Re: [PATCH v5] media: i2c: add lt6911uxe hdmi bridge driver

["Yan, Dongcheng" <dongcheng.yan@linux.intel.com>]

Hi hans,

On 2/26/2025 6:51 PM, Hans Verkuil wrote:
> On 10/02/2025 07:09, 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@intel.com>
>> ---
>> v1 -> v2: replaced mutex with state_lock
>> v2 -> v3: fixed some pm_runtime err handlings
>> v3 -> v4: add dv_timings api
>> v4 -> v5: use get_mbus_config to replace link_freq v4l2_ctrl_handler
>> 	  rm lt6911uxe_enum_frame_size & lt6911uxe_enum_frame_interval
>>
>> patch has been tested with Intel IPU isp.
>> ---
>>  drivers/media/i2c/Kconfig     |  12 +
>>  drivers/media/i2c/Makefile    |   1 +
>>  drivers/media/i2c/lt6911uxe.c | 717 ++++++++++++++++++++++++++++++++++
>>  3 files changed, 730 insertions(+)
>>  create mode 100644 drivers/media/i2c/lt6911uxe.c
>>
>> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
>> index 8ba096b8ebca..fbe3d0fe4ce6 100644
>> --- a/drivers/media/i2c/Kconfig
>> +++ b/drivers/media/i2c/Kconfig
>> @@ -1526,6 +1526,18 @@ 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 fbb988bd067a..6c23a4463527 100644
>> --- a/drivers/media/i2c/Makefile
>> +++ b/drivers/media/i2c/Makefile
>> @@ -64,6 +64,7 @@ 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..4f74648e4545
>> --- /dev/null
>> +++ b/drivers/media/i2c/lt6911uxe.c
>> @@ -0,0 +1,717 @@
>> +// 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 <linux/v4l2-dv-timings.h>
>> +
>> +#include <media/v4l2-cci.h>
>> +#include <media/v4l2-ctrls.h>
>> +#include <media/v4l2-device.h>
>> +#include <media/v4l2-dv-timings.h>
>> +#include <media/v4l2-event.h>
>> +#include <media/v4l2-fwnode.h>
>> +
>> +#define LT6911UXE_CHIP_ID		0x2102
>> +#define REG_CHIP_ID			CCI_REG16(0xe100)
>> +
>> +#define REG_ENABLE_I2C			CCI_REG8(0xe0ee)
>> +#define REG_HALF_PIX_CLK		CCI_REG24(0xe085)
>> +#define REG_BYTE_CLK			CCI_REG24(0xe092)
>> +#define REG_HALF_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_LANES		4
>> +#define LT9611_PAGE_CONTROL		0xff
>> +#define YUV422_8_BIT			0x7
>> +
>> +static const struct v4l2_dv_timings_cap lt6911uxe_timings_cap_4kp30 = {
>> +	.type = V4L2_DV_BT_656_1120,
>> +	/* Pixel clock from REF_01 p. 20. Min/max height/width are unknown */
>> +	V4L2_INIT_BT_TIMINGS(
>> +		160, 3840,				/* min/max width */
>> +		120, 2160,				/* min/max height */
>> +		50000000, 594000000,			/* min/max pixelclock */
>> +		V4L2_DV_BT_STD_CEA861 | V4L2_DV_BT_STD_DMT |
>> +		V4L2_DV_BT_STD_CVT,
>> +		V4L2_DV_BT_CAP_PROGRESSIVE | V4L2_DV_BT_CAP_CUSTOM |
>> +		V4L2_DV_BT_CAP_REDUCED_BLANKING)
>> +};
>> +
>> +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 htotal;
>> +	u32 vtotal;
>> +	u32 code;
>> +	u32 fps;
>> +	u32 lanes;
>> +	s64 link_freq;
>> +	u64 pixel_clk;
>> +};
>> +
>> +struct lt6911uxe {
>> +	struct v4l2_subdev sd;
>> +	struct media_pad pad;
>> +	struct v4l2_ctrl_handler ctrl_handler;
>> +	struct v4l2_ctrl *pixel_rate;
>> +	struct v4l2_dv_timings timings;
>> +	struct lt6911uxe_mode cur_mode;
>> +	struct regmap *regmap;
>> +	struct gpio_desc *reset_gpio;
>> +	struct gpio_desc *irq_gpio;
>> +};
>> +
>> +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 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_get_detected_timings(struct v4l2_subdev *sd,
>> +					  struct v4l2_dv_timings *timings)
>> +{
>> +	struct lt6911uxe *lt6911uxe = to_lt6911uxe(sd);
>> +	struct v4l2_bt_timings *bt = &timings->bt;
>> +
>> +	memset(timings, 0, sizeof(struct v4l2_dv_timings));
>> +
>> +	timings->type = V4L2_DV_BT_656_1120;
>> +
>> +	bt->width = lt6911uxe->cur_mode.width;
>> +	bt->height = lt6911uxe->cur_mode.height;
>> +	bt->vsync = lt6911uxe->cur_mode.vtotal - lt6911uxe->cur_mode.height;
>> +	bt->hsync = lt6911uxe->cur_mode.htotal - lt6911uxe->cur_mode.width;
>> +	bt->pixelclock = lt6911uxe->cur_mode.pixel_clk;
>> +
>> +	return 0;
>> +}
>> +
>> +static int lt6911uxe_s_dv_timings(struct v4l2_subdev *sd, unsigned int pad,
>> +				  struct v4l2_dv_timings *timings)
>> +{
>> +	struct lt6911uxe *lt6911uxe = to_lt6911uxe(sd);
>> +	struct v4l2_subdev_state *state;
>> +
>> +	state = v4l2_subdev_lock_and_get_active_state(sd);
>> +	if (v4l2_match_dv_timings(&lt6911uxe->timings, timings, 0, false))
> 
> You're not unlocking the state here.
> 
>> +		return 0;
>> +
>> +	if (!v4l2_valid_dv_timings(timings, &lt6911uxe_timings_cap_4kp30,
>> +				   NULL, NULL)) {
>> +		v4l2_warn(sd, "timings out of range\n");
> 
> Drop this. You don't want to log if the userspace input is invalid in the kernel log,
> and the error code really says it all anyway.
> 

They will all fixed in patch v6(send to LKML today), I also replace
lt6911uxe_get_fmt with v4l2_subdev_get_fmt, and update current format in
irq_handle func, so that the bridge always keeps the same format as the
HDMI source.

Thanks,
Dongcheng

>> +		v4l2_subdev_unlock_state(state);
>> +		return -ERANGE;
>> +	}
>> +	lt6911uxe->timings = *timings;
>> +	v4l2_subdev_unlock_state(state);
>> +
>> +	return 0;
>> +}
>> +
>> +static int lt6911uxe_g_dv_timings(struct v4l2_subdev *sd, unsigned int pad,
>> +				  struct v4l2_dv_timings *timings)
>> +{
>> +	struct lt6911uxe *lt6911uxe = to_lt6911uxe(sd);
>> +	struct v4l2_subdev_state *state;
>> +
>> +	state = v4l2_subdev_lock_and_get_active_state(sd);
>> +
>> +	*timings = lt6911uxe->timings;
>> +	v4l2_subdev_unlock_state(state);
>> +
>> +	return 0;
>> +}
>> +
>> +static int lt6911uxe_query_dv_timings(struct v4l2_subdev *sd, unsigned int pad,
>> +				      struct v4l2_dv_timings *timings)
>> +{
>> +	struct v4l2_subdev_state *state;
>> +	int ret;
>> +
>> +	state = v4l2_subdev_lock_and_get_active_state(sd);
>> +	ret = lt6911uxe_get_detected_timings(sd, timings);
>> +	if (ret) {
>> +		v4l2_subdev_unlock_state(state);
>> +		return ret;
>> +	}
>> +
>> +	if (!v4l2_valid_dv_timings(timings, &lt6911uxe_timings_cap_4kp30,
>> +				   NULL, NULL)) {
>> +		v4l2_subdev_unlock_state(state);
>> +		return -ERANGE;
>> +	}
>> +
>> +	v4l2_subdev_unlock_state(state);
>> +	return 0;
>> +}
>> +
>> +static int lt6911uxe_enum_dv_timings(struct v4l2_subdev *sd,
>> +				     struct v4l2_enum_dv_timings *timings)
>> +{
>> +	return v4l2_enum_dv_timings_cap(timings,
>> +			&lt6911uxe_timings_cap_4kp30, NULL, NULL);
>> +}
>> +
>> +static int lt6911uxe_dv_timings_cap(struct v4l2_subdev *sd,
>> +				    struct v4l2_dv_timings_cap *cap)
>> +{
>> +	*cap = lt6911uxe_timings_cap_4kp30;
>> +	return 0;
>> +}
>> +
>> +static int lt6911uxe_status_update(struct lt6911uxe *lt6911uxe)
>> +{
>> +	struct i2c_client *client = v4l2_get_subdevdata(&lt6911uxe->sd);
>> +	u64 int_event;
>> +	u64 byte_clk, half_pix_clk, fps, format;
>> +	u64 half_htotal, vtotal, half_width, height;
>> +	int ret = 0;
>> +
>> +	/* Read interrupt event */
>> +	cci_read(lt6911uxe->regmap, REG_INT_HDMI, &int_event, &ret);
>> +	if (ret) {
>> +		dev_err(&client->dev, "failed to read interrupt event: %d\n",
>> +			ret);
>> +		return ret;
>> +	}
>> +
>> +	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_HALF_PIX_CLK,
>> +			 &half_pix_clk, &ret);
>> +		half_pix_clk *= 1000;
>> +
>> +		if (ret || byte_clk == 0 || half_pix_clk == 0) {
>> +			dev_dbg(&client->dev,
>> +				"invalid ByteClock or PixelClock\n");
>> +			return -EINVAL;
>> +		}
>> +
>> +		cci_read(lt6911uxe->regmap, REG_HALF_H_TOTAL,
>> +			 &half_htotal, &ret);
>> +		cci_read(lt6911uxe->regmap, REG_V_TOTAL, &vtotal, &ret);
>> +		if (ret || half_htotal == 0 || vtotal == 0) {
>> +			dev_dbg(&client->dev, "invalid htotal or vtotal\n");
>> +			return -EINVAL;
>> +		}
>> +
>> +		fps = div_u64(half_pix_clk, half_htotal * vtotal);
>> +		if (fps > 60) {
>> +			dev_dbg(&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_dbg(&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_dbg(&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;
>> +		lt6911uxe->cur_mode.pixel_clk = half_pix_clk * 2;
>> +		lt6911uxe->cur_mode.vtotal = vtotal;
>> +		lt6911uxe->cur_mode.htotal = half_htotal * 2;
>> +		break;
>> +
>> +	case INT_VIDEO_DISAPPEAR:
>> +		cci_write(lt6911uxe->regmap, REG_MIPI_TX_CTRL, 0x0, &ret);
>> +		lt6911uxe->cur_mode.height = 0;
>> +		lt6911uxe->cur_mode.width = 0;
>> +		lt6911uxe->cur_mode.fps = 0;
>> +		lt6911uxe->cur_mode.link_freq = 0;
>> +		break;
>> +
>> +	default:
>> +		ret = -ENOLINK;
>> +	}
>> +	v4l2_subdev_notify_event(&lt6911uxe->sd,
>> +					 &lt6911uxe_ev_source_change);
>> +	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;
>> +
>> +	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_enable_streams(struct v4l2_subdev *sd,
>> +				    struct v4l2_subdev_state *state,
>> +				    u32 pad, u64 streams_mask)
>> +{
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +	struct lt6911uxe *lt6911uxe = to_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: %d\n", ret);
>> +		goto err_rpm_put;
>> +	}
>> +
>> +	return 0;
>> +
>> +err_rpm_put:
>> +	pm_runtime_put(&client->dev);
>> +	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;
>> +
>> +	ret = cci_write(lt6911uxe->regmap, REG_MIPI_TX_CTRL, 0x0, NULL);
>> +	if (ret)
>> +		dev_err(&client->dev, "failed to stop stream: %d\n", ret);
>> +
>> +	pm_runtime_put(&client->dev);
>> +	return 0;
>> +}
>> +
>> +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;
>> +
>> +	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)
>> +		return 0;
>> +
>> +	pixel_rate = get_pixel_rate(lt6911uxe);
>> +	__v4l2_ctrl_modify_range(lt6911uxe->pixel_rate, pixel_rate,
>> +				 pixel_rate, 1, pixel_rate);
>> +
>> +	return 0;
>> +}
>> +
>> +static int lt6911uxe_get_format(struct v4l2_subdev *sd,
>> +				struct v4l2_subdev_state *sd_state,
>> +				struct v4l2_subdev_format *fmt)
>> +{
>> +	struct lt6911uxe *lt6911uxe = to_lt6911uxe(sd);
>> +
>> +	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY)
>> +		fmt->format = *v4l2_subdev_state_get_format(sd_state, fmt->pad);
>> +	else
>> +		lt6911uxe_update_pad_format(&lt6911uxe->cur_mode, &fmt->format);
>> +
>> +	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->index)
>> +		return -EINVAL;
>> +
>> +	code->code = lt6911uxe->cur_mode.code;
>> +
>> +	return 0;
>> +}
>> +
>> +static int lt6911uxe_get_mbus_config(struct v4l2_subdev *sd,
>> +				     unsigned int pad,
>> +				     struct v4l2_mbus_config *cfg)
>> +{
>> +	struct lt6911uxe *lt6911uxe = to_lt6911uxe(sd);
>> +	struct v4l2_subdev_state *state;
>> +
>> +	state = v4l2_subdev_lock_and_get_active_state(sd);
>> +	cfg->type = V4L2_MBUS_CSI2_DPHY;
>> +	cfg->link_freq = lt6911uxe->cur_mode.link_freq;
>> +	v4l2_subdev_unlock_state(state);
>> +
>> +	return 0;
>> +}
>> +
>> +static int lt6911uxe_init_state(struct v4l2_subdev *sd,
>> +				struct v4l2_subdev_state *sd_state)
>> +{
>> +	struct v4l2_subdev_format fmt = {
>> +		.which = sd_state ? V4L2_SUBDEV_FORMAT_TRY
>> +		: V4L2_SUBDEV_FORMAT_ACTIVE,
>> +	};
>> +
>> +	return lt6911uxe_set_format(sd, sd_state, &fmt);
>> +}
>> +
>> +static const struct v4l2_subdev_video_ops lt6911uxe_video_ops = {
>> +	.s_stream = v4l2_subdev_s_stream_helper,
>> +};
>> +
>> +/*
>> + * lt6911uxe provides editable EDID for customers, but only can be edited like
>> + * updating flash. Due to this limitation, it is not possible to implement
>> + * EDID support.
>> + */
>> +static const struct v4l2_subdev_pad_ops lt6911uxe_pad_ops = {
>> +	.set_fmt = lt6911uxe_set_format,
>> +	.get_fmt = lt6911uxe_get_format,
>> +	.enable_streams = lt6911uxe_enable_streams,
>> +	.disable_streams = lt6911uxe_disable_streams,
>> +	.enum_mbus_code = lt6911uxe_enum_mbus_code,
>> +	.get_frame_interval = v4l2_subdev_get_frame_interval,
>> +	.s_dv_timings = lt6911uxe_s_dv_timings,
>> +	.g_dv_timings = lt6911uxe_g_dv_timings,
>> +	.query_dv_timings = lt6911uxe_query_dv_timings,
>> +	.enum_dv_timings = lt6911uxe_enum_dv_timings,
>> +	.dv_timings_cap = lt6911uxe_dv_timings_cap,
>> +	.get_mbus_config = lt6911uxe_get_mbus_config,
>> +};
>> +
>> +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)
>> +		return dev_err_probe(dev, -EPROBE_DEFER,
>> +				     "endpoint node not found\n");
>> +
>> +	ret = v4l2_fwnode_endpoint_parse(endpoint, &bus_cfg);
>> +	fwnode_handle_put(endpoint);
>> +	if (ret) {
>> +		dev_err(dev, "failed to parse endpoint node: %d\n", ret);
>> +		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;
>> +	}
>> +	lt6911uxe->cur_mode.lanes = bus_cfg.bus.mipi_csi2.num_data_lanes;
>> +	lt6911uxe->cur_mode.code = MEDIA_BUS_FMT_UYVY8_1X16;
>> +
>> +	return 0;
>> +
>> +out_err:
>> +	v4l2_fwnode_endpoint_free(&bus_cfg);
>> +	return ret;
>> +}
>> +
>> +static int lt6911uxe_identify_module(struct lt6911uxe *lt6911uxe,
>> +				     struct device *dev)
>> +{
>> +	u64 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, &val, &ret);
>> +	cci_write(lt6911uxe->regmap, REG_ENABLE_I2C, 0x0, &ret);
>> +	if (ret)
>> +		return dev_err_probe(dev, ret, "fail to read chip id\n");
>> +
>> +	if (val != LT6911UXE_CHIP_ID) {
>> +		return dev_err_probe(dev, -ENXIO, "chip id mismatch: %x!=%x\n",
>> +				     LT6911UXE_CHIP_ID, (u16)val);
>> +	}
>> +
>> +	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);
>> +	struct v4l2_subdev_state *state;
>> +
>> +	state = v4l2_subdev_lock_and_get_active_state(sd);
>> +	lt6911uxe_status_update(lt6911uxe);
>> +	v4l2_subdev_unlock_state(state);
>> +
>> +	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(sd);
>> +	v4l2_subdev_cleanup(sd);
>> +	media_entity_cleanup(&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;
>> +	struct device *dev = &client->dev;
>> +	u64 irq_pin_flags;
>> +	int ret;
>> +
>> +	lt6911uxe = devm_kzalloc(dev, sizeof(*lt6911uxe), GFP_KERNEL);
>> +	if (!lt6911uxe)
>> +		return -ENOMEM;
>> +
>> +	lt6911uxe->regmap = devm_regmap_init_i2c(client,
>> +						 &lt9611uxe_regmap_config);
>> +	if (IS_ERR(lt6911uxe->regmap))
>> +		return dev_err_probe(dev, PTR_ERR(lt6911uxe->regmap),
>> +				     "failed to init CCI\n");
>> +
>> +	v4l2_i2c_subdev_init(&lt6911uxe->sd, client, &lt6911uxe_subdev_ops);
>> +
>> +	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");
>> +
>> +	ret = lt6911uxe_fwnode_parse(lt6911uxe, dev);
>> +	if (ret)
>> +		return ret;
>> +
>> +	usleep_range(10000, 10500);
>> +
>> +	ret = lt6911uxe_identify_module(lt6911uxe, dev);
>> +	if (ret)
>> +		return dev_err_probe(dev, ret, "failed to find chip\n");
>> +
>> +	ret = lt6911uxe_init_controls(lt6911uxe);
>> +	if (ret)
>> +		return dev_err_probe(dev, ret, "failed to init control\n");
>> +
>> +	lt6911uxe->sd.dev = dev;
>> +	lt6911uxe->sd.internal_ops = &lt6911uxe_internal_ops;
>> +	lt6911uxe->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
>> +	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(dev, "failed to init entity pads: %d\n", ret);
>> +		goto 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(dev);
>> +	pm_runtime_enable(dev);
>> +	pm_runtime_idle(dev);
>> +
>> +	ret = v4l2_subdev_init_finalize(&lt6911uxe->sd);
>> +	if (ret) {
>> +		dev_err(dev, "failed to init v4l2 subdev: %d\n", ret);
>> +		goto media_entity_cleanup;
>> +	}
>> +
>> +	/* Setting irq */
>> +	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,
>> +				   irq_pin_flags, NULL, lt6911uxe);
>> +	if (ret) {
>> +		dev_err(dev, "failed to request IRQ: %d\n", ret);
>> +		goto subdev_cleanup;
>> +	}
>> +
>> +	ret = v4l2_async_register_subdev_sensor(&lt6911uxe->sd);
>> +	if (ret) {
>> +		dev_err(dev, "failed to register V4L2 subdev: %d\n", ret);
>> +		goto free_irq;
>> +	}
>> +
>> +	return 0;
>> +
>> +free_irq:
>> +	free_irq(gpiod_to_irq(lt6911uxe->irq_gpio), lt6911uxe);
>> +
>> +subdev_cleanup:
>> +	v4l2_subdev_cleanup(&lt6911uxe->sd);
>> +
>> +media_entity_cleanup:
>> +	pm_runtime_disable(dev);
>> +	pm_runtime_set_suspended(dev);
>> +	media_entity_cleanup(&lt6911uxe->sd.entity);
>> +
>> +v4l2_ctrl_handler_free:
>> +	v4l2_ctrl_handler_free(lt6911uxe->sd.ctrl_handler);
>> +
>> +	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@intel.com>");
>> +MODULE_DESCRIPTION("Lontium lt6911uxe HDMI to MIPI Bridge Driver");
>> +MODULE_LICENSE("GPL");
>>
>> base-commit: 2f87d0916ce0d2925cedbc9e8f5d6291ba2ac7b2
> 
> Regards,
> 
> 	Hans