text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   * Sony imx334 sensor driver
   *
   * Copyright (C) 2021 Intel Corporation
   */
  #include <asm/unaligned.h>
  
  #include <linux/clk.h>
  #include <linux/delay.h>
  #include <linux/i2c.h>
  #include <linux/module.h>
  #include <linux/pm_runtime.h>
  
  #include <media/v4l2-ctrls.h>
  #include <media/v4l2-fwnode.h>
  #include <media/v4l2-subdev.h>
  
  /* Streaming Mode */
  #define IMX334_REG_MODE_SELECT	0x3000
  #define IMX334_MODE_STANDBY	0x01
  #define IMX334_MODE_STREAMING	0x00
  
  /* Lines per frame */
  #define IMX334_REG_LPFR		0x3030
  
  /* Chip ID */
  #define IMX334_REG_ID		0x3044
  #define IMX334_ID		0x1e
  
  /* Exposure control */
  #define IMX334_REG_SHUTTER	0x3058
  #define IMX334_EXPOSURE_MIN	1
  #define IMX334_EXPOSURE_OFFSET	5
  #define IMX334_EXPOSURE_STEP	1
  #define IMX334_EXPOSURE_DEFAULT	0x0648
  
  /* Analog gain control */
  #define IMX334_REG_AGAIN	0x30e8
  #define IMX334_AGAIN_MIN	0
  #define IMX334_AGAIN_MAX	240
  #define IMX334_AGAIN_STEP	1
  #define IMX334_AGAIN_DEFAULT	0
  
  /* Group hold register */
  #define IMX334_REG_HOLD		0x3001
  
  /* Input clock rate */
  #define IMX334_INCLK_RATE	24000000
  
  /* CSI2 HW configuration */
  #define IMX334_LINK_FREQ	891000000
  #define IMX334_NUM_DATA_LANES	4
  
  #define IMX334_REG_MIN		0x00
  #define IMX334_REG_MAX		0xfffff
  
  /**
   * struct imx334_reg - imx334 sensor register
   * @address: Register address
   * @val: Register value
   */
  struct imx334_reg {
  	u16 address;
  	u8 val;
  };
  
  /**
   * struct imx334_reg_list - imx334 sensor register list
   * @num_of_regs: Number of registers in the list
   * @regs: Pointer to register list
   */
  struct imx334_reg_list {
  	u32 num_of_regs;
  	const struct imx334_reg *regs;
  };
  
  /**
   * struct imx334_mode - imx334 sensor mode structure
   * @width: Frame width
   * @height: Frame height
   * @code: Format code
   * @hblank: Horizontal blanking in lines
   * @vblank: Vertical blanking in lines
   * @vblank_min: Minimal vertical blanking in lines
   * @vblank_max: Maximum vertical blanking in lines
   * @pclk: Sensor pixel clock
   * @link_freq_idx: Link frequency index
   * @reg_list: Register list for sensor mode
   */
  struct imx334_mode {
  	u32 width;
  	u32 height;
  	u32 code;
  	u32 hblank;
  	u32 vblank;
  	u32 vblank_min;
  	u32 vblank_max;
  	u64 pclk;
  	u32 link_freq_idx;
  	struct imx334_reg_list reg_list;
  };
  
  /**
   * struct imx334 - imx334 sensor device structure
   * @dev: Pointer to generic device
   * @client: Pointer to i2c client
   * @sd: V4L2 sub-device
   * @pad: Media pad. Only one pad supported
   * @reset_gpio: Sensor reset gpio
   * @inclk: Sensor input clock
   * @ctrl_handler: V4L2 control handler
   * @link_freq_ctrl: Pointer to link frequency control
   * @pclk_ctrl: Pointer to pixel clock control
   * @hblank_ctrl: Pointer to horizontal blanking control
   * @vblank_ctrl: Pointer to vertical blanking control
   * @exp_ctrl: Pointer to exposure control
   * @again_ctrl: Pointer to analog gain control
   * @vblank: Vertical blanking in lines
   * @cur_mode: Pointer to current selected sensor mode
   * @mutex: Mutex for serializing sensor controls
   * @streaming: Flag indicating streaming state
   */
  struct imx334 {
  	struct device *dev;
  	struct i2c_client *client;
  	struct v4l2_subdev sd;
  	struct media_pad pad;
  	struct gpio_desc *reset_gpio;
  	struct clk *inclk;
  	struct v4l2_ctrl_handler ctrl_handler;
  	struct v4l2_ctrl *link_freq_ctrl;
  	struct v4l2_ctrl *pclk_ctrl;
  	struct v4l2_ctrl *hblank_ctrl;
  	struct v4l2_ctrl *vblank_ctrl;
  	struct {
  		struct v4l2_ctrl *exp_ctrl;
  		struct v4l2_ctrl *again_ctrl;
  	};
  	u32 vblank;
  	const struct imx334_mode *cur_mode;
  	struct mutex mutex;
  	bool streaming;
  };
  
  static const s64 link_freq[] = {
  	IMX334_LINK_FREQ,
  };
  
  /* Sensor mode registers */
  static const struct imx334_reg mode_3840x2160_regs[] = {
  	{0x3000, 0x01},
  	{0x3002, 0x00},
  	{0x3018, 0x04},
  	{0x37b0, 0x36},
  	{0x304c, 0x00},
  	{0x300c, 0x3b},
  	{0x300d, 0x2a},
  	{0x3034, 0x26},
  	{0x3035, 0x02},
  	{0x314c, 0x29},
  	{0x314d, 0x01},
  	{0x315a, 0x02},
  	{0x3168, 0xa0},
  	{0x316a, 0x7e},
  	{0x3288, 0x21},
  	{0x328a, 0x02},
  	{0x302c, 0x3c},
  	{0x302e, 0x00},
  	{0x302f, 0x0f},
  	{0x3076, 0x70},
  	{0x3077, 0x08},
  	{0x3090, 0x70},
  	{0x3091, 0x08},
  	{0x30d8, 0x20},
  	{0x30d9, 0x12},
  	{0x3308, 0x70},
  	{0x3309, 0x08},
  	{0x3414, 0x05},
  	{0x3416, 0x18},
  	{0x35ac, 0x0e},
  	{0x3648, 0x01},
  	{0x364a, 0x04},
  	{0x364c, 0x04},
  	{0x3678, 0x01},
  	{0x367c, 0x31},
  	{0x367e, 0x31},
  	{0x3708, 0x02},
  	{0x3714, 0x01},
  	{0x3715, 0x02},
  	{0x3716, 0x02},
  	{0x3717, 0x02},
  	{0x371c, 0x3d},
  	{0x371d, 0x3f},
  	{0x372c, 0x00},
  	{0x372d, 0x00},
  	{0x372e, 0x46},
  	{0x372f, 0x00},
  	{0x3730, 0x89},
  	{0x3731, 0x00},
  	{0x3732, 0x08},
  	{0x3733, 0x01},
  	{0x3734, 0xfe},
  	{0x3735, 0x05},
  	{0x375d, 0x00},
  	{0x375e, 0x00},
  	{0x375f, 0x61},
  	{0x3760, 0x06},
  	{0x3768, 0x1b},
  	{0x3769, 0x1b},
  	{0x376a, 0x1a},
  	{0x376b, 0x19},
  	{0x376c, 0x18},
  	{0x376d, 0x14},
  	{0x376e, 0x0f},
  	{0x3776, 0x00},
  	{0x3777, 0x00},
  	{0x3778, 0x46},
  	{0x3779, 0x00},
  	{0x377a, 0x08},
  	{0x377b, 0x01},
  	{0x377c, 0x45},
  	{0x377d, 0x01},
  	{0x377e, 0x23},
  	{0x377f, 0x02},
  	{0x3780, 0xd9},
  	{0x3781, 0x03},
  	{0x3782, 0xf5},
  	{0x3783, 0x06},
  	{0x3784, 0xa5},
  	{0x3788, 0x0f},
  	{0x378a, 0xd9},
  	{0x378b, 0x03},
  	{0x378c, 0xeb},
  	{0x378d, 0x05},
  	{0x378e, 0x87},
  	{0x378f, 0x06},
  	{0x3790, 0xf5},
  	{0x3792, 0x43},
  	{0x3794, 0x7a},
  	{0x3796, 0xa1},
  	{0x3e04, 0x0e},
  	{0x3a00, 0x01},
  };
  
  /* Supported sensor mode configurations */
  static const struct imx334_mode supported_mode = {
  	.width = 3840,
  	.height = 2160,
  	.hblank = 560,
  	.vblank = 2340,
  	.vblank_min = 90,
  	.vblank_max = 132840,
  	.pclk = 594000000,
  	.link_freq_idx = 0,
  	.code = MEDIA_BUS_FMT_SRGGB12_1X12,
  	.reg_list = {
  		.num_of_regs = ARRAY_SIZE(mode_3840x2160_regs),
  		.regs = mode_3840x2160_regs,
  	},
  };
  
  /**
   * to_imx334() - imv334 V4L2 sub-device to imx334 device.
   * @subdev: pointer to imx334 V4L2 sub-device
   *
   * Return: pointer to imx334 device
   */
  static inline struct imx334 *to_imx334(struct v4l2_subdev *subdev)
  {
  	return container_of(subdev, struct imx334, sd);
  }
  
  /**
   * imx334_read_reg() - Read registers.
   * @imx334: pointer to imx334 device
   * @reg: register address
   * @len: length of bytes to read. Max supported bytes is 4
   * @val: pointer to register value to be filled.
   *
   * Big endian register addresses with little endian values.
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_read_reg(struct imx334 *imx334, u16 reg, u32 len, u32 *val)
  {
  	struct i2c_client *client = v4l2_get_subdevdata(&imx334->sd);
  	struct i2c_msg msgs[2] = {0};
  	u8 addr_buf[2] = {0};
  	u8 data_buf[4] = {0};
  	int ret;
  
  	if (WARN_ON(len > 4))
  		return -EINVAL;
  
  	put_unaligned_be16(reg, addr_buf);
  
  	/* Write register address */
  	msgs[0].addr = client->addr;
  	msgs[0].flags = 0;
  	msgs[0].len = ARRAY_SIZE(addr_buf);
  	msgs[0].buf = addr_buf;
  
  	/* Read data from register */
  	msgs[1].addr = client->addr;
  	msgs[1].flags = I2C_M_RD;
  	msgs[1].len = len;
  	msgs[1].buf = data_buf;
  
  	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
  	if (ret != ARRAY_SIZE(msgs))
  		return -EIO;
  
  	*val = get_unaligned_le32(data_buf);
  
  	return 0;
  }
  
  /**
   * imx334_write_reg() - Write register
   * @imx334: pointer to imx334 device
   * @reg: register address
   * @len: length of bytes. Max supported bytes is 4
   * @val: register value
   *
   * Big endian register addresses with little endian values.
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_write_reg(struct imx334 *imx334, u16 reg, u32 len, u32 val)
  {
  	struct i2c_client *client = v4l2_get_subdevdata(&imx334->sd);
  	u8 buf[6] = {0};
  
  	if (WARN_ON(len > 4))
  		return -EINVAL;
  
  	put_unaligned_be16(reg, buf);
  	put_unaligned_le32(val, buf + 2);
  	if (i2c_master_send(client, buf, len + 2) != len + 2)
  		return -EIO;
  
  	return 0;
  }
  
  /**
   * imx334_write_regs() - Write a list of registers
   * @imx334: pointer to imx334 device
   * @regs: list of registers to be written
   * @len: length of registers array
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_write_regs(struct imx334 *imx334,
  			     const struct imx334_reg *regs, u32 len)
  {
  	unsigned int i;
  	int ret;
  
  	for (i = 0; i < len; i++) {
  		ret = imx334_write_reg(imx334, regs[i].address, 1, regs[i].val);
  		if (ret)
  			return ret;
  	}
  
  	return 0;
  }
  
  /**
   * imx334_update_controls() - Update control ranges based on streaming mode
   * @imx334: pointer to imx334 device
   * @mode: pointer to imx334_mode sensor mode
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_update_controls(struct imx334 *imx334,
  				  const struct imx334_mode *mode)
  {
  	int ret;
  
  	ret = __v4l2_ctrl_s_ctrl(imx334->link_freq_ctrl, mode->link_freq_idx);
  	if (ret)
  		return ret;
  
  	ret = __v4l2_ctrl_s_ctrl(imx334->hblank_ctrl, mode->hblank);
  	if (ret)
  		return ret;
  
  	return __v4l2_ctrl_modify_range(imx334->vblank_ctrl, mode->vblank_min,
  					mode->vblank_max, 1, mode->vblank);
  }
  
  /**
   * imx334_update_exp_gain() - Set updated exposure and gain
   * @imx334: pointer to imx334 device
   * @exposure: updated exposure value
   * @gain: updated analog gain value
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_update_exp_gain(struct imx334 *imx334, u32 exposure, u32 gain)
  {
  	u32 lpfr, shutter;
  	int ret;
  
  	lpfr = imx334->vblank + imx334->cur_mode->height;
  	shutter = lpfr - exposure;
  
  	dev_dbg(imx334->dev, "Set long exp %u analog gain %u sh0 %u lpfr %u",
  		exposure, gain, shutter, lpfr);
  
  	ret = imx334_write_reg(imx334, IMX334_REG_HOLD, 1, 1);
  	if (ret)
  		return ret;
  
  	ret = imx334_write_reg(imx334, IMX334_REG_LPFR, 3, lpfr);
  	if (ret)
  		goto error_release_group_hold;
  
  	ret = imx334_write_reg(imx334, IMX334_REG_SHUTTER, 3, shutter);
  	if (ret)
  		goto error_release_group_hold;
  
  	ret = imx334_write_reg(imx334, IMX334_REG_AGAIN, 1, gain);
  
  error_release_group_hold:
  	imx334_write_reg(imx334, IMX334_REG_HOLD, 1, 0);
  
  	return ret;
  }
  
  /**
   * imx334_set_ctrl() - Set subdevice control
   * @ctrl: pointer to v4l2_ctrl structure
   *
   * Supported controls:
   * - V4L2_CID_VBLANK
   * - cluster controls:
   *   - V4L2_CID_ANALOGUE_GAIN
   *   - V4L2_CID_EXPOSURE
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_set_ctrl(struct v4l2_ctrl *ctrl)
  {
  	struct imx334 *imx334 =
  		container_of(ctrl->handler, struct imx334, ctrl_handler);
  	u32 analog_gain;
  	u32 exposure;
  	int ret;
  
  	switch (ctrl->id) {
  	case V4L2_CID_VBLANK:
  		imx334->vblank = imx334->vblank_ctrl->val;
  
  		dev_dbg(imx334->dev, "Received vblank %u, new lpfr %u",
  			imx334->vblank,
  			imx334->vblank + imx334->cur_mode->height);
  
  		ret = __v4l2_ctrl_modify_range(imx334->exp_ctrl,
  					       IMX334_EXPOSURE_MIN,
  					       imx334->vblank +
  					       imx334->cur_mode->height -
  					       IMX334_EXPOSURE_OFFSET,
  					       1, IMX334_EXPOSURE_DEFAULT);
  		break;
  	case V4L2_CID_EXPOSURE:
  
  		/* Set controls only if sensor is in power on state */
  		if (!pm_runtime_get_if_in_use(imx334->dev))
  			return 0;
  
  		exposure = ctrl->val;
  		analog_gain = imx334->again_ctrl->val;
  
  		dev_dbg(imx334->dev, "Received exp %u analog gain %u",
  			exposure, analog_gain);
  
  		ret = imx334_update_exp_gain(imx334, exposure, analog_gain);
  
  		pm_runtime_put(imx334->dev);
  
  		break;
  	default:
  		dev_err(imx334->dev, "Invalid control %d", ctrl->id);
  		ret = -EINVAL;
  	}
  
  	return ret;
  }
  
  /* V4l2 subdevice control ops*/
  static const struct v4l2_ctrl_ops imx334_ctrl_ops = {
  	.s_ctrl = imx334_set_ctrl,
  };
  
  /**
   * imx334_enum_mbus_code() - Enumerate V4L2 sub-device mbus codes
   * @sd: pointer to imx334 V4L2 sub-device structure
   * @sd_state: V4L2 sub-device state
   * @code: V4L2 sub-device code enumeration need to be filled
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_enum_mbus_code(struct v4l2_subdev *sd,
  				 struct v4l2_subdev_state *sd_state,
  				 struct v4l2_subdev_mbus_code_enum *code)
  {
  	if (code->index > 0)
  		return -EINVAL;
  
  	code->code = supported_mode.code;
  
  	return 0;
  }
  
  /**
   * imx334_enum_frame_size() - Enumerate V4L2 sub-device frame sizes
   * @sd: pointer to imx334 V4L2 sub-device structure
   * @sd_state: V4L2 sub-device state
   * @fsize: V4L2 sub-device size enumeration need to be filled
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_enum_frame_size(struct v4l2_subdev *sd,
  				  struct v4l2_subdev_state *sd_state,
  				  struct v4l2_subdev_frame_size_enum *fsize)
  {
  	if (fsize->index > 0)
  		return -EINVAL;
  
  	if (fsize->code != supported_mode.code)
  		return -EINVAL;
  
  	fsize->min_width = supported_mode.width;
  	fsize->max_width = fsize->min_width;
  	fsize->min_height = supported_mode.height;
  	fsize->max_height = fsize->min_height;
  
  	return 0;
  }
  
  /**
   * imx334_fill_pad_format() - Fill subdevice pad format
   *                            from selected sensor mode
   * @imx334: pointer to imx334 device
   * @mode: pointer to imx334_mode sensor mode
   * @fmt: V4L2 sub-device format need to be filled
   */
  static void imx334_fill_pad_format(struct imx334 *imx334,
  				   const struct imx334_mode *mode,
  				   struct v4l2_subdev_format *fmt)
  {
  	fmt->format.width = mode->width;
  	fmt->format.height = mode->height;
  	fmt->format.code = mode->code;
  	fmt->format.field = V4L2_FIELD_NONE;
  	fmt->format.colorspace = V4L2_COLORSPACE_RAW;
  	fmt->format.ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
  	fmt->format.quantization = V4L2_QUANTIZATION_DEFAULT;
  	fmt->format.xfer_func = V4L2_XFER_FUNC_NONE;
  }
  
  /**
   * imx334_get_pad_format() - Get subdevice pad format
   * @sd: pointer to imx334 V4L2 sub-device structure
   * @sd_state: V4L2 sub-device state
   * @fmt: V4L2 sub-device format need to be set
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_get_pad_format(struct v4l2_subdev *sd,
  				 struct v4l2_subdev_state *sd_state,
  				 struct v4l2_subdev_format *fmt)
  {
  	struct imx334 *imx334 = to_imx334(sd);
  
  	mutex_lock(&imx334->mutex);
  
  	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY) {
  		struct v4l2_mbus_framefmt *framefmt;
  
  		framefmt = v4l2_subdev_get_try_format(sd, sd_state, fmt->pad);
  		fmt->format = *framefmt;
  	} else {
  		imx334_fill_pad_format(imx334, imx334->cur_mode, fmt);
  	}
  
  	mutex_unlock(&imx334->mutex);
  
  	return 0;
  }
  
  /**
   * imx334_set_pad_format() - Set subdevice pad format
   * @sd: pointer to imx334 V4L2 sub-device structure
   * @sd_state: V4L2 sub-device state
   * @fmt: V4L2 sub-device format need to be set
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_set_pad_format(struct v4l2_subdev *sd,
  				 struct v4l2_subdev_state *sd_state,
  				 struct v4l2_subdev_format *fmt)
  {
  	struct imx334 *imx334 = to_imx334(sd);
  	const struct imx334_mode *mode;
  	int ret = 0;
  
  	mutex_lock(&imx334->mutex);
  
  	mode = &supported_mode;
  	imx334_fill_pad_format(imx334, mode, fmt);
  
  	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY) {
  		struct v4l2_mbus_framefmt *framefmt;
  
  		framefmt = v4l2_subdev_get_try_format(sd, sd_state, fmt->pad);
  		*framefmt = fmt->format;
  	} else {
  		ret = imx334_update_controls(imx334, mode);
  		if (!ret)
  			imx334->cur_mode = mode;
  	}
  
  	mutex_unlock(&imx334->mutex);
  
  	return ret;
  }
  
  /**
   * imx334_init_pad_cfg() - Initialize sub-device pad configuration
   * @sd: pointer to imx334 V4L2 sub-device structure
   * @sd_state: V4L2 sub-device state
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_init_pad_cfg(struct v4l2_subdev *sd,
  			       struct v4l2_subdev_state *sd_state)
  {
  	struct imx334 *imx334 = to_imx334(sd);
  	struct v4l2_subdev_format fmt = { 0 };
  
  	fmt.which = sd_state ? V4L2_SUBDEV_FORMAT_TRY : V4L2_SUBDEV_FORMAT_ACTIVE;
  	imx334_fill_pad_format(imx334, &supported_mode, &fmt);
  
  	return imx334_set_pad_format(sd, sd_state, &fmt);
  }
  
  /**
   * imx334_start_streaming() - Start sensor stream
   * @imx334: pointer to imx334 device
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_start_streaming(struct imx334 *imx334)
  {
  	const struct imx334_reg_list *reg_list;
  	int ret;
  
  	/* Write sensor mode registers */
  	reg_list = &imx334->cur_mode->reg_list;
  	ret = imx334_write_regs(imx334, reg_list->regs,
  				reg_list->num_of_regs);
  	if (ret) {
  		dev_err(imx334->dev, "fail to write initial registers");
  		return ret;
  	}
  
  	/* Setup handler will write actual exposure and gain */
  	ret =  __v4l2_ctrl_handler_setup(imx334->sd.ctrl_handler);
  	if (ret) {
  		dev_err(imx334->dev, "fail to setup handler");
  		return ret;
  	}
  
  	/* Start streaming */
  	ret = imx334_write_reg(imx334, IMX334_REG_MODE_SELECT,
  			       1, IMX334_MODE_STREAMING);
  	if (ret) {
  		dev_err(imx334->dev, "fail to start streaming");
  		return ret;
  	}
  
  	return 0;
  }
  
  /**
   * imx334_stop_streaming() - Stop sensor stream
   * @imx334: pointer to imx334 device
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_stop_streaming(struct imx334 *imx334)
  {
  	return imx334_write_reg(imx334, IMX334_REG_MODE_SELECT,
  				1, IMX334_MODE_STANDBY);
  }
  
  /**
   * imx334_set_stream() - Enable sensor streaming
   * @sd: pointer to imx334 subdevice
   * @enable: set to enable sensor streaming
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_set_stream(struct v4l2_subdev *sd, int enable)
  {
  	struct imx334 *imx334 = to_imx334(sd);
  	int ret;
  
  	mutex_lock(&imx334->mutex);
  
  	if (imx334->streaming == enable) {
  		mutex_unlock(&imx334->mutex);
  		return 0;
  	}
  
  	if (enable) {
  		ret = pm_runtime_resume_and_get(imx334->dev);
  		if (ret < 0)
  			goto error_unlock;
  
  		ret = imx334_start_streaming(imx334);
  		if (ret)
  			goto error_power_off;
  	} else {
  		imx334_stop_streaming(imx334);
  		pm_runtime_put(imx334->dev);
  	}
  
  	imx334->streaming = enable;
  
  	mutex_unlock(&imx334->mutex);
  
  	return 0;
  
  error_power_off:
  	pm_runtime_put(imx334->dev);
  error_unlock:
  	mutex_unlock(&imx334->mutex);
  
  	return ret;
  }
  
  /**
   * imx334_detect() - Detect imx334 sensor
   * @imx334: pointer to imx334 device
   *
   * Return: 0 if successful, -EIO if sensor id does not match
   */
  static int imx334_detect(struct imx334 *imx334)
  {
  	int ret;
  	u32 val;
  
  	ret = imx334_read_reg(imx334, IMX334_REG_ID, 2, &val);
  	if (ret)
  		return ret;
  
  	if (val != IMX334_ID) {
  		dev_err(imx334->dev, "chip id mismatch: %x!=%x",
  			IMX334_ID, val);
  		return -ENXIO;
  	}
  
  	return 0;
  }
  
  /**
   * imx334_parse_hw_config() - Parse HW configuration and check if supported
   * @imx334: pointer to imx334 device
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_parse_hw_config(struct imx334 *imx334)
  {
  	struct fwnode_handle *fwnode = dev_fwnode(imx334->dev);
  	struct v4l2_fwnode_endpoint bus_cfg = {
  		.bus_type = V4L2_MBUS_CSI2_DPHY
  	};
  	struct fwnode_handle *ep;
  	unsigned long rate;
  	int ret;
  	int i;
  
  	if (!fwnode)
  		return -ENXIO;
  
  	/* Request optional reset pin */
  	imx334->reset_gpio = devm_gpiod_get_optional(imx334->dev, "reset",
  						     GPIOD_OUT_LOW);
  	if (IS_ERR(imx334->reset_gpio)) {
  		dev_err(imx334->dev, "failed to get reset gpio %ld",
  			PTR_ERR(imx334->reset_gpio));
  		return PTR_ERR(imx334->reset_gpio);
  	}
  
  	/* Get sensor input clock */
  	imx334->inclk = devm_clk_get(imx334->dev, NULL);
  	if (IS_ERR(imx334->inclk)) {
  		dev_err(imx334->dev, "could not get inclk");
  		return PTR_ERR(imx334->inclk);
  	}
  
  	rate = clk_get_rate(imx334->inclk);
  	if (rate != IMX334_INCLK_RATE) {
  		dev_err(imx334->dev, "inclk frequency mismatch");
  		return -EINVAL;
  	}
  
  	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
  	if (!ep)
  		return -ENXIO;
  
  	ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);
  	fwnode_handle_put(ep);
  	if (ret)
  		return ret;
  
  	if (bus_cfg.bus.mipi_csi2.num_data_lanes != IMX334_NUM_DATA_LANES) {
  		dev_err(imx334->dev,
  			"number of CSI2 data lanes %d is not supported",
  			bus_cfg.bus.mipi_csi2.num_data_lanes);
  		ret = -EINVAL;
  		goto done_endpoint_free;
  	}
  
  	if (!bus_cfg.nr_of_link_frequencies) {
  		dev_err(imx334->dev, "no link frequencies defined");
  		ret = -EINVAL;
  		goto done_endpoint_free;
  	}
  
  	for (i = 0; i < bus_cfg.nr_of_link_frequencies; i++)
  		if (bus_cfg.link_frequencies[i] == IMX334_LINK_FREQ)
  			goto done_endpoint_free;
  
  	ret = -EINVAL;
  
  done_endpoint_free:
  	v4l2_fwnode_endpoint_free(&bus_cfg);
  
  	return ret;
  }
  
  /* V4l2 subdevice ops */
  static const struct v4l2_subdev_video_ops imx334_video_ops = {
  	.s_stream = imx334_set_stream,
  };
  
  static const struct v4l2_subdev_pad_ops imx334_pad_ops = {
  	.init_cfg = imx334_init_pad_cfg,
  	.enum_mbus_code = imx334_enum_mbus_code,
  	.enum_frame_size = imx334_enum_frame_size,
  	.get_fmt = imx334_get_pad_format,
  	.set_fmt = imx334_set_pad_format,
  };
  
  static const struct v4l2_subdev_ops imx334_subdev_ops = {
  	.video = &imx334_video_ops,
  	.pad = &imx334_pad_ops,
  };
  
  /**
   * imx334_power_on() - Sensor power on sequence
   * @dev: pointer to i2c device
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_power_on(struct device *dev)
  {
  	struct v4l2_subdev *sd = dev_get_drvdata(dev);
  	struct imx334 *imx334 = to_imx334(sd);
  	int ret;
  
  	gpiod_set_value_cansleep(imx334->reset_gpio, 1);
  
  	ret = clk_prepare_enable(imx334->inclk);
  	if (ret) {
  		dev_err(imx334->dev, "fail to enable inclk");
  		goto error_reset;
  	}
  
  	usleep_range(18000, 20000);
  
  	return 0;
  
  error_reset:
  	gpiod_set_value_cansleep(imx334->reset_gpio, 0);
  
  	return ret;
  }
  
  /**
   * imx334_power_off() - Sensor power off sequence
   * @dev: pointer to i2c device
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_power_off(struct device *dev)
  {
  	struct v4l2_subdev *sd = dev_get_drvdata(dev);
  	struct imx334 *imx334 = to_imx334(sd);
  
  	gpiod_set_value_cansleep(imx334->reset_gpio, 0);
  
  	clk_disable_unprepare(imx334->inclk);
  
  	return 0;
  }
  
  /**
   * imx334_init_controls() - Initialize sensor subdevice controls
   * @imx334: pointer to imx334 device
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_init_controls(struct imx334 *imx334)
  {
  	struct v4l2_ctrl_handler *ctrl_hdlr = &imx334->ctrl_handler;
  	const struct imx334_mode *mode = imx334->cur_mode;
  	u32 lpfr;
  	int ret;
  
  	ret = v4l2_ctrl_handler_init(ctrl_hdlr, 6);
  	if (ret)
  		return ret;
  
  	/* Serialize controls with sensor device */
  	ctrl_hdlr->lock = &imx334->mutex;
  
  	/* Initialize exposure and gain */
  	lpfr = mode->vblank + mode->height;
  	imx334->exp_ctrl = v4l2_ctrl_new_std(ctrl_hdlr,
  					     &imx334_ctrl_ops,
  					     V4L2_CID_EXPOSURE,
  					     IMX334_EXPOSURE_MIN,
  					     lpfr - IMX334_EXPOSURE_OFFSET,
  					     IMX334_EXPOSURE_STEP,
  					     IMX334_EXPOSURE_DEFAULT);
  
  	imx334->again_ctrl = v4l2_ctrl_new_std(ctrl_hdlr,
  					       &imx334_ctrl_ops,
  					       V4L2_CID_ANALOGUE_GAIN,
  					       IMX334_AGAIN_MIN,
  					       IMX334_AGAIN_MAX,
  					       IMX334_AGAIN_STEP,
  					       IMX334_AGAIN_DEFAULT);
  
  	v4l2_ctrl_cluster(2, &imx334->exp_ctrl);
  
  	imx334->vblank_ctrl = v4l2_ctrl_new_std(ctrl_hdlr,
  						&imx334_ctrl_ops,
  						V4L2_CID_VBLANK,
  						mode->vblank_min,
  						mode->vblank_max,
  						1, mode->vblank);
  
  	/* Read only controls */
  	imx334->pclk_ctrl = v4l2_ctrl_new_std(ctrl_hdlr,
  					      &imx334_ctrl_ops,
  					      V4L2_CID_PIXEL_RATE,
  					      mode->pclk, mode->pclk,
  					      1, mode->pclk);
  
  	imx334->link_freq_ctrl = v4l2_ctrl_new_int_menu(ctrl_hdlr,
  							&imx334_ctrl_ops,
  							V4L2_CID_LINK_FREQ,
  							ARRAY_SIZE(link_freq) -
  							1,
  							mode->link_freq_idx,
  							link_freq);
  	if (imx334->link_freq_ctrl)
  		imx334->link_freq_ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
  
  	imx334->hblank_ctrl = v4l2_ctrl_new_std(ctrl_hdlr,
  						&imx334_ctrl_ops,
  						V4L2_CID_HBLANK,
  						IMX334_REG_MIN,
  						IMX334_REG_MAX,
  						1, mode->hblank);
  	if (imx334->hblank_ctrl)
  		imx334->hblank_ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
  
  	if (ctrl_hdlr->error) {
  		dev_err(imx334->dev, "control init failed: %d",
  			ctrl_hdlr->error);
  		v4l2_ctrl_handler_free(ctrl_hdlr);
  		return ctrl_hdlr->error;
  	}
  
  	imx334->sd.ctrl_handler = ctrl_hdlr;
  
  	return 0;
  }
  
  /**
   * imx334_probe() - I2C client device binding
   * @client: pointer to i2c client device
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_probe(struct i2c_client *client)
  {
  	struct imx334 *imx334;
  	int ret;
  
  	imx334 = devm_kzalloc(&client->dev, sizeof(*imx334), GFP_KERNEL);
  	if (!imx334)
  		return -ENOMEM;
  
  	imx334->dev = &client->dev;
  
  	/* Initialize subdev */
  	v4l2_i2c_subdev_init(&imx334->sd, client, &imx334_subdev_ops);
  
  	ret = imx334_parse_hw_config(imx334);
  	if (ret) {
  		dev_err(imx334->dev, "HW configuration is not supported");
  		return ret;
  	}
  
  	mutex_init(&imx334->mutex);
  
  	ret = imx334_power_on(imx334->dev);
  	if (ret) {
  		dev_err(imx334->dev, "failed to power-on the sensor");
  		goto error_mutex_destroy;
  	}
  
  	/* Check module identity */
  	ret = imx334_detect(imx334);
  	if (ret) {
  		dev_err(imx334->dev, "failed to find sensor: %d", ret);
  		goto error_power_off;
  	}
  
  	/* Set default mode to max resolution */
  	imx334->cur_mode = &supported_mode;
  	imx334->vblank = imx334->cur_mode->vblank;
  
  	ret = imx334_init_controls(imx334);
  	if (ret) {
  		dev_err(imx334->dev, "failed to init controls: %d", ret);
  		goto error_power_off;
  	}
  
  	/* Initialize subdev */
  	imx334->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
  	imx334->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
  
  	/* Initialize source pad */
  	imx334->pad.flags = MEDIA_PAD_FL_SOURCE;
  	ret = media_entity_pads_init(&imx334->sd.entity, 1, &imx334->pad);
  	if (ret) {
  		dev_err(imx334->dev, "failed to init entity pads: %d", ret);
  		goto error_handler_free;
  	}
  
  	ret = v4l2_async_register_subdev_sensor(&imx334->sd);
  	if (ret < 0) {
  		dev_err(imx334->dev,
  			"failed to register async subdev: %d", ret);
  		goto error_media_entity;
  	}
  
  	pm_runtime_set_active(imx334->dev);
  	pm_runtime_enable(imx334->dev);
  	pm_runtime_idle(imx334->dev);
  
  	return 0;
  
  error_media_entity:
  	media_entity_cleanup(&imx334->sd.entity);
  error_handler_free:
  	v4l2_ctrl_handler_free(imx334->sd.ctrl_handler);
  error_power_off:
  	imx334_power_off(imx334->dev);
  error_mutex_destroy:
  	mutex_destroy(&imx334->mutex);
  
  	return ret;
  }
  
  /**
   * imx334_remove() - I2C client device unbinding
   * @client: pointer to I2C client device
   *
   * Return: 0 if successful, error code otherwise.
   */
  static int imx334_remove(struct i2c_client *client)
  {
  	struct v4l2_subdev *sd = i2c_get_clientdata(client);
  	struct imx334 *imx334 = to_imx334(sd);
  
  	v4l2_async_unregister_subdev(sd);
  	media_entity_cleanup(&sd->entity);
  	v4l2_ctrl_handler_free(sd->ctrl_handler);
  
  	pm_runtime_disable(&client->dev);
  	pm_runtime_suspended(&client->dev);
  
  	mutex_destroy(&imx334->mutex);
  
  	return 0;
  }
  
  static const struct dev_pm_ops imx334_pm_ops = {
  	SET_RUNTIME_PM_OPS(imx334_power_off, imx334_power_on, NULL)
  };
  
  static const struct of_device_id imx334_of_match[] = {
  	{ .compatible = "sony,imx334" },
  	{ }
  };
  
  MODULE_DEVICE_TABLE(of, imx334_of_match);
  
  static struct i2c_driver imx334_driver = {
  	.probe_new = imx334_probe,
  	.remove = imx334_remove,
  	.driver = {
  		.name = "imx334",
  		.pm = &imx334_pm_ops,
  		.of_match_table = imx334_of_match,
  	},
  };
  
  module_i2c_driver(imx334_driver);
  
  MODULE_DESCRIPTION("Sony imx334 sensor driver");
  MODULE_LICENSE("GPL");
  