Re: [V3, 2/2] media: i2c: Add Omnivision OV02A10 camera sensor driver

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Hi Dongchun,

Thanks for the update.

On Mon, Aug 19, 2019 at 11:43:31AM +0800, dongchun.zhu@mediatek.com wrote:
> From: Dongchun Zhu <dongchun.zhu@mediatek.com>
> 
> This patch adds a V4L2 sub-device driver for OV02A10 image sensor.
> The OV02A10 is a 1/5" CMOS sensor from Omnivision,
> which supports output format: 10-bit Raw.
> The OV02A10 has a single MIPI lane interface and use the I2C bus
> for control and the CSI-2 bus for data.
> 
> Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
> ---
>  MAINTAINERS                 |    1 +
>  drivers/media/i2c/Kconfig   |   11 +
>  drivers/media/i2c/Makefile  |    1 +
>  drivers/media/i2c/ov02a10.c | 1018 +++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 1031 insertions(+)
>  create mode 100644 drivers/media/i2c/ov02a10.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 41734fb..4b714a2 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -11821,6 +11821,7 @@ M:	Dongchun Zhu <dongchun.zhu@mediatek.com>
>  L:	linux-media@vger.kernel.org
>  T:	git git://linuxtv.org/media_tree.git
>  S:	Maintained
> +F:	drivers/media/i2c/ov02a10.c
>  F:	Documentation/devicetree/bindings/media/i2c/ov02a10.txt
>  
>  OMNIVISION OV2680 SENSOR DRIVER
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 79ce9ec..d063a82 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -617,6 +617,17 @@ config VIDEO_IMX355
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called imx355.
>  
> +config VIDEO_OV02A10
> +	tristate "OmniVision OV02A10 sensor support"
> +	depends on I2C && VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
> +	depends on MEDIA_CAMERA_SUPPORT
> +	help
> +	  This is a Video4Linux2 sensor driver for the OmniVision
> +	  OV02A10 camera.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called ov02a10.
> +
>  config VIDEO_OV2640
>  	tristate "OmniVision OV2640 sensor support"
>  	depends on VIDEO_V4L2 && I2C
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index fd4ea86..f34a7ac 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -71,6 +71,7 @@ obj-$(CONFIG_VIDEO_OV5645) += ov5645.o
>  obj-$(CONFIG_VIDEO_OV5647) += ov5647.o
>  obj-$(CONFIG_VIDEO_OV5670) += ov5670.o
>  obj-$(CONFIG_VIDEO_OV5695) += ov5695.o
> +obj-$(CONFIG_VIDEO_OV02A10) += ov02a10.o
>  obj-$(CONFIG_VIDEO_OV6650) += ov6650.o
>  obj-$(CONFIG_VIDEO_OV7251) += ov7251.o
>  obj-$(CONFIG_VIDEO_OV7640) += ov7640.o
> diff --git a/drivers/media/i2c/ov02a10.c b/drivers/media/i2c/ov02a10.c
> new file mode 100644
> index 0000000..ff5460a
> --- /dev/null
> +++ b/drivers/media/i2c/ov02a10.c
> @@ -0,0 +1,1018 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2018 MediaTek Inc.
> + */
> +
> +#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>
> +
> +#define CHIP_ID                                         0x2509
> +#define OV02A10_REG_CHIP_ID_H                           0x02
> +#define OV02A10_REG_CHIP_ID_L                           0x03
> +#define OV02A10_ID(_msb, _lsb)                          ((_msb) << 8 | (_lsb))
> +
> +/* Bit[1] vertical upside down */
> +/* Bit[0] horizontal mirror */
> +#define REG_MIRROR_FLIP_CONTROL                         0x3f
> +
> +/* Orientation */
> +#define REG_CONFIG_MIRROR_FLIP		                0x03
> +
> +#define REG_PAGE_SWITCH                                 0xfd
> +#define REG_GLOBAL_EFFECTIVE                            0x01
> +#define REG_ENABLE                                      BIT(0)
> +
> +#define REG_SC_CTRL_MODE                                0xac
> +#define SC_CTRL_MODE_STANDBY                            0x00
> +#define SC_CTRL_MODE_STREAMING                          0x01
> +
> +#define OV02A10_REG_EXPOSURE_H                          0x03
> +#define OV02A10_REG_EXPOSURE_L                          0x04
> +#define	OV02A10_EXPOSURE_MIN                            4
> +#define	OV02A10_EXPOSURE_STEP                           1
> +
> +#define OV02A10_REG_VTS_H                               0x05
> +#define OV02A10_REG_VTS_L                               0x06
> +#define OV02A10_VTS_MAX                                 0x209f
> +#define OV02A10_VTS_MIN                                 0x04cf
> +#define OV02A10_BASIC_LINE				1224
> +
> +#define OV02A10_REG_GAIN                                0x24
> +#define OV02A10_GAIN_MIN                                0x10
> +#define OV02A10_GAIN_MAX                                0xf8
> +#define OV02A10_GAIN_STEP                               0x01
> +#define OV02A10_GAIN_DEFAULT                            0x40
> +
> +#define REG_NULL                                        0xff
> +
> +#define OV02A10_LANES                                   1
> +#define OV02A10_BITS_PER_SAMPLE                         10
> +
> +static const char * const ov02a10_supply_names[] = {
> +	"dovdd",	/* Digital I/O power */
> +	"avdd",		/* Analog power */
> +	"dvdd",		/* Digital core power */
> +};
> +
> +#define OV02A10_NUM_SUPPLIES ARRAY_SIZE(ov02a10_supply_names)
> +
> +struct regval {
> +	u16 addr;
> +	u8 val;
> +};
> +
> +struct ov02a10_mode {
> +	u32 width;
> +	u32 height;
> +	u32 exp_def;
> +	u32 hts_def;
> +	u32 vts_def;
> +	const struct regval *reg_list;
> +};
> +
> +struct ov02a10 {
> +	struct clk		*xvclk;
> +	struct gpio_desc	*powerdown_gpio;
> +	struct gpio_desc	*reset_gpio;
> +	struct regulator_bulk_data supplies[OV02A10_NUM_SUPPLIES];
> +
> +	bool			streaming;
> +	bool			upside_down;
> +
> +	/*
> +	 * Serialize control access, get/set format, get selection
> +	 * and start streaming.
> +	 */
> +	struct mutex		mutex;
> +	struct v4l2_subdev	subdev;
> +	struct media_pad	pad;
> +	struct v4l2_ctrl	*anal_gain;
> +	struct v4l2_ctrl	*exposure;
> +	struct v4l2_ctrl	*hblank;
> +	struct v4l2_ctrl	*vblank;
> +	struct v4l2_ctrl	*hflip;
> +	struct v4l2_ctrl	*vflip;
> +	struct v4l2_ctrl	*test_pattern;
> +	struct v4l2_mbus_framefmt	fmt;
> +	struct v4l2_ctrl_handler ctrl_handler;
> +
> +	const struct ov02a10_mode *cur_mode;
> +};
> +
> +#define to_ov02a10(sd) container_of(sd, struct ov02a10, subdev)
> +
> +static inline void msleep_range(unsigned int delay_base)
> +{
> +	usleep_range(delay_base * 1000, delay_base * 1000 + 500);
> +}
> +
> +/* MIPI color bar enable output */
> +static const struct regval ov02a10_test_pattern_enable_regs[] = {
> +	{0xfd, 0x01},
> +	{0x0d, 0x00},
> +	{0xb6, 0x01},
> +	{0x01, 0x01},
> +	{0xfd, 0x01},
> +	{0xac, 0x01},
> +	{REG_NULL, 0x00}
> +};
> +
> +/* MIPI color bar disable output */
> +static const struct regval ov02a10_test_pattern_disable_regs[] = {
> +	{0xfd, 0x01},
> +	{0x0d, 0x00},
> +	{0xb6, 0x00},
> +	{0x01, 0x01},
> +	{0xfd, 0x01},
> +	{0xac, 0x01},
> +	{REG_NULL, 0x00}
> +};
> +
> +/*
> + * xvclk 24Mhz
> + * pclk 39Mhz
> + * linelength 934(0x3a6)
> + * framelength 1390(0x56e)
> + * grabwindow_width 1600
> + * grabwindow_height 1200
> + * max_framerate 30fps
> + * mipi_datarate per lane 780Mbps
> + */
> +static const struct regval ov02a10_1600x1200_regs[] = {
> +	{0xfd, 0x01},
> +	{0xac, 0x00},
> +	{0xfd, 0x00},
> +	{0x2f, 0x29},
> +	{0x34, 0x00},
> +	{0x35, 0x21},
> +	{0x30, 0x15},
> +	{0x33, 0x01},
> +	{0xfd, 0x01},
> +	{0x44, 0x00},
> +	{0x2a, 0x4c},
> +	{0x2b, 0x1e},
> +	{0x2c, 0x60},
> +	{0x25, 0x11},
> +	{0x03, 0x01},
> +	{0x04, 0xae},
> +	{0x09, 0x00},
> +	{0x0a, 0x02},
> +	{0x06, 0xa6},
> +	{0x31, 0x00},
> +	{0x24, 0x40},
> +	{0x01, 0x01},
> +	{0xfb, 0x73},
> +	{0xfd, 0x01},
> +	{0x16, 0x04},
> +	{0x1c, 0x09},
> +	{0x21, 0x42},
> +	{0x12, 0x04},
> +	{0x13, 0x10},
> +	{0x11, 0x40},
> +	{0x33, 0x81},
> +	{0xd0, 0x00},
> +	{0xd1, 0x01},
> +	{0xd2, 0x00},
> +	{0x50, 0x10},
> +	{0x51, 0x23},
> +	{0x52, 0x20},
> +	{0x53, 0x10},
> +	{0x54, 0x02},
> +	{0x55, 0x20},
> +	{0x56, 0x02},
> +	{0x58, 0x48},
> +	{0x5d, 0x15},
> +	{0x5e, 0x05},
> +	{0x66, 0x66},
> +	{0x68, 0x68},
> +	{0x6b, 0x00},
> +	{0x6c, 0x00},
> +	{0x6f, 0x40},
> +	{0x70, 0x40},
> +	{0x71, 0x0a},
> +	{0x72, 0xf0},
> +	{0x73, 0x10},
> +	{0x75, 0x80},
> +	{0x76, 0x10},
> +	{0x84, 0x00},
> +	{0x85, 0x10},
> +	{0x86, 0x10},
> +	{0x87, 0x00},
> +	{0x8a, 0x22},
> +	{0x8b, 0x22},
> +	{0x19, 0xf1},
> +	{0x29, 0x01},
> +	{0xfd, 0x01},
> +	{0x9d, 0xd6},
> +	{0xa0, 0x29},
> +	{0xa1, 0x03},
> +	{0xad, 0x62},
> +	{0xae, 0x00},
> +	{0xaf, 0x85},
> +	{0xb1, 0x01},
> +	{0x8e, 0x06},
> +	{0x8f, 0x40},
> +	{0x90, 0x04},
> +	{0x91, 0xb0},
> +	{0x45, 0x01},
> +	{0x46, 0x00},
> +	{0x47, 0x6c},
> +	{0x48, 0x03},
> +	{0x49, 0x8b},
> +	{0x4a, 0x00},
> +	{0x4b, 0x07},
> +	{0x4c, 0x04},
> +	{0x4d, 0xb7},
> +	{0xf0, 0x40},
> +	{0xf1, 0x40},
> +	{0xf2, 0x40},
> +	{0xf3, 0x40},
> +	{0x3f, 0x00},
> +	{0xfd, 0x01},
> +	{0x05, 0x00},
> +	{0x06, 0xa6},
> +	{0xfd, 0x01},
> +	{REG_NULL, 0x00}
> +};
> +
> +#define OV02A10_LINK_FREQ_390MHZ		390000000
> +static const s64 link_freq_menu_items[] = {
> +	OV02A10_LINK_FREQ_390MHZ
> +};
> +
> +static const char * const ov02a10_test_pattern_menu[] = {
> +	"Disabled",
> +	"Color Bar",
> +};
> +
> +static const struct ov02a10_mode supported_modes[] = {
> +	{
> +		.width = 1600,
> +		.height = 1200,
> +		.exp_def = 0x01ae,
> +		.hts_def = 0x03a6,
> +		.vts_def = 0x056e,
> +		.reg_list = ov02a10_1600x1200_regs,
> +	},
> +};
> +
> +/* Write a register */
> +static int ov02a10_write_reg(struct ov02a10 *ov02a10, u8 addr, u8 val)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> +	u8 buf[2] = {addr, val};
> +	int ret;
> +
> +	ret = i2c_master_send(client, buf, 2);
> +
> +	if (ret != 2) {
> +		dev_err(&client->dev, "%s: error: reg=%x, val=%x\n",
> +			__func__, addr, val);
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ov02a10_write_array(struct ov02a10 *ov02a10,
> +			       const struct regval *regs)
> +{
> +	u32 i;

unsigned int, please.

> +	int ret;
> +
> +	for (i = 0; regs[i].addr != REG_NULL; i++) {
> +		ret = ov02a10_write_reg(ov02a10, regs[i].addr, regs[i].val);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +/* Read a register */
> +static int ov02a10_read_reg(struct ov02a10 *ov02a10, u8 reg, u8 *val)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> +	u8 data = reg;
> +	struct i2c_msg msg = {
> +		.addr	= client->addr,
> +		.flags	= 0,
> +		.len	= 1,
> +		.buf	= &data,
> +	};
> +	int ret;
> +
> +	ret = i2c_transfer(client->adapter, &msg, 1);
> +	if (ret < 0)
> +		goto err_wr;
> +
> +	msg.flags = I2C_M_RD;
> +	ret = i2c_transfer(client->adapter, &msg, 1);
> +	if (ret < 0)
> +		goto err_rd;
> +
> +	*val = data;
> +	return 0;
> +
> +err_rd:
> +	dev_err(&client->dev, "i2c_transfer --I2C_M_RD failed\n");
> +err_wr:
> +	dev_err(&client->dev, "read error: reg=0x%02x: %d\n", reg, ret);
> +	return ret;
> +}
> +
> +static void ov02a10_fill_fmt(const struct ov02a10_mode *mode,
> +			     struct v4l2_mbus_framefmt *fmt)
> +{
> +	fmt->width = mode->width;
> +	fmt->height = mode->height;
> +	fmt->field = V4L2_FIELD_NONE;
> +}
> +
> +static int ov02a10_set_fmt(struct v4l2_subdev *sd,
> +			   struct v4l2_subdev_pad_config *cfg,
> +			   struct v4l2_subdev_format *fmt)
> +{
> +	struct ov02a10 *ov02a10 = to_ov02a10(sd);
> +	struct v4l2_mbus_framefmt *mbus_fmt = &fmt->format;
> +
> +	mutex_lock(&ov02a10->mutex);
> +
> +	if (ov02a10->streaming) {
> +		mutex_unlock(&ov02a10->mutex);
> +		return -EBUSY;
> +	}
> +
> +	/* Only one sensor mode supported */
> +	mbus_fmt->code = ov02a10->fmt.code;
> +	ov02a10_fill_fmt(ov02a10->cur_mode, mbus_fmt);
> +	ov02a10->fmt = fmt->format;
> +
> +	mutex_unlock(&ov02a10->mutex);
> +
> +	return 0;
> +}
> +
> +static int ov02a10_get_fmt(struct v4l2_subdev *sd,
> +			   struct v4l2_subdev_pad_config *cfg,
> +			   struct v4l2_subdev_format *fmt)
> +{
> +	struct ov02a10 *ov02a10 = to_ov02a10(sd);
> +	struct v4l2_mbus_framefmt *mbus_fmt = &fmt->format;
> +
> +	mutex_lock(&ov02a10->mutex);
> +
> +	fmt->format = ov02a10->fmt;
> +	mbus_fmt->code = ov02a10->fmt.code;
> +	ov02a10_fill_fmt(ov02a10->cur_mode, mbus_fmt);
> +
> +	mutex_unlock(&ov02a10->mutex);
> +
> +	return 0;
> +}
> +
> +static int ov02a10_enum_mbus_code(struct v4l2_subdev *sd,
> +				  struct v4l2_subdev_pad_config *cfg,
> +				  struct v4l2_subdev_mbus_code_enum *code)
> +{
> +	struct ov02a10 *ov02a10 = to_ov02a10(sd);
> +
> +	if (code->index >= ARRAY_SIZE(supported_modes) || !(code->index))

This doesn't make sense. The supported modes, should more be added in the
future, are presumably using the same mbus code. If you only have one, then
non-zero code->index would result in -EINVAL (and not zero code->index).

> +		return -EINVAL;
> +
> +	code->code = ov02a10->fmt.code;
> +
> +	return 0;
> +}
> +
> +static int ov02a10_enum_frame_sizes(struct v4l2_subdev *sd,
> +				    struct v4l2_subdev_pad_config *cfg,
> +				    struct v4l2_subdev_frame_size_enum *fse)
> +{
> +	if (fse->index >= ARRAY_SIZE(supported_modes) || !(fse->index))
> +		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 __ov02a10_power_on(struct ov02a10 *ov02a10)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> +	struct device *dev = &client->dev;
> +	int ret;
> +
> +	ret = clk_prepare_enable(ov02a10->xvclk);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to enable xvclk\n");
> +		return ret;
> +	}
> +
> +	/* Note: set 0 is high, set 1 is low */
> +	gpiod_set_value_cansleep(ov02a10->reset_gpio, 1);
> +	gpiod_set_value_cansleep(ov02a10->powerdown_gpio, 0);
> +
> +	ret = regulator_bulk_enable(OV02A10_NUM_SUPPLIES, ov02a10->supplies);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to enable regulators\n");
> +		goto disable_clk;
> +	}
> +	msleep_range(7);

This has some potential of clashing with more generic functions in the
future. Please use usleep_range directly, or msleep.

> +
> +	gpiod_set_value_cansleep(ov02a10->powerdown_gpio, 1);
> +	msleep_range(10);
> +
> +	gpiod_set_value_cansleep(ov02a10->reset_gpio, 0);
> +	msleep_range(10);
> +
> +	return 0;
> +
> +disable_clk:
> +	clk_disable_unprepare(ov02a10->xvclk);
> +
> +	return ret;
> +}
> +
> +static void __ov02a10_power_off(struct ov02a10 *ov02a10)
> +{
> +	clk_disable_unprepare(ov02a10->xvclk);
> +	gpiod_set_value_cansleep(ov02a10->reset_gpio, 1);
> +	gpiod_set_value_cansleep(ov02a10->powerdown_gpio, 1);
> +	regulator_bulk_disable(OV02A10_NUM_SUPPLIES, ov02a10->supplies);
> +}
> +
> +static int __ov02a10_start_stream(struct ov02a10 *ov02a10)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> +	int ret;
> +
> +	/* Apply default values of current mode */
> +	ret = ov02a10_write_array(ov02a10, ov02a10->cur_mode->reg_list);
> +	if (ret)
> +		return ret;
> +
> +	/* Apply customized values from user */
> +	ret = __v4l2_ctrl_handler_setup(ov02a10->subdev.ctrl_handler);
> +	if (ret)
> +		return ret;
> +
> +	/* Set orientation to 180 degree */
> +	if (ov02a10->upside_down) {
> +		ret = ov02a10_write_reg(ov02a10, REG_MIRROR_FLIP_CONTROL,
> +					REG_CONFIG_MIRROR_FLIP);
> +		if (ret) {
> +			dev_err(&client->dev, "%s failed to set orientation\n",
> +				__func__);
> +			return ret;
> +		}
> +		ret = ov02a10_write_reg(ov02a10, REG_GLOBAL_EFFECTIVE,
> +					REG_ENABLE);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	/* Set stream on register */
> +	return ov02a10_write_reg(ov02a10,
> +				 REG_SC_CTRL_MODE, SC_CTRL_MODE_STREAMING);
> +}
> +
> +static int __ov02a10_stop_stream(struct ov02a10 *ov02a10)
> +{
> +	return ov02a10_write_reg(ov02a10,
> +				 REG_SC_CTRL_MODE, SC_CTRL_MODE_STANDBY);
> +}
> +
> +static int ov02a10_entity_init_cfg(struct v4l2_subdev *subdev,
> +				   struct v4l2_subdev_pad_config *cfg)
> +{
> +	struct v4l2_subdev_format fmt = { 0 };
> +
> +	fmt.which = cfg ? V4L2_SUBDEV_FORMAT_TRY : V4L2_SUBDEV_FORMAT_ACTIVE;
> +	fmt.format.width = 1600;
> +	fmt.format.height = 1200;
> +
> +	ov02a10_set_fmt(subdev, cfg, &fmt);
> +
> +	return 0;
> +}
> +
> +static int ov02a10_s_stream(struct v4l2_subdev *sd, int on)
> +{
> +	struct ov02a10 *ov02a10 = to_ov02a10(sd);
> +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> +	int ret = 0;
> +
> +	mutex_lock(&ov02a10->mutex);
> +
> +	if (ov02a10->streaming == on)
> +		goto unlock_and_return;
> +
> +	if (on) {
> +		ret = pm_runtime_get_sync(&client->dev);
> +		if (ret < 0) {
> +			pm_runtime_put_noidle(&client->dev);
> +			goto unlock_and_return;
> +		}
> +
> +		ret = __ov02a10_start_stream(ov02a10);
> +		if (ret) {
> +			__ov02a10_stop_stream(ov02a10);
> +			ov02a10->streaming = !on;
> +			goto err_rpm_put;
> +		}
> +	} else {
> +		__ov02a10_stop_stream(ov02a10);
> +		pm_runtime_put(&client->dev);
> +	}
> +
> +	ov02a10->streaming = on;
> +	mutex_unlock(&ov02a10->mutex);
> +
> +	return ret;
> +
> +err_rpm_put:
> +	pm_runtime_put(&client->dev);
> +unlock_and_return:
> +	mutex_unlock(&ov02a10->mutex);
> +
> +	return ret;
> +}
> +
> +static int ov02a10_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> +	struct ov02a10 *ov02a10 = to_ov02a10(sd);
> +	struct v4l2_mbus_framefmt *try_fmt = v4l2_subdev_get_try_format(sd,
> +									fh->pad,
> +									0);
> +
> +	mutex_lock(&ov02a10->mutex);
> +	/* Initialize try_fmt */
> +	try_fmt->code = ov02a10->fmt.code;
> +	ov02a10_fill_fmt(&supported_modes[0], try_fmt);
> +
> +	mutex_unlock(&ov02a10->mutex);

No need for the mutex: the supported values are static and there is no
parallel access to try_fmt.

Btw. you don't need to do this here as you have init_cfg implemented, i.e.
you can omit the open callback.

> +
> +	return 0;
> +}
> +
> +static int __maybe_unused ov02a10_runtime_resume(struct device *dev)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct ov02a10 *ov02a10 = to_ov02a10(sd);
> +
> +	return __ov02a10_power_on(ov02a10);
> +}
> +
> +static int __maybe_unused ov02a10_runtime_suspend(struct device *dev)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct ov02a10 *ov02a10 = to_ov02a10(sd);
> +
> +	__ov02a10_power_off(ov02a10);
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops ov02a10_pm_ops = {
> +	SET_RUNTIME_PM_OPS(ov02a10_runtime_suspend,
> +			   ov02a10_runtime_resume, NULL)
> +};
> +
> +static int ov02a10_set_test_pattern(struct ov02a10 *ov02a10, s32 value)
> +{
> +	if (value)
> +		return ov02a10_write_array(ov02a10,
> +					   ov02a10_test_pattern_enable_regs);
> +
> +	return ov02a10_write_array(ov02a10,
> +		ov02a10_test_pattern_disable_regs);

Fits on previous line.

> +}
> +
> +static int ov02a10_set_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +	struct ov02a10 *ov02a10 = container_of(ctrl->handler,
> +					     struct ov02a10, ctrl_handler);
> +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> +	s64 max_expo;
> +	int ret;
> +
> +	/* Propagate change of current control to all related controls */
> +	if (ctrl->id == V4L2_CID_VBLANK) {
> +		/* Update max exposure while meeting expected vblanking */
> +		max_expo = ov02a10->cur_mode->height + ctrl->val - 4;
> +		__v4l2_ctrl_modify_range(ov02a10->exposure,
> +					 ov02a10->exposure->minimum, max_expo,
> +					 ov02a10->exposure->step,
> +					 ov02a10->exposure->default_value);
> +	}
> +
> +	/* V4L2 controls values will be applied only when power is already up */
> +	if (!pm_runtime_get_if_in_use(&client->dev))
> +		return 0;
> +
> +	switch (ctrl->id) {
> +	case V4L2_CID_EXPOSURE:
> +		ret = ov02a10_write_reg(ov02a10, REG_PAGE_SWITCH, REG_ENABLE);
> +		if (ret < 0)
> +			return ret;
> +		ret = ov02a10_write_reg(ov02a10, OV02A10_REG_EXPOSURE_H,
> +					((ctrl->val >> 8) & 0xFF));
> +		if (!ret) {
> +			ret = ov02a10_write_reg(ov02a10, OV02A10_REG_EXPOSURE_L,
> +						(ctrl->val & 0xFF));
> +			if (ret < 0)
> +				return ret;
> +		}
> +		ret = ov02a10_write_reg(ov02a10, REG_GLOBAL_EFFECTIVE,
> +					REG_ENABLE);
> +		if (ret < 0)
> +			return ret;
> +		break;
> +	case V4L2_CID_ANALOGUE_GAIN:
> +		ret = ov02a10_write_reg(ov02a10, REG_PAGE_SWITCH, REG_ENABLE);
> +		if (ret < 0)
> +			return ret;
> +		ret = ov02a10_write_reg(ov02a10, OV02A10_REG_GAIN,
> +					(ctrl->val & 0xFF));
> +		if (ret < 0)
> +			return ret;
> +		ret = ov02a10_write_reg(ov02a10, REG_GLOBAL_EFFECTIVE,
> +					REG_ENABLE);
> +		if (ret < 0)
> +			return ret;
> +		break;
> +	case V4L2_CID_VBLANK:
> +		ret = ov02a10_write_reg(ov02a10, REG_PAGE_SWITCH, REG_ENABLE);
> +		if (ret < 0)
> +			return ret;
> +		ret = ov02a10_write_reg(ov02a10, OV02A10_REG_VTS_H,
> +					(((ctrl->val +
> +					ov02a10->cur_mode->height -
> +					OV02A10_BASIC_LINE) >> 8)
> +					& 0xFF));
> +		if (!ret) {
> +			ret = ov02a10_write_reg(ov02a10, OV02A10_REG_VTS_L,
> +						((ctrl->val +
> +						ov02a10->cur_mode->height -
> +						OV02A10_BASIC_LINE) & 0xFF));
> +			if (ret < 0)
> +				return ret;
> +		}
> +		ret = ov02a10_write_reg(ov02a10, REG_GLOBAL_EFFECTIVE,
> +					REG_ENABLE);
> +		if (ret < 0)
> +			return ret;
> +		break;
> +	case V4L2_CID_TEST_PATTERN:
> +		ret = ov02a10_set_test_pattern(ov02a10, ctrl->val);
> +		if (ret < 0)
> +			return ret;
> +		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_subdev_video_ops ov02a10_video_ops = {
> +	.s_stream = ov02a10_s_stream,
> +};
> +
> +static const struct v4l2_subdev_pad_ops ov02a10_pad_ops = {
> +	.init_cfg = ov02a10_entity_init_cfg,
> +	.enum_mbus_code = ov02a10_enum_mbus_code,
> +	.enum_frame_size = ov02a10_enum_frame_sizes,
> +	.get_fmt = ov02a10_get_fmt,
> +	.set_fmt = ov02a10_set_fmt,
> +};
> +
> +static const struct v4l2_subdev_ops ov02a10_subdev_ops = {
> +	.video	= &ov02a10_video_ops,
> +	.pad	= &ov02a10_pad_ops,
> +};
> +
> +static const struct media_entity_operations ov02a10_subdev_entity_ops = {
> +	.link_validate = v4l2_subdev_link_validate,
> +};
> +
> +static const struct v4l2_subdev_internal_ops ov02a10_internal_ops = {
> +	.open = ov02a10_open,
> +};
> +
> +static const struct v4l2_ctrl_ops ov02a10_ctrl_ops = {
> +	.s_ctrl = ov02a10_set_ctrl,
> +};
> +
> +static int ov02a10_initialize_controls(struct ov02a10 *ov02a10)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> +	const struct ov02a10_mode *mode;
> +	struct v4l2_ctrl_handler *handler;
> +	struct v4l2_ctrl *ctrl;
> +	u64 exposure_max;
> +	u32 pixel_rate, h_blank;
> +	int ret;
> +
> +	handler = &ov02a10->ctrl_handler;
> +	mode = ov02a10->cur_mode;
> +	ret = v4l2_ctrl_handler_init(handler, 10);
> +	if (ret)
> +		return ret;

An extra newline here, please.

> +	handler->lock = &ov02a10->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 * OV02A10_LANES) /
> +		     OV02A10_BITS_PER_SAMPLE;

Please use do_div(). The values are static so the compiler may not emit the
instructions for division but better be safe than sorry.

> +	v4l2_ctrl_new_std(handler, NULL, V4L2_CID_PIXEL_RATE,
> +			  0, pixel_rate, 1, pixel_rate);
> +
> +	h_blank = mode->hts_def - mode->width;
> +	ov02a10->hblank = v4l2_ctrl_new_std(handler, NULL, V4L2_CID_HBLANK,
> +					    h_blank, h_blank, 1, h_blank);
> +	if (ov02a10->hblank)
> +		ov02a10->hblank->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +
> +	ov02a10->vblank = v4l2_ctrl_new_std(handler, &ov02a10_ctrl_ops,
> +					    V4L2_CID_VBLANK, mode->vts_def -
> +					    mode->height,
> +					    OV02A10_VTS_MAX - mode->height, 1,
> +					    mode->vts_def - mode->height);
> +
> +	exposure_max = mode->vts_def - 4;
> +	ov02a10->exposure = v4l2_ctrl_new_std(handler, &ov02a10_ctrl_ops,
> +					      V4L2_CID_EXPOSURE,
> +					      OV02A10_EXPOSURE_MIN,
> +					      exposure_max,
> +					      OV02A10_EXPOSURE_STEP,
> +					      mode->exp_def);
> +
> +	ov02a10->anal_gain = v4l2_ctrl_new_std(handler, &ov02a10_ctrl_ops,
> +					       V4L2_CID_ANALOGUE_GAIN,
> +					       OV02A10_GAIN_MIN,
> +					       OV02A10_GAIN_MAX,
> +					       OV02A10_GAIN_STEP,
> +					       OV02A10_GAIN_DEFAULT);
> +
> +	ov02a10->test_pattern =
> +	   v4l2_ctrl_new_std_menu_items(handler,

Indentation. If some of the arguments slip over 80 I guess we can live with
that.

> +					&ov02a10_ctrl_ops,
> +					V4L2_CID_TEST_PATTERN,
> +					ARRAY_SIZE(ov02a10_test_pattern_menu) -
> +					1, 0, 0, ov02a10_test_pattern_menu);
> +
> +	if (handler->error) {
> +		ret = handler->error;
> +		dev_err(&client->dev,
> +			"Failed to init controls(%d)\n", ret);

Fits on the previous line.

> +		goto err_free_handler;
> +	}
> +
> +	ov02a10->subdev.ctrl_handler = handler;
> +
> +	return 0;
> +
> +err_free_handler:
> +	v4l2_ctrl_handler_free(handler);
> +
> +	return ret;
> +}
> +
> +static int ov02a10_check_sensor_id(struct ov02a10 *ov02a10)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> +	u16 id;
> +	u8 pid = 0;
> +	u8 ver = 0;
> +	int ret;
> +
> +	/* Check sensor revision */
> +	ret = ov02a10_read_reg(ov02a10, OV02A10_REG_CHIP_ID_H, &pid);
> +	if (ret)
> +		return ret;
> +
> +	ret = ov02a10_read_reg(ov02a10, OV02A10_REG_CHIP_ID_L, &ver);
> +	if (ret)
> +		return ret;
> +
> +	id = OV02A10_ID(pid, ver);
> +	if (id != CHIP_ID) {
> +		dev_err(&client->dev, "Unexpected sensor id(%04x)\n", id);
> +		return ret;
> +	}
> +
> +	dev_info(&client->dev, "Detected OV%04X sensor\n", id);
> +
> +	return 0;
> +}
> +
> +static int ov02a10_configure_regulators(struct ov02a10 *ov02a10)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> +	unsigned int i;
> +
> +	for (i = 0; i < OV02A10_NUM_SUPPLIES; i++)
> +		ov02a10->supplies[i].supply = ov02a10_supply_names[i];
> +
> +	return devm_regulator_bulk_get(&client->dev,
> +				       OV02A10_NUM_SUPPLIES,
> +				       ov02a10->supplies);
> +}
> +
> +static int ov02a10_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct ov02a10 *ov02a10;
> +	u32 rotation;
> +	u32 xclk_freq;
> +	int ret;
> +
> +	ov02a10 = devm_kzalloc(dev, sizeof(*ov02a10), GFP_KERNEL);
> +	if (!ov02a10)
> +		return -ENOMEM;
> +
> +	v4l2_i2c_subdev_init(&ov02a10->subdev, client, &ov02a10_subdev_ops);
> +	ov02a10->fmt.code = MEDIA_BUS_FMT_SBGGR10_1X10;
> +
> +	/* Optional indication of physical rotation of sensor */
> +	ret = fwnode_property_read_u32(dev_fwnode(dev), "rotation",
> +				       &rotation);
> +	if (!ret) {
> +		switch (rotation) {
> +		case 180:
> +			ov02a10->upside_down = true;
> +			ov02a10->fmt.code = MEDIA_BUS_FMT_SRGGB10_1X10;
> +			break;
> +		case 0:
> +			break;
> +		default:
> +			dev_warn(dev, "%u degrees rotation is not supported, ignoring...\n",
> +				 rotation);
> +		}
> +	}
> +

Please also check that the link frequencies in DT match with what the
driver expects. See e.g. drivers/media/i2c/ov8856.c driver for an example.

> +	/* Get system clock (xvclk) */
> +	ov02a10->xvclk = devm_clk_get(dev, "xvclk");
> +	if (IS_ERR(ov02a10->xvclk)) {
> +		dev_err(dev, "Failed to get xvclk\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = of_property_read_u32(dev->of_node, "clock-frequency", &xclk_freq);
> +	if (ret) {
> +		dev_err(dev, "Failed to get xclk frequency\n");
> +		return ret;
> +	}
> +
> +	/* External clock must be 24MHz, allow 1% tolerance */
> +	if (xclk_freq < 23760000 || xclk_freq > 24240000) {
> +		dev_err(dev, "external clock frequency %u is not supported\n",
> +			xclk_freq);
> +		return -EINVAL;
> +	}
> +	dev_dbg(dev, "external clock frequency %u\n", xclk_freq);
> +
> +	ret = clk_set_rate(ov02a10->xvclk, xclk_freq);
> +	if (ret) {
> +		dev_err(dev, "Failed to set xvclk frequency (24MHz)\n");
> +		return ret;
> +	}
> +
> +	ov02a10->powerdown_gpio = devm_gpiod_get(dev, "powerdown",
> +						 GPIOD_OUT_LOW);
> +	if (IS_ERR(ov02a10->powerdown_gpio)) {
> +		dev_err(dev, "Failed to get powerdown-gpios\n");
> +		return -EINVAL;
> +	}
> +
> +	ov02a10->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(ov02a10->reset_gpio)) {
> +		dev_err(dev, "Failed to get reset-gpios\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = ov02a10_configure_regulators(ov02a10);
> +	if (ret) {
> +		dev_err(dev, "Failed to get power regulators\n");
> +		return ret;
> +	}
> +
> +	mutex_init(&ov02a10->mutex);
> +	ov02a10->cur_mode = &supported_modes[0];
> +	ret = ov02a10_initialize_controls(ov02a10);
> +	if (ret) {
> +		dev_err(dev, "Failed to initialize controls\n");
> +		goto err_destroy_mutex;
> +	}
> +
> +	ret = __ov02a10_power_on(ov02a10);
> +	if (ret)
> +		goto err_free_handler;
> +
> +	ret = ov02a10_check_sensor_id(ov02a10);
> +	if (ret)
> +		goto err_power_off;
> +
> +	ov02a10->subdev.internal_ops = &ov02a10_internal_ops;
> +	ov02a10->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	ov02a10->subdev.entity.ops = &ov02a10_subdev_entity_ops;
> +	ov02a10->subdev.entity.function = MEDIA_ENT_F_CAM_SENSOR;
> +	ov02a10->pad.flags = MEDIA_PAD_FL_SOURCE;
> +	ret = media_entity_pads_init(&ov02a10->subdev.entity, 1, &ov02a10->pad);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to init entity pads: %d", ret);
> +		goto err_power_off;
> +	}
> +
> +	ret = v4l2_async_register_subdev(&ov02a10->subdev);
> +	if (ret) {
> +		dev_err(dev, "failed to register V4L2 subdev: %d",
> +			ret);
> +		goto err_clean_entity;
> +	}
> +
> +	pm_runtime_set_active(dev);
> +	pm_runtime_enable(dev);
> +	pm_runtime_idle(dev);
> +
> +	dev_info(dev, "ov02a10 probe --\n");

This isn't very informative. The driver already prints errors when probing
fails and otherwise it succeeds. Please remove.

> +	return 0;
> +
> +err_clean_entity:
> +	media_entity_cleanup(&ov02a10->subdev.entity);
> +err_power_off:
> +	__ov02a10_power_off(ov02a10);
> +err_free_handler:
> +	v4l2_ctrl_handler_free(ov02a10->subdev.ctrl_handler);
> +err_destroy_mutex:
> +	mutex_destroy(&ov02a10->mutex);
> +
> +	return ret;
> +}
> +
> +static int ov02a10_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct ov02a10 *ov02a10 = to_ov02a10(sd);
> +
> +	v4l2_async_unregister_subdev(sd);
> +	media_entity_cleanup(&sd->entity);
> +	v4l2_ctrl_handler_free(sd->ctrl_handler);
> +	pm_runtime_disable(&client->dev);
> +	if (!pm_runtime_status_suspended(&client->dev))
> +		__ov02a10_power_off(ov02a10);
> +	pm_runtime_set_suspended(&client->dev);
> +	mutex_destroy(&ov02a10->mutex);
> +
> +	return 0;
> +}
> +
> +#if IS_ENABLED(CONFIG_OF)
> +static const struct of_device_id ov02a10_of_match[] = {
> +	{ .compatible = "ovti,ov02a10" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, ov02a10_of_match);
> +#endif
> +
> +static struct i2c_driver ov02a10_i2c_driver = {
> +	.driver = {
> +		.name = "ov02a10",
> +		.pm = &ov02a10_pm_ops,
> +		.of_match_table = ov02a10_of_match,
> +	},
> +	.probe_new	= &ov02a10_probe,
> +	.remove		= &ov02a10_remove,
> +};
> +
> +module_i2c_driver(ov02a10_i2c_driver);
> +
> +MODULE_AUTHOR("Dongchun Zhu <dongchun.zhu@mediatek.com>");
> +MODULE_DESCRIPTION("OmniVision OV02A10 sensor driver");
> +MODULE_LICENSE("GPL v2");

-- 
Kind regards,

Sakari Ailus
sakari.ailus@linux.intel.com