Re: [PATCH v1] media: i2c: add lt6911uxe hdmi bridge driver

[Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>]

Hi Dongcheng,

Thanks for the patch.

On Thu, Oct 10, 2024 at 03:10:10PM +0800, Dongcheng Yan wrote:
> Lontium LT9611UXE is a HDMI to MIPI CSI-2 bridge,
> It supports modes up to 4k60fps, switches current mode when
> plugging HDMI or changing the source active signal mode.
> 
> Signed-off-by: Dongcheng Yan <dongcheng.yan@xxxxxxxxx>
> ---
>  drivers/media/i2c/Kconfig     |  12 +
>  drivers/media/i2c/Makefile    |   1 +
>  drivers/media/i2c/lt6911uxe.c | 667 ++++++++++++++++++++++++++++++++++
>  3 files changed, 680 insertions(+)
>  create mode 100644 drivers/media/i2c/lt6911uxe.c
> 
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index c6d3ee472d81..abd7faaae305 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -1494,6 +1494,18 @@ config VIDEO_I2C
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called video-i2c
>  
> +config VIDEO_LT6911UXE
> +        tristate "Lontium LT6911UXE decoder"
> +        depends on ACPI && VIDEO_DEV
> +        select V4L2_FWNODE
> +        select V4L2_CCI_I2C
> +        help
> +          This is a Video4Linux2 sensor-level driver for the Lontium
> +          LT6911UXE HDMI to MIPI CSI-2 bridge.
> +
> +          To compile this driver as a module, choose M here: the
> +          module will be called lt6911uxe.
> +
>  config VIDEO_M52790
>  	tristate "Mitsubishi M52790 A/V switch"
>  	depends on VIDEO_DEV && I2C
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index dfbe6448b549..87005dafa079 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -61,6 +61,7 @@ obj-$(CONFIG_VIDEO_ISL7998X) += isl7998x.o
>  obj-$(CONFIG_VIDEO_KS0127) += ks0127.o
>  obj-$(CONFIG_VIDEO_LM3560) += lm3560.o
>  obj-$(CONFIG_VIDEO_LM3646) += lm3646.o
> +obj-$(CONFIG_VIDEO_LT6911UXE) += lt6911uxe.o
>  obj-$(CONFIG_VIDEO_M52790) += m52790.o
>  obj-$(CONFIG_VIDEO_MAX9271_LIB) += max9271.o
>  obj-$(CONFIG_VIDEO_MAX9286) += max9286.o
> diff --git a/drivers/media/i2c/lt6911uxe.c b/drivers/media/i2c/lt6911uxe.c
> new file mode 100644
> index 000000000000..11ad78b83137
> --- /dev/null
> +++ b/drivers/media/i2c/lt6911uxe.c
> @@ -0,0 +1,667 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (c) 2023 - 2024 Intel Corporation.
> +
> +#include <linux/acpi.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <media/v4l2-cci.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-event.h>
> +#include <media/v4l2-fwnode.h>
> +
> +#define LT6911UXE_CHIP_ID		0x2102
> +#define REG_CHIP_ID_H			CCI_REG8(0xe100)
> +#define REG_CHIP_ID_L			CCI_REG8(0xe101)
> +
> +#define REG_ENABLE_I2C			CCI_REG8(0xe0ee)
> +#define REG_PIX_CLK			CCI_REG24(0xe085)
> +#define REG_BYTE_CLK			CCI_REG24(0xe092)
> +#define REG_H_TOTAL			CCI_REG16(0xe088)
> +#define REG_V_TOTAL			CCI_REG16(0xe08a)
> +#define REG_HALF_H_ACTIVE		CCI_REG16(0xe08c)
> +#define REG_V_ACTIVE			CCI_REG16(0xe08e)
> +#define REG_MIPI_FORMAT			CCI_REG8(0xe096)
> +#define REG_MIPI_TX_CTRL		CCI_REG8(0xe0b0)
> +
> +/* Interrupts */
> +#define REG_INT_HDMI			CCI_REG8(0xe084)
> +#define INT_VIDEO_DISAPPEAR		0x0
> +#define INT_VIDEO_READY			0x1
> +
> +#define LT6911UXE_DEFAULT_WIDTH		3840
> +#define LT6911UXE_DEFAULT_HEIGHT	2160
> +#define LT6911UXE_DEFAULT_LANES		4
> +#define LT6911UXE_DEFAULT_FPS		30
> +#define LT6911UXE_MAX_LINK_FREQ		297000000
> +#define LT9611_PAGE_CONTROL		0xff
> +#define YUV422_8_BIT			0x7
> +
> +static const struct regmap_range_cfg lt9611uxe_ranges[] = {
> +	{
> +		.name = "register_range",
> +		.range_min =  0,
> +		.range_max = 0xffff,
> +		.selector_reg = LT9611_PAGE_CONTROL,
> +		.selector_mask = 0xff,
> +		.selector_shift = 0,
> +		.window_start = 0,
> +		.window_len = 0x100,
> +	},
> +};
> +
> +static const struct regmap_config lt9611uxe_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = 0xffff,
> +	.ranges = lt9611uxe_ranges,
> +	.num_ranges = ARRAY_SIZE(lt9611uxe_ranges),
> +};
> +
> +struct lt6911uxe_mode {
> +	u32 width;
> +	u32 height;
> +	u32 code;
> +	u32 fps;
> +	u32 lanes;
> +	s64 link_freq;
> +};
> +
> +struct lt6911uxe {
> +	struct v4l2_subdev sd;
> +	struct media_pad pad;
> +	struct v4l2_ctrl_handler ctrl_handler;
> +	struct v4l2_ctrl *pixel_rate;
> +	struct v4l2_ctrl *link_freq;
> +
> +	struct lt6911uxe_mode cur_mode;
> +	struct regmap *regmap;
> +	unsigned int irq_pin_flags;
> +	struct gpio_desc *reset_gpio;
> +	struct gpio_desc *irq_gpio;
> +	struct mutex mutex;
> +};
> +
> +static const struct v4l2_event lt6911uxe_ev_source_change = {
> +	.type = V4L2_EVENT_SOURCE_CHANGE,
> +	.u.src_change.changes = V4L2_EVENT_SRC_CH_RESOLUTION,
> +};
> +
> +static const struct v4l2_event lt6911uxe_ev_stream_end = {
> +	.type = V4L2_EVENT_EOS,
> +};
> +
> +static inline struct lt6911uxe *to_lt6911uxe(struct v4l2_subdev *sd)
> +{
> +	return container_of(sd, struct lt6911uxe, sd);
> +}
> +
> +static const struct lt6911uxe_mode default_mode = {
> +	.width = LT6911UXE_DEFAULT_WIDTH,
> +	.height = LT6911UXE_DEFAULT_HEIGHT,
> +	.code = MEDIA_BUS_FMT_UYVY8_1X16,
> +	.fps = LT6911UXE_DEFAULT_FPS,
> +	.lanes = LT6911UXE_DEFAULT_LANES,
> +	.link_freq = LT6911UXE_MAX_LINK_FREQ,
> +};
> +
> +static s64 get_pixel_rate(struct lt6911uxe *lt6911uxe)
> +{
> +	s64 pixel_rate;
> +
> +	pixel_rate = (s64)lt6911uxe->cur_mode.width *
> +		     lt6911uxe->cur_mode.height *
> +		     lt6911uxe->cur_mode.fps * 16;
> +	do_div(pixel_rate, lt6911uxe->cur_mode.lanes);
> +
> +	return pixel_rate;
> +}
> +
> +static int lt6911uxe_status_update(struct lt6911uxe *lt6911uxe)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&lt6911uxe->sd);
> +	u64 int_event;
> +	u64 byte_clk, pixel_clk, fps, format;
> +	u64 htotal, vtotal, half_width, height;
> +	int ret = 0;
> +
> +	/* Read interrupt event */
> +	cci_read(lt6911uxe->regmap, REG_INT_HDMI, &int_event, &ret);
> +	if (ret)
> +		return dev_err_probe(&client->dev, ret,
> +				     "failed to read interrupt event\n");
> +
> +	switch (int_event) {
> +	case INT_VIDEO_READY:
> +		cci_read(lt6911uxe->regmap, REG_BYTE_CLK, &byte_clk, &ret);
> +		byte_clk *= 1000;
> +		cci_read(lt6911uxe->regmap, REG_PIX_CLK, &pixel_clk, &ret);
> +		pixel_clk *= 1000;
> +
> +		if (ret || byte_clk == 0 || pixel_clk == 0) {
> +			dev_err(&client->dev,
> +				"invalid ByteClock or PixelClock\n");
> +			return -EINVAL;
> +		}
> +
> +		cci_read(lt6911uxe->regmap, REG_H_TOTAL, &htotal, &ret);
> +		cci_read(lt6911uxe->regmap, REG_V_TOTAL, &vtotal, &ret);
> +		if (ret || htotal == 0 || vtotal == 0) {
> +			dev_err(&client->dev, "invalid htotal or vtotal\n");
> +			return -EINVAL;
> +		}
> +
> +		fps = div_u64(pixel_clk, htotal * vtotal);
> +		if (fps > 60) {
> +			dev_err(&client->dev,
> +				"max fps is 60, current fps: %llu\n", fps);
> +			return -EINVAL;
> +		}
> +
> +		cci_read(lt6911uxe->regmap, REG_HALF_H_ACTIVE,
> +			 &half_width, &ret);
> +		cci_read(lt6911uxe->regmap, REG_V_ACTIVE, &height, &ret);
> +		if (ret || half_width == 0 || half_width * 2 > 3840 ||
> +		    height == 0 || height > 2160) {
> +			dev_err(&client->dev, "invalid width or height\n");
> +			return -EINVAL;
> +		}
> +
> +		/*
> +		 * Get MIPI format, YUV422_8_BIT is expected in lt6911uxe
> +		 */
> +		cci_read(lt6911uxe->regmap, REG_MIPI_FORMAT, &format, &ret);
> +		if (format != YUV422_8_BIT) {
> +			dev_err(&client->dev, "invalid MIPI format\n");
> +			return -EINVAL;
> +		}
> +		lt6911uxe->cur_mode.height = height;
> +		lt6911uxe->cur_mode.width = half_width * 2;
> +		lt6911uxe->cur_mode.fps = fps;
> +		/* MIPI Clock Rate = ByteClock × 4, defined in lt6911uxe spec */
> +		lt6911uxe->cur_mode.link_freq = byte_clk * 4;
> +		v4l2_subdev_notify_event(&lt6911uxe->sd,
> +					 &lt6911uxe_ev_source_change);
> +		break;
> +
> +	case INT_VIDEO_DISAPPEAR:
> +		cci_write(lt6911uxe->regmap, REG_MIPI_TX_CTRL, 0x0, NULL);
> +		lt6911uxe->cur_mode.height = 0;
> +		lt6911uxe->cur_mode.width = 0;
> +		lt6911uxe->cur_mode.fps = 0;
> +		lt6911uxe->cur_mode.link_freq = 0;
> +		v4l2_subdev_notify_event(&lt6911uxe->sd,
> +					 &lt6911uxe_ev_stream_end);
> +		break;
> +
> +	default:
> +		return  -ENOLINK;
> +	}
> +
> +	return ret;
> +}
> +
> +static int lt6911uxe_init_controls(struct lt6911uxe *lt6911uxe)
> +{
> +	struct v4l2_ctrl_handler *ctrl_hdlr;
> +	s64 pixel_rate;
> +	int ret;
> +
> +	ctrl_hdlr = &lt6911uxe->ctrl_handler;
> +	ret = v4l2_ctrl_handler_init(ctrl_hdlr, 8);
> +	if (ret)
> +		return ret;
> +
> +	ctrl_hdlr->lock = &lt6911uxe->mutex;
> +	lt6911uxe->link_freq = v4l2_ctrl_new_std(ctrl_hdlr, NULL,
> +						 V4L2_CID_CUR_LINK_FREQ, 0,
> +						 LT6911UXE_MAX_LINK_FREQ, 1,
> +						 lt6911uxe->cur_mode.link_freq);
> +
> +	pixel_rate = get_pixel_rate(lt6911uxe);
> +	lt6911uxe->pixel_rate = v4l2_ctrl_new_std(ctrl_hdlr, NULL,
> +						  V4L2_CID_PIXEL_RATE,
> +						  pixel_rate, pixel_rate, 1,
> +						  pixel_rate);
> +
> +	if (ctrl_hdlr->error) {
> +		ret = ctrl_hdlr->error;
> +		goto hdlr_free;
> +	}
> +	lt6911uxe->sd.ctrl_handler = ctrl_hdlr;
> +
> +	return 0;
> +
> +hdlr_free:
> +	v4l2_ctrl_handler_free(ctrl_hdlr);
> +	return ret;
> +}
> +
> +static void lt6911uxe_update_pad_format(const struct lt6911uxe_mode *mode,
> +					struct v4l2_mbus_framefmt *fmt)
> +{
> +	fmt->width = mode->width;
> +	fmt->height = mode->height;
> +	fmt->code = mode->code;
> +	fmt->field = V4L2_FIELD_NONE;
> +}
> +
> +static int lt6911uxe_start_streaming(struct lt6911uxe *lt6911uxe)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&lt6911uxe->sd);
> +	int ret;
> +
> +	ret = pm_runtime_resume_and_get(&client->dev);
> +	if (ret < 0)
> +		return ret;
> +
> +	cci_write(lt6911uxe->regmap, REG_MIPI_TX_CTRL, 0x1, &ret);
> +	if (ret) {
> +		dev_err(&client->dev, "failed to start stream\n");
> +		goto err_rpm_put;
> +	}
> +
> +	return 0;
> +
> +err_rpm_put:
> +	pm_runtime_put(&client->dev);
> +	return ret;
> +}
> +
> +static int lt6911uxe_enable_streams(struct v4l2_subdev *sd,
> +				    struct v4l2_subdev_state *state,
> +				    u32 pad, u64 streams_mask)
> +{
> +	struct lt6911uxe *lt6911uxe = to_lt6911uxe(sd);
> +	int ret;
> +
> +	if (pad != 0)
> +		return -EINVAL;
> +
> +	mutex_lock(&lt6911uxe->mutex);

You should rely on sub-device (active) state lock here and not use driver
specific locks. It's already taken by the caller, this holds for all ops
where state is an argument.

> +	ret = lt6911uxe_start_streaming(lt6911uxe);
> +	mutex_unlock(&lt6911uxe->mutex);
> +
> +	return ret;
> +}
> +
> +static int lt6911uxe_disable_streams(struct v4l2_subdev *sd,
> +				     struct v4l2_subdev_state *state,
> +				     u32 pad, u64 streams_mask)
> +{
> +	struct lt6911uxe *lt6911uxe = to_lt6911uxe(sd);
> +	struct i2c_client *client = v4l2_get_subdevdata(&lt6911uxe->sd);
> +	int ret;
> +
> +	if (pad != 0)
> +		return -EINVAL;
> +
> +	mutex_lock(&lt6911uxe->mutex);
> +	ret = cci_write(lt6911uxe->regmap, REG_MIPI_TX_CTRL, 0x0, NULL);
> +	if (ret)
> +		dev_err(&client->dev, "failed to stop stream\n");
> +	mutex_unlock(&lt6911uxe->mutex);
> +
> +	return ret;
> +}
> +
> +static int lt6911uxe_set_format(struct v4l2_subdev *sd,
> +				struct v4l2_subdev_state *sd_state,
> +				struct v4l2_subdev_format *fmt)
> +{
> +	struct lt6911uxe *lt6911uxe = to_lt6911uxe(sd);
> +	u64 pixel_rate;
> +
> +	mutex_lock(&lt6911uxe->mutex);
> +	lt6911uxe_update_pad_format(&lt6911uxe->cur_mode, &fmt->format);
> +	*v4l2_subdev_state_get_format(sd_state, fmt->pad) = fmt->format;
> +	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY) {
> +		mutex_unlock(&lt6911uxe->mutex);
> +		return 0;
> +	}
> +
> +	pixel_rate = get_pixel_rate(lt6911uxe);
> +	__v4l2_ctrl_modify_range(lt6911uxe->pixel_rate, pixel_rate,
> +				 pixel_rate, 1, pixel_rate);
> +
> +	mutex_unlock(&lt6911uxe->mutex);
> +	return 0;
> +}
> +
> +static int lt6911uxe_enum_mbus_code(struct v4l2_subdev *sd,
> +				    struct v4l2_subdev_state *sd_state,
> +				    struct v4l2_subdev_mbus_code_enum *code)
> +{
> +	struct lt6911uxe *lt6911uxe = to_lt6911uxe(sd);
> +
> +	if (code->pad || code->index)
> +		return -EINVAL;

No need to check pad, this has been checked on caller side already. Same
for {en,dis}able_streams, too.

> +
> +	code->code = lt6911uxe->cur_mode.code;
> +
> +	return 0;
> +}
> +
> +static int lt6911uxe_enum_frame_size(struct v4l2_subdev *sd,
> +				     struct v4l2_subdev_state *sd_state,
> +				     struct v4l2_subdev_frame_size_enum *fse)
> +{
> +	struct lt6911uxe *lt6911uxe = to_lt6911uxe(sd);
> +
> +	if (fse->index != 0)
> +		return -EINVAL;
> +
> +	if (fse->code != MEDIA_BUS_FMT_UYVY8_1X16)
> +		return -EINVAL;
> +
> +	fse->min_width = lt6911uxe->cur_mode.width;
> +	fse->max_width = fse->min_width;
> +	fse->min_height = lt6911uxe->cur_mode.height;
> +	fse->max_height = fse->min_height;
> +
> +	return 0;
> +}
> +
> +static int lt6911uxe_enum_frame_interval(struct v4l2_subdev *sd,
> +		struct v4l2_subdev_state *sd_state,
> +		struct v4l2_subdev_frame_interval_enum *fie)
> +{
> +	struct lt6911uxe *lt6911uxe = to_lt6911uxe(sd);
> +
> +	if (fie->index != 0)
> +		return -EINVAL;
> +
> +	fie->interval.numerator = 1;
> +	fie->interval.denominator = lt6911uxe->cur_mode.fps;
> +
> +	return 0;
> +}
> +
> +static int lt6911uxe_init_state(struct v4l2_subdev *sd,
> +				struct v4l2_subdev_state *sd_state)
> +{
> +	struct v4l2_subdev_format fmt = {
> +		.which = V4L2_SUBDEV_FORMAT_TRY,
> +		.pad = 0,
> +		.format = {
> +			.code = MEDIA_BUS_FMT_UYVY8_1X16,
> +			.width = LT6911UXE_DEFAULT_WIDTH,
> +			.height = LT6911UXE_DEFAULT_HEIGHT,
> +		},
> +	};
> +	int ret;
> +
> +	ret = lt6911uxe_set_format(sd, sd_state, &fmt);

return ...;

> +
> +	return ret;
> +}
> +
> +static const struct v4l2_subdev_video_ops lt6911uxe_video_ops = {
> +	.s_stream = v4l2_subdev_s_stream_helper,
> +};
> +
> +static const struct v4l2_subdev_pad_ops lt6911uxe_pad_ops = {
> +	.set_fmt = lt6911uxe_set_format,
> +	.get_fmt = v4l2_subdev_get_fmt,
> +	.enable_streams = lt6911uxe_enable_streams,
> +	.disable_streams = lt6911uxe_disable_streams,
> +	.enum_mbus_code = lt6911uxe_enum_mbus_code,
> +	.enum_frame_size = lt6911uxe_enum_frame_size,
> +	.enum_frame_interval = lt6911uxe_enum_frame_interval,
> +};
> +
> +static const struct v4l2_subdev_core_ops lt6911uxe_subdev_core_ops = {
> +	.subscribe_event = v4l2_ctrl_subdev_subscribe_event,
> +	.unsubscribe_event = v4l2_event_subdev_unsubscribe,
> +};
> +
> +static const struct v4l2_subdev_ops lt6911uxe_subdev_ops = {
> +	.core = &lt6911uxe_subdev_core_ops,
> +	.video = &lt6911uxe_video_ops,
> +	.pad = &lt6911uxe_pad_ops,
> +};
> +
> +static const struct media_entity_operations lt6911uxe_subdev_entity_ops = {
> +	.link_validate = v4l2_subdev_link_validate,
> +};
> +
> +static const struct v4l2_subdev_internal_ops lt6911uxe_internal_ops = {
> +	.init_state = lt6911uxe_init_state,
> +};
> +
> +static int lt6911uxe_fwnode_parse(struct lt6911uxe *lt6911uxe,
> +				  struct device *dev)
> +{
> +	struct fwnode_handle *endpoint;
> +	struct v4l2_fwnode_endpoint bus_cfg = {
> +		.bus_type = V4L2_MBUS_CSI2_DPHY,
> +	};
> +	int ret;
> +
> +	endpoint = fwnode_graph_get_endpoint_by_id(dev_fwnode(dev), 0, 0,
> +						   FWNODE_GRAPH_ENDPOINT_NEXT);
> +	if (!endpoint) {
> +		dev_err(dev, "endpoint node not found\n");
> +		return -EPROBE_DEFER;
> +	}
> +
> +	ret = v4l2_fwnode_endpoint_parse(endpoint, &bus_cfg);
> +	if (ret) {
> +		dev_err(dev, "failed to parse endpoint node\n");
> +		goto out_err;
> +	}
> +
> +	/*
> +	 * Check the number of MIPI CSI2 data lanes,
> +	 * lt6911uxe only support 4 lanes.
> +	 */
> +	if (bus_cfg.bus.mipi_csi2.num_data_lanes != LT6911UXE_DEFAULT_LANES) {
> +		dev_err(dev, "only 4 data lanes are currently supported\n");
> +		goto out_err;
> +	}
> +
> +	return 0;
> +
> +out_err:
> +	v4l2_fwnode_endpoint_free(&bus_cfg);
> +	fwnode_handle_put(endpoint);
> +	return ret;
> +}
> +
> +static int lt6911uxe_identify_module(struct lt6911uxe *lt6911uxe)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&lt6911uxe->sd);
> +	u64 val_h, val_l;
> +	u16 val;
> +	int ret = 0;
> +
> +	/* Chip ID should be confirmed when the I2C slave is active */
> +	cci_write(lt6911uxe->regmap, REG_ENABLE_I2C, 0x1, &ret);
> +	cci_read(lt6911uxe->regmap, REG_CHIP_ID_H, &val_h, &ret);
> +	cci_read(lt6911uxe->regmap, REG_CHIP_ID_L, &val_l, &ret);

Would a single 16-bit read work?

> +	cci_write(lt6911uxe->regmap, REG_ENABLE_I2C, 0x0, &ret);
> +	if (ret) {
> +		dev_err(&client->dev, "fail to read chip id\n");
> +		return ret;
> +	}
> +
> +	val = (val_h << 8) | val_l;
> +
> +	if (val != LT6911UXE_CHIP_ID) {
> +		dev_err(&client->dev, "chip id mismatch: %x!=%x\n",
> +			LT6911UXE_CHIP_ID, val);
> +		return -ENXIO;
> +	}
> +
> +	return 0;
> +}
> +
> +static int lt6911uxe_parse_gpio(struct lt6911uxe *lt6911uxe, struct device *dev)
> +{
> +	lt6911uxe->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_IN);
> +	if (IS_ERR(lt6911uxe->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(lt6911uxe->reset_gpio),
> +				     "failed to get reset gpio\n");
> +
> +	lt6911uxe->irq_gpio = devm_gpiod_get(dev, "readystat", GPIOD_IN);
> +	if (IS_ERR(lt6911uxe->irq_gpio))
> +		return dev_err_probe(dev, PTR_ERR(lt6911uxe->irq_gpio),
> +				     "failed to get ready_stat gpio\n");
> +
> +	return 0;
> +}
> +
> +static irqreturn_t lt6911uxe_threaded_irq_fn(int irq, void *dev_id)
> +{
> +	struct v4l2_subdev *sd = dev_id;
> +	struct lt6911uxe *lt6911uxe = to_lt6911uxe(sd);
> +
> +	mutex_lock(&lt6911uxe->mutex);

Please acquire the sub-device active state lock here instead. You can use
v4l2_subdev_lock_and_get_active_state().

> +	lt6911uxe_status_update(lt6911uxe);
> +	mutex_unlock(&lt6911uxe->mutex);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static void lt6911uxe_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct lt6911uxe *lt6911uxe = to_lt6911uxe(sd);
> +
> +	free_irq(gpiod_to_irq(lt6911uxe->irq_gpio), lt6911uxe);
> +	v4l2_async_unregister_subdev(&lt6911uxe->sd);
> +	v4l2_subdev_cleanup(sd);
> +	media_entity_cleanup(&lt6911uxe->sd.entity);
> +	v4l2_ctrl_handler_free(&lt6911uxe->ctrl_handler);
> +	pm_runtime_disable(&client->dev);
> +	pm_runtime_set_suspended(&client->dev);
> +}
> +
> +static int lt6911uxe_probe(struct i2c_client *client)
> +{
> +	struct lt6911uxe *lt6911uxe;
> +	int ret;
> +
> +	lt6911uxe = devm_kzalloc(&client->dev, sizeof(*lt6911uxe), GFP_KERNEL);
> +	if (!lt6911uxe)
> +		return -ENOMEM;
> +
> +	/* define default mode: 4k@60fps, changed when interrupt occurs. */
> +	lt6911uxe->cur_mode = default_mode;
> +
> +	lt6911uxe->regmap = devm_regmap_init_i2c(client,
> +						 &lt9611uxe_regmap_config);
> +	if (IS_ERR(lt6911uxe->regmap))
> +		return dev_err_probe(&client->dev, PTR_ERR(lt6911uxe->regmap),
> +				     "failed to init CCI\n");
> +
> +	ret = lt6911uxe_parse_gpio(lt6911uxe, &client->dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = lt6911uxe_fwnode_parse(lt6911uxe, &client->dev);
> +	if (ret)
> +		return ret;
> +
> +	usleep_range(10000, 10500);
> +
> +	ret = lt6911uxe_identify_module(lt6911uxe);
> +	if (ret)
> +		return dev_err_probe(&client->dev, ret,
> +				     "failed to find chip\n");
> +
> +	mutex_init(&lt6911uxe->mutex);
> +	v4l2_i2c_subdev_init(&lt6911uxe->sd, client, &lt6911uxe_subdev_ops);
> +	ret = lt6911uxe_init_controls(lt6911uxe);
> +	if (ret) {
> +		dev_info(&client->dev, "failed to init control: %d\n", ret);
> +		goto probe_error_v4l2_ctrl_handler_free;
> +	}
> +
> +	lt6911uxe->sd.dev = &client->dev;
> +	lt6911uxe->sd.internal_ops = &lt6911uxe_internal_ops;
> +	lt6911uxe->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE |
> +			       V4L2_SUBDEV_FL_HAS_EVENTS;
> +	lt6911uxe->sd.entity.ops = &lt6911uxe_subdev_entity_ops;
> +	lt6911uxe->sd.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
> +	lt6911uxe->pad.flags = MEDIA_PAD_FL_SOURCE;
> +	ret = media_entity_pads_init(&lt6911uxe->sd.entity, 1, &lt6911uxe->pad);
> +	if (ret) {
> +		dev_err(&client->dev, "failed to init entity pads: %d\n", ret);
> +		goto probe_error_v4l2_ctrl_handler_free;
> +	}
> +
> +	/*
> +	 * Device is already turned on by i2c-core with ACPI domain PM.
> +	 * Enable runtime PM and turn off the device.
> +	 */
> +	pm_runtime_set_active(&client->dev);
> +	pm_runtime_enable(&client->dev);
> +	pm_runtime_idle(&client->dev);
> +
> +	ret = v4l2_subdev_init_finalize(&lt6911uxe->sd);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "failed to init v4l2 subdev: %d\n", ret);
> +		goto probe_error_media_entity_cleanup;
> +	}
> +
> +	ret = v4l2_async_register_subdev_sensor(&lt6911uxe->sd);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "failed to register V4L2 subdev: %d\n",
> +			ret);
> +		goto rpm;
> +	}
> +
> +	/* Setting irq */
> +	lt6911uxe->irq_pin_flags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING |
> +				   IRQF_ONESHOT;
> +
> +	ret = request_threaded_irq(gpiod_to_irq(lt6911uxe->irq_gpio), NULL,
> +				   lt6911uxe_threaded_irq_fn,
> +				   lt6911uxe->irq_pin_flags, NULL, lt6911uxe);

As registering an IRQ can fail, you should do that before registering the
async sub-device.

> +	if (ret) {
> +		dev_err(&client->dev, "failed to request IRQ\n");
> +		free_irq(gpiod_to_irq(lt6911uxe->irq_gpio), lt6911uxe);
> +		goto rpm;
> +	}
> +
> +	return 0;
> +
> +rpm:
> +	pm_runtime_disable(&client->dev);
> +	v4l2_subdev_cleanup(&lt6911uxe->sd);
> +
> +probe_error_media_entity_cleanup:
> +	media_entity_cleanup(&lt6911uxe->sd.entity);
> +
> +probe_error_v4l2_ctrl_handler_free:
> +	v4l2_ctrl_handler_free(lt6911uxe->sd.ctrl_handler);
> +	mutex_destroy(&lt6911uxe->mutex);
> +	return ret;
> +}
> +
> +static const struct acpi_device_id lt6911uxe_acpi_ids[] = {
> +	{ "INTC10C5" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(acpi, lt6911uxe_acpi_ids);
> +
> +static struct i2c_driver lt6911uxe_i2c_driver = {
> +	.driver = {
> +		.name = "lt6911uxe",
> +		.acpi_match_table = ACPI_PTR(lt6911uxe_acpi_ids),
> +	},
> +	.probe = lt6911uxe_probe,
> +	.remove = lt6911uxe_remove,
> +};
> +
> +module_i2c_driver(lt6911uxe_i2c_driver);
> +
> +MODULE_AUTHOR("Yan Dongcheng <dongcheng.yan@xxxxxxxxx>");
> +MODULE_DESCRIPTION("Lontium lt6911uxe HDMI to MIPI Bridge Driver");
> +MODULE_LICENSE("GPL");
> 
> base-commit: 6ba59ff4227927d3a8530fc2973b80e94b54d58f

-- 
Kind regards,

Sakari Ailus