[media] v4l: Add driver for Micron MT9M032 camera sensor

The MT9M032 is a parallel 1.6MP sensor from Micron controlled through I2C.

The driver creates a V4L2 subdevice. It currently supports cropping, gain,
exposure and v/h flipping controls in monochrome mode with an
external pixel clock.

[Lots of clean up, fixes and enhancements]

Signed-off-by: Martin Hostettler <[e-mail]>
Signed-off-by: Laurent Pinchart <[e-mail]>
Reviewed-by: Sylwester Nawrocki <[e-mail]>
Acked-by: Sakari Ailus <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/video/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called vs6624.
 
+config VIDEO_MT9M032
+	tristate "MT9M032 camera sensor support"
+	depends on I2C && VIDEO_V4L2
+	select VIDEO_APTINA_PLL
+	---help---
+	  This driver supports MT9M032 camera sensors from Aptina, monochrome
+	  models only.
+
 config VIDEO_MT9P031
 	tristate "Aptina MT9P031 support"
 	depends on I2C && VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API

drivers/media/video/Makefile

···
 obj-$(CONFIG_VIDEO_OV7670) 	+= ov7670.o
 obj-$(CONFIG_VIDEO_TCM825X) += tcm825x.o
 obj-$(CONFIG_VIDEO_TVEEPROM) += tveeprom.o
+obj-$(CONFIG_VIDEO_MT9M032) += mt9m032.o
 obj-$(CONFIG_VIDEO_MT9P031) += mt9p031.o
 obj-$(CONFIG_VIDEO_MT9T001) += mt9t001.o
 obj-$(CONFIG_VIDEO_MT9V011) += mt9v011.o

drivers/media/video/mt9m032.c

···
+/*
+ * Driver for MT9M032 CMOS Image Sensor from Micron
+ *
+ * Copyright (C) 2010-2011 Lund Engineering
+ * Contact: Gil Lund <[e-mail]>
+ * Author: Martin Hostettler <[e-mail]>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/v4l2-mediabus.h>
+
+#include <media/media-entity.h>
+#include <media/mt9m032.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-subdev.h>
+
+#include "aptina-pll.h"
+
+/*
+ * width and height include active boundary and black parts
+ *
+ * column    0-  15 active boundary
+ * column   16-1455 image
+ * column 1456-1471 active boundary
+ * column 1472-1599 black
+ *
+ * row       0-  51 black
+ * row      53-  59 active boundary
+ * row      60-1139 image
+ * row    1140-1147 active boundary
+ * row    1148-1151 black
+ */
+
+#define MT9M032_PIXEL_ARRAY_WIDTH			1600
+#define MT9M032_PIXEL_ARRAY_HEIGHT			1152
+
+#define MT9M032_CHIP_VERSION				0x00
+#define		MT9M032_CHIP_VERSION_VALUE		0x1402
+#define MT9M032_ROW_START				0x01
+#define		MT9M032_ROW_START_MIN			0
+#define		MT9M032_ROW_START_MAX			1152
+#define		MT9M032_ROW_START_DEF			60
+#define MT9M032_COLUMN_START				0x02
+#define		MT9M032_COLUMN_START_MIN		0
+#define		MT9M032_COLUMN_START_MAX		1600
+#define		MT9M032_COLUMN_START_DEF		16
+#define MT9M032_ROW_SIZE				0x03
+#define		MT9M032_ROW_SIZE_MIN			32
+#define		MT9M032_ROW_SIZE_MAX			1152
+#define		MT9M032_ROW_SIZE_DEF			1080
+#define MT9M032_COLUMN_SIZE				0x04
+#define		MT9M032_COLUMN_SIZE_MIN			32
+#define		MT9M032_COLUMN_SIZE_MAX			1600
+#define		MT9M032_COLUMN_SIZE_DEF			1440
+#define MT9M032_HBLANK					0x05
+#define MT9M032_VBLANK					0x06
+#define		MT9M032_VBLANK_MAX			0x7ff
+#define MT9M032_SHUTTER_WIDTH_HIGH			0x08
+#define MT9M032_SHUTTER_WIDTH_LOW			0x09
+#define		MT9M032_SHUTTER_WIDTH_MIN		1
+#define		MT9M032_SHUTTER_WIDTH_MAX		1048575
+#define		MT9M032_SHUTTER_WIDTH_DEF		1943
+#define MT9M032_PIX_CLK_CTRL				0x0a
+#define		MT9M032_PIX_CLK_CTRL_INV_PIXCLK		0x8000
+#define MT9M032_RESTART					0x0b
+#define MT9M032_RESET					0x0d
+#define MT9M032_PLL_CONFIG1				0x11
+#define		MT9M032_PLL_CONFIG1_OUTDIV_MASK		0x3f
+#define		MT9M032_PLL_CONFIG1_MUL_SHIFT		8
+#define MT9M032_READ_MODE1				0x1e
+#define MT9M032_READ_MODE2				0x20
+#define		MT9M032_READ_MODE2_VFLIP_SHIFT		15
+#define		MT9M032_READ_MODE2_HFLIP_SHIFT		14
+#define		MT9M032_READ_MODE2_ROW_BLC		0x40
+#define MT9M032_GAIN_GREEN1				0x2b
+#define MT9M032_GAIN_BLUE				0x2c
+#define MT9M032_GAIN_RED				0x2d
+#define MT9M032_GAIN_GREEN2				0x2e
+
+/* write only */
+#define MT9M032_GAIN_ALL				0x35
+#define		MT9M032_GAIN_DIGITAL_MASK		0x7f
+#define		MT9M032_GAIN_DIGITAL_SHIFT		8
+#define		MT9M032_GAIN_AMUL_SHIFT			6
+#define		MT9M032_GAIN_ANALOG_MASK		0x3f
+#define MT9M032_FORMATTER1				0x9e
+#define MT9M032_FORMATTER2				0x9f
+#define		MT9M032_FORMATTER2_DOUT_EN		0x1000
+#define		MT9M032_FORMATTER2_PIXCLK_EN		0x2000
+
+/*
+ * The available MT9M032 datasheet is missing documentation for register 0x10
+ * MT9P031 seems to be close enough, so use constants from that datasheet for
+ * now.
+ * But keep the name MT9P031 to remind us, that this isn't really confirmed
+ * for this sensor.
+ */
+#define MT9P031_PLL_CONTROL				0x10
+#define		MT9P031_PLL_CONTROL_PWROFF		0x0050
+#define		MT9P031_PLL_CONTROL_PWRON		0x0051
+#define		MT9P031_PLL_CONTROL_USEPLL		0x0052
+#define MT9P031_PLL_CONFIG2				0x11
+#define		MT9P031_PLL_CONFIG2_P1_DIV_MASK		0x1f
+
+struct mt9m032 {
+	struct v4l2_subdev subdev;
+	struct media_pad pad;
+	struct mt9m032_platform_data *pdata;
+
+	unsigned int pix_clock;
+
+	struct v4l2_ctrl_handler ctrls;
+	struct {
+		struct v4l2_ctrl *hflip;
+		struct v4l2_ctrl *vflip;
+	};
+
+	struct mutex lock; /* Protects streaming, format, interval and crop */
+
+	bool streaming;
+
+	struct v4l2_mbus_framefmt format;
+	struct v4l2_rect crop;
+	struct v4l2_fract frame_interval;
+};
+
+#define to_mt9m032(sd)	container_of(sd, struct mt9m032, subdev)
+#define to_dev(sensor) \
+	(&((struct i2c_client *)v4l2_get_subdevdata(&(sensor)->subdev))->dev)
+
+static int mt9m032_read(struct i2c_client *client, u8 reg)
+{
+	return i2c_smbus_read_word_swapped(client, reg);
+}
+
+static int mt9m032_write(struct i2c_client *client, u8 reg, const u16 data)
+{
+	return i2c_smbus_write_word_swapped(client, reg, data);
+}
+
+static u32 mt9m032_row_time(struct mt9m032 *sensor, unsigned int width)
+{
+	unsigned int effective_width;
+	u32 ns;
+
+	effective_width = width + 716; /* empirical value */
+	ns = div_u64(1000000000ULL * effective_width, sensor->pix_clock);
+	dev_dbg(to_dev(sensor),	"MT9M032 line time: %u ns\n", ns);
+	return ns;
+}
+
+static int mt9m032_update_timing(struct mt9m032 *sensor,
+				 struct v4l2_fract *interval)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&sensor->subdev);
+	struct v4l2_rect *crop = &sensor->crop;
+	unsigned int min_vblank;
+	unsigned int vblank;
+	u32 row_time;
+
+	if (!interval)
+		interval = &sensor->frame_interval;
+
+	row_time = mt9m032_row_time(sensor, crop->width);
+
+	vblank = div_u64(1000000000ULL * interval->numerator,
+			 (u64)row_time * interval->denominator)
+	       - crop->height;
+
+	if (vblank > MT9M032_VBLANK_MAX) {
+		/* hardware limits to 11 bit values */
+		interval->denominator = 1000;
+		interval->numerator =
+			div_u64((crop->height + MT9M032_VBLANK_MAX) *
+				(u64)row_time * interval->denominator,
+				1000000000ULL);
+		vblank = div_u64(1000000000ULL * interval->numerator,
+				 (u64)row_time * interval->denominator)
+		       - crop->height;
+	}
+	/* enforce minimal 1.6ms blanking time. */
+	min_vblank = 1600000 / row_time;
+	vblank = clamp_t(unsigned int, vblank, min_vblank, MT9M032_VBLANK_MAX);
+
+	return mt9m032_write(client, MT9M032_VBLANK, vblank);
+}
+
+static int mt9m032_update_geom_timing(struct mt9m032 *sensor)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&sensor->subdev);
+	int ret;
+
+	ret = mt9m032_write(client, MT9M032_COLUMN_SIZE,
+			    sensor->crop.width - 1);
+	if (!ret)
+		ret = mt9m032_write(client, MT9M032_ROW_SIZE,
+				    sensor->crop.height - 1);
+	if (!ret)
+		ret = mt9m032_write(client, MT9M032_COLUMN_START,
+				    sensor->crop.left);
+	if (!ret)
+		ret = mt9m032_write(client, MT9M032_ROW_START,
+				    sensor->crop.top);
+	if (!ret)
+		ret = mt9m032_update_timing(sensor, NULL);
+	return ret;
+}
+
+static int update_formatter2(struct mt9m032 *sensor, bool streaming)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&sensor->subdev);
+	u16 reg_val =   MT9M032_FORMATTER2_DOUT_EN
+		      | 0x0070;  /* parts reserved! */
+				 /* possibly for changing to 14-bit mode */
+
+	if (streaming)
+		reg_val |= MT9M032_FORMATTER2_PIXCLK_EN;   /* pixclock enable */
+
+	return mt9m032_write(client, MT9M032_FORMATTER2, reg_val);
+}
+
+static int mt9m032_setup_pll(struct mt9m032 *sensor)
+{
+	static const struct aptina_pll_limits limits = {
+		.ext_clock_min = 8000000,
+		.ext_clock_max = 16500000,
+		.int_clock_min = 2000000,
+		.int_clock_max = 24000000,
+		.out_clock_min = 322000000,
+		.out_clock_max = 693000000,
+		.pix_clock_max = 99000000,
+		.n_min = 1,
+		.n_max = 64,
+		.m_min = 16,
+		.m_max = 255,
+		.p1_min = 1,
+		.p1_max = 128,
+	};
+
+	struct i2c_client *client = v4l2_get_subdevdata(&sensor->subdev);
+	struct mt9m032_platform_data *pdata = sensor->pdata;
+	struct aptina_pll pll;
+	int ret;
+
+	pll.ext_clock = pdata->ext_clock;
+	pll.pix_clock = pdata->pix_clock;
+
+	ret = aptina_pll_calculate(&client->dev, &limits, &pll);
+	if (ret < 0)
+		return ret;
+
+	sensor->pix_clock = pdata->pix_clock;
+
+	ret = mt9m032_write(client, MT9M032_PLL_CONFIG1,
+			    (pll.m << MT9M032_PLL_CONFIG1_MUL_SHIFT)
+			    | (pll.p1 - 1));
+	if (!ret)
+		ret = mt9m032_write(client, MT9P031_PLL_CONFIG2, pll.n - 1);
+	if (!ret)
+		ret = mt9m032_write(client, MT9P031_PLL_CONTROL,
+				    MT9P031_PLL_CONTROL_PWRON |
+				    MT9P031_PLL_CONTROL_USEPLL);
+	if (!ret)		/* more reserved, Continuous, Master Mode */
+		ret = mt9m032_write(client, MT9M032_READ_MODE1, 0x8006);
+	if (!ret)		/* Set 14-bit mode, select 7 divider */
+		ret = mt9m032_write(client, MT9M032_FORMATTER1, 0x111e);
+
+	return ret;
+}
+
+/* -----------------------------------------------------------------------------
+ * Subdev pad operations
+ */
+
+static int mt9m032_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_Y8_1X8;
+	return 0;
+}
+
+static int mt9m032_enum_frame_size(struct v4l2_subdev *subdev,
+				   struct v4l2_subdev_fh *fh,
+				   struct v4l2_subdev_frame_size_enum *fse)
+{
+	if (fse->index != 0 || fse->code != V4L2_MBUS_FMT_Y8_1X8)
+		return -EINVAL;
+
+	fse->min_width = MT9M032_COLUMN_SIZE_DEF;
+	fse->max_width = MT9M032_COLUMN_SIZE_DEF;
+	fse->min_height = MT9M032_ROW_SIZE_DEF;
+	fse->max_height = MT9M032_ROW_SIZE_DEF;
+
+	return 0;
+}
+
+/**
+ * __mt9m032_get_pad_crop() - get crop rect
+ * @sensor: pointer to the sensor struct
+ * @fh: file handle for getting the try crop rect from
+ * @which: select try or active crop rect
+ *
+ * Returns a pointer the current active or fh relative try crop rect
+ */
+static struct v4l2_rect *
+__mt9m032_get_pad_crop(struct mt9m032 *sensor, struct v4l2_subdev_fh *fh,
+		       enum v4l2_subdev_format_whence which)
+{
+	switch (which) {
+	case V4L2_SUBDEV_FORMAT_TRY:
+		return v4l2_subdev_get_try_crop(fh, 0);
+	case V4L2_SUBDEV_FORMAT_ACTIVE:
+		return &sensor->crop;
+	default:
+		return NULL;
+	}
+}
+
+/**
+ * __mt9m032_get_pad_format() - get format
+ * @sensor: pointer to the sensor struct
+ * @fh: file handle for getting the try format from
+ * @which: select try or active format
+ *
+ * Returns a pointer the current active or fh relative try format
+ */
+static struct v4l2_mbus_framefmt *
+__mt9m032_get_pad_format(struct mt9m032 *sensor, struct v4l2_subdev_fh *fh,
+			 enum v4l2_subdev_format_whence which)
+{
+	switch (which) {
+	case V4L2_SUBDEV_FORMAT_TRY:
+		return v4l2_subdev_get_try_format(fh, 0);
+	case V4L2_SUBDEV_FORMAT_ACTIVE:
+		return &sensor->format;
+	default:
+		return NULL;
+	}
+}
+
+static int mt9m032_get_pad_format(struct v4l2_subdev *subdev,
+				  struct v4l2_subdev_fh *fh,
+				  struct v4l2_subdev_format *fmt)
+{
+	struct mt9m032 *sensor = to_mt9m032(subdev);
+
+	mutex_lock(&sensor->lock);
+	fmt->format = *__mt9m032_get_pad_format(sensor, fh, fmt->which);
+	mutex_unlock(&sensor->lock);
+
+	return 0;
+}
+
+static int mt9m032_set_pad_format(struct v4l2_subdev *subdev,
+				  struct v4l2_subdev_fh *fh,
+				  struct v4l2_subdev_format *fmt)
+{
+	struct mt9m032 *sensor = to_mt9m032(subdev);
+	int ret;
+
+	mutex_lock(&sensor->lock);
+
+	if (sensor->streaming && fmt->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
+		ret = -EBUSY;
+		goto done;
+	}
+
+	/* Scaling is not supported, the format is thus fixed. */
+	ret = mt9m032_get_pad_format(subdev, fh, fmt);
+
+done:
+	mutex_lock(&sensor->lock);
+	return ret;
+}
+
+static int mt9m032_get_pad_crop(struct v4l2_subdev *subdev,
+				struct v4l2_subdev_fh *fh,
+				struct v4l2_subdev_crop *crop)
+{
+	struct mt9m032 *sensor = to_mt9m032(subdev);
+
+	mutex_lock(&sensor->lock);
+	crop->rect = *__mt9m032_get_pad_crop(sensor, fh, crop->which);
+	mutex_unlock(&sensor->lock);
+
+	return 0;
+}
+
+static int mt9m032_set_pad_crop(struct v4l2_subdev *subdev,
+				struct v4l2_subdev_fh *fh,
+				struct v4l2_subdev_crop *crop)
+{
+	struct mt9m032 *sensor = to_mt9m032(subdev);
+	struct v4l2_mbus_framefmt *format;
+	struct v4l2_rect *__crop;
+	struct v4l2_rect rect;
+	int ret = 0;
+
+	mutex_lock(&sensor->lock);
+
+	if (sensor->streaming && crop->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
+		ret = -EBUSY;
+		goto done;
+	}
+
+	/* Clamp the crop rectangle boundaries and align them to a multiple of 2
+	 * pixels to ensure a GRBG Bayer pattern.
+	 */
+	rect.left = clamp(ALIGN(crop->rect.left, 2), MT9M032_COLUMN_START_MIN,
+			  MT9M032_COLUMN_START_MAX);
+	rect.top = clamp(ALIGN(crop->rect.top, 2), MT9M032_ROW_START_MIN,
+			 MT9M032_ROW_START_MAX);
+	rect.width = clamp(ALIGN(crop->rect.width, 2), MT9M032_COLUMN_SIZE_MIN,
+			   MT9M032_COLUMN_SIZE_MAX);
+	rect.height = clamp(ALIGN(crop->rect.height, 2), MT9M032_ROW_SIZE_MIN,
+			    MT9M032_ROW_SIZE_MAX);
+
+	rect.width = min(rect.width, MT9M032_PIXEL_ARRAY_WIDTH - rect.left);
+	rect.height = min(rect.height, MT9M032_PIXEL_ARRAY_HEIGHT - rect.top);
+
+	__crop = __mt9m032_get_pad_crop(sensor, fh, 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 = __mt9m032_get_pad_format(sensor, fh, crop->which);
+		format->width = rect.width;
+		format->height = rect.height;
+	}
+
+	*__crop = rect;
+	crop->rect = rect;
+
+	if (crop->which == V4L2_SUBDEV_FORMAT_ACTIVE)
+		ret = mt9m032_update_geom_timing(sensor);
+
+done:
+	mutex_unlock(&sensor->lock);
+	return ret;
+}
+
+static int mt9m032_get_frame_interval(struct v4l2_subdev *subdev,
+				      struct v4l2_subdev_frame_interval *fi)
+{
+	struct mt9m032 *sensor = to_mt9m032(subdev);
+
+	mutex_lock(&sensor->lock);
+	memset(fi, 0, sizeof(*fi));
+	fi->interval = sensor->frame_interval;
+	mutex_unlock(&sensor->lock);
+
+	return 0;
+}
+
+static int mt9m032_set_frame_interval(struct v4l2_subdev *subdev,
+				      struct v4l2_subdev_frame_interval *fi)
+{
+	struct mt9m032 *sensor = to_mt9m032(subdev);
+	int ret;
+
+	mutex_lock(&sensor->lock);
+
+	if (sensor->streaming) {
+		ret = -EBUSY;
+		goto done;
+	}
+
+	/* Avoid divisions by 0. */
+	if (fi->interval.denominator == 0)
+		fi->interval.denominator = 1;
+
+	ret = mt9m032_update_timing(sensor, &fi->interval);
+	if (!ret)
+		sensor->frame_interval = fi->interval;
+
+done:
+	mutex_unlock(&sensor->lock);
+	return ret;
+}
+
+static int mt9m032_s_stream(struct v4l2_subdev *subdev, int streaming)
+{
+	struct mt9m032 *sensor = to_mt9m032(subdev);
+	int ret;
+
+	mutex_lock(&sensor->lock);
+	ret = update_formatter2(sensor, streaming);
+	if (!ret)
+		sensor->streaming = streaming;
+	mutex_unlock(&sensor->lock);
+
+	return ret;
+}
+
+/* -----------------------------------------------------------------------------
+ * V4L2 subdev core operations
+ */
+
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+static int mt9m032_g_register(struct v4l2_subdev *sd,
+			      struct v4l2_dbg_register *reg)
+{
+	struct mt9m032 *sensor = to_mt9m032(sd);
+	struct i2c_client *client = v4l2_get_subdevdata(&sensor->subdev);
+	int val;
+
+	if (reg->match.type != V4L2_CHIP_MATCH_I2C_ADDR || reg->reg > 0xff)
+		return -EINVAL;
+	if (reg->match.addr != client->addr)
+		return -ENODEV;
+
+	val = mt9m032_read(client, reg->reg);
+	if (val < 0)
+		return -EIO;
+
+	reg->size = 2;
+	reg->val = val;
+
+	return 0;
+}
+
+static int mt9m032_s_register(struct v4l2_subdev *sd,
+			      struct v4l2_dbg_register *reg)
+{
+	struct mt9m032 *sensor = to_mt9m032(sd);
+	struct i2c_client *client = v4l2_get_subdevdata(&sensor->subdev);
+
+	if (reg->match.type != V4L2_CHIP_MATCH_I2C_ADDR || reg->reg > 0xff)
+		return -EINVAL;
+
+	if (reg->match.addr != client->addr)
+		return -ENODEV;
+
+	return mt9m032_write(client, reg->reg, reg->val);
+}
+#endif
+
+/* -----------------------------------------------------------------------------
+ * V4L2 subdev control operations
+ */
+
+static int update_read_mode2(struct mt9m032 *sensor, bool vflip, bool hflip)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&sensor->subdev);
+	int reg_val = (vflip << MT9M032_READ_MODE2_VFLIP_SHIFT)
+		    | (hflip << MT9M032_READ_MODE2_HFLIP_SHIFT)
+		    | MT9M032_READ_MODE2_ROW_BLC
+		    | 0x0007;
+
+	return mt9m032_write(client, MT9M032_READ_MODE2, reg_val);
+}
+
+static int mt9m032_set_gain(struct mt9m032 *sensor, s32 val)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&sensor->subdev);
+	int digital_gain_val;	/* in 1/8th (0..127) */
+	int analog_mul;		/* 0 or 1 */
+	int analog_gain_val;	/* in 1/16th. (0..63) */
+	u16 reg_val;
+
+	digital_gain_val = 51; /* from setup example */
+
+	if (val < 63) {
+		analog_mul = 0;
+		analog_gain_val = val;
+	} else {
+		analog_mul = 1;
+		analog_gain_val = val / 2;
+	}
+
+	/* a_gain = (1 + analog_mul) + (analog_gain_val + 1) / 16 */
+	/* overall_gain = a_gain * (1 + digital_gain_val / 8) */
+
+	reg_val = ((digital_gain_val & MT9M032_GAIN_DIGITAL_MASK)
+		   << MT9M032_GAIN_DIGITAL_SHIFT)
+		| ((analog_mul & 1) << MT9M032_GAIN_AMUL_SHIFT)
+		| (analog_gain_val & MT9M032_GAIN_ANALOG_MASK);
+
+	return mt9m032_write(client, MT9M032_GAIN_ALL, reg_val);
+}
+
+static int mt9m032_try_ctrl(struct v4l2_ctrl *ctrl)
+{
+	if (ctrl->id == V4L2_CID_GAIN && ctrl->val >= 63) {
+		/* round because of multiplier used for values >= 63 */
+		ctrl->val &= ~1;
+	}
+
+	return 0;
+}
+
+static int mt9m032_set_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct mt9m032 *sensor =
+		container_of(ctrl->handler, struct mt9m032, ctrls);
+	struct i2c_client *client = v4l2_get_subdevdata(&sensor->subdev);
+	int ret;
+
+	switch (ctrl->id) {
+	case V4L2_CID_GAIN:
+		return mt9m032_set_gain(sensor, ctrl->val);
+
+	case V4L2_CID_HFLIP:
+	/* case V4L2_CID_VFLIP: -- In the same cluster */
+		return update_read_mode2(sensor, sensor->vflip->val,
+					 sensor->hflip->val);
+
+	case V4L2_CID_EXPOSURE:
+		ret = mt9m032_write(client, MT9M032_SHUTTER_WIDTH_HIGH,
+				    (ctrl->val >> 16) & 0xffff);
+		if (ret < 0)
+			return ret;
+
+		return mt9m032_write(client, MT9M032_SHUTTER_WIDTH_LOW,
+				     ctrl->val & 0xffff);
+	}
+
+	return 0;
+}
+
+static struct v4l2_ctrl_ops mt9m032_ctrl_ops = {
+	.s_ctrl = mt9m032_set_ctrl,
+	.try_ctrl = mt9m032_try_ctrl,
+};
+
+/* -------------------------------------------------------------------------- */
+
+static const struct v4l2_subdev_core_ops mt9m032_core_ops = {
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+	.g_register = mt9m032_g_register,
+	.s_register = mt9m032_s_register,
+#endif
+};
+
+static const struct v4l2_subdev_video_ops mt9m032_video_ops = {
+	.s_stream = mt9m032_s_stream,
+	.g_frame_interval = mt9m032_get_frame_interval,
+	.s_frame_interval = mt9m032_set_frame_interval,
+};
+
+static const struct v4l2_subdev_pad_ops mt9m032_pad_ops = {
+	.enum_mbus_code = mt9m032_enum_mbus_code,
+	.enum_frame_size = mt9m032_enum_frame_size,
+	.get_fmt = mt9m032_get_pad_format,
+	.set_fmt = mt9m032_set_pad_format,
+	.set_crop = mt9m032_set_pad_crop,
+	.get_crop = mt9m032_get_pad_crop,
+};
+
+static const struct v4l2_subdev_ops mt9m032_ops = {
+	.core = &mt9m032_core_ops,
+	.video = &mt9m032_video_ops,
+	.pad = &mt9m032_pad_ops,
+};
+
+/* -----------------------------------------------------------------------------
+ * Driver initialization and probing
+ */
+
+static int mt9m032_probe(struct i2c_client *client,
+			 const struct i2c_device_id *devid)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	struct mt9m032 *sensor;
+	int chip_version;
+	int ret;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA)) {
+		dev_warn(&client->dev,
+			 "I2C-Adapter doesn't support I2C_FUNC_SMBUS_WORD\n");
+		return -EIO;
+	}
+
+	if (!client->dev.platform_data)
+		return -ENODEV;
+
+	sensor = kzalloc(sizeof(*sensor), GFP_KERNEL);
+	if (sensor == NULL)
+		return -ENOMEM;
+
+	mutex_init(&sensor->lock);
+
+	sensor->pdata = client->dev.platform_data;
+
+	v4l2_i2c_subdev_init(&sensor->subdev, client, &mt9m032_ops);
+	sensor->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+
+	chip_version = mt9m032_read(client, MT9M032_CHIP_VERSION);
+	if (chip_version != MT9M032_CHIP_VERSION_VALUE) {
+		dev_err(&client->dev, "MT9M032 not detected, wrong version "
+			"0x%04x\n", chip_version);
+		ret = -ENODEV;
+		goto error_sensor;
+	}
+
+	dev_info(&client->dev, "MT9M032 detected at address 0x%02x\n",
+		 client->addr);
+
+	sensor->frame_interval.numerator = 1;
+	sensor->frame_interval.denominator = 30;
+
+	sensor->crop.left = MT9M032_COLUMN_START_DEF;
+	sensor->crop.top = MT9M032_ROW_START_DEF;
+	sensor->crop.width = MT9M032_COLUMN_SIZE_DEF;
+	sensor->crop.height = MT9M032_ROW_SIZE_DEF;
+
+	sensor->format.width = sensor->crop.width;
+	sensor->format.height = sensor->crop.height;
+	sensor->format.code = V4L2_MBUS_FMT_Y8_1X8;
+	sensor->format.field = V4L2_FIELD_NONE;
+	sensor->format.colorspace = V4L2_COLORSPACE_SRGB;
+
+	v4l2_ctrl_handler_init(&sensor->ctrls, 4);
+
+	v4l2_ctrl_new_std(&sensor->ctrls, &mt9m032_ctrl_ops,
+			  V4L2_CID_GAIN, 0, 127, 1, 64);
+
+	sensor->hflip = v4l2_ctrl_new_std(&sensor->ctrls,
+					  &mt9m032_ctrl_ops,
+					  V4L2_CID_HFLIP, 0, 1, 1, 0);
+	sensor->vflip = v4l2_ctrl_new_std(&sensor->ctrls,
+					  &mt9m032_ctrl_ops,
+					  V4L2_CID_VFLIP, 0, 1, 1, 0);
+
+	v4l2_ctrl_new_std(&sensor->ctrls, &mt9m032_ctrl_ops,
+			  V4L2_CID_EXPOSURE, MT9M032_SHUTTER_WIDTH_MIN,
+			  MT9M032_SHUTTER_WIDTH_MAX, 1,
+			  MT9M032_SHUTTER_WIDTH_DEF);
+
+	if (sensor->ctrls.error) {
+		ret = sensor->ctrls.error;
+		dev_err(&client->dev, "control initialization error %d\n", ret);
+		goto error_ctrl;
+	}
+
+	v4l2_ctrl_cluster(2, &sensor->hflip);
+
+	sensor->subdev.ctrl_handler = &sensor->ctrls;
+	sensor->pad.flags = MEDIA_PAD_FL_SOURCE;
+	ret = media_entity_init(&sensor->subdev.entity, 1, &sensor->pad, 0);
+	if (ret < 0)
+		goto error_ctrl;
+
+	ret = mt9m032_write(client, MT9M032_RESET, 1);	/* reset on */
+	if (ret < 0)
+		goto error_entity;
+	mt9m032_write(client, MT9M032_RESET, 0);	/* reset off */
+	if (ret < 0)
+		goto error_entity;
+
+	ret = mt9m032_setup_pll(sensor);
+	if (ret < 0)
+		goto error_entity;
+	usleep_range(10000, 11000);
+
+	ret = v4l2_ctrl_handler_setup(&sensor->ctrls);
+	if (ret < 0)
+		goto error_entity;
+
+	/* SIZE */
+	ret = mt9m032_update_geom_timing(sensor);
+	if (ret < 0)
+		goto error_entity;
+
+	ret = mt9m032_write(client, 0x41, 0x0000);	/* reserved !!! */
+	if (ret < 0)
+		goto error_entity;
+	ret = mt9m032_write(client, 0x42, 0x0003);	/* reserved !!! */
+	if (ret < 0)
+		goto error_entity;
+	ret = mt9m032_write(client, 0x43, 0x0003);	/* reserved !!! */
+	if (ret < 0)
+		goto error_entity;
+	ret = mt9m032_write(client, 0x7f, 0x0000);	/* reserved !!! */
+	if (ret < 0)
+		goto error_entity;
+	if (sensor->pdata->invert_pixclock) {
+		ret = mt9m032_write(client, MT9M032_PIX_CLK_CTRL,
+				    MT9M032_PIX_CLK_CTRL_INV_PIXCLK);
+		if (ret < 0)
+			goto error_entity;
+	}
+
+	ret = mt9m032_write(client, MT9M032_RESTART, 1); /* Restart on */
+	if (ret < 0)
+		goto error_entity;
+	msleep(100);
+	ret = mt9m032_write(client, MT9M032_RESTART, 0); /* Restart off */
+	if (ret < 0)
+		goto error_entity;
+	msleep(100);
+	ret = update_formatter2(sensor, false);
+	if (ret < 0)
+		goto error_entity;
+
+	return ret;
+
+error_entity:
+	media_entity_cleanup(&sensor->subdev.entity);
+error_ctrl:
+	v4l2_ctrl_handler_free(&sensor->ctrls);
+error_sensor:
+	mutex_destroy(&sensor->lock);
+	kfree(sensor);
+	return ret;
+}
+
+static int mt9m032_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *subdev = i2c_get_clientdata(client);
+	struct mt9m032 *sensor = to_mt9m032(subdev);
+
+	v4l2_device_unregister_subdev(&sensor->subdev);
+	v4l2_ctrl_handler_free(&sensor->ctrls);
+	media_entity_cleanup(&sensor->subdev.entity);
+	mutex_destroy(&sensor->lock);
+	kfree(sensor);
+	return 0;
+}
+
+static const struct i2c_device_id mt9m032_id_table[] = {
+	{ MT9M032_NAME, 0 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(i2c, mt9m032_id_table);
+
+static struct i2c_driver mt9m032_i2c_driver = {
+	.driver = {
+		.name = MT9M032_NAME,
+	},
+	.probe = mt9m032_probe,
+	.remove = mt9m032_remove,
+	.id_table = mt9m032_id_table,
+};
+
+module_i2c_driver(mt9m032_i2c_driver);
+
+MODULE_AUTHOR("Martin Hostettler <[e-mail]>");
+MODULE_DESCRIPTION("MT9M032 camera sensor driver");
+MODULE_LICENSE("GPL v2");

include/media/mt9m032.h

···
+/*
+ * Driver for MT9M032 CMOS Image Sensor from Micron
+ *
+ * Copyright (C) 2010-2011 Lund Engineering
+ * Contact: Gil Lund <[e-mail]>
+ * Author: Martin Hostettler <[e-mail]>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ */
+
+#ifndef MT9M032_H
+#define MT9M032_H
+
+#define MT9M032_NAME		"mt9m032"
+#define MT9M032_I2C_ADDR	(0xb8 >> 1)
+
+struct mt9m032_platform_data {
+	u32 ext_clock;
+	u32 pix_clock;
+	bool invert_pixclock;
+
+};
+#endif /* MT9M032_H */