Re: [PATCH v14 2/2] media: i2c: Add OV02A10 image sensor driver

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Hello Andy,

Thanks for the review.

On Wed, 2020-09-02 at 16:44 +0300, Andy Shevchenko wrote:
> On Wed, Sep 02, 2020 at 08:01:22PM +0800, Dongchun Zhu wrote:
> > Add a V4L2 sub-device driver for OmniVision OV02A10 image sensor.
> > 
> 
> Some nit-picks below, after addressing, FWIW,
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> 
> > Signed-off-by: Dongchun Zhu <dongchun.zhu@xxxxxxxxxxxx>
> > ---
> >  MAINTAINERS                 |    1 +
> >  drivers/media/i2c/Kconfig   |   13 +
> >  drivers/media/i2c/Makefile  |    1 +
> >  drivers/media/i2c/ov02a10.c | 1083 +++++++++++++++++++++++++++++++++++++++++++
> >  4 files changed, 1098 insertions(+)
> >  create mode 100644 drivers/media/i2c/ov02a10.c
> > 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 48aa7a7..ce7d8fa 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -12724,6 +12724,7 @@ L:	linux-media@xxxxxxxxxxxxxxx
> >  S:	Maintained
> >  T:	git git://linuxtv.org/media_tree.git
> >  F:	Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml
> > +F:	drivers/media/i2c/ov02a10.c
> >  
> >  OMNIVISION OV13858 SENSOR DRIVER
> >  M:	Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> > diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> > index 48ae60a..f458804 100644
> > --- a/drivers/media/i2c/Kconfig
> > +++ b/drivers/media/i2c/Kconfig
> > @@ -825,6 +825,19 @@ 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
> 
> Dunno if V4L2 modules allow COMPILE_TEST, but looking below, can we stick with one pattern like
> 	depends on VIDEO_V4L2 && I2C
> ?
> 
> Or is it the opposite (de facto in use)?
> 

It seems there is no uniform standard for the dependency sequence
currently.

> > +	select MEDIA_CONTROLLER
> > +	select VIDEO_V4L2_SUBDEV_API
> > +	select V4L2_FWNODE
> > +	help
> > +	  This is a Video4Linux2 sensor driver for the OmniVision
> > +	  OV02A10 camera sensor.
> > +
> > +	  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 f0a7747..dc27e14 100644
> > --- a/drivers/media/i2c/Makefile
> > +++ b/drivers/media/i2c/Makefile
> > @@ -64,6 +64,7 @@ obj-$(CONFIG_VIDEO_VP27SMPX) += vp27smpx.o
> >  obj-$(CONFIG_VIDEO_SONY_BTF_MPX) += sony-btf-mpx.o
> >  obj-$(CONFIG_VIDEO_UPD64031A) += upd64031a.o
> >  obj-$(CONFIG_VIDEO_UPD64083) += upd64083.o
> > +obj-$(CONFIG_VIDEO_OV02A10) += ov02a10.o
> >  obj-$(CONFIG_VIDEO_OV2640) += ov2640.o
> >  obj-$(CONFIG_VIDEO_OV2680) += ov2680.o
> >  obj-$(CONFIG_VIDEO_OV2685) += ov2685.o
> > diff --git a/drivers/media/i2c/ov02a10.c b/drivers/media/i2c/ov02a10.c
> > new file mode 100644
> > index 0000000..1f8c525
> > --- /dev/null
> > +++ b/drivers/media/i2c/ov02a10.c
> > @@ -0,0 +1,1083 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +// Copyright (c) 2020 MediaTek Inc.
> > +
> > +#include <linux/clk.h>
> > +#include <linux/delay.h>
> > +#include <linux/device.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						0x2509
> > +#define OV02A10_REG_CHIP_ID_H				0x02
> > +#define OV02A10_REG_CHIP_ID_L				0x03
> > +
> > +/* Bit[1] vertical upside down */
> > +/* Bit[0] horizontal mirror */
> > +#define REG_MIRROR_FLIP_CONTROL				0x3f
> > +
> > +/* Orientation */
> > +#define REG_MIRROR_FLIP_ENABLE				0x03
> > +
> > +/* Bit[2:0] MIPI transmission speed select */
> > +#define TX_SPEED_AREA_SEL				0xa1
> > +#define OV02A10_MIPI_TX_SPEED_DEFAULT			0x04
> > +
> > +#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_EXP_SHIFT				8
> > +#define OV02A10_REG_EXPOSURE_H				0x03
> > +#define OV02A10_REG_EXPOSURE_L				0x04
> > +#define	OV02A10_EXPOSURE_MIN				4
> > +#define OV02A10_EXPOSURE_MAX_MARGIN			4
> > +#define	OV02A10_EXPOSURE_STEP				1
> > +
> > +#define OV02A10_VTS_SHIFT				8
> > +#define OV02A10_REG_VTS_H				0x05
> > +#define OV02A10_REG_VTS_L				0x06
> 
> > +#define OV02A10_VTS_MAX					0x209f
> 
> Hex? (1)
> 
> > +#define OV02A10_BASIC_LINE				1224
> 
> Decimal? (2)
> 
> > +
> > +#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
> 
> Not sure why these are in hex, but okay. Probably a reason behind (1) and (2)
> as well.
> 

>From my perspective, OV02A10_BASIC_LINE is defined from the aspect of
'u32 height' in 'struct ov02a10_mode'; while the others are related with
sensor specific control registers, like VTS, GAIN, EXPSOURE...

> > +/* Test pattern control */
> > +#define OV02A10_REG_TEST_PATTERN			0xb6
> 
> I'm wondering if you can rearrange registers that they will be sorted by value.
> 

They are supposed to be classified by category.

> > +#define HZ_PER_MHZ					1000000L
> > +#define OV02A10_LINK_FREQ_390MHZ			(390 * HZ_PER_MHZ)
> > +#define OV02A10_ECLK_FREQ				(24 * HZ_PER_MHZ)
> > +#define OV02A10_DATA_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 */
> > +};
> > +
> > +struct ov02a10_reg {
> > +	u8 addr;
> > +	u8 val;
> > +};
> > +
> > +struct ov02a10_reg_list {
> > +	u32 num_of_regs;
> > +	const struct ov02a10_reg *regs;
> > +};
> > +
> > +struct ov02a10_mode {
> > +	u32 width;
> > +	u32 height;
> > +	u32 exp_def;
> > +	u32 hts_def;
> > +	u32 vts_def;
> > +	const struct ov02a10_reg_list reg_list;
> > +};
> > +
> > +struct ov02a10 {
> > +	u32 eclk_freq;
> > +	/* Indication of MIPI transmission speed select */
> > +	u32 mipi_clock_voltage;
> > +	/* Index of link frequency config to be used */
> > +	u32 freq_index;
> > +
> > +	struct clk *eclk;
> > +	struct gpio_desc *pd_gpio;
> > +	struct gpio_desc *rst_gpio;
> > +	struct regulator_bulk_data supplies[ARRAY_SIZE(ov02a10_supply_names)];
> > +
> > +	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_mbus_framefmt fmt;
> > +	struct v4l2_ctrl_handler ctrl_handler;
> > +	struct v4l2_ctrl *exposure;
> > +
> > +	const struct ov02a10_mode *cur_mode;
> > +};
> > +
> > +static inline struct ov02a10 *to_ov02a10(struct v4l2_subdev *sd)
> > +{
> > +	return container_of(sd, struct ov02a10, subdev);
> > +}
> > +
> > +/*
> > + * eclk 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 ov02a10_reg 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, 0x16},
> > +	{0xa0, 0x29},
> > +	{0xa1, 0x04},
> > +	{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},
> > +};
> > +
> > +static const char * const ov02a10_test_pattern_menu[] = {
> > +	"Disabled",
> > +	"Eight Vertical Colour Bars",
> > +};
> > +
> > +static const s64 link_freq_menu_items[] = {
> > +	OV02A10_LINK_FREQ_390MHZ,
> > +};
> > +
> > +static u64 to_pixel_rate(u32 f_index)
> > +{
> > +	u64 pixel_rate = link_freq_menu_items[f_index] * 2 * OV02A10_DATA_LANES;
> > +
> > +	do_div(pixel_rate, OV02A10_BITS_PER_SAMPLE);
> > +
> > +	return pixel_rate;
> > +}
> > +
> > +static const struct ov02a10_mode supported_modes[] = {
> > +	{
> > +		.width = 1600,
> > +		.height = 1200,
> > +		.exp_def = 0x01ae,
> > +		.hts_def = 0x03a6,
> > +		.vts_def = 0x056e,
> > +		.reg_list = {
> > +			.num_of_regs = ARRAY_SIZE(ov02a10_1600x1200_regs),
> > +			.regs = ov02a10_1600x1200_regs,
> > +		},
> > +	},
> > +};
> > +
> > +static int ov02a10_write_array(struct ov02a10 *ov02a10,
> > +			       const struct ov02a10_reg_list *r_list)
> > +{
> > +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> > +	unsigned int i;
> > +	int ret;
> > +
> > +	for (i = 0; i < r_list->num_of_regs; i++) {
> > +		ret = i2c_smbus_write_byte_data(client, r_list->regs[i].addr,
> > +						r_list->regs[i].val);
> > +		if (ret < 0)
> > +			return ret;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int ov02a10_read_smbus(struct ov02a10 *ov02a10, unsigned char reg,
> > +			      unsigned char *val)
> > +{
> > +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> > +	int ret;
> > +
> > +	ret = i2c_smbus_read_byte_data(client, reg);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	*val = (unsigned char)ret;
> 
> No sure why you have casting and why returned value is not u8.
> 

Fine. 'unsigned char' would be replaced of 'u8' in next release.

> > +	return 0;
> > +}
> > +
> > +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;
> > +	struct v4l2_mbus_framefmt *frame_fmt;
> > +	int ret = 0;
> > +
> > +	mutex_lock(&ov02a10->mutex);
> > +
> > +	if (ov02a10->streaming && fmt->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> > +		ret = -EBUSY;
> > +		goto error;
> > +	}
> > +
> > +	/* Only one sensor mode supported */
> > +	mbus_fmt->code = ov02a10->fmt.code;
> > +	ov02a10_fill_fmt(ov02a10->cur_mode, mbus_fmt);
> > +
> > +	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY)
> > +		frame_fmt = v4l2_subdev_get_try_format(sd, cfg, 0);
> > +	else
> > +		frame_fmt = &ov02a10->fmt;
> > +
> > +	*frame_fmt = *mbus_fmt;
> > +
> > +error:
> 
> Like in other places be more precise
> 
> out_unlock:
> 

Sounds good naming.
Fixed in next release.

> > +	mutex_unlock(&ov02a10->mutex);
> > +	return ret;
> > +}
> > +
> > +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);
> > +
> > +	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY) {
> > +		fmt->format = *v4l2_subdev_get_try_format(sd, cfg, fmt->pad);
> > +	} else {
> > +		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 != 0)
> > +		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))
> > +		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_check_sensor_id(struct ov02a10 *ov02a10)
> > +{
> > +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> > +	u16 id;
> > +	u8 chip_id_h;
> > +	u8 chip_id_l;
> > +	int ret;
> > +
> > +	/* Check sensor revision */
> > +	ret = ov02a10_read_smbus(ov02a10, OV02A10_REG_CHIP_ID_H, &chip_id_h);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = ov02a10_read_smbus(ov02a10, OV02A10_REG_CHIP_ID_L, &chip_id_l);
> > +	if (ret)
> > +		return ret;
> 
> I'm wondering if above can be done in one bulk transfer (reading 16-bit value).
> 
> > +	id = (chip_id_h << 8) | chip_id_l;
> 
> If above can be achieved, this one should be rather something like
> le16_to_cpu() (or be16) with corresponding type of chip_id.
> 

Yes. i2c_smbus_read_word_data() functions could read both registers in
using a single i2c transaction.
Let me try locally first.

> > +	if (id != CHIP_ID) {
> > +		dev_err(&client->dev, "Unexpected sensor id(%04x)\n", id);
> > +		return -EINVAL;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int ov02a10_power_on(struct device *dev)
> > +{
> 
> > +	struct i2c_client *client = to_i2c_client(dev);
> > +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> 
> 	struct v4l2_subdev *sd = dev_get_drvdata(dev);
> 
> Same for the rest similar cases.
> 

We've discussed the issue in DW9768 V2.

For V4L2 sub-device drivers, dev_get_drvdata() shouldn't be used
directly.

More details please check the Google Issue:
https://partnerissuetracker.corp.google.com/issues/147957975


> > +	struct ov02a10 *ov02a10 = to_ov02a10(sd);
> > +	int ret;
> > +
> > +	gpiod_set_value_cansleep(ov02a10->rst_gpio, 1);
> > +	gpiod_set_value_cansleep(ov02a10->pd_gpio, 1);
> > +
> > +	ret = clk_prepare_enable(ov02a10->eclk);
> > +	if (ret < 0) {
> > +		dev_err(dev, "failed to enable eclk\n");
> > +		return ret;
> > +	}
> > +
> > +	ret = regulator_bulk_enable(ARRAY_SIZE(ov02a10_supply_names),
> > +				    ov02a10->supplies);
> > +	if (ret < 0) {
> > +		dev_err(dev, "failed to enable regulators\n");
> > +		goto disable_clk;
> > +	}
> > +	usleep_range(5000, 6000);
> > +
> > +	gpiod_set_value_cansleep(ov02a10->pd_gpio, 0);
> > +	usleep_range(5000, 6000);
> > +
> > +	gpiod_set_value_cansleep(ov02a10->rst_gpio, 0);
> > +	usleep_range(5000, 6000);
> > +
> > +	ret = ov02a10_check_sensor_id(ov02a10);
> > +	if (ret)
> > +		goto disable_regulator;
> > +
> > +	return 0;
> > +
> > +disable_regulator:
> > +	regulator_bulk_disable(ARRAY_SIZE(ov02a10_supply_names),
> > +			       ov02a10->supplies);
> > +disable_clk:
> > +	clk_disable_unprepare(ov02a10->eclk);
> > +
> > +	return ret;
> > +}
> > +
> > +static int ov02a10_power_off(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);
> > +
> > +	gpiod_set_value_cansleep(ov02a10->rst_gpio, 1);
> > +	clk_disable_unprepare(ov02a10->eclk);
> > +	gpiod_set_value_cansleep(ov02a10->pd_gpio, 1);
> > +	regulator_bulk_disable(ARRAY_SIZE(ov02a10_supply_names),
> > +			       ov02a10->supplies);
> > +
> > +	return 0;
> > +}
> > +
> > +static int __ov02a10_start_stream(struct ov02a10 *ov02a10)
> > +{
> > +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> > +	const struct ov02a10_reg_list *reg_list;
> > +	int ret;
> > +
> > +	/* Apply default values of current mode */
> > +	reg_list = &ov02a10->cur_mode->reg_list;
> > +	ret = ov02a10_write_array(ov02a10, 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 = i2c_smbus_write_byte_data(client, REG_MIRROR_FLIP_CONTROL,
> > +						REG_MIRROR_FLIP_ENABLE);
> > +		if (ret) {
> > +			dev_err(&client->dev, "failed to set orientation\n");
> > +			return ret;
> > +		}
> > +		ret = i2c_smbus_write_byte_data(client, REG_GLOBAL_EFFECTIVE,
> > +						REG_ENABLE);
> > +		if (ret < 0)
> > +			return ret;
> > +	}
> > +
> > +	/* Set MIPI TX speed according to DT property */
> > +	if (ov02a10->mipi_clock_voltage != OV02A10_MIPI_TX_SPEED_DEFAULT) {
> > +		ret = i2c_smbus_write_byte_data(client, TX_SPEED_AREA_SEL,
> > +						ov02a10->mipi_clock_voltage);
> > +		if (ret < 0)
> > +			return ret;
> > +	}
> > +
> > +	/* Set stream on register */
> > +	return i2c_smbus_write_byte_data(client, REG_SC_CTRL_MODE,
> > +					 SC_CTRL_MODE_STREAMING);
> > +}
> > +
> > +static int __ov02a10_stop_stream(struct ov02a10 *ov02a10)
> > +{
> > +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> > +
> > +	return i2c_smbus_write_byte_data(client, REG_SC_CTRL_MODE,
> > +					 SC_CTRL_MODE_STANDBY);
> > +}
> > +
> > +static int ov02a10_entity_init_cfg(struct v4l2_subdev *sd,
> > +				   struct v4l2_subdev_pad_config *cfg)
> > +{
> > +	struct v4l2_subdev_format fmt = {
> > +		.which = V4L2_SUBDEV_FORMAT_TRY,
> > +		.format = {
> > +			.width = 1600,
> > +			.height = 1200,
> > +		}
> > +	};
> > +
> > +	ov02a10_set_fmt(sd, 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;
> > +
> > +	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 0;
> > +
> > +err_rpm_put:
> > +	pm_runtime_put(&client->dev);
> > +unlock_and_return:
> > +	mutex_unlock(&ov02a10->mutex);
> > +
> > +	return ret;
> > +}
> > +
> > +static const struct dev_pm_ops ov02a10_pm_ops = {
> > +	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> > +				pm_runtime_force_resume)
> > +	SET_RUNTIME_PM_OPS(ov02a10_power_off, ov02a10_power_on, NULL)
> > +};
> > +
> > +/*
> > + * ov02a10_set_exposure - Function called when setting exposure time
> > + * @priv: Pointer to device structure
> > + * @val: Variable for exposure time, in the unit of micro-second
> > + *
> > + * Set exposure time based on input value.
> > + *
> > + * Return: 0 on success
> > + */
> > +static int ov02a10_set_exposure(struct ov02a10 *ov02a10, int val)
> > +{
> > +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> > +	int ret;
> > +
> > +	ret = i2c_smbus_write_byte_data(client, REG_PAGE_SWITCH, REG_ENABLE);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = i2c_smbus_write_byte_data(client, OV02A10_REG_EXPOSURE_H,
> > +					val >> OV02A10_EXP_SHIFT);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = i2c_smbus_write_byte_data(client, OV02A10_REG_EXPOSURE_L, val);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	return i2c_smbus_write_byte_data(client, REG_GLOBAL_EFFECTIVE,
> > +					 REG_ENABLE);
> > +}
> > +
> > +static int ov02a10_set_gain(struct ov02a10 *ov02a10, int val)
> > +{
> > +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> > +	int ret;
> > +
> > +	ret = i2c_smbus_write_byte_data(client, REG_PAGE_SWITCH, REG_ENABLE);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = i2c_smbus_write_byte_data(client, OV02A10_REG_GAIN, val);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	return i2c_smbus_write_byte_data(client, REG_GLOBAL_EFFECTIVE,
> > +					 REG_ENABLE);
> > +}
> > +
> > +static int ov02a10_set_vblank(struct ov02a10 *ov02a10, int val)
> > +{
> > +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> > +	u32 vts = val + ov02a10->cur_mode->height - OV02A10_BASIC_LINE;
> > +	int ret;
> > +
> > +	ret = i2c_smbus_write_byte_data(client, REG_PAGE_SWITCH, REG_ENABLE);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = i2c_smbus_write_byte_data(client, OV02A10_REG_VTS_H,
> > +					vts >> OV02A10_VTS_SHIFT);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = i2c_smbus_write_byte_data(client, OV02A10_REG_VTS_L, vts);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	return i2c_smbus_write_byte_data(client, REG_GLOBAL_EFFECTIVE,
> > +					 REG_ENABLE);
> > +}
> > +
> > +static int ov02a10_set_test_pattern(struct ov02a10 *ov02a10, int pattern)
> > +{
> > +	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> > +	int ret;
> > +
> > +	ret = i2c_smbus_write_byte_data(client, REG_PAGE_SWITCH, REG_ENABLE);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = i2c_smbus_write_byte_data(client, OV02A10_REG_TEST_PATTERN,
> > +					pattern);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = i2c_smbus_write_byte_data(client, REG_GLOBAL_EFFECTIVE,
> > +					REG_ENABLE);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	return i2c_smbus_write_byte_data(client, REG_SC_CTRL_MODE,
> > +					 SC_CTRL_MODE_STREAMING);
> > +}
> > +
> > +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 -
> > +			   OV02A10_EXPOSURE_MAX_MARGIN;
> > +		__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_set_exposure(ov02a10, ctrl->val);
> > +		break;
> > +	case V4L2_CID_ANALOGUE_GAIN:
> > +		ret = ov02a10_set_gain(ov02a10, ctrl->val);
> > +		break;
> > +	case V4L2_CID_VBLANK:
> > +		ret = ov02a10_set_vblank(ov02a10, ctrl->val);
> > +		break;
> > +	case V4L2_CID_TEST_PATTERN:
> > +		ret = ov02a10_set_test_pattern(ov02a10, ctrl->val);
> > +		break;
> > +	default:
> > +		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_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;
> > +	s64 exposure_max;
> > +	s64 vblank_def;
> > +	s64 pixel_rate;
> > +	s64 h_blank;
> > +	int ret;
> > +
> > +	handler = &ov02a10->ctrl_handler;
> > +	mode = ov02a10->cur_mode;
> > +	ret = v4l2_ctrl_handler_init(handler, 7);
> > +	if (ret)
> > +		return ret;
> > +
> > +	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 = to_pixel_rate(0);
> > +	v4l2_ctrl_new_std(handler, NULL, V4L2_CID_PIXEL_RATE, 0, pixel_rate, 1,
> > +			  pixel_rate);
> > +
> > +	h_blank = mode->hts_def - mode->width;
> > +	v4l2_ctrl_new_std(handler, NULL, V4L2_CID_HBLANK, h_blank, h_blank, 1,
> > +			  h_blank);
> > +
> > +	vblank_def = mode->vts_def - mode->height;
> > +	v4l2_ctrl_new_std(handler, &ov02a10_ctrl_ops, V4L2_CID_VBLANK,
> > +			  vblank_def, OV02A10_VTS_MAX - mode->height, 1,
> > +			  vblank_def);
> > +
> > +	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);
> > +
> > +	v4l2_ctrl_new_std(handler, &ov02a10_ctrl_ops,
> > +			  V4L2_CID_ANALOGUE_GAIN, OV02A10_GAIN_MIN,
> > +			  OV02A10_GAIN_MAX, OV02A10_GAIN_STEP,
> > +			  OV02A10_GAIN_DEFAULT);
> > +
> > +	v4l2_ctrl_new_std_menu_items(handler, &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);
> > +		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_hwcfg(struct device *dev, struct ov02a10 *ov02a10)
> > +{
> > +	struct fwnode_handle *ep;
> > +	struct fwnode_handle *fwnode = dev_fwnode(dev);
> > +	struct v4l2_fwnode_endpoint bus_cfg = {
> > +		.bus_type = V4L2_MBUS_CSI2_DPHY,
> > +	};
> > +	unsigned int i, j;
> > +	int ret;
> > +
> > +	if (!fwnode)
> > +		return -EINVAL;
> > +
> > +	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
> > +	if (!ep)
> > +		return -ENXIO;
> > +
> > +	ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);
> > +	fwnode_handle_put(ep);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (!bus_cfg.nr_of_link_frequencies) {
> > +		dev_err(dev, "no link frequencies defined\n");
> > +		ret = -EINVAL;
> > +		goto check_hwcfg_error;
> > +	}
> 
> If it's 0, the below will break on 'if (j == 0)' with slightly different but
> informative enough message. What do you keep above check for?
> 

I still prefer to the original version.
If 'bus_cfg.nr_of_link_frequencies' is 0, shouldn't we directly return
error?

> > +	for (i = 0; i < ARRAY_SIZE(link_freq_menu_items); i++) {
> > +		for (j = 0; j < bus_cfg.nr_of_link_frequencies; j++) {
> > +			if (link_freq_menu_items[i] ==
> > +				bus_cfg.link_frequencies[j]) {
> > +				ov02a10->freq_index = i;
> > +				break;
> > +			}
> > +		}
> > +
> > +		if (j == bus_cfg.nr_of_link_frequencies) {
> > +			dev_err(dev, "no link frequency %lld supported\n",
> > +				link_freq_menu_items[i]);
> > +			ret = -EINVAL;
> 
> > +			goto check_hwcfg_error;
> 
> 'break;' won't work?
> 
> > +		}
> > +	}
> > +
> > +check_hwcfg_error:
> 
> out_endpoint_free:
> 

It seems that OV8856 keeps the same pattern.

> > +	v4l2_fwnode_endpoint_free(&bus_cfg);
> > +
> > +	return ret;
> > +}
> > +
> > +static int ov02a10_probe(struct i2c_client *client)
> > +{
> > +	struct device *dev = &client->dev;
> > +	struct ov02a10 *ov02a10;
> > +	unsigned int rotation;
> > +	unsigned int cnt = 0;
> > +	unsigned int i;
> 
> > +	unsigned int num_freq_clk_volt = 2 * ARRAY_SIZE(link_freq_menu_items);
> 
> Can it be moved upper to improve readability?
> 

Fixed in next release.

> > +	int ret;
> > +
> > +	ov02a10 = devm_kzalloc(dev, sizeof(*ov02a10), GFP_KERNEL);
> > +	if (!ov02a10)
> > +		return -ENOMEM;
> > +
> > +	ret = ov02a10_check_hwcfg(dev, ov02a10);
> > +	if (ret) {
> > +		dev_err(dev, "failed to check HW configuration: %d\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	v4l2_i2c_subdev_init(&ov02a10->subdev, client, &ov02a10_subdev_ops);
> > +	ov02a10->mipi_clock_voltage = OV02A10_MIPI_TX_SPEED_DEFAULT;
> > +	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 && rotation == 180) {
> 
> Can be simplified (but I'm fine with above):
> 
> 	unsigned int rotation = 0;
> 	...
> 	fwnode_property_read_u32(..., &rotation);
> 	if (rotation == 180) {
> 		...
> 	}
> 

Sounds like the readability is improved using the latter style :-)

> > +		ov02a10->upside_down = true;
> > +		ov02a10->fmt.code = MEDIA_BUS_FMT_SRGGB10_1X10;
> > +	}
> > +
> > +	/* Optional indication of MIPI clock voltage unit */
> > +	ret = fwnode_property_read_u32_array(dev_fwnode(dev),
> > +					     "ovti,mipi-clock-voltage", NULL,
> > +					     0);
> 
> 	ret = fwnode_property_count_u32(...); // will be one line
> 

Great APIs!

> > +	if (ret > 0 && ret % 2 == 0) {
> > +		u32 freq_clk_volt[ret];
> > +
> > +		fwnode_property_read_u32_array(dev_fwnode(dev),
> > +					       "ovti,mipi-clock-voltage",
> > +					       freq_clk_volt,
> > +					       ARRAY_SIZE(freq_clk_volt));
> > +
> > +		while (num_freq_clk_volt) {
> > +			unsigned long freq;
> > +			unsigned long volt;
> > +
> > +			if (cnt >= ARRAY_SIZE(freq_clk_volt)) {
> > +				dev_warn(dev, "mismatched link frequency\n");
> > +				break;
> > +			}
> > +
> 
> > +			freq = freq_clk_volt[cnt++] * 1000;
> 
> HZ_PER_KHZ?
> 

Fixed in next release.

> > +			volt = freq_clk_volt[cnt++];
> > +
> > +			/* Get clock voltage unit value from DT */
> > +			if (freq == link_freq_menu_items[ov02a10->freq_index]) {
> > +				ov02a10->mipi_clock_voltage = volt;
> > +				break;
> > +			}
> > +
> > +			num_freq_clk_volt -= 2;
> > +		}
> > +	}
> > +
> > +	/* Get external input clock (eclk) */
> > +	ov02a10->eclk = devm_clk_get(dev, "eclk");
> > +	if (IS_ERR(ov02a10->eclk)) {
> > +		ret = PTR_ERR(ov02a10->eclk);
> > +		dev_err(dev, "failed to get eclk %d\n", ret);
> > +		return ret;
> 
> 	return dev_err_probe(...);
> 

Great APIs...

> > +	}
> > +
> > +	ret = fwnode_property_read_u32(dev_fwnode(dev), "clock-frequency",
> > +				       &ov02a10->eclk_freq);
> > +	if (ret) {
> > +		dev_err(dev, "failed to get eclk frequency\n");
> > +		return ret;
> > +	}
> 
> > +	ret = clk_set_rate(ov02a10->eclk, ov02a10->eclk_freq);
> > +	if (ret) {
> > +		dev_err(dev, "failed to set eclk frequency (24MHz)\n");
> > +		return ret;
> > +	}
> > +
> > +	if (clk_get_rate(ov02a10->eclk) != OV02A10_ECLK_FREQ) {
> > +		dev_warn(dev, "eclk mismatched, mode is based on 24MHz\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	ov02a10->pd_gpio = devm_gpiod_get(dev, "powerdown", GPIOD_OUT_HIGH);
> > +	if (IS_ERR(ov02a10->pd_gpio)) {
> 
> > +		ret = PTR_ERR(ov02a10->pd_gpio);
> > +		dev_err(dev, "failed to get powerdown-gpios %d\n", ret);
> > +		return ret;
> 
> 	return dev_err_probe(...);
> 

It would be simplified using dev_err_probe directly in next release.

> > +	}
> > +
> > +	ov02a10->rst_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> > +	if (IS_ERR(ov02a10->rst_gpio)) {
> > +		ret = PTR_ERR(ov02a10->rst_gpio);
> > +		dev_err(dev, "failed to get reset-gpios %d\n", ret);
> > +		return ret;
> 
> Ditto.
> 

Fixed in next release.

> > +	}
> > +
> > +	for (i = 0; i < ARRAY_SIZE(ov02a10_supply_names); i++)
> > +		ov02a10->supplies[i].supply = ov02a10_supply_names[i];
> > +
> > +	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(ov02a10_supply_names),
> > +				      ov02a10->supplies);
> > +	if (ret) {
> 
> > +		dev_err(dev, "failed to get regulators\n");
> > +		return ret;
> 
> Ditto.
> 

Fixed in next release.

> > +	}
> > +
> > +	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;
> > +	}
> > +
> > +	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_free_handler;
> > +	}
> > +
> > +	pm_runtime_enable(dev);
> > +	if (!pm_runtime_enabled(dev)) {
> > +		ret = ov02a10_power_on(dev);
> > +		if (ret < 0) {
> > +			dev_err(dev, "failed to power on: %d\n", ret);
> > +			goto err_clean_entity;
> > +		}
> > +	}
> > +
> > +	ret = v4l2_async_register_subdev(&ov02a10->subdev);
> > +	if (ret) {
> > +		dev_err(dev, "failed to register V4L2 subdev: %d\n", ret);
> > +		goto err_power_off;
> > +	}
> > +
> > +	return 0;
> > +
> > +err_power_off:
> > +	if (pm_runtime_enabled(dev))
> > +		pm_runtime_disable(dev);
> > +	else
> > +		ov02a10_power_off(dev);
> > +err_clean_entity:
> > +	media_entity_cleanup(&ov02a10->subdev.entity);
> > +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(&client->dev);
> > +	pm_runtime_set_suspended(&client->dev);
> > +	mutex_destroy(&ov02a10->mutex);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id ov02a10_of_match[] = {
> > +	{ .compatible = "ovti,ov02a10" },
> > +	{}
> > +};
> > +MODULE_DEVICE_TABLE(of, ov02a10_of_match);
> > +
> > +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,
> > +};
> 
> > +
> 
> Redundant blank line.
> 

Fixed in next release.

> > +module_i2c_driver(ov02a10_i2c_driver);
> > +
> > +MODULE_AUTHOR("Dongchun Zhu <dongchun.zhu@xxxxxxxxxxxx>");
> > +MODULE_DESCRIPTION("OmniVision OV02A10 sensor driver");
> > +MODULE_LICENSE("GPL v2");
> > -- 
> > 2.9.2
> 






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