V4L/DVB (10099): soc-camera: add support for MT9T031 CMOS camera sensor from Micron

This camera is rather similar to MT9M001, but also has a couple of
enhanced features, like pixel binning.

 create mode 100644 drivers/media/video/mt9t031.c

Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

3 files changed, 743 insertions, 0 deletions

diff --git a/drivers/media/video/Kconfig b/drivers/media/video/Kconfig
index 9785eeb..19cf3b8 100644
--- a/drivers/media/video/Kconfig
+++ b/drivers/media/video/Kconfig
@@ -741,6 +741,12 @@ config SOC_CAMERA_MT9M111
 	help
 	  This driver supports MT9M111 and MT9M112 cameras from Micron
 
+config SOC_CAMERA_MT9T031
+	tristate "mt9t031 support"
+	depends on SOC_CAMERA && I2C
+	help
+	  This driver supports MT9T031 cameras from Micron.
+
 config SOC_CAMERA_MT9V022
 	tristate "mt9v022 support"
 	depends on SOC_CAMERA && I2C
diff --git a/drivers/media/video/Makefile b/drivers/media/video/Makefile
index 40c69af..1611c33 100644
--- a/drivers/media/video/Makefile
+++ b/drivers/media/video/Makefile
@@ -137,6 +137,7 @@ obj-$(CONFIG_VIDEO_OMAP2)		+= omap2cam.o
 obj-$(CONFIG_SOC_CAMERA)	+= soc_camera.o
 obj-$(CONFIG_SOC_CAMERA_MT9M001)	+= mt9m001.o
 obj-$(CONFIG_SOC_CAMERA_MT9M111)	+= mt9m111.o
+obj-$(CONFIG_SOC_CAMERA_MT9T031)	+= mt9t031.o
 obj-$(CONFIG_SOC_CAMERA_MT9V022)	+= mt9v022.o
 obj-$(CONFIG_SOC_CAMERA_OV772X)		+= ov772x.o
 obj-$(CONFIG_SOC_CAMERA_PLATFORM)	+= soc_camera_platform.o
diff --git a/drivers/media/video/mt9t031.c b/drivers/media/video/mt9t031.c
new file mode 100644
index 0000000..1a9d539
--- /dev/null
+++ b/drivers/media/video/mt9t031.c
@@ -0,0 +1,736 @@
+/*
+ * Driver for MT9T031 CMOS Image Sensor from Micron
+ *
+ * Copyright (C) 2008, Guennadi Liakhovetski, DENX Software Engineering <lg@denx.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/videodev2.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/log2.h>
+
+#include <media/v4l2-common.h>
+#include <media/v4l2-chip-ident.h>
+#include <media/soc_camera.h>
+
+/* mt9t031 i2c address 0x5d
+ * The platform has to define i2c_board_info
+ * and call i2c_register_board_info() */
+
+/* mt9t031 selected register addresses */
+#define MT9T031_CHIP_VERSION		0x00
+#define MT9T031_ROW_START		0x01
+#define MT9T031_COLUMN_START		0x02
+#define MT9T031_WINDOW_HEIGHT		0x03
+#define MT9T031_WINDOW_WIDTH		0x04
+#define MT9T031_HORIZONTAL_BLANKING	0x05
+#define MT9T031_VERTICAL_BLANKING	0x06
+#define MT9T031_OUTPUT_CONTROL		0x07
+#define MT9T031_SHUTTER_WIDTH_UPPER	0x08
+#define MT9T031_SHUTTER_WIDTH		0x09
+#define MT9T031_PIXEL_CLOCK_CONTROL	0x0a
+#define MT9T031_FRAME_RESTART		0x0b
+#define MT9T031_SHUTTER_DELAY		0x0c
+#define MT9T031_RESET			0x0d
+#define MT9T031_READ_MODE_1		0x1e
+#define MT9T031_READ_MODE_2		0x20
+#define MT9T031_READ_MODE_3		0x21
+#define MT9T031_ROW_ADDRESS_MODE	0x22
+#define MT9T031_COLUMN_ADDRESS_MODE	0x23
+#define MT9T031_GLOBAL_GAIN		0x35
+#define MT9T031_CHIP_ENABLE		0xF8
+
+#define MT9T031_MAX_HEIGHT		1536
+#define MT9T031_MAX_WIDTH		2048
+#define MT9T031_MIN_HEIGHT		2
+#define MT9T031_MIN_WIDTH		2
+#define MT9T031_HORIZONTAL_BLANK	142
+#define MT9T031_VERTICAL_BLANK		25
+#define MT9T031_COLUMN_SKIP		32
+#define MT9T031_ROW_SKIP		20
+
+#define MT9T031_BUS_PARAM	(SOCAM_PCLK_SAMPLE_RISING |	\
+	SOCAM_PCLK_SAMPLE_FALLING | SOCAM_HSYNC_ACTIVE_HIGH |	\
+	SOCAM_VSYNC_ACTIVE_HIGH | SOCAM_DATA_ACTIVE_HIGH |	\
+	SOCAM_MASTER | SOCAM_DATAWIDTH_10)
+
+static const struct soc_camera_data_format mt9t031_colour_formats[] = {
+	{
+		.name		= "Bayer (sRGB) 10 bit",
+		.depth		= 10,
+		.fourcc		= V4L2_PIX_FMT_SGRBG10,
+		.colorspace	= V4L2_COLORSPACE_SRGB,
+	}
+};
+
+struct mt9t031 {
+	struct i2c_client *client;
+	struct soc_camera_device icd;
+	int model;	/* V4L2_IDENT_MT9T031* codes from v4l2-chip-ident.h */
+	unsigned char autoexposure;
+	u16 xskip;
+	u16 yskip;
+};
+
+static int reg_read(struct soc_camera_device *icd, const u8 reg)
+{
+	struct mt9t031 *mt9t031 = container_of(icd, struct mt9t031, icd);
+	struct i2c_client *client = mt9t031->client;
+	s32 data = i2c_smbus_read_word_data(client, reg);
+	return data < 0 ? data : swab16(data);
+}
+
+static int reg_write(struct soc_camera_device *icd, const u8 reg,
+		     const u16 data)
+{
+	struct mt9t031 *mt9t031 = container_of(icd, struct mt9t031, icd);
+	return i2c_smbus_write_word_data(mt9t031->client, reg, swab16(data));
+}
+
+static int reg_set(struct soc_camera_device *icd, const u8 reg,
+		   const u16 data)
+{
+	int ret;
+
+	ret = reg_read(icd, reg);
+	if (ret < 0)
+		return ret;
+	return reg_write(icd, reg, ret | data);
+}
+
+static int reg_clear(struct soc_camera_device *icd, const u8 reg,
+		     const u16 data)
+{
+	int ret;
+
+	ret = reg_read(icd, reg);
+	if (ret < 0)
+		return ret;
+	return reg_write(icd, reg, ret & ~data);
+}
+
+static int set_shutter(struct soc_camera_device *icd, const u32 data)
+{
+	int ret;
+
+	ret = reg_write(icd, MT9T031_SHUTTER_WIDTH_UPPER, data >> 16);
+
+	if (ret >= 0)
+		ret = reg_write(icd, MT9T031_SHUTTER_WIDTH, data & 0xffff);
+
+	return ret;
+}
+
+static int get_shutter(struct soc_camera_device *icd, u32 *data)
+{
+	int ret;
+
+	ret = reg_read(icd, MT9T031_SHUTTER_WIDTH_UPPER);
+	*data = ret << 16;
+
+	if (ret >= 0)
+		ret = reg_read(icd, MT9T031_SHUTTER_WIDTH);
+	*data |= ret & 0xffff;
+
+	return ret < 0 ? ret : 0;
+}
+
+static int mt9t031_init(struct soc_camera_device *icd)
+{
+	int ret;
+
+	/* Disable chip output, synchronous option update */
+	dev_dbg(icd->vdev->parent, "%s\n", __func__);
+
+	ret = reg_write(icd, MT9T031_RESET, 1);
+	if (ret >= 0)
+		ret = reg_write(icd, MT9T031_RESET, 0);
+	if (ret >= 0)
+		ret = reg_clear(icd, MT9T031_OUTPUT_CONTROL, 3);
+
+	return ret >= 0 ? 0 : -EIO;
+}
+
+static int mt9t031_release(struct soc_camera_device *icd)
+{
+	/* Disable the chip */
+	reg_clear(icd, MT9T031_OUTPUT_CONTROL, 3);
+	return 0;
+}
+
+static int mt9t031_start_capture(struct soc_camera_device *icd)
+{
+	/* Switch to master "normal" mode */
+	if (reg_set(icd, MT9T031_OUTPUT_CONTROL, 3) < 0)
+		return -EIO;
+	return 0;
+}
+
+static int mt9t031_stop_capture(struct soc_camera_device *icd)
+{
+	/* Stop sensor readout */
+	if (reg_clear(icd, MT9T031_OUTPUT_CONTROL, 3) < 0)
+		return -EIO;
+	return 0;
+}
+
+static int mt9t031_set_bus_param(struct soc_camera_device *icd,
+				 unsigned long flags)
+{
+	/* The caller should have queried our parameters, check anyway */
+	if (flags & ~MT9T031_BUS_PARAM)
+		return -EINVAL;
+
+	if (flags & SOCAM_PCLK_SAMPLE_FALLING)
+		reg_set(icd, MT9T031_PIXEL_CLOCK_CONTROL, 0x8000);
+	else
+		reg_clear(icd, MT9T031_PIXEL_CLOCK_CONTROL, 0x8000);
+
+	return 0;
+}
+
+static unsigned long mt9t031_query_bus_param(struct soc_camera_device *icd)
+{
+	struct mt9t031 *mt9t031 = container_of(icd, struct mt9t031, icd);
+	struct soc_camera_link *icl = mt9t031->client->dev.platform_data;
+
+	return soc_camera_apply_sensor_flags(icl, MT9T031_BUS_PARAM);
+}
+
+static int mt9t031_set_fmt(struct soc_camera_device *icd,
+			   __u32 pixfmt, struct v4l2_rect *rect)
+{
+	struct mt9t031 *mt9t031 = container_of(icd, struct mt9t031, icd);
+	int ret;
+	const u16 hblank = MT9T031_HORIZONTAL_BLANK,
+		vblank = MT9T031_VERTICAL_BLANK;
+	u16 xbin, xskip = mt9t031->xskip, ybin, yskip = mt9t031->yskip,
+		width = rect->width * xskip, height = rect->height * yskip;
+
+	if (pixfmt) {
+		/* S_FMT - use binning and skipping for scaling, recalculate */
+		/* Is this more optimal than just a division? */
+		for (xskip = 8; xskip > 1; xskip--)
+			if (rect->width * xskip <= icd->width_max)
+				break;
+
+		for (yskip = 8; yskip > 1; yskip--)
+			if (rect->height * yskip <= icd->height_max)
+				break;
+
+		width = rect->width * xskip;
+		height = rect->height * yskip;
+
+		dev_dbg(&icd->dev, "xskip %u, width %u, yskip %u, height %u\n",
+			xskip, width, yskip, height);
+	}
+
+	xbin = min(xskip, (u16)3);
+	ybin = min(yskip, (u16)3);
+
+	/* Make sure we don't exceed frame limits */
+	if (rect->left + width > icd->width_max)
+		rect->left = (icd->width_max - width) / 2;
+
+	if (rect->top + height > icd->height_max)
+		rect->top = (icd->height_max - height) / 2;
+
+	/* Could just do roundup(rect->left, [xy]bin); but this is cheaper */
+	switch (xbin) {
+	case 2:
+		rect->left = (rect->left + 1) & ~1;
+		break;
+	case 3:
+		rect->left = roundup(rect->left, 3);
+	}
+
+	switch (ybin) {
+	case 2:
+		rect->top = (rect->top + 1) & ~1;
+		break;
+	case 3:
+		rect->top = roundup(rect->top, 3);
+	}
+
+	/* Blanking and start values - default... */
+	ret = reg_write(icd, MT9T031_HORIZONTAL_BLANKING, hblank);
+	if (ret >= 0)
+		ret = reg_write(icd, MT9T031_VERTICAL_BLANKING, vblank);
+
+	if (pixfmt) {
+		/* Binning, skipping */
+		if (ret >= 0)
+			ret = reg_write(icd, MT9T031_COLUMN_ADDRESS_MODE,
+					((xbin - 1) << 4) | (xskip - 1));
+		if (ret >= 0)
+			ret = reg_write(icd, MT9T031_ROW_ADDRESS_MODE,
+					((ybin - 1) << 4) | (yskip - 1));
+	}
+	dev_dbg(&icd->dev, "new left %u, top %u\n", rect->left, rect->top);
+
+	/* The caller provides a supported format, as guaranteed by
+	 * icd->try_fmt_cap(), soc_camera_s_crop() and soc_camera_cropcap() */
+	if (ret >= 0)
+		ret = reg_write(icd, MT9T031_COLUMN_START, rect->left);
+	if (ret >= 0)
+		ret = reg_write(icd, MT9T031_ROW_START, rect->top);
+	if (ret >= 0)
+		ret = reg_write(icd, MT9T031_WINDOW_WIDTH, width - 1);
+	if (ret >= 0)
+		ret = reg_write(icd, MT9T031_WINDOW_HEIGHT,
+				height + icd->y_skip_top - 1);
+	if (ret >= 0 && mt9t031->autoexposure) {
+		ret = set_shutter(icd, height + icd->y_skip_top + vblank);
+		if (ret >= 0) {
+			const u32 shutter_max = MT9T031_MAX_HEIGHT + vblank;
+			const struct v4l2_queryctrl *qctrl =
+				soc_camera_find_qctrl(icd->ops,
+						      V4L2_CID_EXPOSURE);
+			icd->exposure = (shutter_max / 2 + (height +
+					 icd->y_skip_top + vblank - 1) *
+					 (qctrl->maximum - qctrl->minimum)) /
+				shutter_max + qctrl->minimum;
+		}
+	}
+
+	if (!ret && pixfmt) {
+		mt9t031->xskip = xskip;
+		mt9t031->yskip = yskip;
+	}
+
+	return ret < 0 ? ret : 0;
+}
+
+static int mt9t031_try_fmt(struct soc_camera_device *icd,
+			   struct v4l2_format *f)
+{
+	struct v4l2_pix_format *pix = &f->fmt.pix;
+
+	if (pix->height < icd->height_min)
+		pix->height = icd->height_min;
+	if (pix->height > icd->height_max)
+		pix->height = icd->height_max;
+	if (pix->width < icd->width_min)
+		pix->width = icd->width_min;
+	if (pix->width > icd->width_max)
+		pix->width = icd->width_max;
+
+	pix->width &= ~0x01; /* has to be even */
+	pix->height &= ~0x01; /* has to be even */
+
+	return 0;
+}
+
+static int mt9t031_get_chip_id(struct soc_camera_device *icd,
+			       struct v4l2_chip_ident *id)
+{
+	struct mt9t031 *mt9t031 = container_of(icd, struct mt9t031, icd);
+
+	if (id->match_type != V4L2_CHIP_MATCH_I2C_ADDR)
+		return -EINVAL;
+
+	if (id->match_chip != mt9t031->client->addr)
+		return -ENODEV;
+
+	id->ident	= mt9t031->model;
+	id->revision	= 0;
+
+	return 0;
+}
+
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+static int mt9t031_get_register(struct soc_camera_device *icd,
+				struct v4l2_register *reg)
+{
+	struct mt9t031 *mt9t031 = container_of(icd, struct mt9t031, icd);
+
+	if (reg->match_type != V4L2_CHIP_MATCH_I2C_ADDR || reg->reg > 0xff)
+		return -EINVAL;
+
+	if (reg->match_chip != mt9t031->client->addr)
+		return -ENODEV;
+
+	reg->val = reg_read(icd, reg->reg);
+
+	if (reg->val > 0xffff)
+		return -EIO;
+
+	return 0;
+}
+
+static int mt9t031_set_register(struct soc_camera_device *icd,
+				struct v4l2_register *reg)
+{
+	struct mt9t031 *mt9t031 = container_of(icd, struct mt9t031, icd);
+
+	if (reg->match_type != V4L2_CHIP_MATCH_I2C_ADDR || reg->reg > 0xff)
+		return -EINVAL;
+
+	if (reg->match_chip != mt9t031->client->addr)
+		return -ENODEV;
+
+	if (reg_write(icd, reg->reg, reg->val) < 0)
+		return -EIO;
+
+	return 0;
+}
+#endif
+
+static const struct v4l2_queryctrl mt9t031_controls[] = {
+	{
+		.id		= V4L2_CID_VFLIP,
+		.type		= V4L2_CTRL_TYPE_BOOLEAN,
+		.name		= "Flip Vertically",
+		.minimum	= 0,
+		.maximum	= 1,
+		.step		= 1,
+		.default_value	= 0,
+	}, {
+		.id		= V4L2_CID_GAIN,
+		.type		= V4L2_CTRL_TYPE_INTEGER,
+		.name		= "Gain",
+		.minimum	= 0,
+		.maximum	= 127,
+		.step		= 1,
+		.default_value	= 64,
+		.flags		= V4L2_CTRL_FLAG_SLIDER,
+	}, {
+		.id		= V4L2_CID_EXPOSURE,
+		.type		= V4L2_CTRL_TYPE_INTEGER,
+		.name		= "Exposure",
+		.minimum	= 1,
+		.maximum	= 255,
+		.step		= 1,
+		.default_value	= 255,
+		.flags		= V4L2_CTRL_FLAG_SLIDER,
+	}, {
+		.id		= V4L2_CID_EXPOSURE_AUTO,
+		.type		= V4L2_CTRL_TYPE_BOOLEAN,
+		.name		= "Automatic Exposure",
+		.minimum	= 0,
+		.maximum	= 1,
+		.step		= 1,
+		.default_value	= 1,
+	}
+};
+
+static int mt9t031_video_probe(struct soc_camera_device *);
+static void mt9t031_video_remove(struct soc_camera_device *);
+static int mt9t031_get_control(struct soc_camera_device *, struct v4l2_control *);
+static int mt9t031_set_control(struct soc_camera_device *, struct v4l2_control *);
+
+static struct soc_camera_ops mt9t031_ops = {
+	.owner			= THIS_MODULE,
+	.probe			= mt9t031_video_probe,
+	.remove			= mt9t031_video_remove,
+	.init			= mt9t031_init,
+	.release		= mt9t031_release,
+	.start_capture		= mt9t031_start_capture,
+	.stop_capture		= mt9t031_stop_capture,
+	.set_fmt		= mt9t031_set_fmt,
+	.try_fmt		= mt9t031_try_fmt,
+	.set_bus_param		= mt9t031_set_bus_param,
+	.query_bus_param	= mt9t031_query_bus_param,
+	.controls		= mt9t031_controls,
+	.num_controls		= ARRAY_SIZE(mt9t031_controls),
+	.get_control		= mt9t031_get_control,
+	.set_control		= mt9t031_set_control,
+	.get_chip_id		= mt9t031_get_chip_id,
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+	.get_register		= mt9t031_get_register,
+	.set_register		= mt9t031_set_register,
+#endif
+};
+
+static int mt9t031_get_control(struct soc_camera_device *icd, struct v4l2_control *ctrl)
+{
+	struct mt9t031 *mt9t031 = container_of(icd, struct mt9t031, icd);
+	int data;
+
+	switch (ctrl->id) {
+	case V4L2_CID_VFLIP:
+		data = reg_read(icd, MT9T031_READ_MODE_2);
+		if (data < 0)
+			return -EIO;
+		ctrl->value = !!(data & 0x8000);
+		break;
+	case V4L2_CID_HFLIP:
+		data = reg_read(icd, MT9T031_READ_MODE_2);
+		if (data < 0)
+			return -EIO;
+		ctrl->value = !!(data & 0x4000);
+		break;
+	case V4L2_CID_EXPOSURE_AUTO:
+		ctrl->value = mt9t031->autoexposure;
+		break;
+	}
+	return 0;
+}
+
+static int mt9t031_set_control(struct soc_camera_device *icd, struct v4l2_control *ctrl)
+{
+	struct mt9t031 *mt9t031 = container_of(icd, struct mt9t031, icd);
+	const struct v4l2_queryctrl *qctrl;
+	int data;
+
+	qctrl = soc_camera_find_qctrl(&mt9t031_ops, ctrl->id);
+
+	if (!qctrl)
+		return -EINVAL;
+
+	switch (ctrl->id) {
+	case V4L2_CID_VFLIP:
+		if (ctrl->value)
+			data = reg_set(icd, MT9T031_READ_MODE_2, 0x8000);
+		else
+			data = reg_clear(icd, MT9T031_READ_MODE_2, 0x8000);
+		if (data < 0)
+			return -EIO;
+		break;
+	case V4L2_CID_HFLIP:
+		if (ctrl->value)
+			data = reg_set(icd, MT9T031_READ_MODE_2, 0x4000);
+		else
+			data = reg_clear(icd, MT9T031_READ_MODE_2, 0x4000);
+		if (data < 0)
+			return -EIO;
+		break;
+	case V4L2_CID_GAIN:
+		if (ctrl->value > qctrl->maximum || ctrl->value < qctrl->minimum)
+			return -EINVAL;
+		/* See Datasheet Table 7, Gain settings. */
+		if (ctrl->value <= qctrl->default_value) {
+			/* Pack it into 0..1 step 0.125, register values 0..8 */
+			unsigned long range = qctrl->default_value - qctrl->minimum;
+			data = ((ctrl->value - qctrl->minimum) * 8 + range / 2) / range;
+
+			dev_dbg(&icd->dev, "Setting gain %d\n", data);
+			data = reg_write(icd, MT9T031_GLOBAL_GAIN, data);
+			if (data < 0)
+				return -EIO;
+		} else {
+			/* Pack it into 1.125..15 variable step, register values 9..67 */
+			/* We assume qctrl->maximum - qctrl->default_value - 1 > 0 */
+			unsigned long range = qctrl->maximum - qctrl->default_value - 1;
+			unsigned long gain = ((ctrl->value - qctrl->default_value - 1) *
+					       111 + range / 2) / range + 9;
+
+			if (gain <= 32)
+				data = gain;
+			else if (gain <= 64)
+				data = ((gain - 32) * 16 + 16) / 32 + 80;
+			else
+				data = ((gain - 64) * 7 + 28) / 56 + 96;
+
+			dev_dbg(&icd->dev, "Setting gain from %d to %d\n",
+				 reg_read(icd, MT9T031_GLOBAL_GAIN), data);
+			data = reg_write(icd, MT9T031_GLOBAL_GAIN, data);
+			if (data < 0)
+				return -EIO;
+		}
+
+		/* Success */
+		icd->gain = ctrl->value;
+		break;
+	case V4L2_CID_EXPOSURE:
+		/* mt9t031 has maximum == default */
+		if (ctrl->value > qctrl->maximum || ctrl->value < qctrl->minimum)
+			return -EINVAL;
+		else {
+			const unsigned long range = qctrl->maximum - qctrl->minimum;
+			const u32 shutter = ((ctrl->value - qctrl->minimum) * 1048 +
+					     range / 2) / range + 1;
+			u32 old;
+
+			get_shutter(icd, &old);
+			dev_dbg(&icd->dev, "Setting shutter width from %u to %u\n",
+				old, shutter);
+			if (set_shutter(icd, shutter) < 0)
+				return -EIO;
+			icd->exposure = ctrl->value;
+			mt9t031->autoexposure = 0;
+		}
+		break;
+	case V4L2_CID_EXPOSURE_AUTO:
+		if (ctrl->value) {
+			const u16 vblank = MT9T031_VERTICAL_BLANK;
+			const u32 shutter_max = MT9T031_MAX_HEIGHT + vblank;
+			if (set_shutter(icd, icd->height +
+					icd->y_skip_top + vblank) < 0)
+				return -EIO;
+			qctrl = soc_camera_find_qctrl(icd->ops, V4L2_CID_EXPOSURE);
+			icd->exposure = (shutter_max / 2 + (icd->height +
+					 icd->y_skip_top + vblank - 1) *
+					 (qctrl->maximum - qctrl->minimum)) /
+				shutter_max + qctrl->minimum;
+			mt9t031->autoexposure = 1;
+		} else
+			mt9t031->autoexposure = 0;
+		break;
+	}
+	return 0;
+}
+
+/* Interface active, can use i2c. If it fails, it can indeed mean, that
+ * this wasn't our capture interface, so, we wait for the right one */
+static int mt9t031_video_probe(struct soc_camera_device *icd)
+{
+	struct mt9t031 *mt9t031 = container_of(icd, struct mt9t031, icd);
+	s32 data;
+	int ret;
+
+	/* We must have a parent by now. And it cannot be a wrong one.
+	 * So this entire test is completely redundant. */
+	if (!icd->dev.parent ||
+	    to_soc_camera_host(icd->dev.parent)->nr != icd->iface)
+		return -ENODEV;
+
+	/* Enable the chip */
+	data = reg_write(icd, MT9T031_CHIP_ENABLE, 1);
+	dev_dbg(&icd->dev, "write: %d\n", data);
+
+	/* Read out the chip version register */
+	data = reg_read(icd, MT9T031_CHIP_VERSION);
+
+	switch (data) {
+	case 0x1621:
+		mt9t031->model = V4L2_IDENT_MT9T031;
+		icd->formats = mt9t031_colour_formats;
+		icd->num_formats = ARRAY_SIZE(mt9t031_colour_formats);
+		break;
+	default:
+		ret = -ENODEV;
+		dev_err(&icd->dev,
+			"No MT9T031 chip detected, register read %x\n", data);
+		goto ei2c;
+	}
+
+	dev_info(&icd->dev, "Detected a MT9T031 chip ID %x\n", data);
+
+	/* Now that we know the model, we can start video */
+	ret = soc_camera_video_start(icd);
+	if (ret)
+		goto evstart;
+
+	return 0;
+
+evstart:
+ei2c:
+	return ret;
+}
+
+static void mt9t031_video_remove(struct soc_camera_device *icd)
+{
+	struct mt9t031 *mt9t031 = container_of(icd, struct mt9t031, icd);
+
+	dev_dbg(&icd->dev, "Video %x removed: %p, %p\n", mt9t031->client->addr,
+		icd->dev.parent, icd->vdev);
+	soc_camera_video_stop(icd);
+}
+
+static int mt9t031_probe(struct i2c_client *client,
+			 const struct i2c_device_id *did)
+{
+	struct mt9t031 *mt9t031;
+	struct soc_camera_device *icd;
+	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
+	struct soc_camera_link *icl = client->dev.platform_data;
+	int ret;
+
+	if (!icl) {
+		dev_err(&client->dev, "MT9T031 driver needs platform data\n");
+		return -EINVAL;
+	}
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA)) {
+		dev_warn(&adapter->dev,
+			 "I2C-Adapter doesn't support I2C_FUNC_SMBUS_WORD\n");
+		return -EIO;
+	}
+
+	mt9t031 = kzalloc(sizeof(struct mt9t031), GFP_KERNEL);
+	if (!mt9t031)
+		return -ENOMEM;
+
+	mt9t031->client = client;
+	i2c_set_clientdata(client, mt9t031);
+
+	/* Second stage probe - when a capture adapter is there */
+	icd = &mt9t031->icd;
+	icd->ops	= &mt9t031_ops;
+	icd->control	= &client->dev;
+	icd->x_min	= MT9T031_COLUMN_SKIP;
+	icd->y_min	= MT9T031_ROW_SKIP;
+	icd->x_current	= icd->x_min;
+	icd->y_current	= icd->y_min;
+	icd->width_min	= MT9T031_MIN_WIDTH;
+	icd->width_max	= MT9T031_MAX_WIDTH;
+	icd->height_min	= MT9T031_MIN_HEIGHT;
+	icd->height_max	= MT9T031_MAX_HEIGHT;
+	icd->y_skip_top	= 0;
+	icd->iface	= icl->bus_id;
+	/* Simulated autoexposure. If enabled, we calculate shutter width
+	 * ourselves in the driver based on vertical blanking and frame width */
+	mt9t031->autoexposure = 1;
+
+	mt9t031->xskip = 1;
+	mt9t031->yskip = 1;
+
+	ret = soc_camera_device_register(icd);
+	if (ret)
+		goto eisdr;
+
+	return 0;
+
+eisdr:
+	i2c_set_clientdata(client, NULL);
+	kfree(mt9t031);
+	return ret;
+}
+
+static int mt9t031_remove(struct i2c_client *client)
+{
+	struct mt9t031 *mt9t031 = i2c_get_clientdata(client);
+
+	soc_camera_device_unregister(&mt9t031->icd);
+	i2c_set_clientdata(client, NULL);
+	kfree(mt9t031);
+
+	return 0;
+}
+
+static const struct i2c_device_id mt9t031_id[] = {
+	{ "mt9t031", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, mt9t031_id);
+
+static struct i2c_driver mt9t031_i2c_driver = {
+	.driver = {
+		.name = "mt9t031",
+	},
+	.probe		= mt9t031_probe,
+	.remove		= mt9t031_remove,
+	.id_table	= mt9t031_id,
+};
+
+static int __init mt9t031_mod_init(void)
+{
+	return i2c_add_driver(&mt9t031_i2c_driver);
+}
+
+static void __exit mt9t031_mod_exit(void)
+{
+	i2c_del_driver(&mt9t031_i2c_driver);
+}
+
+module_init(mt9t031_mod_init);
+module_exit(mt9t031_mod_exit);
+
+MODULE_DESCRIPTION("Micron MT9T031 Camera driver");
+MODULE_AUTHOR("Guennadi Liakhovetski <lg@denx.de>");
+MODULE_LICENSE("GPL v2");