 4;
> +		__v4l2_ctrl_modify_range(ov4689->exposure,
> +					 ov4689->exposure->minimum, max_expo,
> +					 ov4689->exposure->step,
> +					 ov4689->exposure->default_value);
> +		break;
> +	}
> +
> +	if (!pm_runtime_get_if_in_use(&client->dev))
> +		return 0;
> +
> +	switch (ctrl->id) {
> +	case V4L2_CID_EXPOSURE:
> +		/* 4 least significant bits of expsoure are fractional part */
> +		ret = ov4689_write_reg(ov4689->client, OV4689_REG_EXPOSURE,
> +				       OV4689_REG_VALUE_24BIT, ctrl->val << 4);
> +		break;
> +	case V4L2_CID_ANALOGUE_GAIN:
> +		ret = ov4689_write_reg(ov4689->client, OV4689_REG_GAIN_H,
> +				       OV4689_REG_VALUE_08BIT,
> +				       (ctrl->val >> OV4689_GAIN_H_SHIFT) &
> +					       OV4689_GAIN_H_MASK);
> +		ret |= ov4689_write_reg(ov4689->client, OV4689_REG_GAIN_L,
> +					OV4689_REG_VALUE_08BIT,
> +					ctrl->val & OV4689_GAIN_L_MASK);
> +		break;
> +	case V4L2_CID_VBLANK:
> +		ret = ov4689_write_reg(ov4689->client, OV4689_REG_VTS,
> +				       OV4689_REG_VALUE_16BIT,
> +				       ctrl->val + ov4689->cur_mode->height);
> +		break;
> +	case V4L2_CID_TEST_PATTERN:
> +		ret = ov4689_enable_test_pattern(ov4689, ctrl->val);
> +		break;
> +	default:
> +		dev_warn(&client->dev, "%s Unhandled id:0x%x, val:0x%x\n",
> +			 __func__, ctrl->id, ctrl->val);
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	pm_runtime_put(&client->dev);
> +
> +	return ret;
> +}
> +
> +static const struct v4l2_ctrl_ops ov4689_ctrl_ops = {
> +	.s_ctrl = ov4689_set_ctrl,
> +};
> +
> +static int ov4689_initialize_controls(struct ov4689 *ov4689)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&ov4689->subdev);
> +	struct v4l2_fwnode_device_properties props;
> +	struct v4l2_ctrl_handler *handler;
> +	const struct ov4689_mode *mode;
> +	s64 exposure_max, vblank_def;
> +	struct v4l2_ctrl *ctrl;
> +	u32 h_blank, pixel_rate;
> +	int ret;
> +
> +	handler = &ov4689->ctrl_handler;
> +	mode = ov4689->cur_mode;
> +	ret = v4l2_ctrl_handler_init(handler, 10);
> +	if (ret)
> +		return ret;
> +	handler->lock = &ov4689->mutex;
> +
> +	ctrl = v4l2_ctrl_new_int_menu(handler, NULL, V4L2_CID_LINK_FREQ, 0, 0,
> +				      link_freq_menu_items);
> +	if (ctrl)
> +		ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +
> +	pixel_rate = (link_freq_menu_items[0] * 2 * OV4689_LANES) /
> +		     OV4689_BITS_PER_SAMPLE;
> +	v4l2_ctrl_new_std(handler, NULL, V4L2_CID_PIXEL_RATE, 0, pixel_rate, 1,
> +			  pixel_rate);
> +
> +	h_blank = mode->hts_def - mode->width;
> +	ov4689->hblank = v4l2_ctrl_new_std(handler, NULL, V4L2_CID_HBLANK,
> +					   h_blank, h_blank, 1, h_blank);
> +	if (ov4689->hblank)
> +		ov4689->hblank->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +
> +	vblank_def = mode->vts_def - mode->height;
> +	ov4689->vblank =
> +		v4l2_ctrl_new_std(handler, &ov4689_ctrl_ops, V4L2_CID_VBLANK,
> +				  vblank_def, OV4689_VTS_MAX - mode->height, 1,
> +				  vblank_def);
> +
> +	exposure_max = mode->vts_def - 4;
> +	ov4689->exposure =
> +		v4l2_ctrl_new_std(handler, &ov4689_ctrl_ops, V4L2_CID_EXPOSURE,
> +				  OV4689_EXPOSURE_MIN, exposure_max,
> +				  OV4689_EXPOSURE_STEP, mode->exp_def);
> +
> +	ov4689->anal_gain =
> +		v4l2_ctrl_new_std(handler, &ov4689_ctrl_ops,
> +				  V4L2_CID_ANALOGUE_GAIN, OV4689_GAIN_MIN,
> +				  OV4689_GAIN_MAX, OV4689_GAIN_STEP,
> +				  OV4689_GAIN_DEFAULT);
> +
> +	ov4689->test_pattern =
> +		v4l2_ctrl_new_std_menu_items(handler, &ov4689_ctrl_ops,
> +					     V4L2_CID_TEST_PATTERN,
> +					     ARRAY_SIZE(ov4689_test_pattern_menu) - 1,
> +					     0, 0, ov4689_test_pattern_menu);
> +
> +	if (handler->error) {
> +		ret = handler->error;
> +		dev_err(&ov4689->client->dev, "Failed to init controls(%d)\n",
> +			ret);
> +		goto err_free_handler;
> +	}
> +
> +	ret = v4l2_fwnode_device_parse(&client->dev, &props);
> +	if (ret)
> +		goto err_free_handler;
> +
> +	ret = v4l2_ctrl_new_fwnode_properties(handler, &ov4689_ctrl_ops,
> +					      &props);
> +	if (ret)
> +		goto err_free_handler;
> +
> +	ov4689->subdev.ctrl_handler = handler;
> +
> +	return 0;
> +
> +err_free_handler:
> +	v4l2_ctrl_handler_free(handler);
> +
> +	return ret;
> +}
> +
> +static int ov4689_check_sensor_id(struct ov4689 *ov4689,
> +				  struct i2c_client *client)
> +{
> +	struct device *dev = &ov4689->client->dev;
> +	u32 id = 0;
> +	int ret;
> +
> +	ret = ov4689_read_reg(client, OV4689_REG_CHIP_ID,
> +			      OV4689_REG_VALUE_16BIT, &id);
> +	if (id != CHIP_ID) {
> +		dev_err(dev, "Unexpected sensor id(%06x), ret(%d)\n", id, ret);
> +		return -ENODEV;
> +	}
> +
> +	dev_info(dev, "Detected OV%06x sensor\n", CHIP_ID);
> +
> +	return 0;
> +}
> +
> +static int ov4689_configure_regulators(struct ov4689 *ov4689)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < OV4689_NUM_SUPPLIES; i++)
> +		ov4689->supplies[i].supply = ov4689_supply_names[i];
> +
> +	return devm_regulator_bulk_get(&ov4689->client->dev,
> +				       OV4689_NUM_SUPPLIES, ov4689->supplies);
> +}
> +
> +static int ov4689_check_hwcfg(struct device *dev)
> +{
> +	struct fwnode_handle *fwnode = dev_fwnode(dev);
> +	struct v4l2_fwnode_endpoint bus_cfg = {
> +		.bus_type = V4L2_MBUS_CSI2_DPHY,
> +	};
> +	struct fwnode_handle *endpoint;
> +	unsigned int i;
> +	int ret;
> +
> +	endpoint = fwnode_graph_get_next_endpoint(fwnode, NULL);
> +	if (!endpoint)
> +		return -EPROBE_DEFER;
> +
> +	ret = v4l2_fwnode_endpoint_alloc_parse(endpoint, &bus_cfg);
> +	fwnode_handle_put(endpoint);
> +	if (ret)
> +		return ret;
> +
> +	if (bus_cfg.bus.mipi_csi2.num_data_lanes != 4) {
> +		dev_err(dev, "only a 4-lane CSI2 config is supported");
> +		ret = -EINVAL;
> +		goto out_free_bus_cfg;
> +	}
> +
> +	if (!bus_cfg.nr_of_link_frequencies) {
> +		dev_err(dev, "no link frequencies defined\n");
> +		ret = -EINVAL;
> +		goto out_free_bus_cfg;
> +	}
> +
> +	for (i = 0; i < bus_cfg.nr_of_link_frequencies; i++)
> +		if (bus_cfg.link_frequencies[i] == OV4689_LINK_FREQ_500MHZ)
> +			break;
> +
> +	if (i == bus_cfg.nr_of_link_frequencies) {
> +		dev_err(dev, "supported link freq %ull not found\n",
> +			OV4689_LINK_FREQ_500MHZ);
> +		ret = -EINVAL;
> +		goto out_free_bus_cfg;
> +	}
> +
> +out_free_bus_cfg:
> +	v4l2_fwnode_endpoint_free(&bus_cfg);
> +
> +	return ret;
> +}
> +
> +static int ov4689_probe(struct i2c_client *client,
> +			const struct i2c_device_id *id)

We are sure that we need need i2c_device_id *id?

> +{
> +	struct device *dev = &client->dev;
> +	struct v4l2_subdev *sd;
> +	struct ov4689 *ov4689;
> +	int ret;
> +
> +	ret = ov4689_check_hwcfg(dev);
> +	if (ret)
> +		return ret;
> +
> +	ov4689 = devm_kzalloc(dev, sizeof(*ov4689), GFP_KERNEL);
> +	if (!ov4689)
> +		return -ENOMEM;
> +
> +	ov4689->client = client;
> +	ov4689->cur_mode = &supported_modes[0];

Here aswell we can use:
	ov4689->cur_mode = &supported_modes[OV4689_MODE_2688_1520];

> +
> +	ov4689->xvclk = devm_clk_get(dev, "xvclk");
> +	if (IS_ERR(ov4689->xvclk)) {
> +		dev_err(dev, "Failed to get xvclk\n");
> +		return -EINVAL;
> +	}

^ I think is better to use devm_clk_get_optional instead of clck_get.
clck_get can fail in CPU's that use ACPI

> +
> +	ret = clk_set_rate(ov4689->xvclk, OV4689_XVCLK_FREQ);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to set xvclk rate (24MHz)\n");
> +		return ret;
> +	}
> +	if (clk_get_rate(ov4689->xvclk) != OV4689_XVCLK_FREQ)
> +		dev_warn(dev, "xvclk mismatched, modes are based on 24MHz\n");


What do you think about?
Thanks.

Regards,
Tommaso

> +
> +	ov4689->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> +	if (IS_ERR(ov4689->reset_gpio)) {
> +		dev_err(dev, "Failed to get reset-gpios\n");
> +		return -EINVAL;
> +	}
> +
> +	ov4689->pwdn_gpio = devm_gpiod_get(dev, "pwdn", GPIOD_OUT_LOW);
> +	if (IS_ERR(ov4689->pwdn_gpio)) {
> +		dev_err(dev, "Failed to get pwdn-gpios\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = ov4689_configure_regulators(ov4689);
> +	if (ret) {
> +		dev_err(dev, "Failed to get power regulators\n");
> +		return ret;
> +	}
> +
> +	mutex_init(&ov4689->mutex);
> +
> +	sd = &ov4689->subdev;
> +	v4l2_i2c_subdev_init(sd, client, &ov4689_subdev_ops);
> +	ret = ov4689_initialize_controls(ov4689);
> +	if (ret)
> +		goto err_destroy_mutex;
> +
> +	ret = __ov4689_power_on(ov4689);
> +	if (ret)
> +		goto err_free_handler;
> +
> +	ret = ov4689_check_sensor_id(ov4689, client);
> +	if (ret)
> +		goto err_power_off;
> +
> +#ifdef CONFIG_VIDEO_V4L2_SUBDEV_API
> +	sd->internal_ops = &ov4689_internal_ops;
> +	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +#endif
> +#if defined(CONFIG_MEDIA_CONTROLLER)
> +	ov4689->pad.flags = MEDIA_PAD_FL_SOURCE;
> +	sd->entity.function = MEDIA_ENT_F_CAM_SENSOR;
> +	ret = media_entity_pads_init(&sd->entity, 1, &ov4689->pad);
> +	if (ret < 0)
> +		goto err_power_off;
> +#endif
> +
> +	ret = v4l2_async_register_subdev_sensor(sd);
> +	if (ret) {
> +		dev_err(dev, "v4l2 async register subdev failed\n");
> +		goto err_clean_entity;
> +	}
> +
> +	pm_runtime_set_active(dev);
> +	pm_runtime_enable(dev);
> +	pm_runtime_idle(dev);
> +
> +	return 0;
> +
> +err_clean_entity:
> +#if defined(CONFIG_MEDIA_CONTROLLER)
> +	media_entity_cleanup(&sd->entity);
> +#endif
> +err_power_off:
> +	__ov4689_power_off(ov4689);
> +err_free_handler:
> +	v4l2_ctrl_handler_free(&ov4689->ctrl_handler);
> +err_destroy_mutex:
> +	mutex_destroy(&ov4689->mutex);
> +
> +	return ret;
> +}
> +
> +static int ov4689_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct ov4689 *ov4689 = to_ov4689(sd);
> +
> +	v4l2_async_unregister_subdev(sd);
> +#if defined(CONFIG_MEDIA_CONTROLLER)
> +	media_entity_cleanup(&sd->entity);
> +#endif
> +	v4l2_ctrl_handler_free(&ov4689->ctrl_handler);
> +	mutex_destroy(&ov4689->mutex);
> +
> +	pm_runtime_disable(&client->dev);
> +	if (!pm_runtime_status_suspended(&client->dev))
> +		__ov4689_power_off(ov4689);
> +	pm_runtime_set_suspended(&client->dev);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id ov4689_id[] = {
> +	{ "ov4689", 0 },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(i2c, ov4689_id);
> +
> +static const struct of_device_id ov4689_of_match[] = {
> +	{ .compatible = "ovti,ov4689" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, ov4689_of_match);
> +
> +static struct i2c_driver ov4689_i2c_driver = {
> +	.driver = {
> +		.name = "ov4689",
> +		.pm = &ov4689_pm_ops,
> +		.of_match_table = of_match_ptr(ov4689_of_match),
> +	},
> +	.probe = ov4689_probe,
> +	.remove	= ov4689_remove,
> +	.id_table = ov4689_id,
> +};
> +
> +module_i2c_driver(ov4689_i2c_driver);
> +
> +MODULE_DESCRIPTION("OmniVision ov4689 sensor driver");
> +MODULE_LICENSE("GPL");
> -- 
> 2.37.3
> 

-- 
Tommaso Merciai
Embedded Linux Engineer
tommaso.merciai@amarulasolutions.com
__________________________________

Amarula Solutions SRL
Via Le Canevare 30, 31100 Treviso, Veneto, IT
T. +39 042 243 5310
info@amarulasolutions.com
www.amarulasolutions.com