text: /*
   * Driver for MT9T001 CMOS Image Sensor from Aptina (Micron)
   *
   * Copyright (C) 2010-2011, Laurent Pinchart <laurent.pinchart@ideasonboard.com>
   *
   * Based on the MT9M001 driver,
   *
   * Copyright (C) 2008, Guennadi Liakhovetski <kernel@pengutronix.de>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  
  #include <linux/i2c.h>
  #include <linux/module.h>
  #include <linux/log2.h>
  #include <linux/slab.h>
  #include <linux/videodev2.h>
  #include <linux/v4l2-mediabus.h>
  
  #include <media/mt9t001.h>
  #include <media/v4l2-ctrls.h>
  #include <media/v4l2-device.h>
  #include <media/v4l2-subdev.h>
  
  #define MT9T001_PIXEL_ARRAY_HEIGHT			1568
  #define MT9T001_PIXEL_ARRAY_WIDTH			2112
  
  #define MT9T001_CHIP_VERSION				0x00
  #define		MT9T001_CHIP_ID				0x1621
  #define MT9T001_ROW_START				0x01
  #define		MT9T001_ROW_START_MIN			0
  #define		MT9T001_ROW_START_DEF			20
  #define		MT9T001_ROW_START_MAX			1534
  #define MT9T001_COLUMN_START				0x02
  #define		MT9T001_COLUMN_START_MIN		0
  #define		MT9T001_COLUMN_START_DEF		32
  #define		MT9T001_COLUMN_START_MAX		2046
  #define MT9T001_WINDOW_HEIGHT				0x03
  #define		MT9T001_WINDOW_HEIGHT_MIN		1
  #define		MT9T001_WINDOW_HEIGHT_DEF		1535
  #define		MT9T001_WINDOW_HEIGHT_MAX		1567
  #define MT9T001_WINDOW_WIDTH				0x04
  #define		MT9T001_WINDOW_WIDTH_MIN		1
  #define		MT9T001_WINDOW_WIDTH_DEF		2047
  #define		MT9T001_WINDOW_WIDTH_MAX		2111
  #define MT9T001_HORIZONTAL_BLANKING			0x05
  #define		MT9T001_HORIZONTAL_BLANKING_MIN		21
  #define		MT9T001_HORIZONTAL_BLANKING_MAX		1023
  #define MT9T001_VERTICAL_BLANKING			0x06
  #define		MT9T001_VERTICAL_BLANKING_MIN		3
  #define		MT9T001_VERTICAL_BLANKING_MAX		1023
  #define MT9T001_OUTPUT_CONTROL				0x07
  #define		MT9T001_OUTPUT_CONTROL_SYNC		(1 << 0)
  #define		MT9T001_OUTPUT_CONTROL_CHIP_ENABLE	(1 << 1)
  #define		MT9T001_OUTPUT_CONTROL_TEST_DATA	(1 << 6)
  #define MT9T001_SHUTTER_WIDTH_HIGH			0x08
  #define MT9T001_SHUTTER_WIDTH_LOW			0x09
  #define		MT9T001_SHUTTER_WIDTH_MIN		1
  #define		MT9T001_SHUTTER_WIDTH_DEF		1561
  #define		MT9T001_SHUTTER_WIDTH_MAX		(1024 * 1024)
  #define MT9T001_PIXEL_CLOCK				0x0a
  #define		MT9T001_PIXEL_CLOCK_INVERT		(1 << 15)
  #define		MT9T001_PIXEL_CLOCK_SHIFT_MASK		(7 << 8)
  #define		MT9T001_PIXEL_CLOCK_SHIFT_SHIFT		8
  #define		MT9T001_PIXEL_CLOCK_DIVIDE_MASK		(0x7f << 0)
  #define MT9T001_FRAME_RESTART				0x0b
  #define MT9T001_SHUTTER_DELAY				0x0c
  #define		MT9T001_SHUTTER_DELAY_MAX		2047
  #define MT9T001_RESET					0x0d
  #define MT9T001_READ_MODE1				0x1e
  #define		MT9T001_READ_MODE_SNAPSHOT		(1 << 8)
  #define		MT9T001_READ_MODE_STROBE_ENABLE		(1 << 9)
  #define		MT9T001_READ_MODE_STROBE_WIDTH		(1 << 10)
  #define		MT9T001_READ_MODE_STROBE_OVERRIDE	(1 << 11)
  #define MT9T001_READ_MODE2				0x20
  #define		MT9T001_READ_MODE_BAD_FRAMES		(1 << 0)
  #define		MT9T001_READ_MODE_LINE_VALID_CONTINUOUS	(1 << 9)
  #define		MT9T001_READ_MODE_LINE_VALID_FRAME	(1 << 10)
  #define MT9T001_READ_MODE3				0x21
  #define		MT9T001_READ_MODE_GLOBAL_RESET		(1 << 0)
  #define		MT9T001_READ_MODE_GHST_CTL		(1 << 1)
  #define MT9T001_ROW_ADDRESS_MODE			0x22
  #define		MT9T001_ROW_SKIP_MASK			(7 << 0)
  #define		MT9T001_ROW_BIN_MASK			(3 << 3)
  #define		MT9T001_ROW_BIN_SHIFT			3
  #define MT9T001_COLUMN_ADDRESS_MODE			0x23
  #define		MT9T001_COLUMN_SKIP_MASK		(7 << 0)
  #define		MT9T001_COLUMN_BIN_MASK			(3 << 3)
  #define		MT9T001_COLUMN_BIN_SHIFT		3
  #define MT9T001_GREEN1_GAIN				0x2b
  #define MT9T001_BLUE_GAIN				0x2c
  #define MT9T001_RED_GAIN				0x2d
  #define MT9T001_GREEN2_GAIN				0x2e
  #define MT9T001_TEST_DATA				0x32
  #define MT9T001_GLOBAL_GAIN				0x35
  #define		MT9T001_GLOBAL_GAIN_MIN			8
  #define		MT9T001_GLOBAL_GAIN_MAX			1024
  #define MT9T001_BLACK_LEVEL				0x49
  #define MT9T001_ROW_BLACK_DEFAULT_OFFSET		0x4b
  #define MT9T001_BLC_DELTA_THRESHOLDS			0x5d
  #define MT9T001_CAL_THRESHOLDS				0x5f
  #define MT9T001_GREEN1_OFFSET				0x60
  #define MT9T001_GREEN2_OFFSET				0x61
  #define MT9T001_BLACK_LEVEL_CALIBRATION			0x62
  #define		MT9T001_BLACK_LEVEL_OVERRIDE		(1 << 0)
  #define		MT9T001_BLACK_LEVEL_DISABLE_OFFSET	(1 << 1)
  #define		MT9T001_BLACK_LEVEL_RECALCULATE		(1 << 12)
  #define		MT9T001_BLACK_LEVEL_LOCK_RED_BLUE	(1 << 13)
  #define		MT9T001_BLACK_LEVEL_LOCK_GREEN		(1 << 14)
  #define MT9T001_RED_OFFSET				0x63
  #define MT9T001_BLUE_OFFSET				0x64
  
  struct mt9t001 {
  	struct v4l2_subdev subdev;
  	struct media_pad pad;
  
  	struct v4l2_mbus_framefmt format;
  	struct v4l2_rect crop;
  
  	struct v4l2_ctrl_handler ctrls;
  	struct v4l2_ctrl *gains[4];
  
  	u16 output_control;
  	u16 black_level;
  };
  
  static inline struct mt9t001 *to_mt9t001(struct v4l2_subdev *sd)
  {
  	return container_of(sd, struct mt9t001, subdev);
  }
  
  static int mt9t001_read(struct i2c_client *client, u8 reg)
  {
  	return i2c_smbus_read_word_swapped(client, reg);
  }
  
  static int mt9t001_write(struct i2c_client *client, u8 reg, u16 data)
  {
  	return i2c_smbus_write_word_swapped(client, reg, data);
  }
  
  static int mt9t001_set_output_control(struct mt9t001 *mt9t001, u16 clear,
  				      u16 set)
  {
  	struct i2c_client *client = v4l2_get_subdevdata(&mt9t001->subdev);
  	u16 value = (mt9t001->output_control & ~clear) | set;
  	int ret;
  
  	if (value == mt9t001->output_control)
  		return 0;
  
  	ret = mt9t001_write(client, MT9T001_OUTPUT_CONTROL, value);
  	if (ret < 0)
  		return ret;
  
  	mt9t001->output_control = value;
  	return 0;
  }
  
  /* -----------------------------------------------------------------------------
   * V4L2 subdev video operations
   */
  
  static struct v4l2_mbus_framefmt *
  __mt9t001_get_pad_format(struct mt9t001 *mt9t001, struct v4l2_subdev_fh *fh,
  			 unsigned int pad, enum v4l2_subdev_format_whence which)
  {
  	switch (which) {
  	case V4L2_SUBDEV_FORMAT_TRY:
  		return v4l2_subdev_get_try_format(fh, pad);
  	case V4L2_SUBDEV_FORMAT_ACTIVE:
  		return &mt9t001->format;
  	default:
  		return NULL;
  	}
  }
  
  static struct v4l2_rect *
  __mt9t001_get_pad_crop(struct mt9t001 *mt9t001, struct v4l2_subdev_fh *fh,
  		       unsigned int pad, enum v4l2_subdev_format_whence which)
  {
  	switch (which) {
  	case V4L2_SUBDEV_FORMAT_TRY:
  		return v4l2_subdev_get_try_crop(fh, pad);
  	case V4L2_SUBDEV_FORMAT_ACTIVE:
  		return &mt9t001->crop;
  	default:
  		return NULL;
  	}
  }
  
  static int mt9t001_s_stream(struct v4l2_subdev *subdev, int enable)
  {
  	const u16 mode = MT9T001_OUTPUT_CONTROL_CHIP_ENABLE;
  	struct i2c_client *client = v4l2_get_subdevdata(subdev);
  	struct mt9t001 *mt9t001 = to_mt9t001(subdev);
  	struct v4l2_mbus_framefmt *format = &mt9t001->format;
  	struct v4l2_rect *crop = &mt9t001->crop;
  	unsigned int hratio;
  	unsigned int vratio;
  	int ret;
  
  	if (!enable)
  		return mt9t001_set_output_control(mt9t001, mode, 0);
  
  	/* Configure the window size and row/column bin */
  	hratio = DIV_ROUND_CLOSEST(crop->width, format->width);
  	vratio = DIV_ROUND_CLOSEST(crop->height, format->height);
  
  	ret = mt9t001_write(client, MT9T001_ROW_ADDRESS_MODE, hratio - 1);
  	if (ret < 0)
  		return ret;
  
  	ret = mt9t001_write(client, MT9T001_COLUMN_ADDRESS_MODE, vratio - 1);
  	if (ret < 0)
  		return ret;
  
  	ret = mt9t001_write(client, MT9T001_COLUMN_START, crop->left);
  	if (ret < 0)
  		return ret;
  
  	ret = mt9t001_write(client, MT9T001_ROW_START, crop->top);
  	if (ret < 0)
  		return ret;
  
  	ret = mt9t001_write(client, MT9T001_WINDOW_WIDTH, crop->width - 1);
  	if (ret < 0)
  		return ret;
  
  	ret = mt9t001_write(client, MT9T001_WINDOW_HEIGHT, crop->height - 1);
  	if (ret < 0)
  		return ret;
  
  	/* Switch to master "normal" mode */
  	return mt9t001_set_output_control(mt9t001, 0, mode);
  }
  
  static int mt9t001_enum_mbus_code(struct v4l2_subdev *subdev,
  				  struct v4l2_subdev_fh *fh,
  				  struct v4l2_subdev_mbus_code_enum *code)
  {
  	if (code->index > 0)
  		return -EINVAL;
  
  	code->code = V4L2_MBUS_FMT_SGRBG10_1X10;
  	return 0;
  }
  
  static int mt9t001_enum_frame_size(struct v4l2_subdev *subdev,
  				   struct v4l2_subdev_fh *fh,
  				   struct v4l2_subdev_frame_size_enum *fse)
  {
  	if (fse->index >= 8 || fse->code != V4L2_MBUS_FMT_SGRBG10_1X10)
  		return -EINVAL;
  
  	fse->min_width = (MT9T001_WINDOW_WIDTH_DEF + 1) / fse->index;
  	fse->max_width = fse->min_width;
  	fse->min_height = (MT9T001_WINDOW_HEIGHT_DEF + 1) / fse->index;
  	fse->max_height = fse->min_height;
  
  	return 0;
  }
  
  static int mt9t001_get_format(struct v4l2_subdev *subdev,
  			      struct v4l2_subdev_fh *fh,
  			      struct v4l2_subdev_format *format)
  {
  	struct mt9t001 *mt9t001 = to_mt9t001(subdev);
  
  	format->format = *__mt9t001_get_pad_format(mt9t001, fh, format->pad,
  						   format->which);
  	return 0;
  }
  
  static int mt9t001_set_format(struct v4l2_subdev *subdev,
  			      struct v4l2_subdev_fh *fh,
  			      struct v4l2_subdev_format *format)
  {
  	struct mt9t001 *mt9t001 = to_mt9t001(subdev);
  	struct v4l2_mbus_framefmt *__format;
  	struct v4l2_rect *__crop;
  	unsigned int width;
  	unsigned int height;
  	unsigned int hratio;
  	unsigned int vratio;
  
  	__crop = __mt9t001_get_pad_crop(mt9t001, fh, format->pad,
  					format->which);
  
  	/* Clamp the width and height to avoid dividing by zero. */
  	width = clamp_t(unsigned int, ALIGN(format->format.width, 2),
  			max(__crop->width / 8, MT9T001_WINDOW_HEIGHT_MIN + 1),
  			__crop->width);
  	height = clamp_t(unsigned int, ALIGN(format->format.height, 2),
  			 max(__crop->height / 8, MT9T001_WINDOW_HEIGHT_MIN + 1),
  			 __crop->height);
  
  	hratio = DIV_ROUND_CLOSEST(__crop->width, width);
  	vratio = DIV_ROUND_CLOSEST(__crop->height, height);
  
  	__format = __mt9t001_get_pad_format(mt9t001, fh, format->pad,
  					    format->which);
  	__format->width = __crop->width / hratio;
  	__format->height = __crop->height / vratio;
  
  	format->format = *__format;
  
  	return 0;
  }
  
  static int mt9t001_get_crop(struct v4l2_subdev *subdev,
  			    struct v4l2_subdev_fh *fh,
  			    struct v4l2_subdev_crop *crop)
  {
  	struct mt9t001 *mt9t001 = to_mt9t001(subdev);
  
  	crop->rect = *__mt9t001_get_pad_crop(mt9t001, fh, crop->pad,
  					     crop->which);
  	return 0;
  }
  
  static int mt9t001_set_crop(struct v4l2_subdev *subdev,
  			    struct v4l2_subdev_fh *fh,
  			    struct v4l2_subdev_crop *crop)
  {
  	struct mt9t001 *mt9t001 = to_mt9t001(subdev);
  	struct v4l2_mbus_framefmt *__format;
  	struct v4l2_rect *__crop;
  	struct v4l2_rect rect;
  
  	/* Clamp the crop rectangle boundaries and align them to a multiple of 2
  	 * pixels.
  	 */
  	rect.left = clamp(ALIGN(crop->rect.left, 2),
  			  MT9T001_COLUMN_START_MIN,
  			  MT9T001_COLUMN_START_MAX);
  	rect.top = clamp(ALIGN(crop->rect.top, 2),
  			 MT9T001_ROW_START_MIN,
  			 MT9T001_ROW_START_MAX);
  	rect.width = clamp(ALIGN(crop->rect.width, 2),
  			   MT9T001_WINDOW_WIDTH_MIN + 1,
  			   MT9T001_WINDOW_WIDTH_MAX + 1);
  	rect.height = clamp(ALIGN(crop->rect.height, 2),
  			    MT9T001_WINDOW_HEIGHT_MIN + 1,
  			    MT9T001_WINDOW_HEIGHT_MAX + 1);
  
  	rect.width = min(rect.width, MT9T001_PIXEL_ARRAY_WIDTH - rect.left);
  	rect.height = min(rect.height, MT9T001_PIXEL_ARRAY_HEIGHT - rect.top);
  
  	__crop = __mt9t001_get_pad_crop(mt9t001, fh, crop->pad, crop->which);
  
  	if (rect.width != __crop->width || rect.height != __crop->height) {
  		/* Reset the output image size if the crop rectangle size has
  		 * been modified.
  		 */
  		__format = __mt9t001_get_pad_format(mt9t001, fh, crop->pad,
  						    crop->which);
  		__format->width = rect.width;
  		__format->height = rect.height;
  	}
  
  	*__crop = rect;
  	crop->rect = rect;
  
  	return 0;
  }
  
  /* -----------------------------------------------------------------------------
   * V4L2 subdev control operations
   */
  
  #define V4L2_CID_TEST_PATTERN		(V4L2_CID_USER_BASE | 0x1001)
  #define V4L2_CID_BLACK_LEVEL_AUTO	(V4L2_CID_USER_BASE | 0x1002)
  #define V4L2_CID_BLACK_LEVEL_OFFSET	(V4L2_CID_USER_BASE | 0x1003)
  #define V4L2_CID_BLACK_LEVEL_CALIBRATE	(V4L2_CID_USER_BASE | 0x1004)
  
  #define V4L2_CID_GAIN_RED		(V4L2_CTRL_CLASS_CAMERA | 0x1001)
  #define V4L2_CID_GAIN_GREEN_RED		(V4L2_CTRL_CLASS_CAMERA | 0x1002)
  #define V4L2_CID_GAIN_GREEN_BLUE	(V4L2_CTRL_CLASS_CAMERA | 0x1003)
  #define V4L2_CID_GAIN_BLUE		(V4L2_CTRL_CLASS_CAMERA | 0x1004)
  
  static u16 mt9t001_gain_value(s32 *gain)
  {
  	/* Gain is controlled by 2 analog stages and a digital stage. Valid
  	 * values for the 3 stages are
  	 *
  	 * Stage		Min	Max	Step
  	 * ------------------------------------------
  	 * First analog stage	x1	x2	1
  	 * Second analog stage	x1	x4	0.125
  	 * Digital stage	x1	x16	0.125
  	 *
  	 * To minimize noise, the gain stages should be used in the second
  	 * analog stage, first analog stage, digital stage order. Gain from a
  	 * previous stage should be pushed to its maximum value before the next
  	 * stage is used.
  	 */
  	if (*gain <= 32)
  		return *gain;
  
  	if (*gain <= 64) {
  		*gain &= ~1;
  		return (1 << 6) | (*gain >> 1);
  	}
  
  	*gain &= ~7;
  	return ((*gain - 64) << 5) | (1 << 6) | 32;
  }
  
  static int mt9t001_ctrl_freeze(struct mt9t001 *mt9t001, bool freeze)
  {
  	return mt9t001_set_output_control(mt9t001,
  		freeze ? 0 : MT9T001_OUTPUT_CONTROL_SYNC,
  		freeze ? MT9T001_OUTPUT_CONTROL_SYNC : 0);
  }
  
  static int mt9t001_s_ctrl(struct v4l2_ctrl *ctrl)
  {
  	static const u8 gains[4] = {
  		MT9T001_RED_GAIN, MT9T001_GREEN1_GAIN,
  		MT9T001_GREEN2_GAIN, MT9T001_BLUE_GAIN
  	};
  
  	struct mt9t001 *mt9t001 =
  			container_of(ctrl->handler, struct mt9t001, ctrls);
  	struct i2c_client *client = v4l2_get_subdevdata(&mt9t001->subdev);
  	unsigned int count;
  	unsigned int i;
  	u16 value;
  	int ret;
  
  	switch (ctrl->id) {
  	case V4L2_CID_GAIN_RED:
  	case V4L2_CID_GAIN_GREEN_RED:
  	case V4L2_CID_GAIN_GREEN_BLUE:
  	case V4L2_CID_GAIN_BLUE:
  
  		/* Disable control updates if more than one control has changed
  		 * in the cluster.
  		 */
  		for (i = 0, count = 0; i < 4; ++i) {
  			struct v4l2_ctrl *gain = mt9t001->gains[i];
  
  			if (gain->val != gain->cur.val)
  				count++;
  		}
  
  		if (count > 1) {
  			ret = mt9t001_ctrl_freeze(mt9t001, true);
  			if (ret < 0)
  				return ret;
  		}
  
  		/* Update the gain controls. */
  		for (i = 0; i < 4; ++i) {
  			struct v4l2_ctrl *gain = mt9t001->gains[i];
  
  			if (gain->val == gain->cur.val)
  				continue;
  
  			value = mt9t001_gain_value(&gain->val);
  			ret = mt9t001_write(client, gains[i], value);
  			if (ret < 0) {
  				mt9t001_ctrl_freeze(mt9t001, false);
  				return ret;
  			}
  		}
  
  		/* Enable control updates. */
  		if (count > 1) {
  			ret = mt9t001_ctrl_freeze(mt9t001, false);
  			if (ret < 0)
  				return ret;
  		}
  
  		break;
  
  	case V4L2_CID_EXPOSURE:
  		ret = mt9t001_write(client, MT9T001_SHUTTER_WIDTH_LOW,
  				    ctrl->val & 0xffff);
  		if (ret < 0)
  			return ret;
  
  		return mt9t001_write(client, MT9T001_SHUTTER_WIDTH_HIGH,
  				     ctrl->val >> 16);
  
  	case V4L2_CID_TEST_PATTERN:
  		ret = mt9t001_set_output_control(mt9t001,
  			ctrl->val ? 0 : MT9T001_OUTPUT_CONTROL_TEST_DATA,
  			ctrl->val ? MT9T001_OUTPUT_CONTROL_TEST_DATA : 0);
  		if (ret < 0)
  			return ret;
  
  		return mt9t001_write(client, MT9T001_TEST_DATA, ctrl->val << 2);
  
  	case V4L2_CID_BLACK_LEVEL_AUTO:
  		value = ctrl->val ? 0 : MT9T001_BLACK_LEVEL_OVERRIDE;
  		ret = mt9t001_write(client, MT9T001_BLACK_LEVEL_CALIBRATION,
  				    value);
  		if (ret < 0)
  			return ret;
  
  		mt9t001->black_level = value;
  		break;
  
  	case V4L2_CID_BLACK_LEVEL_OFFSET:
  		ret = mt9t001_write(client, MT9T001_GREEN1_OFFSET, ctrl->val);
  		if (ret < 0)
  			return ret;
  
  		ret = mt9t001_write(client, MT9T001_GREEN2_OFFSET, ctrl->val);
  		if (ret < 0)
  			return ret;
  
  		ret = mt9t001_write(client, MT9T001_RED_OFFSET, ctrl->val);
  		if (ret < 0)
  			return ret;
  
  		return mt9t001_write(client, MT9T001_BLUE_OFFSET, ctrl->val);
  
  	case V4L2_CID_BLACK_LEVEL_CALIBRATE:
  		return mt9t001_write(client, MT9T001_BLACK_LEVEL_CALIBRATION,
  				     MT9T001_BLACK_LEVEL_RECALCULATE |
  				     mt9t001->black_level);
  	}
  
  	return 0;
  }
  
  static struct v4l2_ctrl_ops mt9t001_ctrl_ops = {
  	.s_ctrl = mt9t001_s_ctrl,
  };
  
  static const struct v4l2_ctrl_config mt9t001_ctrls[] = {
  	{
  		.ops		= &mt9t001_ctrl_ops,
  		.id		= V4L2_CID_TEST_PATTERN,
  		.type		= V4L2_CTRL_TYPE_INTEGER,
  		.name		= "Test pattern",
  		.min		= 0,
  		.max		= 1023,
  		.step		= 1,
  		.def		= 0,
  		.flags		= 0,
  	}, {
  		.ops		= &mt9t001_ctrl_ops,
  		.id		= V4L2_CID_BLACK_LEVEL_AUTO,
  		.type		= V4L2_CTRL_TYPE_BOOLEAN,
  		.name		= "Black Level, Auto",
  		.min		= 0,
  		.max		= 1,
  		.step		= 1,
  		.def		= 1,
  		.flags		= 0,
  	}, {
  		.ops		= &mt9t001_ctrl_ops,
  		.id		= V4L2_CID_BLACK_LEVEL_OFFSET,
  		.type		= V4L2_CTRL_TYPE_INTEGER,
  		.name		= "Black Level, Offset",
  		.min		= -256,
  		.max		= 255,
  		.step		= 1,
  		.def		= 32,
  		.flags		= 0,
  	}, {
  		.ops		= &mt9t001_ctrl_ops,
  		.id		= V4L2_CID_BLACK_LEVEL_CALIBRATE,
  		.type		= V4L2_CTRL_TYPE_BUTTON,
  		.name		= "Black Level, Calibrate",
  		.min		= 0,
  		.max		= 0,
  		.step		= 0,
  		.def		= 0,
  		.flags		= V4L2_CTRL_FLAG_WRITE_ONLY,
  	},
  };
  
  static const struct v4l2_ctrl_config mt9t001_gains[] = {
  	{
  		.ops		= &mt9t001_ctrl_ops,
  		.id		= V4L2_CID_GAIN_RED,
  		.type		= V4L2_CTRL_TYPE_INTEGER,
  		.name		= "Gain, Red",
  		.min		= MT9T001_GLOBAL_GAIN_MIN,
  		.max		= MT9T001_GLOBAL_GAIN_MAX,
  		.step		= 1,
  		.def		= MT9T001_GLOBAL_GAIN_MIN,
  		.flags		= 0,
  	}, {
  		.ops		= &mt9t001_ctrl_ops,
  		.id		= V4L2_CID_GAIN_GREEN_RED,
  		.type		= V4L2_CTRL_TYPE_INTEGER,
  		.name		= "Gain, Green (R)",
  		.min		= MT9T001_GLOBAL_GAIN_MIN,
  		.max		= MT9T001_GLOBAL_GAIN_MAX,
  		.step		= 1,
  		.def		= MT9T001_GLOBAL_GAIN_MIN,
  		.flags		= 0,
  	}, {
  		.ops		= &mt9t001_ctrl_ops,
  		.id		= V4L2_CID_GAIN_GREEN_BLUE,
  		.type		= V4L2_CTRL_TYPE_INTEGER,
  		.name		= "Gain, Green (B)",
  		.min		= MT9T001_GLOBAL_GAIN_MIN,
  		.max		= MT9T001_GLOBAL_GAIN_MAX,
  		.step		= 1,
  		.def		= MT9T001_GLOBAL_GAIN_MIN,
  		.flags		= 0,
  	}, {
  		.ops		= &mt9t001_ctrl_ops,
  		.id		= V4L2_CID_GAIN_BLUE,
  		.type		= V4L2_CTRL_TYPE_INTEGER,
  		.name		= "Gain, Blue",
  		.min		= MT9T001_GLOBAL_GAIN_MIN,
  		.max		= MT9T001_GLOBAL_GAIN_MAX,
  		.step		= 1,
  		.def		= MT9T001_GLOBAL_GAIN_MIN,
  		.flags		= 0,
  	},
  };
  
  /* -----------------------------------------------------------------------------
   * V4L2 subdev internal operations
   */
  
  static int mt9t001_open(struct v4l2_subdev *subdev, struct v4l2_subdev_fh *fh)
  {
  	struct v4l2_mbus_framefmt *format;
  	struct v4l2_rect *crop;
  
  	crop = v4l2_subdev_get_try_crop(fh, 0);
  	crop->left = MT9T001_COLUMN_START_DEF;
  	crop->top = MT9T001_ROW_START_DEF;
  	crop->width = MT9T001_WINDOW_WIDTH_DEF + 1;
  	crop->height = MT9T001_WINDOW_HEIGHT_DEF + 1;
  
  	format = v4l2_subdev_get_try_format(fh, 0);
  	format->code = V4L2_MBUS_FMT_SGRBG10_1X10;
  	format->width = MT9T001_WINDOW_WIDTH_DEF + 1;
  	format->height = MT9T001_WINDOW_HEIGHT_DEF + 1;
  	format->field = V4L2_FIELD_NONE;
  	format->colorspace = V4L2_COLORSPACE_SRGB;
  
  	return 0;
  }
  
  static struct v4l2_subdev_video_ops mt9t001_subdev_video_ops = {
  	.s_stream = mt9t001_s_stream,
  };
  
  static struct v4l2_subdev_pad_ops mt9t001_subdev_pad_ops = {
  	.enum_mbus_code = mt9t001_enum_mbus_code,
  	.enum_frame_size = mt9t001_enum_frame_size,
  	.get_fmt = mt9t001_get_format,
  	.set_fmt = mt9t001_set_format,
  	.get_crop = mt9t001_get_crop,
  	.set_crop = mt9t001_set_crop,
  };
  
  static struct v4l2_subdev_ops mt9t001_subdev_ops = {
  	.video = &mt9t001_subdev_video_ops,
  	.pad = &mt9t001_subdev_pad_ops,
  };
  
  static struct v4l2_subdev_internal_ops mt9t001_subdev_internal_ops = {
  	.open = mt9t001_open,
  };
  
  static int mt9t001_video_probe(struct i2c_client *client)
  {
  	struct mt9t001_platform_data *pdata = client->dev.platform_data;
  	s32 data;
  	int ret;
  
  	dev_info(&client->dev, "Probing MT9T001 at address 0x%02x\n",
  		 client->addr);
  
  	/* Reset the chip and stop data read out */
  	ret = mt9t001_write(client, MT9T001_RESET, 1);
  	if (ret < 0)
  		return ret;
  
  	ret = mt9t001_write(client, MT9T001_RESET, 0);
  	if (ret < 0)
  		return ret;
  
  	ret  = mt9t001_write(client, MT9T001_OUTPUT_CONTROL, 0);
  	if (ret < 0)
  		return ret;
  
  	/* Configure the pixel clock polarity */
  	if (pdata && pdata->clk_pol) {
  		ret  = mt9t001_write(client, MT9T001_PIXEL_CLOCK,
  				     MT9T001_PIXEL_CLOCK_INVERT);
  		if (ret < 0)
  			return ret;
  	}
  
  	/* Read and check the sensor version */
  	data = mt9t001_read(client, MT9T001_CHIP_VERSION);
  	if (data != MT9T001_CHIP_ID) {
  		dev_err(&client->dev, "MT9T001 not detected, wrong version "
  			"0x%04x\n", data);
  		return -ENODEV;
  	}
  
  	dev_info(&client->dev, "MT9T001 detected at address 0x%02x\n",
  		 client->addr);
  
  	return ret;
  }
  
  static int mt9t001_probe(struct i2c_client *client,
  			 const struct i2c_device_id *did)
  {
  	struct mt9t001 *mt9t001;
  	unsigned int i;
  	int ret;
  
  	if (!i2c_check_functionality(client->adapter,
  				     I2C_FUNC_SMBUS_WORD_DATA)) {
  		dev_warn(&client->adapter->dev,
  			 "I2C-Adapter doesn't support I2C_FUNC_SMBUS_WORD\n");
  		return -EIO;
  	}
  
  	ret = mt9t001_video_probe(client);
  	if (ret < 0)
  		return ret;
  
  	mt9t001 = kzalloc(sizeof(*mt9t001), GFP_KERNEL);
  	if (!mt9t001)
  		return -ENOMEM;
  
  	v4l2_ctrl_handler_init(&mt9t001->ctrls, ARRAY_SIZE(mt9t001_ctrls) +
  						ARRAY_SIZE(mt9t001_gains) + 2);
  
  	v4l2_ctrl_new_std(&mt9t001->ctrls, &mt9t001_ctrl_ops,
  			  V4L2_CID_EXPOSURE, MT9T001_SHUTTER_WIDTH_MIN,
  			  MT9T001_SHUTTER_WIDTH_MAX, 1,
  			  MT9T001_SHUTTER_WIDTH_DEF);
  	v4l2_ctrl_new_std(&mt9t001->ctrls, &mt9t001_ctrl_ops,
  			  V4L2_CID_BLACK_LEVEL, 1, 1, 1, 1);
  
  	for (i = 0; i < ARRAY_SIZE(mt9t001_ctrls); ++i)
  		v4l2_ctrl_new_custom(&mt9t001->ctrls, &mt9t001_ctrls[i], NULL);
  
  	for (i = 0; i < ARRAY_SIZE(mt9t001_gains); ++i)
  		mt9t001->gains[i] = v4l2_ctrl_new_custom(&mt9t001->ctrls,
  			&mt9t001_gains[i], NULL);
  
  	v4l2_ctrl_cluster(ARRAY_SIZE(mt9t001_gains), mt9t001->gains);
  
  	mt9t001->subdev.ctrl_handler = &mt9t001->ctrls;
  
  	if (mt9t001->ctrls.error) {
  		printk(KERN_INFO "%s: control initialization error %d\n",
  		       __func__, mt9t001->ctrls.error);
  		ret = -EINVAL;
  		goto done;
  	}
  
  	mt9t001->crop.left = MT9T001_COLUMN_START_DEF;
  	mt9t001->crop.top = MT9T001_ROW_START_DEF;
  	mt9t001->crop.width = MT9T001_WINDOW_WIDTH_DEF + 1;
  	mt9t001->crop.height = MT9T001_WINDOW_HEIGHT_DEF + 1;
  
  	mt9t001->format.code = V4L2_MBUS_FMT_SGRBG10_1X10;
  	mt9t001->format.width = MT9T001_WINDOW_WIDTH_DEF + 1;
  	mt9t001->format.height = MT9T001_WINDOW_HEIGHT_DEF + 1;
  	mt9t001->format.field = V4L2_FIELD_NONE;
  	mt9t001->format.colorspace = V4L2_COLORSPACE_SRGB;
  
  	v4l2_i2c_subdev_init(&mt9t001->subdev, client, &mt9t001_subdev_ops);
  	mt9t001->subdev.internal_ops = &mt9t001_subdev_internal_ops;
  	mt9t001->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
  
  	mt9t001->pad.flags = MEDIA_PAD_FL_SOURCE;
  	ret = media_entity_init(&mt9t001->subdev.entity, 1, &mt9t001->pad, 0);
  
  done:
  	if (ret < 0) {
  		v4l2_ctrl_handler_free(&mt9t001->ctrls);
  		media_entity_cleanup(&mt9t001->subdev.entity);
  		kfree(mt9t001);
  	}
  
  	return ret;
  }
  
  static int mt9t001_remove(struct i2c_client *client)
  {
  	struct v4l2_subdev *subdev = i2c_get_clientdata(client);
  	struct mt9t001 *mt9t001 = to_mt9t001(subdev);
  
  	v4l2_ctrl_handler_free(&mt9t001->ctrls);
  	v4l2_device_unregister_subdev(subdev);
  	media_entity_cleanup(&subdev->entity);
  	kfree(mt9t001);
  	return 0;
  }
  
  static const struct i2c_device_id mt9t001_id[] = {
  	{ "mt9t001", 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, mt9t001_id);
  
  static struct i2c_driver mt9t001_driver = {
  	.driver = {
  		.name = "mt9t001",
  	},
  	.probe		= mt9t001_probe,
  	.remove		= mt9t001_remove,
  	.id_table	= mt9t001_id,
  };
  
  static int __init mt9t001_init(void)
  {
  	return i2c_add_driver(&mt9t001_driver);
  }
  
  static void __exit mt9t001_exit(void)
  {
  	i2c_del_driver(&mt9t001_driver);
  }
  
  module_init(mt9t001_init);
  module_exit(mt9t001_exit);
  
  MODULE_DESCRIPTION("Aptina (Micron) MT9T001 Camera driver");
  MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
  MODULE_LICENSE("GPL");
  