[v6,8/8] media: i2c: add DS90UB953 driver

Add driver for TI DS90UB953 FPD-Link III Serializer.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/media/i2c/Kconfig     |   13 +
 drivers/media/i2c/Makefile    |    1 +
 drivers/media/i2c/ds90ub953.c | 1590 +++++++++++++++++++++++++++++++++
 3 files changed, 1604 insertions(+)
 create mode 100644 drivers/media/i2c/ds90ub953.c

Hi Tomi,

Thank you for the patch.

I won't repeat here the comments made on 7/8 that also apply to this
patch.

On Thu, Jan 05, 2023 at 04:03:07PM +0200, Tomi Valkeinen wrote:
> Add driver for TI DS90UB953 FPD-Link III Serializer.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
>  drivers/media/i2c/Kconfig     |   13 +
>  drivers/media/i2c/Makefile    |    1 +
>  drivers/media/i2c/ds90ub953.c | 1590 +++++++++++++++++++++++++++++++++
>  3 files changed, 1604 insertions(+)
>  create mode 100644 drivers/media/i2c/ds90ub953.c
> 
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index eb312d6e9cf6..29594c724307 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -1614,6 +1614,19 @@ config VIDEO_DS90UB913
>  	  Device driver for the Texas Instruments DS90UB913
>  	  FPD-Link III Serializer.
>  
> +config VIDEO_DS90UB953
> +	tristate "TI DS90UB953 Serializer"

I'd mention the DS90UB971 too.

> +	depends on OF && I2C && VIDEO_DEV
> +	select MEDIA_CONTROLLER
> +	select VIDEO_V4L2_SUBDEV_API
> +	select V4L2_FWNODE
> +	select REGMAP_I2C
> +	select OF_GPIO
> +	select I2C_ATR
> +	help
> +	  Device driver for the Texas Instruments DS90UB953
> +	  FPD-Link III Serializer and DS90UB971 FPD-Link IV Serializer.
> +
>  config VIDEO_DS90UB960
>  	tristate "TI DS90UB960 Deserializer"
>  	depends on OF && I2C && VIDEO_DEV
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index c4875ec8c3b9..efd5f717a5f7 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -143,4 +143,5 @@ obj-$(CONFIG_VIDEO_VS6624) += vs6624.o
>  obj-$(CONFIG_VIDEO_WM8739) += wm8739.o
>  obj-$(CONFIG_VIDEO_WM8775) += wm8775.o
>  obj-$(CONFIG_VIDEO_DS90UB913)	+= ds90ub913.o
> +obj-$(CONFIG_VIDEO_DS90UB953)	+= ds90ub953.o
>  obj-$(CONFIG_VIDEO_DS90UB960)	+= ds90ub960.o
> diff --git a/drivers/media/i2c/ds90ub953.c b/drivers/media/i2c/ds90ub953.c
> new file mode 100644
> index 000000000000..251dc8e8adfa
> --- /dev/null
> +++ b/drivers/media/i2c/ds90ub953.c
> @@ -0,0 +1,1590 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for the Texas Instruments DS90UB953 video serializer
> + *
> + * Based on a driver from Luca Ceresoli <luca@lucaceresoli.net>
> + *
> + * Copyright (c) 2019 Luca Ceresoli <luca@lucaceresoli.net>
> + * Copyright (c) 2022 Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> + */
> +
> +#include <linux/clk-provider.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/i2c-atr.h>
> +#include <linux/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/math64.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_graph.h>
> +#include <linux/rational.h>
> +#include <linux/regmap.h>
> +
> +#include <media/i2c/ds90ub9xx.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-event.h>
> +#include <media/v4l2-subdev.h>
> +
> +#define UB953_PAD_SINK			0
> +#define UB953_PAD_SOURCE		1
> +
> +#define UB953_NUM_GPIOS			4
> +
> +#define UB953_REG_RESET_CTL			0x01
> +#define UB953_REG_RESET_CTL_DIGITAL_RESET_1	BIT(1)
> +#define UB953_REG_RESET_CTL_DIGITAL_RESET_0	BIT(0)
> +
> +#define UB953_REG_GENERAL_CFG			0x02
> +#define UB953_REG_GENERAL_CFG_CONT_CLK		BIT(6)
> +#define UB953_REG_GENERAL_CFG_CSI_LANE_SEL_SHIFT	4
> +#define UB953_REG_GENERAL_CFG_CSI_LANE_SEL_MASK	GENMASK(5, 4)
> +#define UB953_REG_GENERAL_CFG_CRC_TX_GEN_ENABLE	BIT(1)
> +#define UB953_REG_GENERAL_CFG_I2C_STRAP_MODE	BIT(0)
> +
> +#define UB953_REG_MODE_SEL			0x03
> +#define UB953_REG_MODE_SEL_MODE_DONE		BIT(3)
> +#define UB953_REG_MODE_SEL_MODE_OVERRIDE	BIT(4)
> +#define UB953_REG_MODE_SEL_MODE_MASK		GENMASK(2, 0)
> +
> +#define UB953_REG_CLKOUT_CTRL0			0x06
> +#define UB953_REG_CLKOUT_CTRL1			0x07
> +
> +#define UB953_REG_SCL_HIGH_TIME			0x0B
> +#define UB953_REG_SCL_LOW_TIME			0x0C
> +
> +#define UB953_REG_LOCAL_GPIO_DATA		0x0d
> +#define UB953_REG_LOCAL_GPIO_DATA_GPIO_RMTEN(n)		BIT(4 + (n))
> +#define UB953_REG_LOCAL_GPIO_DATA_GPIO_OUT_SRC(n)	BIT(0 + (n))
> +
> +#define UB953_REG_GPIO_INPUT_CTRL		0x0e
> +#define UB953_REG_GPIO_INPUT_CTRL_OUT_EN(n)	BIT(4 + (n))
> +#define UB953_REG_GPIO_INPUT_CTRL_INPUT_EN(n)	BIT(0 + (n))
> +
> +#define UB953_REG_REV_MASK_ID			0x50
> +#define UB953_REG_GENERAL_STATUS		0x52
> +
> +#define UB953_REG_GPIO_PIN_STS			0x53
> +#define UB953_REG_GPIO_PIN_STS_GPIO_STS(n)	BIT(0 + (n))
> +
> +#define UB953_REG_BIST_ERR_CNT			0x54
> +#define UB953_REG_CRC_ERR_CNT1			0x55
> +#define UB953_REG_CRC_ERR_CNT2			0x56
> +
> +#define UB953_REG_CSI_ERR_CNT			0x5c
> +#define UB953_REG_CSI_ERR_STATUS		0x5D
> +#define UB953_REG_CSI_ERR_DLANE01		0x5E
> +#define UB953_REG_CSI_ERR_DLANE23		0x5F
> +#define UB953_REG_CSI_ERR_CLK_LANE		0x60
> +#define UB953_REG_CSI_PKT_HDR_VC_ID		0x61
> +#define UB953_REG_PKT_HDR_WC_LSB		0x62
> +#define UB953_REG_PKT_HDR_WC_MSB		0x63
> +#define UB953_REG_CSI_ECC			0x64
> +
> +#define UB953_REG_IND_ACC_CTL			0xb0
> +#define UB953_REG_IND_ACC_ADDR			0xb1
> +#define UB953_REG_IND_ACC_DATA			0xb2
> +
> +#define UB953_REG_FPD3_RX_ID(n)			(0xf0 + (n))
> +
> +/* Indirect register blocks */
> +#define UB953_IND_TARGET_PAT_GEN		0x00
> +#define UB953_IND_TARGET_FPD3_TX		0x01
> +#define UB953_IND_TARGET_DIE_ID			0x02
> +
> +#define UB953_IND_PGEN_CTL			0x01
> +#define UB953_IND_PGEN_CTL_PGEN_ENABLE		BIT(0)
> +#define UB953_IND_PGEN_CFG			0x02
> +#define UB953_IND_PGEN_CSI_DI			0x03
> +#define UB953_IND_PGEN_LINE_SIZE1		0x04
> +#define UB953_IND_PGEN_LINE_SIZE0		0x05
> +#define UB953_IND_PGEN_BAR_SIZE1		0x06
> +#define UB953_IND_PGEN_BAR_SIZE0		0x07
> +#define UB953_IND_PGEN_ACT_LPF1			0x08
> +#define UB953_IND_PGEN_ACT_LPF0			0x09
> +#define UB953_IND_PGEN_TOT_LPF1			0x0A
> +#define UB953_IND_PGEN_TOT_LPF0			0x0B
> +#define UB953_IND_PGEN_LINE_PD1			0x0C
> +#define UB953_IND_PGEN_LINE_PD0			0x0D
> +#define UB953_IND_PGEN_VBP			0x0E
> +#define UB953_IND_PGEN_VFP			0x0F
> +#define UB953_IND_PGEN_COLOR(n)			(0x10 + (n)) /* n <= 15 */
> +
> +/* Note: Only sync mode supported for now */
> +enum ub953_mode {
> +	/* FPD-Link III CSI-2 synchronous mode */
> +	UB953_MODE_SYNC,
> +	/* FPD-Link III CSI-2 non-synchronous mode, external ref clock */
> +	UB953_MODE_NONSYNC_EXT,
> +	/* FPD-Link III CSI-2 non-synchronous mode, internal ref clock */
> +	UB953_MODE_NONSYNC_INT,
> +	/* FPD-Link III DVP mode */
> +	UB953_MODE_DVP,
> +};
> +
> +struct ub953_hw_data {
> +	const char *model;
> +	bool ub971;

Maybe is_ub971, although a model enum could be nicer. Up to you.

> +};
> +
> +struct ub953_data {
> +	const struct ub953_hw_data	*hw_data;
> +
> +	struct i2c_client	*client;
> +	struct regmap		*regmap;
> +
> +	u32			num_data_lanes;
> +
> +	struct gpio_chip	gpio_chip;
> +	char			gpio_chip_name[64];
> +
> +	struct v4l2_subdev	sd;
> +	struct media_pad	pads[2];
> +
> +	struct v4l2_async_notifier	notifier;
> +
> +	struct v4l2_subdev	*source_sd;
> +
> +	struct v4l2_ctrl_handler   ctrl_handler;
> +
> +	u64			enabled_source_streams;
> +
> +	struct device_node	*tx_ep_np;
> +
> +	/* lock for register access */
> +	struct mutex		reg_lock;

Why is this needed, can you access registers from multiple contexts ?

> +
> +	u8			current_indirect_target;
> +
> +	struct clk_hw		clkout_clk_hw;
> +
> +	enum ub953_mode		mode;
> +
> +	struct ds90ub9xx_platform_data *plat_data;
> +};
> +
> +static inline struct ub953_data *sd_to_ub953(struct v4l2_subdev *sd)
> +{
> +	return container_of(sd, struct ub953_data, sd);
> +}
> +
> +/*
> + * HW Access
> + */
> +
> +static int ub953_read(struct ub953_data *priv, u8 reg, u8 *val)
> +{
> +	unsigned int v;
> +	int ret;
> +
> +	mutex_lock(&priv->reg_lock);
> +
> +	ret = regmap_read(priv->regmap, reg, &v);
> +	if (ret)
> +		dev_err(&priv->client->dev,
> +			"Cannot read register 0x%02x: %d!\n", reg, ret);
> +	else
> +		*val = v;
> +
> +	mutex_unlock(&priv->reg_lock);
> +
> +	return ret;
> +}
> +
> +static int ub953_write(struct ub953_data *priv, u8 reg, u8 val)
> +{
> +	int ret;
> +
> +	mutex_lock(&priv->reg_lock);
> +
> +	ret = regmap_write(priv->regmap, reg, val);
> +	if (ret)
> +		dev_err(&priv->client->dev,
> +			"Cannot write register 0x%02x: %d!\n", reg, ret);
> +
> +	mutex_unlock(&priv->reg_lock);
> +
> +	return ret;
> +}
> +
> +static int _ub953_select_ind_reg_block(struct ub953_data *priv, u8 block)
> +{
> +	struct device *dev = &priv->client->dev;
> +	int ret;
> +
> +	if (priv->current_indirect_target == block)
> +		return 0;
> +
> +	ret = regmap_write(priv->regmap, UB953_REG_IND_ACC_CTL, block << 2);
> +	if (ret) {
> +		dev_err(dev, "%s: cannot select indirect target %u (%d)!\n",
> +			__func__, block, ret);
> +		return ret;
> +	}
> +
> +	priv->current_indirect_target = block;
> +
> +	return 0;
> +}
> +
> +__maybe_unused

Looks like it's more than maybe unused, it's never used at all. Can the
function be dropped ?

> +static int ub953_read_ind(struct ub953_data *priv, u8 block, u8 reg, u8 *val)
> +{
> +	unsigned int v;
> +	int ret;
> +
> +	mutex_lock(&priv->reg_lock);
> +
> +	ret = _ub953_select_ind_reg_block(priv, block);
> +	if (ret)
> +		goto out;
> +
> +	ret = regmap_write(priv->regmap, UB953_REG_IND_ACC_ADDR, reg);
> +	if (ret)
> +		goto out;
> +
> +	ret = regmap_read(priv->regmap, UB953_REG_IND_ACC_DATA, &v);
> +	if (ret)
> +		goto out;
> +
> +	*val = v;
> +
> +out:
> +	mutex_unlock(&priv->reg_lock);
> +
> +	return ret;
> +}
> +
> +static int ub953_write_ind(struct ub953_data *priv, u8 block, u8 reg, u8 val)
> +{
> +	int ret;
> +
> +	mutex_lock(&priv->reg_lock);
> +
> +	ret = _ub953_select_ind_reg_block(priv, block);
> +	if (ret)
> +		goto out;
> +
> +	ret = regmap_write(priv->regmap, UB953_REG_IND_ACC_ADDR, reg);
> +	if (ret)
> +		goto out;
> +
> +	ret = regmap_write(priv->regmap, UB953_REG_IND_ACC_DATA, val);
> +
> +out:
> +	mutex_unlock(&priv->reg_lock);
> +

An error message would be useful on failure. Same in the next function.

> +	return ret;
> +}
> +
> +static int ub953_write_ind16(struct ub953_data *priv, u8 block, u8 reg, u16 val)
> +{
> +	int ret;
> +
> +	mutex_lock(&priv->reg_lock);
> +
> +	ret = _ub953_select_ind_reg_block(priv, block);
> +	if (ret)
> +		goto out;
> +
> +	ret = regmap_write(priv->regmap, UB953_REG_IND_ACC_ADDR, reg);
> +	if (ret)
> +		goto out;
> +
> +	ret = regmap_write(priv->regmap, UB953_REG_IND_ACC_DATA, val >> 8);
> +	if (ret)
> +		goto out;
> +
> +	ret = regmap_write(priv->regmap, UB953_REG_IND_ACC_ADDR, reg + 1);

There's no auto-increment ? :-(

> +	if (ret)
> +		goto out;
> +
> +	ret = regmap_write(priv->regmap, UB953_REG_IND_ACC_DATA, val & 0xff);
> +	if (ret)
> +		goto out;
> +
> +out:
> +	mutex_unlock(&priv->reg_lock);
> +
> +	return ret;
> +}
> +
> +/*
> + * GPIO chip
> + */
> +static int ub953_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
> +{
> +	struct ub953_data *priv = gpiochip_get_data(gc);
> +	int ret;
> +	u8 v;
> +
> +	ret = ub953_read(priv, UB953_REG_GPIO_INPUT_CTRL, &v);
> +	if (ret)
> +		return ret;
> +
> +	if (v & UB953_REG_GPIO_INPUT_CTRL_INPUT_EN(offset))
> +		return GPIO_LINE_DIRECTION_IN;
> +	else
> +		return GPIO_LINE_DIRECTION_OUT;
> +}
> +
> +static int ub953_gpio_direction_in(struct gpio_chip *gc, unsigned int offset)
> +{
> +	struct ub953_data *priv = gpiochip_get_data(gc);
> +
> +	return regmap_update_bits(
> +		priv->regmap, UB953_REG_GPIO_INPUT_CTRL,
> +		UB953_REG_GPIO_INPUT_CTRL_INPUT_EN(offset) |
> +			UB953_REG_GPIO_INPUT_CTRL_OUT_EN(offset),
> +		UB953_REG_GPIO_INPUT_CTRL_INPUT_EN(offset));
> +}
> +
> +static int ub953_gpio_direction_out(struct gpio_chip *gc, unsigned int offset,
> +				    int value)
> +{
> +	struct ub953_data *priv = gpiochip_get_data(gc);
> +	int ret;
> +
> +	ret = regmap_update_bits(
> +		priv->regmap, UB953_REG_LOCAL_GPIO_DATA,
> +		UB953_REG_LOCAL_GPIO_DATA_GPIO_OUT_SRC(offset),
> +		value ? UB953_REG_LOCAL_GPIO_DATA_GPIO_OUT_SRC(offset) : 0);
> +
> +	if (ret)
> +		return ret;
> +
> +	return regmap_update_bits(
> +		priv->regmap, UB953_REG_GPIO_INPUT_CTRL,
> +		UB953_REG_GPIO_INPUT_CTRL_INPUT_EN(offset) |
> +			UB953_REG_GPIO_INPUT_CTRL_OUT_EN(offset),
> +		UB953_REG_GPIO_INPUT_CTRL_OUT_EN(offset));
> +}
> +
> +static int ub953_gpio_get(struct gpio_chip *gc, unsigned int offset)
> +{
> +	struct ub953_data *priv = gpiochip_get_data(gc);
> +	int ret;
> +	u8 v;
> +
> +	ret = ub953_read(priv, UB953_REG_GPIO_PIN_STS, &v);
> +	if (ret)
> +		return ret;
> +
> +	return !!(v & UB953_REG_GPIO_PIN_STS_GPIO_STS(offset));
> +}
> +
> +static void ub953_gpio_set(struct gpio_chip *gc, unsigned int offset, int value)
> +{
> +	struct ub953_data *priv = gpiochip_get_data(gc);
> +
> +	regmap_update_bits(
> +		priv->regmap, UB953_REG_LOCAL_GPIO_DATA,
> +		UB953_REG_LOCAL_GPIO_DATA_GPIO_OUT_SRC(offset),
> +		value ? UB953_REG_LOCAL_GPIO_DATA_GPIO_OUT_SRC(offset) : 0);
> +}
> +
> +static int ub953_gpio_of_xlate(struct gpio_chip *gc,
> +			       const struct of_phandle_args *gpiospec,
> +			       u32 *flags)
> +{
> +	if (flags)
> +		*flags = gpiospec->args[1];
> +
> +	return gpiospec->args[0];
> +}
> +
> +static int ub953_gpiochip_probe(struct ub953_data *priv)
> +{
> +	struct device *dev = &priv->client->dev;
> +	struct gpio_chip *gc = &priv->gpio_chip;
> +	int ret;
> +
> +	/* Set all GPIOs to local input mode */
> +	ub953_write(priv, UB953_REG_LOCAL_GPIO_DATA, 0);
> +	ub953_write(priv, UB953_REG_GPIO_INPUT_CTRL, 0xf);
> +
> +	scnprintf(priv->gpio_chip_name, sizeof(priv->gpio_chip_name), "%s",
> +		  dev_name(dev));
> +
> +	gc->label = priv->gpio_chip_name;
> +	gc->parent = dev;
> +	gc->owner = THIS_MODULE;
> +	gc->base = -1;
> +	gc->can_sleep = 1;
> +	gc->ngpio = UB953_NUM_GPIOS;
> +	gc->get_direction = ub953_gpio_get_direction;
> +	gc->direction_input = ub953_gpio_direction_in;
> +	gc->direction_output = ub953_gpio_direction_out;
> +	gc->get = ub953_gpio_get;
> +	gc->set = ub953_gpio_set;
> +	gc->of_xlate = ub953_gpio_of_xlate;
> +	gc->of_node = priv->client->dev.of_node;
> +	gc->of_gpio_n_cells = 2;
> +
> +	ret = gpiochip_add_data(gc, priv);
> +	if (ret) {
> +		dev_err(dev, "Failed to add GPIOs: %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void ub953_gpiochip_remove(struct ub953_data *priv)
> +{
> +	gpiochip_remove(&priv->gpio_chip);
> +}
> +
> +/*
> + * V4L2
> + */
> +
> +static int _ub953_set_routing(struct v4l2_subdev *sd,
> +			      struct v4l2_subdev_state *state,
> +			      struct v4l2_subdev_krouting *routing)
> +{
> +	static const struct v4l2_mbus_framefmt format = {
> +		.width = 640,
> +		.height = 480,
> +		.code = MEDIA_BUS_FMT_UYVY8_1X16,
> +		.field = V4L2_FIELD_NONE,
> +		.colorspace = V4L2_COLORSPACE_SRGB,
> +		.ycbcr_enc = V4L2_YCBCR_ENC_601,
> +		.quantization = V4L2_QUANTIZATION_LIM_RANGE,
> +		.xfer_func = V4L2_XFER_FUNC_SRGB,
> +	};
> +	int ret;
> +
> +	/*
> +	 * Note: we can only support up to V4L2_FRAME_DESC_ENTRY_MAX, until
> +	 * frame desc is made dynamically allocated.
> +	 */
> +
> +	if (routing->num_routes > V4L2_FRAME_DESC_ENTRY_MAX)
> +		return -EINVAL;
> +
> +	ret = v4l2_subdev_routing_validate(sd, routing,
> +					   V4L2_SUBDEV_ROUTING_ONLY_1_TO_1);
> +	if (ret)
> +		return ret;
> +
> +	ret = v4l2_subdev_set_routing_with_fmt(sd, state, routing, &format);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int ub953_set_routing(struct v4l2_subdev *sd,
> +			     struct v4l2_subdev_state *state,
> +			     enum v4l2_subdev_format_whence which,
> +			     struct v4l2_subdev_krouting *routing)
> +{
> +	struct ub953_data *priv = sd_to_ub953(sd);
> +
> +	if (which == V4L2_SUBDEV_FORMAT_ACTIVE && priv->enabled_source_streams)
> +		return -EBUSY;
> +
> +	return _ub953_set_routing(sd, state, routing);
> +}
> +
> +static int ub953_get_source_frame_desc(struct ub953_data *priv,
> +				       struct v4l2_mbus_frame_desc *desc)
> +{
> +	struct media_pad *pad;
> +	int ret;
> +
> +	pad = media_pad_remote_pad_first(&priv->pads[UB953_PAD_SINK]);
> +	if (!pad)
> +		return -EPIPE;
> +
> +	ret = v4l2_subdev_call(priv->source_sd, pad, get_frame_desc, pad->index,
> +			       desc);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int ub953_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
> +				struct v4l2_mbus_frame_desc *fd)
> +{
> +	struct ub953_data *priv = sd_to_ub953(sd);
> +	const struct v4l2_subdev_krouting *routing;
> +	struct v4l2_mbus_frame_desc source_fd;
> +	struct v4l2_subdev_route *route;
> +	struct v4l2_subdev_state *state;
> +	int ret;
> +
> +	if (pad != UB953_PAD_SOURCE)
> +		return -EINVAL;
> +
> +	ret = ub953_get_source_frame_desc(priv, &source_fd);
> +	if (ret)
> +		return ret;
> +
> +	state = v4l2_subdev_lock_and_get_active_state(sd);
> +
> +	routing = &state->routing;
> +
> +	memset(fd, 0, sizeof(*fd));
> +
> +	fd->type = V4L2_MBUS_FRAME_DESC_TYPE_CSI2;
> +
> +	for_each_active_route(routing, route) {
> +		struct v4l2_mbus_frame_desc_entry *source_entry = NULL;
> +		unsigned int i;
> +
> +		if (route->source_pad != pad)
> +			continue;
> +
> +		for (i = 0; i < source_fd.num_entries; ++i)
> +			if (source_fd.entry[i].stream == route->sink_stream) {
> +				source_entry = &source_fd.entry[i];
> +				break;
> +			}
> +
> +		if (!source_entry) {
> +			dev_err(&priv->client->dev,
> +				"Failed to find stream from source frame desc\n");
> +			ret = -EPIPE;
> +			goto out;
> +		}
> +
> +		fd->entry[fd->num_entries].stream = route->source_stream;
> +		fd->entry[fd->num_entries].flags = source_entry->flags;
> +		fd->entry[fd->num_entries].length = source_entry->length;
> +		fd->entry[fd->num_entries].pixelcode = source_entry->pixelcode;
> +		fd->entry[fd->num_entries].bus.csi2.vc =
> +			source_entry->bus.csi2.vc;
> +		fd->entry[fd->num_entries].bus.csi2.dt =
> +			source_entry->bus.csi2.dt;
> +
> +		fd->num_entries++;
> +	}
> +
> +out:
> +	v4l2_subdev_unlock_state(state);
> +
> +	return ret;
> +}
> +
> +static int ub953_set_fmt(struct v4l2_subdev *sd,
> +			 struct v4l2_subdev_state *state,
> +			 struct v4l2_subdev_format *format)
> +{
> +	struct ub953_data *priv = sd_to_ub953(sd);
> +	struct v4l2_mbus_framefmt *fmt;
> +
> +	if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE &&
> +	    priv->enabled_source_streams)
> +		return -EBUSY;
> +
> +	/* No transcoding, source and sink formats must match. */
> +	if (format->pad == UB953_PAD_SOURCE)
> +		return v4l2_subdev_get_fmt(sd, state, format);
> +
> +	/* Set sink format */
> +	fmt = v4l2_subdev_state_get_stream_format(state, format->pad,
> +						  format->stream);
> +	if (!fmt)
> +		return -EINVAL;
> +
> +	*fmt = format->format;
> +
> +	/* Propagate to source format */
> +	fmt = v4l2_subdev_state_get_opposite_stream_format(state, format->pad,
> +							   format->stream);
> +	if (!fmt)
> +		return -EINVAL;
> +
> +	*fmt = format->format;
> +
> +	return 0;
> +}
> +
> +static int ub953_init_cfg(struct v4l2_subdev *sd,
> +			  struct v4l2_subdev_state *state)
> +{
> +	struct v4l2_subdev_route routes[] = {
> +		{
> +			.sink_pad = UB953_PAD_SINK,
> +			.sink_stream = 0,
> +			.source_pad = UB953_PAD_SOURCE,
> +			.source_stream = 0,
> +			.flags = V4L2_SUBDEV_ROUTE_FL_ACTIVE,
> +		},
> +	};
> +
> +	struct v4l2_subdev_krouting routing = {
> +		.num_routes = ARRAY_SIZE(routes),
> +		.routes = routes,
> +	};
> +
> +	return _ub953_set_routing(sd, state, &routing);
> +}
> +
> +static int ub953_log_status(struct v4l2_subdev *sd)
> +{
> +	struct ub953_data *priv = sd_to_ub953(sd);
> +	struct device *dev = &priv->client->dev;
> +	u8 v = 0, v1 = 0, v2 = 0;
> +	unsigned int i;
> +	char id[7];
> +	u8 gpio_local_data;
> +	u8 gpio_input_ctrl;
> +	u8 gpio_pin_sts;
> +
> +	for (i = 0; i < 6; ++i)
> +		ub953_read(priv, UB953_REG_FPD3_RX_ID(i), &id[i]);
> +	id[6] = 0;
> +
> +	dev_info(dev, "ID '%s'\n", id);
> +
> +	ub953_read(priv, UB953_REG_GENERAL_STATUS, &v);
> +	dev_info(dev, "GENERAL_STATUS %#x\n", v);
> +
> +	ub953_read(priv, UB953_REG_CRC_ERR_CNT1, &v1);
> +	ub953_read(priv, UB953_REG_CRC_ERR_CNT2, &v2);
> +	dev_info(dev, "CRC error count %u\n", v1 | (v2 << 8));
> +
> +	ub953_read(priv, UB953_REG_CSI_ERR_CNT, &v);
> +	dev_info(dev, "CSI error count %u\n", v);
> +
> +	ub953_read(priv, UB953_REG_CSI_ERR_STATUS, &v);
> +	dev_info(dev, "CSI_ERR_STATUS %#x\n", v);
> +
> +	ub953_read(priv, UB953_REG_CSI_ERR_DLANE01, &v);
> +	dev_info(dev, "CSI_ERR_DLANE01 %#x\n", v);
> +
> +	ub953_read(priv, UB953_REG_CSI_ERR_DLANE23, &v);
> +	dev_info(dev, "CSI_ERR_DLANE23 %#x\n", v);
> +
> +	ub953_read(priv, UB953_REG_CSI_ERR_CLK_LANE, &v);
> +	dev_info(dev, "CSI_ERR_CLK_LANE %#x\n", v);
> +
> +	ub953_read(priv, UB953_REG_CSI_PKT_HDR_VC_ID, &v);
> +	dev_info(dev, "CSI packet header VC %u ID %u\n", v >> 6, v & 0x3f);
> +
> +	ub953_read(priv, UB953_REG_PKT_HDR_WC_LSB, &v1);
> +	ub953_read(priv, UB953_REG_PKT_HDR_WC_MSB, &v2);
> +	dev_info(dev, "CSI packet header WC %u\n", (v2 << 8) | v1);
> +
> +	ub953_read(priv, UB953_REG_CSI_ECC, &v);
> +	dev_info(dev, "CSI ECC %#x\n", v);
> +
> +	ub953_read(priv, UB953_REG_LOCAL_GPIO_DATA, &gpio_local_data);
> +	ub953_read(priv, UB953_REG_GPIO_INPUT_CTRL, &gpio_input_ctrl);
> +	ub953_read(priv, UB953_REG_GPIO_PIN_STS, &gpio_pin_sts);
> +
> +	for (i = 0; i < UB953_NUM_GPIOS; ++i) {
> +		dev_info(dev,
> +			 "GPIO%u: remote: %u is_input: %u is_output: %u val: %u sts: %u\n",
> +			 i,
> +			 !!(gpio_local_data & UB953_REG_LOCAL_GPIO_DATA_GPIO_RMTEN(i)),
> +			 !!(gpio_input_ctrl & UB953_REG_GPIO_INPUT_CTRL_INPUT_EN(i)),
> +			 !!(gpio_input_ctrl & UB953_REG_GPIO_INPUT_CTRL_OUT_EN(i)),
> +			 !!(gpio_local_data & UB953_REG_LOCAL_GPIO_DATA_GPIO_OUT_SRC(i)),
> +			 !!(gpio_pin_sts & UB953_REG_GPIO_PIN_STS_GPIO_STS(i)));
> +	}
> +
> +	return 0;
> +}
> +
> +static int ub953_enable_streams(struct v4l2_subdev *sd,
> +				struct v4l2_subdev_state *state, u32 pad,
> +				u64 streams_mask)
> +{
> +	struct ub953_data *priv = sd_to_ub953(sd);
> +	struct media_pad *remote_pad;
> +	u64 sink_streams;
> +	int ret;
> +
> +	if (streams_mask & priv->enabled_source_streams)
> +		return -EALREADY;
> +
> +	sink_streams = v4l2_subdev_state_xlate_streams(
> +		state, UB953_PAD_SOURCE, UB953_PAD_SINK, &streams_mask);
> +
> +	remote_pad = media_pad_remote_pad_first(&priv->pads[UB953_PAD_SINK]);
> +
> +	ret = v4l2_subdev_enable_streams(priv->source_sd, remote_pad->index,
> +					 sink_streams);
> +	if (ret)
> +		return ret;
> +
> +	priv->enabled_source_streams |= streams_mask;
> +
> +	return 0;
> +}
> +
> +static int ub953_disable_streams(struct v4l2_subdev *sd,
> +				 struct v4l2_subdev_state *state, u32 pad,
> +				 u64 streams_mask)
> +{
> +	struct ub953_data *priv = sd_to_ub953(sd);
> +	struct media_pad *remote_pad;
> +	int ret;
> +	u64 sink_streams;
> +
> +	if ((streams_mask & priv->enabled_source_streams) != streams_mask)
> +		return -EALREADY;
> +
> +	sink_streams = v4l2_subdev_state_xlate_streams(
> +		state, UB953_PAD_SOURCE, UB953_PAD_SINK, &streams_mask);
> +
> +	remote_pad = media_pad_remote_pad_first(&priv->pads[UB953_PAD_SINK]);
> +
> +	ret = v4l2_subdev_disable_streams(priv->source_sd, remote_pad->index,
> +					  sink_streams);
> +	if (ret)
> +		return ret;
> +
> +	priv->enabled_source_streams &= ~streams_mask;
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_subdev_pad_ops ub953_pad_ops = {
> +	.enable_streams = ub953_enable_streams,
> +	.disable_streams = ub953_disable_streams,
> +	.set_routing = ub953_set_routing,
> +	.get_frame_desc = ub953_get_frame_desc,
> +	.get_fmt = v4l2_subdev_get_fmt,
> +	.set_fmt = ub953_set_fmt,
> +	.init_cfg = ub953_init_cfg,
> +};
> +
> +static const struct v4l2_subdev_core_ops ub953_subdev_core_ops = {
> +	.log_status		= ub953_log_status,
> +	.subscribe_event	= v4l2_ctrl_subdev_subscribe_event,
> +	.unsubscribe_event	= v4l2_event_subdev_unsubscribe,

Align the = for all structures or for none.

> +};
> +
> +static const struct v4l2_subdev_ops ub953_subdev_ops = {
> +	.core = &ub953_subdev_core_ops,
> +	.pad = &ub953_pad_ops,
> +};
> +
> +static const struct media_entity_operations ub953_entity_ops = {
> +	.link_validate = v4l2_subdev_link_validate,
> +};
> +
> +enum {
> +	TEST_PATTERN_DISABLED = 0,
> +	TEST_PATTERN_V_COLOR_BARS_1,
> +	TEST_PATTERN_V_COLOR_BARS_2,
> +	TEST_PATTERN_V_COLOR_BARS_4,
> +	TEST_PATTERN_V_COLOR_BARS_8,
> +};
> +
> +static const char *const ub953_tpg_qmenu[] = {
> +	"Disabled",
> +	"1 vertical color bar",
> +	"2 vertical color bars",
> +	"4 vertical color bars",
> +	"8 vertical color bars",
> +};
> +
> +static int ub953_enable_tpg(struct ub953_data *priv, int tpg_num)
> +{
> +	struct v4l2_subdev *sd = &priv->sd;
> +	struct v4l2_subdev_state *state;
> +	struct v4l2_mbus_framefmt *fmt;
> +	u8 vbp, vfp;
> +	u16 blank_lines;
> +	u16 width;
> +	u16 height;
> +
> +	u16 bytespp = 2; /* For MEDIA_BUS_FMT_UYVY8_1X16 */
> +	u8 cbars_idx = tpg_num - TEST_PATTERN_V_COLOR_BARS_1;
> +	u8 num_cbars = 1 << cbars_idx;
> +
> +	u16 line_size; /* Line size [bytes] */
> +	u16 bar_size; /* cbar size [bytes] */
> +	u16 act_lpf; /* active lines/frame */
> +	u16 tot_lpf; /* tot lines/frame */
> +	u16 line_pd; /* Line period in 10-ns units */
> +
> +	u16 fps = 30;
> +
> +	vbp = 33;
> +	vfp = 10;
> +	blank_lines = vbp + vfp + 2; /* total blanking lines */
> +
> +	state = v4l2_subdev_get_locked_active_state(sd);
> +
> +	if (state->routing.num_routes != 1)
> +		return -EINVAL;
> +
> +	fmt = v4l2_subdev_state_get_stream_format(state, UB953_PAD_SOURCE, 0);
> +	if (!fmt)
> +		return -EINVAL;
> +
> +	if (fmt->code != MEDIA_BUS_FMT_UYVY8_1X16)
> +		return -EINVAL;
> +
> +	width = fmt->width;
> +	height = fmt->height;
> +
> +	line_size = width * bytespp;
> +	bar_size = line_size / num_cbars;
> +	act_lpf = height;
> +	tot_lpf = act_lpf + blank_lines;
> +	line_pd = 100000000 / fps / tot_lpf;
> +
> +	ub953_write_ind(priv, UB953_IND_TARGET_PAT_GEN, UB953_IND_PGEN_CTL,
> +			UB953_IND_PGEN_CTL_PGEN_ENABLE);
> +
> +	/* YUV422 8bit: 2 bytes/block, CSI-2 data type 0x1e */
> +	ub953_write_ind(priv, UB953_IND_TARGET_PAT_GEN, UB953_IND_PGEN_CFG,
> +			cbars_idx << 4 | 0x2);
> +	ub953_write_ind(priv, UB953_IND_TARGET_PAT_GEN, UB953_IND_PGEN_CSI_DI,
> +			0x1e);
> +
> +	ub953_write_ind16(priv, UB953_IND_TARGET_PAT_GEN,
> +			  UB953_IND_PGEN_LINE_SIZE1, line_size);
> +	ub953_write_ind16(priv, UB953_IND_TARGET_PAT_GEN,
> +			  UB953_IND_PGEN_BAR_SIZE1, bar_size);
> +	ub953_write_ind16(priv, UB953_IND_TARGET_PAT_GEN,
> +			  UB953_IND_PGEN_ACT_LPF1, act_lpf);
> +	ub953_write_ind16(priv, UB953_IND_TARGET_PAT_GEN,
> +			  UB953_IND_PGEN_TOT_LPF1, tot_lpf);
> +	ub953_write_ind16(priv, UB953_IND_TARGET_PAT_GEN,
> +			  UB953_IND_PGEN_LINE_PD1, line_pd);
> +	ub953_write_ind(priv, UB953_IND_TARGET_PAT_GEN, UB953_IND_PGEN_VBP,
> +			vbp);
> +	ub953_write_ind(priv, UB953_IND_TARGET_PAT_GEN, UB953_IND_PGEN_VFP,
> +			vfp);
> +
> +	return 0;
> +}
> +
> +static void ub953_disable_tpg(struct ub953_data *priv)
> +{
> +	ub953_write_ind(priv, UB953_IND_TARGET_PAT_GEN, UB953_IND_PGEN_CTL,
> +			0x0);
> +}
> +
> +static int ub953_s_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +	struct ub953_data *priv =
> +		container_of(ctrl->handler, struct ub953_data, ctrl_handler);
> +	int ret = 0;
> +
> +	switch (ctrl->id) {
> +	case V4L2_CID_TEST_PATTERN:
> +		if (ctrl->val == 0)
> +			ub953_disable_tpg(priv);
> +		else
> +			ret = ub953_enable_tpg(priv, ctrl->val);
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +static const struct v4l2_ctrl_ops ub953_ctrl_ops = {
> +	.s_ctrl = ub953_s_ctrl,
> +};
> +
> +static int ub953_notify_bound(struct v4l2_async_notifier *notifier,
> +			      struct v4l2_subdev *source_subdev,
> +			      struct v4l2_async_subdev *asd)
> +{
> +	struct ub953_data *priv = sd_to_ub953(notifier->sd);
> +	struct device *dev = &priv->client->dev;
> +	unsigned int src_pad;
> +	int ret;
> +
> +	ret = media_entity_get_fwnode_pad(&source_subdev->entity,
> +					  source_subdev->fwnode,
> +					  MEDIA_PAD_FL_SOURCE);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to find pad for %s\n",
> +			source_subdev->name);
> +		return ret;
> +	}
> +
> +	priv->source_sd = source_subdev;
> +	src_pad = ret;
> +
> +	ret = media_create_pad_link(
> +		&source_subdev->entity, src_pad, &priv->sd.entity, 0,
> +		MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
> +	if (ret) {
> +		dev_err(dev, "Unable to link %s:%u -> %s:0\n",
> +			source_subdev->name, src_pad, priv->sd.name);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_async_notifier_operations ub953_notify_ops = {
> +	.bound = ub953_notify_bound,
> +};
> +
> +static int ub953_v4l2_notifier_register(struct ub953_data *priv)
> +{
> +	struct device *dev = &priv->client->dev;
> +	struct v4l2_async_subdev *asd;
> +	struct device_node *ep_node;
> +	int ret;
> +
> +	ep_node = of_graph_get_endpoint_by_regs(dev->of_node, 0, 0);

s/0, 0/UB953_PAD_SINK, 0/

Similar comment for other calls to this function below.

> +	if (!ep_node) {
> +		dev_err(dev, "No graph endpoint\n");
> +		return -ENODEV;
> +	}
> +
> +	v4l2_async_nf_init(&priv->notifier);
> +
> +	asd = v4l2_async_nf_add_fwnode_remote(&priv->notifier,
> +					      of_fwnode_handle(ep_node),
> +					      struct v4l2_async_subdev);
> +
> +	of_node_put(ep_node);
> +
> +	if (IS_ERR(asd)) {
> +		dev_err(dev, "Failed to add subdev: %ld", PTR_ERR(asd));
> +		v4l2_async_nf_cleanup(&priv->notifier);
> +		return PTR_ERR(asd);
> +	}
> +
> +	priv->notifier.ops = &ub953_notify_ops;
> +
> +	ret = v4l2_async_subdev_nf_register(&priv->sd, &priv->notifier);
> +	if (ret) {
> +		dev_err(dev, "Failed to register subdev_notifier");
> +		v4l2_async_nf_cleanup(&priv->notifier);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void ub953_v4l2_notifier_unregister(struct ub953_data *priv)
> +{
> +	v4l2_async_nf_unregister(&priv->notifier);
> +	v4l2_async_nf_cleanup(&priv->notifier);
> +}
> +
> +/*
> + * Probing
> + */
> +
> +static int ub953_i2c_master_init(struct ub953_data *priv)
> +{
> +	/* i2c fast mode */
> +	u32 ref = 26250000;
> +	u32 scl_high = 915; /* ns */
> +	u32 scl_low = 1641; /* ns */
> +	int ret;
> +
> +	scl_high = div64_u64((u64)scl_high * ref, 1000000000) - 5;
> +	scl_low = div64_u64((u64)scl_low * ref, 1000000000) - 5;
> +
> +	ret = ub953_write(priv, UB953_REG_SCL_HIGH_TIME, scl_high);
> +	if (ret)
> +		return ret;
> +
> +	ret = ub953_write(priv, UB953_REG_SCL_LOW_TIME, scl_low);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static u64 ub953_get_fc_rate(struct ub953_data *priv)
> +{
> +	if (priv->hw_data->ub971) {
> +		switch (priv->mode) {
> +		case UB953_MODE_SYNC:
> +			return priv->plat_data->bc_rate * 160ull;
> +		default:
> +			/* Not supported */
> +			return 0;
> +		}
> +	} else {
> +		switch (priv->mode) {
> +		case UB953_MODE_SYNC:
> +			return priv->plat_data->bc_rate / 2 * 160ull;
> +		default:
> +			/* Not supported */
> +			return 0;
> +		}
> +	}

This could be simplified to

	if (priv->mode != UB953_MODE_SYNC)
		/* Not supported */
		return 0;

	if (priv->hw_data->ub971)
		return priv->plat_data->bc_rate * 160ull;
	else
		return priv->plat_data->bc_rate / 2 * 160ull;

> +}
> +
> +static unsigned long ub953_calc_clkout_ub953(struct ub953_data *priv,
> +					     unsigned long target, u64 fc,
> +					     u8 *hs_div, u8 *m, u8 *n)
> +{
> +	/*
> +	 * We always use 4 as a pre-divider (HS_CLK_DIV = 2).
> +	 *
> +	 * According to the datasheet:
> +	 * - "HS_CLK_DIV typically should be set to either 16, 8, or 4 (default)."
> +	 * - "if it is not possible to have an integer ratio of N/M, it is best to
> +	 *    select a smaller value for HS_CLK_DIV.
> +	 *
> +	 * For above reasons the default HS_CLK_DIV seems the best in the average
> +	 * case. Use always that value to keep the code simple.
> +	 */
> +	static const unsigned long hs_clk_div = 4;
> +
> +	u64 fc_divided;
> +	unsigned long mul, div;
> +	unsigned long res;
> +
> +	/* clkout = fc / hs_clk_div * m / n */
> +
> +	fc_divided = div_u64(fc, hs_clk_div);
> +
> +	rational_best_approximation(target, fc_divided, (1 << 5) - 1,
> +				    (1 << 8) - 1, &mul, &div);
> +
> +	res = div_u64(fc_divided * mul, div);
> +
> +	*hs_div = hs_clk_div;
> +	*m = mul;
> +	*n = div;
> +
> +	return res;
> +}
> +
> +static unsigned long ub953_calc_clkout_ub971(struct ub953_data *priv,
> +					     unsigned long target, u64 fc,
> +					     u8 *m, u8 *n)
> +{
> +	u64 fc_divided;
> +	unsigned long mul, div;
> +	unsigned long res;
> +
> +	/* clkout = fc * m / (8 * n) */
> +
> +	fc_divided = div_u64(fc, 8);
> +
> +	rational_best_approximation(target, fc_divided, (1 << 5) - 1,
> +				    (1 << 8) - 1, &mul, &div);
> +
> +	res = div_u64(fc_divided * mul, div);
> +
> +	*m = mul;
> +	*n = div;
> +
> +	return res;
> +}
> +
> +static unsigned long ub953_clkout_recalc_rate(struct clk_hw *hw,
> +					      unsigned long parent_rate)
> +{
> +	struct ub953_data *priv = container_of(hw, struct ub953_data, clkout_clk_hw);
> +	struct device *dev = &priv->client->dev;
> +	u8 ctrl0, ctrl1;
> +	u32 mul, div;
> +	u64 fc_rate;
> +	u32 hs_clk_div;
> +	u64 rate;
> +	int ret;
> +
> +	ret = ub953_read(priv, UB953_REG_CLKOUT_CTRL0, &ctrl0);
> +	if (ret) {
> +		dev_err(dev, "Failed to read CLKOUT_CTRL0: %d\n", ret);
> +		return 0;
> +	}
> +
> +	ret = ub953_read(priv, UB953_REG_CLKOUT_CTRL1, &ctrl1);
> +	if (ret) {
> +		dev_err(dev, "Failed to read CLKOUT_CTRL1: %d\n", ret);
> +		return 0;
> +	}
> +
> +	fc_rate = ub953_get_fc_rate(priv);
> +
> +	if (priv->hw_data->ub971) {
> +		mul = ctrl0 & 0x1f;
> +		div = ctrl1;
> +
> +		if (div == 0)
> +			return 0;
> +
> +		rate = div_u64(fc_rate * mul, 8 * div);
> +
> +		dev_dbg(dev, "clkout: fc rate %llu, mul %u, div %u = %llu\n",
> +			fc_rate, mul, div, rate);
> +	} else {
> +		mul = ctrl0 & 0x1f;
> +		hs_clk_div = 1 << (ctrl0 >> 5);
> +		div = ctrl1;
> +
> +		if (div == 0)
> +			return 0;
> +
> +		rate = div_u64(div_u64(fc_rate, hs_clk_div) * mul, div);
> +
> +		dev_dbg(dev,
> +			"clkout: fc rate %llu, hs_clk_div %u, mul %u, div %u = %llu\n",
> +			fc_rate, hs_clk_div, mul, div, rate);
> +	}
> +
> +	return rate;
> +}
> +
> +static long ub953_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
> +				    unsigned long *parent_rate)
> +{
> +	struct ub953_data *priv = container_of(hw, struct ub953_data, clkout_clk_hw);
> +	struct device *dev = &priv->client->dev;
> +	unsigned long res;
> +	u64 fc_rate;
> +	u8 hs_div, m, n;
> +
> +	fc_rate = ub953_get_fc_rate(priv);
> +
> +	if (priv->hw_data->ub971) {
> +		res = ub953_calc_clkout_ub971(priv, rate, fc_rate, &m, &n);
> +
> +		dev_dbg(dev,
> +			"%s %llu * %u / (8 * %u) = %lu (requested %lu)",
> +			__func__, fc_rate, m, n, res, rate);
> +	} else {
> +		res = ub953_calc_clkout_ub953(priv, rate, fc_rate, &hs_div, &m, &n);
> +
> +		dev_dbg(dev,
> +			"%s %llu / %u * %u / %u = %lu (requested %lu)",
> +			__func__, fc_rate, hs_div, m, n, res, rate);
> +	}
> +
> +	return res;
> +}
> +
> +static int ub953_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
> +				 unsigned long parent_rate)
> +{
> +	struct ub953_data *priv = container_of(hw, struct ub953_data, clkout_clk_hw);
> +	u64 fc_rate;
> +	u8 hs_div, m, n;
> +	unsigned long res;
> +
> +	fc_rate = ub953_get_fc_rate(priv);
> +
> +	if (priv->hw_data->ub971) {
> +		res = ub953_calc_clkout_ub971(priv, rate, fc_rate, &m, &n);
> +
> +		ub953_write(priv, UB953_REG_CLKOUT_CTRL0, m);
> +		ub953_write(priv, UB953_REG_CLKOUT_CTRL1, n);
> +	} else {
> +		res = ub953_calc_clkout_ub953(priv, rate, fc_rate, &hs_div, &m, &n);
> +
> +		ub953_write(priv, UB953_REG_CLKOUT_CTRL0, (__ffs(hs_div) << 5) | m);
> +		ub953_write(priv, UB953_REG_CLKOUT_CTRL1, n);
> +	}
> +
> +	dev_dbg(&priv->client->dev,
> +		"%s %lu (requested %lu)\n", __func__, res, rate);
> +
> +	return 0;
> +}
> +
> +static const struct clk_ops ub953_clkout_ops = {
> +	.recalc_rate	= ub953_clkout_recalc_rate,
> +	.round_rate	= ub953_clkout_round_rate,
> +	.set_rate	= ub953_clkout_set_rate,
> +};
> +
> +static void ub953_init_clkout_ub953(struct ub953_data *priv)
> +{
> +	u64 fc_rate;
> +	u8 hs_div, m, n;
> +
> +	fc_rate = ub953_get_fc_rate(priv);
> +
> +	ub953_calc_clkout_ub953(priv, 25000000, fc_rate, &hs_div, &m, &n);
> +
> +	ub953_write(priv, UB953_REG_CLKOUT_CTRL0, (__ffs(hs_div) << 5) | m);
> +	ub953_write(priv, UB953_REG_CLKOUT_CTRL1, n);
> +}
> +
> +static void ub953_init_clkout_ub971(struct ub953_data *priv)
> +{
> +	u64 fc_rate;
> +	u8 m, n;
> +
> +	fc_rate = ub953_get_fc_rate(priv);
> +
> +	ub953_calc_clkout_ub971(priv, 25000000, fc_rate, &m, &n);
> +
> +	ub953_write(priv, UB953_REG_CLKOUT_CTRL0, m);
> +	ub953_write(priv, UB953_REG_CLKOUT_CTRL1, n);
> +}
> +
> +static int ub953_register_clkout(struct ub953_data *priv)
> +{
> +	struct device *dev = &priv->client->dev;
> +	const struct clk_init_data init = {
> +		.name = kasprintf(GFP_KERNEL, "ds90%s.%s.clk_out",
> +				  priv->hw_data->model, dev_name(dev)),
> +		.ops = &ub953_clkout_ops,
> +	};
> +	int ret;
> +
> +	/* Initialize clkout to 25MHz by default */
> +	if (priv->hw_data->ub971)
> +		ub953_init_clkout_ub971(priv);
> +	else
> +		ub953_init_clkout_ub953(priv);
> +
> +	priv->clkout_clk_hw.init = &init;
> +
> +	ret = devm_clk_hw_register(dev, &priv->clkout_clk_hw);
> +	kfree(init.name);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Cannot register clock HW\n");
> +
> +	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
> +					  &priv->clkout_clk_hw);
> +	if (ret)
> +		return dev_err_probe(dev, ret,
> +				     "Cannot add OF clock provider\n");
> +
> +	return 0;
> +}
> +
> +static int ub953_add_i2c_adapter(struct ub953_data *priv)
> +{
> +	struct device *dev = &priv->client->dev;
> +	struct fwnode_handle *i2c_handle;
> +	int ret;
> +
> +	i2c_handle = device_get_named_child_node(dev, "i2c");
> +	if (!i2c_handle)
> +		return 0;
> +
> +	ret = i2c_atr_add_adapter(priv->plat_data->atr, priv->plat_data->port,
> +				  i2c_handle);
> +
> +	fwnode_handle_put(i2c_handle);
> +
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static const struct regmap_config ub953_regmap_config = {
> +	.name = "ds90ub953",
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.reg_format_endian = REGMAP_ENDIAN_DEFAULT,
> +	.val_format_endian = REGMAP_ENDIAN_DEFAULT,
> +};
> +
> +static int ub953_parse_dt(struct ub953_data *priv)
> +{
> +	struct device_node *np = priv->client->dev.of_node;
> +	struct device *dev = &priv->client->dev;
> +	struct device_node *ep_np;
> +	int ret;
> +
> +	if (!np) {
> +		dev_err(dev, "OF: no device tree node!\n");
> +		return -ENOENT;
> +	}
> +
> +	ep_np = of_graph_get_endpoint_by_regs(np, 0, 0);
> +	if (!ep_np) {
> +		dev_err(dev, "OF: no endpoint\n");
> +		return -ENOENT;
> +	}
> +
> +	ret = of_property_count_u32_elems(ep_np, "data-lanes");
> +
> +	of_node_put(ep_np);
> +
> +	if (ret <= 0) {
> +		dev_err(dev, "OF: failed to parse data-lanes: %d\n", ret);
> +		return ret;
> +	}
> +
> +	if (ret != 1 && ret != 2 && ret != 4) {
> +		dev_err(dev, "OF: bad number of data-lanes: %d\n", ret);
> +		return -EINVAL;
> +	}
> +
> +	priv->num_data_lanes = ret;
> +
> +	return 0;
> +}
> +
> +static int ub953_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct ub953_data *priv;
> +	int ret;
> +	u8 v;
> +	bool mode_override;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->client = client;
> +
> +	priv->hw_data = of_device_get_match_data(dev);
> +	if (!priv->hw_data)
> +		return -ENODEV;
> +
> +	priv->plat_data = dev_get_platdata(&client->dev);
> +	if (!priv->plat_data) {
> +		dev_err(dev, "Platform data missing\n");
> +		return -ENODEV;
> +	}
> +
> +	mutex_init(&priv->reg_lock);
> +
> +	/*
> +	 * Initialize to invalid values so that the first reg writes will
> +	 * configure the target.
> +	 */
> +	priv->current_indirect_target = 0xff;
> +
> +	priv->regmap = devm_regmap_init_i2c(client, &ub953_regmap_config);
> +	if (IS_ERR(priv->regmap)) {
> +		dev_err(dev, "Failed to init regmap\n");
> +		ret = PTR_ERR(priv->regmap);
> +		goto err_mutex_destroy;
> +	}
> +
> +	ret = ub953_parse_dt(priv);
> +	if (ret)
> +		goto err_mutex_destroy;
> +
> +	ret = ub953_read(priv, UB953_REG_MODE_SEL, &v);
> +	if (ret)
> +		goto err_mutex_destroy;
> +
> +	if (!(v & UB953_REG_MODE_SEL_MODE_DONE)) {
> +		dev_err(dev, "Mode value not stabilized\n");
> +		ret = -ENODEV;
> +		goto err_mutex_destroy;
> +	}
> +
> +	mode_override = v & UB953_REG_MODE_SEL_MODE_OVERRIDE;
> +
> +	switch (v & UB953_REG_MODE_SEL_MODE_MASK) {
> +	case 0:
> +		priv->mode = UB953_MODE_SYNC;
> +		break;
> +	case 2:
> +		priv->mode = UB953_MODE_NONSYNC_EXT;
> +		break;
> +	case 3:
> +		priv->mode = UB953_MODE_NONSYNC_INT;
> +		break;
> +	case 5:
> +		priv->mode = UB953_MODE_DVP;
> +		break;
> +	default:
> +		dev_err(dev, "Illegal mode in mode register\n");
> +		ret = -ENODEV;
> +		goto err_mutex_destroy;
> +	}
> +
> +	dev_dbg(dev, "mode from %s: %#x\n", mode_override ? "reg" : "strap",
> +		priv->mode);
> +
> +	if (priv->mode != UB953_MODE_SYNC) {
> +		dev_err(dev, "Only synchronous mode supported\n");
> +		ret = -ENODEV;
> +		goto err_mutex_destroy;
> +	}
> +
> +	ret = ub953_read(priv, UB953_REG_REV_MASK_ID, &v);
> +	if (ret) {
> +		dev_err(dev, "Failed to read revision: %d", ret);
> +		goto err_mutex_destroy;
> +	}
> +
> +	dev_info(dev, "Found %s rev/mask %#04x\n", priv->hw_data->model, v);
> +
> +	ret = ub953_read(priv, UB953_REG_GENERAL_CFG, &v);
> +	if (ret)
> +		goto err_mutex_destroy;
> +
> +	dev_dbg(dev, "i2c strap setting %s V\n",
> +		(v & UB953_REG_GENERAL_CFG_I2C_STRAP_MODE) ? "1.8" : "3.3");

Please move the hardware checks and initialization to a separate
function, probe() is too big.

> +
> +	ret = ub953_i2c_master_init(priv);
> +	if (ret) {
> +		dev_err(dev, "i2c init failed: %d\n", ret);
> +		goto err_mutex_destroy;
> +	}
> +
> +	ret = ub953_gpiochip_probe(priv);
> +	if (ret) {
> +		dev_err(dev, "Failed to init gpiochip\n");
> +		goto err_mutex_destroy;
> +	}
> +
> +	ub953_write(priv, UB953_REG_GENERAL_CFG,
> +		    UB953_REG_GENERAL_CFG_CONT_CLK |
> +		    ((priv->num_data_lanes - 1) << UB953_REG_GENERAL_CFG_CSI_LANE_SEL_SHIFT) |
> +		    UB953_REG_GENERAL_CFG_CRC_TX_GEN_ENABLE);

This too.

> +
> +	ret = ub953_register_clkout(priv);
> +	if (ret) {
> +		dev_err(dev, "Failed to register clkout\n");
> +		goto err_gpiochip_remove;
> +	}
> +
> +	v4l2_i2c_subdev_init(&priv->sd, priv->client, &ub953_subdev_ops);
> +
> +	v4l2_ctrl_handler_init(&priv->ctrl_handler,
> +			       ARRAY_SIZE(ub953_tpg_qmenu) - 1);
> +	priv->sd.ctrl_handler = &priv->ctrl_handler;
> +
> +	v4l2_ctrl_new_std_menu_items(&priv->ctrl_handler, &ub953_ctrl_ops,
> +				     V4L2_CID_TEST_PATTERN,
> +				     ARRAY_SIZE(ub953_tpg_qmenu) - 1, 0, 0,
> +				     ub953_tpg_qmenu);
> +
> +	if (priv->ctrl_handler.error) {
> +		ret = priv->ctrl_handler.error;
> +		goto err_gpiochip_remove;
> +	}
> +
> +	priv->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_HAS_EVENTS |
> +		V4L2_SUBDEV_FL_STREAMS;
> +	priv->sd.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
> +	priv->sd.entity.ops = &ub953_entity_ops;
> +
> +	priv->pads[0].flags = MEDIA_PAD_FL_SINK;
> +	priv->pads[1].flags = MEDIA_PAD_FL_SOURCE;
> +
> +	ret = media_entity_pads_init(&priv->sd.entity, 2, priv->pads);
> +	if (ret) {
> +		dev_err(dev, "Failed to init pads\n");
> +		goto err_remove_ctrls;
> +	}
> +
> +	priv->tx_ep_np = of_graph_get_endpoint_by_regs(dev->of_node, 1, 0);

Error handling ?

> +	priv->sd.fwnode = of_fwnode_handle(priv->tx_ep_np);
> +
> +	priv->sd.state_lock = priv->sd.ctrl_handler->lock;
> +
> +	ret = v4l2_subdev_init_finalize(&priv->sd);
> +	if (ret)
> +		goto err_entity_cleanup;

I think I would move subdev init to a separate function too.

> +
> +	ret = ub953_v4l2_notifier_register(priv);
> +	if (ret) {
> +		dev_err(dev, "v4l2 subdev notifier register failed: %d\n", ret);
> +		goto err_free_state;
> +	}
> +
> +	ret = v4l2_async_register_subdev(&priv->sd);
> +	if (ret) {
> +		dev_err(dev, "v4l2_async_register_subdev error: %d\n", ret);
> +		goto err_unreg_notif;
> +	}
> +
> +	ret = ub953_add_i2c_adapter(priv);
> +	if (ret) {
> +		dev_err(dev, "failed to add remote i2c adapter\n");
> +		goto err_unreg_async_subdev;
> +	}
> +
> +	return 0;
> +
> +err_unreg_async_subdev:
> +	v4l2_async_unregister_subdev(&priv->sd);
> +err_unreg_notif:
> +	ub953_v4l2_notifier_unregister(priv);
> +err_free_state:
> +	v4l2_subdev_cleanup(&priv->sd);
> +err_entity_cleanup:
> +	if (priv->tx_ep_np)
> +		of_node_put(priv->tx_ep_np);
> +
> +	media_entity_cleanup(&priv->sd.entity);
> +err_remove_ctrls:
> +	v4l2_ctrl_handler_free(&priv->ctrl_handler);
> +err_gpiochip_remove:
> +	ub953_gpiochip_remove(priv);
> +err_mutex_destroy:
> +	mutex_destroy(&priv->reg_lock);
> +
> +	return ret;
> +}
> +
> +static void ub953_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct ub953_data *priv = sd_to_ub953(sd);
> +
> +	i2c_atr_del_adapter(priv->plat_data->atr,
> +			    priv->plat_data->port);
> +
> +	v4l2_async_unregister_subdev(&priv->sd);
> +
> +	ub953_v4l2_notifier_unregister(priv);
> +
> +	v4l2_subdev_cleanup(&priv->sd);
> +
> +	of_node_put(priv->tx_ep_np);
> +
> +	media_entity_cleanup(&priv->sd.entity);
> +
> +	v4l2_ctrl_handler_free(&priv->ctrl_handler);
> +
> +	ub953_gpiochip_remove(priv);
> +	mutex_destroy(&priv->reg_lock);
> +}
> +
> +static const struct ub953_hw_data ds90ub953_hw = {
> +	.model = "ub953",
> +};
> +
> +static const struct ub953_hw_data ds90ub971_hw = {
> +	.model = "ub971",
> +	.ub971 = true,
> +};
> +
> +static const struct i2c_device_id ub953_id[] = {
> +	{ "ds90ub953-q1", 0 },
> +	{ "ds90ub971-q1", 0 },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, ub953_id);
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id ub953_dt_ids[] = {
> +	{ .compatible = "ti,ds90ub953-q1", .data = &ds90ub953_hw },
> +	{ .compatible = "ti,ds90ub971-q1", .data = &ds90ub971_hw },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, ub953_dt_ids);
> +#endif
> +
> +static struct i2c_driver ds90ub953_driver = {
> +	.probe_new	= ub953_probe,
> +	.remove		= ub953_remove,
> +	.id_table	= ub953_id,
> +	.driver = {
> +		.name	= "ds90ub953",
> +		.owner = THIS_MODULE,
> +		.of_match_table = of_match_ptr(ub953_dt_ids),
> +	},
> +};
> +
> +module_i2c_driver(ds90ub953_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Texas Instruments DS90UB953 serializer driver");
> +MODULE_AUTHOR("Luca Ceresoli <luca@lucaceresoli.net>");
> +MODULE_AUTHOR("Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>");
> +MODULE_IMPORT_NS(I2C_ATR);