mt9m001.c

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/*
 * Driver for MT9M001 CMOS Image Sensor from Micron
 *
 * Copyright (C) 2008, Guennadi Liakhovetski <[email protected]>
 *
 * 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 <linux/module.h>

#include <media/soc_camera.h>
#include <media/soc_mediabus.h>
#include <media/v4l2-subdev.h>
#include <media/v4l2-chip-ident.h>
#include <media/v4l2-ctrls.h>

/*
 * mt9m001 i2c address 0x5d
 * The platform has to define struct i2c_board_info objects and link to them
 * from struct soc_camera_link
 */

/* mt9m001 selected register addresses */
#define MT9M001_CHIP_VERSION        0x00
#define MT9M001_ROW_START       0x01
#define MT9M001_COLUMN_START        0x02
#define MT9M001_WINDOW_HEIGHT       0x03
#define MT9M001_WINDOW_WIDTH        0x04
#define MT9M001_HORIZONTAL_BLANKING 0x05
#define MT9M001_VERTICAL_BLANKING   0x06
#define MT9M001_OUTPUT_CONTROL      0x07
#define MT9M001_SHUTTER_WIDTH       0x09
#define MT9M001_FRAME_RESTART       0x0b
#define MT9M001_SHUTTER_DELAY       0x0c
#define MT9M001_RESET           0x0d
#define MT9M001_READ_OPTIONS1       0x1e
#define MT9M001_READ_OPTIONS2       0x20
#define MT9M001_GLOBAL_GAIN     0x35
#define MT9M001_CHIP_ENABLE     0xF1

#define MT9M001_MAX_WIDTH       1280
#define MT9M001_MAX_HEIGHT      1024
#define MT9M001_MIN_WIDTH       48
#define MT9M001_MIN_HEIGHT      32
#define MT9M001_COLUMN_SKIP     20
#define MT9M001_ROW_SKIP        12

/* MT9M001 has only one fixed colorspace per pixelcode */
struct mt9m001_datafmt {
    enum v4l2_mbus_pixelcode    code;
    enum v4l2_colorspace        colorspace;
};

/* Find a data format by a pixel code in an array */
static const struct mt9m001_datafmt *mt9m001_find_datafmt(
    enum v4l2_mbus_pixelcode code, const struct mt9m001_datafmt *fmt,
    int n)
{
    int i;
    for (i = 0; i < n; i++)
        if (fmt[i].code == code)
            return fmt + i;

    return NULL;
}

static const struct mt9m001_datafmt mt9m001_colour_fmts[] = {
    /*
     * Order important: first natively supported,
     * second supported with a GPIO extender
     */
    {V4L2_MBUS_FMT_SBGGR10_1X10, V4L2_COLORSPACE_SRGB},
    {V4L2_MBUS_FMT_SBGGR8_1X8, V4L2_COLORSPACE_SRGB},
};

static const struct mt9m001_datafmt mt9m001_monochrome_fmts[] = {
    /* Order important - see above */
    {V4L2_MBUS_FMT_Y10_1X10, V4L2_COLORSPACE_JPEG},
    {V4L2_MBUS_FMT_Y8_1X8, V4L2_COLORSPACE_JPEG},
};

struct mt9m001 {
    struct v4l2_subdev subdev;
    struct v4l2_ctrl_handler hdl;
    struct {
        /* exposure/auto-exposure cluster */
        struct v4l2_ctrl *autoexposure;
        struct v4l2_ctrl *exposure;
    };
    struct v4l2_rect rect;  /* Sensor window */
    const struct mt9m001_datafmt *fmt;
    const struct mt9m001_datafmt *fmts;
    int num_fmts;
    int model;  /* V4L2_IDENT_MT9M001* codes from v4l2-chip-ident.h */
    unsigned int total_h;
    unsigned short y_skip_top;  /* Lines to skip at the top */
};

static struct mt9m001 *to_mt9m001(const struct i2c_client *client)
{
    return container_of(i2c_get_clientdata(client), struct mt9m001, subdev);
}

static int reg_read(struct i2c_client *client, const u8 reg)
{
    return i2c_smbus_read_word_swapped(client, reg);
}

static int reg_write(struct i2c_client *client, const u8 reg,
             const u16 data)
{
    return i2c_smbus_write_word_swapped(client, reg, data);
}

static int reg_set(struct i2c_client *client, const u8 reg,
           const u16 data)
{
    int ret;

    ret = reg_read(client, reg);
    if (ret < 0)
        return ret;
    return reg_write(client, reg, ret | data);
}

static int reg_clear(struct i2c_client *client, const u8 reg,
             const u16 data)
{
    int ret;

    ret = reg_read(client, reg);
    if (ret < 0)
        return ret;
    return reg_write(client, reg, ret & ~data);
}

static int mt9m001_init(struct i2c_client *client)
{
    int ret;

    dev_dbg(&client->dev, "%s\n", __func__);

    /*
     * We don't know, whether platform provides reset, issue a soft reset
     * too. This returns all registers to their default values.
     */
    ret = reg_write(client, MT9M001_RESET, 1);
    if (!ret)
        ret = reg_write(client, MT9M001_RESET, 0);

    /* Disable chip, synchronous option update */
    if (!ret)
        ret = reg_write(client, MT9M001_OUTPUT_CONTROL, 0);

    return ret;
}

static int mt9m001_s_stream(struct v4l2_subdev *sd, int enable)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);

    /* Switch to master "normal" mode or stop sensor readout */
    if (reg_write(client, MT9M001_OUTPUT_CONTROL, enable ? 2 : 0) < 0)
        return -EIO;
    return 0;
}

static int mt9m001_s_crop(struct v4l2_subdev *sd, const struct v4l2_crop *a)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);
    struct mt9m001 *mt9m001 = to_mt9m001(client);
    struct v4l2_rect rect = a->c;
    int ret;
    const u16 hblank = 9, vblank = 25;

    if (mt9m001->fmts == mt9m001_colour_fmts)
        /*
         * Bayer format - even number of rows for simplicity,
         * but let the user play with the top row.
         */
        rect.height = ALIGN(rect.height, 2);

    /* Datasheet requirement: see register description */
    rect.width = ALIGN(rect.width, 2);
    rect.left = ALIGN(rect.left, 2);

    soc_camera_limit_side(&rect.left, &rect.width,
             MT9M001_COLUMN_SKIP, MT9M001_MIN_WIDTH, MT9M001_MAX_WIDTH);

    soc_camera_limit_side(&rect.top, &rect.height,
             MT9M001_ROW_SKIP, MT9M001_MIN_HEIGHT, MT9M001_MAX_HEIGHT);

    mt9m001->total_h = rect.height + mt9m001->y_skip_top + vblank;

    /* Blanking and start values - default... */
    ret = reg_write(client, MT9M001_HORIZONTAL_BLANKING, hblank);
    if (!ret)
        ret = reg_write(client, MT9M001_VERTICAL_BLANKING, vblank);

    /*
     * The caller provides a supported format, as verified per
     * call to .try_mbus_fmt()
     */
    if (!ret)
        ret = reg_write(client, MT9M001_COLUMN_START, rect.left);
    if (!ret)
        ret = reg_write(client, MT9M001_ROW_START, rect.top);
    if (!ret)
        ret = reg_write(client, MT9M001_WINDOW_WIDTH, rect.width - 1);
    if (!ret)
        ret = reg_write(client, MT9M001_WINDOW_HEIGHT,
                rect.height + mt9m001->y_skip_top - 1);
    if (!ret && v4l2_ctrl_g_ctrl(mt9m001->autoexposure) == V4L2_EXPOSURE_AUTO)
        ret = reg_write(client, MT9M001_SHUTTER_WIDTH, mt9m001->total_h);

    if (!ret)
        mt9m001->rect = rect;

    return ret;
}

static int mt9m001_g_crop(struct v4l2_subdev *sd, struct v4l2_crop *a)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);
    struct mt9m001 *mt9m001 = to_mt9m001(client);

    a->c    = mt9m001->rect;
    a->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

    return 0;
}

static int mt9m001_cropcap(struct v4l2_subdev *sd, struct v4l2_cropcap *a)
{
    a->bounds.left          = MT9M001_COLUMN_SKIP;
    a->bounds.top           = MT9M001_ROW_SKIP;
    a->bounds.width         = MT9M001_MAX_WIDTH;
    a->bounds.height        = MT9M001_MAX_HEIGHT;
    a->defrect          = a->bounds;
    a->type             = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    a->pixelaspect.numerator    = 1;
    a->pixelaspect.denominator  = 1;

    return 0;
}

static int mt9m001_g_fmt(struct v4l2_subdev *sd,
             struct v4l2_mbus_framefmt *mf)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);
    struct mt9m001 *mt9m001 = to_mt9m001(client);

    mf->width   = mt9m001->rect.width;
    mf->height  = mt9m001->rect.height;
    mf->code    = mt9m001->fmt->code;
    mf->colorspace  = mt9m001->fmt->colorspace;
    mf->field   = V4L2_FIELD_NONE;

    return 0;
}

static int mt9m001_s_fmt(struct v4l2_subdev *sd,
             struct v4l2_mbus_framefmt *mf)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);
    struct mt9m001 *mt9m001 = to_mt9m001(client);
    struct v4l2_crop a = {
        .c = {
            .left   = mt9m001->rect.left,
            .top    = mt9m001->rect.top,
            .width  = mf->width,
            .height = mf->height,
        },
    };
    int ret;

    /* No support for scaling so far, just crop. TODO: use skipping */
    ret = mt9m001_s_crop(sd, &a);
    if (!ret) {
        mf->width   = mt9m001->rect.width;
        mf->height  = mt9m001->rect.height;
        mt9m001->fmt    = mt9m001_find_datafmt(mf->code,
                    mt9m001->fmts, mt9m001->num_fmts);
        mf->colorspace  = mt9m001->fmt->colorspace;
    }

    return ret;
}

static int mt9m001_try_fmt(struct v4l2_subdev *sd,
               struct v4l2_mbus_framefmt *mf)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);
    struct mt9m001 *mt9m001 = to_mt9m001(client);
    const struct mt9m001_datafmt *fmt;

    v4l_bound_align_image(&mf->width, MT9M001_MIN_WIDTH,
        MT9M001_MAX_WIDTH, 1,
        &mf->height, MT9M001_MIN_HEIGHT + mt9m001->y_skip_top,
        MT9M001_MAX_HEIGHT + mt9m001->y_skip_top, 0, 0);

    if (mt9m001->fmts == mt9m001_colour_fmts)
        mf->height = ALIGN(mf->height - 1, 2);

    fmt = mt9m001_find_datafmt(mf->code, mt9m001->fmts,
                   mt9m001->num_fmts);
    if (!fmt) {
        fmt = mt9m001->fmt;
        mf->code = fmt->code;
    }

    mf->colorspace  = fmt->colorspace;

    return 0;
}

static int mt9m001_g_chip_ident(struct v4l2_subdev *sd,
                struct v4l2_dbg_chip_ident *id)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);
    struct mt9m001 *mt9m001 = to_mt9m001(client);

    if (id->match.type != V4L2_CHIP_MATCH_I2C_ADDR)
        return -EINVAL;

    if (id->match.addr != client->addr)
        return -ENODEV;

    id->ident   = mt9m001->model;
    id->revision    = 0;

    return 0;
}

#ifdef CONFIG_VIDEO_ADV_DEBUG
static int mt9m001_g_register(struct v4l2_subdev *sd,
                  struct v4l2_dbg_register *reg)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);

    if (reg->match.type != V4L2_CHIP_MATCH_I2C_ADDR || reg->reg > 0xff)
        return -EINVAL;

    if (reg->match.addr != client->addr)
        return -ENODEV;

    reg->size = 2;
    reg->val = reg_read(client, reg->reg);

    if (reg->val > 0xffff)
        return -EIO;

    return 0;
}

static int mt9m001_s_register(struct v4l2_subdev *sd,
                  struct v4l2_dbg_register *reg)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);

    if (reg->match.type != V4L2_CHIP_MATCH_I2C_ADDR || reg->reg > 0xff)
        return -EINVAL;

    if (reg->match.addr != client->addr)
        return -ENODEV;

    if (reg_write(client, reg->reg, reg->val) < 0)
        return -EIO;

    return 0;
}
#endif

static int mt9m001_s_power(struct v4l2_subdev *sd, int on)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);
    struct soc_camera_link *icl = soc_camera_i2c_to_link(client);

    return soc_camera_set_power(&client->dev, icl, on);
}

static int mt9m001_g_volatile_ctrl(struct v4l2_ctrl *ctrl)
{
    struct mt9m001 *mt9m001 = container_of(ctrl->handler,
                           struct mt9m001, hdl);
    s32 min, max;

    switch (ctrl->id) {
    case V4L2_CID_EXPOSURE_AUTO:
        min = mt9m001->exposure->minimum;
        max = mt9m001->exposure->maximum;
        mt9m001->exposure->val =
            (524 + (mt9m001->total_h - 1) * (max - min)) / 1048 + min;
        break;
    }
    return 0;
}

static int mt9m001_s_ctrl(struct v4l2_ctrl *ctrl)
{
    struct mt9m001 *mt9m001 = container_of(ctrl->handler,
                           struct mt9m001, hdl);
    struct v4l2_subdev *sd = &mt9m001->subdev;
    struct i2c_client *client = v4l2_get_subdevdata(sd);
    struct v4l2_ctrl *exp = mt9m001->exposure;
    int data;

    switch (ctrl->id) {
    case V4L2_CID_VFLIP:
        if (ctrl->val)
            data = reg_set(client, MT9M001_READ_OPTIONS2, 0x8000);
        else
            data = reg_clear(client, MT9M001_READ_OPTIONS2, 0x8000);
        if (data < 0)
            return -EIO;
        return 0;

    case V4L2_CID_GAIN:
        /* See Datasheet Table 7, Gain settings. */
        if (ctrl->val <= ctrl->default_value) {
            /* Pack it into 0..1 step 0.125, register values 0..8 */
            unsigned long range = ctrl->default_value - ctrl->minimum;
            data = ((ctrl->val - ctrl->minimum) * 8 + range / 2) / range;

            dev_dbg(&client->dev, "Setting gain %d\n", data);
            data = reg_write(client, MT9M001_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 = ctrl->maximum - ctrl->default_value - 1;
            unsigned long gain = ((ctrl->val - ctrl->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(&client->dev, "Setting gain from %d to %d\n",
                 reg_read(client, MT9M001_GLOBAL_GAIN), data);
            data = reg_write(client, MT9M001_GLOBAL_GAIN, data);
            if (data < 0)
                return -EIO;
        }
        return 0;

    case V4L2_CID_EXPOSURE_AUTO:
        if (ctrl->val == V4L2_EXPOSURE_MANUAL) {
            unsigned long range = exp->maximum - exp->minimum;
            unsigned long shutter = ((exp->val - exp->minimum) * 1048 +
                         range / 2) / range + 1;

            dev_dbg(&client->dev,
                "Setting shutter width from %d to %lu\n",
                reg_read(client, MT9M001_SHUTTER_WIDTH), shutter);
            if (reg_write(client, MT9M001_SHUTTER_WIDTH, shutter) < 0)
                return -EIO;
        } else {
            const u16 vblank = 25;

            mt9m001->total_h = mt9m001->rect.height +
                mt9m001->y_skip_top + vblank;
            if (reg_write(client, MT9M001_SHUTTER_WIDTH, mt9m001->total_h) < 0)
                return -EIO;
        }
        return 0;
    }
    return -EINVAL;
}

/*
 * 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 mt9m001_video_probe(struct soc_camera_link *icl,
                   struct i2c_client *client)
{
    struct mt9m001 *mt9m001 = to_mt9m001(client);
    s32 data;
    unsigned long flags;
    int ret;

    ret = mt9m001_s_power(&mt9m001->subdev, 1);
    if (ret < 0)
        return ret;

    /* Enable the chip */
    data = reg_write(client, MT9M001_CHIP_ENABLE, 1);
    dev_dbg(&client->dev, "write: %d\n", data);

    /* Read out the chip version register */
    data = reg_read(client, MT9M001_CHIP_VERSION);

    /* must be 0x8411 or 0x8421 for colour sensor and 8431 for bw */
    switch (data) {
    case 0x8411:
    case 0x8421:
        mt9m001->model = V4L2_IDENT_MT9M001C12ST;
        mt9m001->fmts = mt9m001_colour_fmts;
        break;
    case 0x8431:
        mt9m001->model = V4L2_IDENT_MT9M001C12STM;
        mt9m001->fmts = mt9m001_monochrome_fmts;
        break;
    default:
        dev_err(&client->dev,
            "No MT9M001 chip detected, register read %x\n", data);
        ret = -ENODEV;
        goto done;
    }

    mt9m001->num_fmts = 0;

    /*
     * This is a 10bit sensor, so by default we only allow 10bit.
     * The platform may support different bus widths due to
     * different routing of the data lines.
     */
    if (icl->query_bus_param)
        flags = icl->query_bus_param(icl);
    else
        flags = SOCAM_DATAWIDTH_10;

    if (flags & SOCAM_DATAWIDTH_10)
        mt9m001->num_fmts++;
    else
        mt9m001->fmts++;

    if (flags & SOCAM_DATAWIDTH_8)
        mt9m001->num_fmts++;

    mt9m001->fmt = &mt9m001->fmts[0];

    dev_info(&client->dev, "Detected a MT9M001 chip ID %x (%s)\n", data,
         data == 0x8431 ? "C12STM" : "C12ST");

    ret = mt9m001_init(client);
    if (ret < 0) {
        dev_err(&client->dev, "Failed to initialise the camera\n");
        goto done;
    }

    /* mt9m001_init() has reset the chip, returning registers to defaults */
    ret = v4l2_ctrl_handler_setup(&mt9m001->hdl);

done:
    mt9m001_s_power(&mt9m001->subdev, 0);
    return ret;
}

static void mt9m001_video_remove(struct soc_camera_link *icl)
{
    if (icl->free_bus)
        icl->free_bus(icl);
}

static int mt9m001_g_skip_top_lines(struct v4l2_subdev *sd, u32 *lines)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);
    struct mt9m001 *mt9m001 = to_mt9m001(client);

    *lines = mt9m001->y_skip_top;

    return 0;
}

static const struct v4l2_ctrl_ops mt9m001_ctrl_ops = {
    .g_volatile_ctrl = mt9m001_g_volatile_ctrl,
    .s_ctrl = mt9m001_s_ctrl,
};

static struct v4l2_subdev_core_ops mt9m001_subdev_core_ops = {
    .g_chip_ident   = mt9m001_g_chip_ident,
#ifdef CONFIG_VIDEO_ADV_DEBUG
    .g_register = mt9m001_g_register,
    .s_register = mt9m001_s_register,
#endif
    .s_power    = mt9m001_s_power,
};

static int mt9m001_enum_fmt(struct v4l2_subdev *sd, unsigned int index,
                enum v4l2_mbus_pixelcode *code)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);
    struct mt9m001 *mt9m001 = to_mt9m001(client);

    if (index >= mt9m001->num_fmts)
        return -EINVAL;

    *code = mt9m001->fmts[index].code;
    return 0;
}

static int mt9m001_g_mbus_config(struct v4l2_subdev *sd,
                struct v4l2_mbus_config *cfg)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);
    struct soc_camera_link *icl = soc_camera_i2c_to_link(client);

    /* MT9M001 has all capture_format parameters fixed */
    cfg->flags = V4L2_MBUS_PCLK_SAMPLE_FALLING |
        V4L2_MBUS_HSYNC_ACTIVE_HIGH | V4L2_MBUS_VSYNC_ACTIVE_HIGH |
        V4L2_MBUS_DATA_ACTIVE_HIGH | V4L2_MBUS_MASTER;
    cfg->type = V4L2_MBUS_PARALLEL;
    cfg->flags = soc_camera_apply_board_flags(icl, cfg);

    return 0;
}

static int mt9m001_s_mbus_config(struct v4l2_subdev *sd,
                const struct v4l2_mbus_config *cfg)
{
    const struct i2c_client *client = v4l2_get_subdevdata(sd);
    struct soc_camera_link *icl = soc_camera_i2c_to_link(client);
    struct mt9m001 *mt9m001 = to_mt9m001(client);
    unsigned int bps = soc_mbus_get_fmtdesc(mt9m001->fmt->code)->bits_per_sample;

    if (icl->set_bus_param)
        return icl->set_bus_param(icl, 1 << (bps - 1));

    /*
     * Without board specific bus width settings we only support the
     * sensors native bus width
     */
    return bps == 10 ? 0 : -EINVAL;
}

static struct v4l2_subdev_video_ops mt9m001_subdev_video_ops = {
    .s_stream   = mt9m001_s_stream,
    .s_mbus_fmt = mt9m001_s_fmt,
    .g_mbus_fmt = mt9m001_g_fmt,
    .try_mbus_fmt   = mt9m001_try_fmt,
    .s_crop     = mt9m001_s_crop,
    .g_crop     = mt9m001_g_crop,
    .cropcap    = mt9m001_cropcap,
    .enum_mbus_fmt  = mt9m001_enum_fmt,
    .g_mbus_config  = mt9m001_g_mbus_config,
    .s_mbus_config  = mt9m001_s_mbus_config,
};

static struct v4l2_subdev_sensor_ops mt9m001_subdev_sensor_ops = {
    .g_skip_top_lines   = mt9m001_g_skip_top_lines,
};

static struct v4l2_subdev_ops mt9m001_subdev_ops = {
    .core   = &mt9m001_subdev_core_ops,
    .video  = &mt9m001_subdev_video_ops,
    .sensor = &mt9m001_subdev_sensor_ops,
};

static int mt9m001_probe(struct i2c_client *client,
             const struct i2c_device_id *did)
{
    struct mt9m001 *mt9m001;
    struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
    struct soc_camera_link *icl = soc_camera_i2c_to_link(client);
    int ret;

    if (!icl) {
        dev_err(&client->dev, "MT9M001 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;
    }

    mt9m001 = kzalloc(sizeof(struct mt9m001), GFP_KERNEL);
    if (!mt9m001)
        return -ENOMEM;

    v4l2_i2c_subdev_init(&mt9m001->subdev, client, &mt9m001_subdev_ops);
    v4l2_ctrl_handler_init(&mt9m001->hdl, 4);
    v4l2_ctrl_new_std(&mt9m001->hdl, &mt9m001_ctrl_ops,
            V4L2_CID_VFLIP, 0, 1, 1, 0);
    v4l2_ctrl_new_std(&mt9m001->hdl, &mt9m001_ctrl_ops,
            V4L2_CID_GAIN, 0, 127, 1, 64);
    mt9m001->exposure = v4l2_ctrl_new_std(&mt9m001->hdl, &mt9m001_ctrl_ops,
            V4L2_CID_EXPOSURE, 1, 255, 1, 255);
    /*
     * Simulated autoexposure. If enabled, we calculate shutter width
     * ourselves in the driver based on vertical blanking and frame width
     */
    mt9m001->autoexposure = v4l2_ctrl_new_std_menu(&mt9m001->hdl,
            &mt9m001_ctrl_ops, V4L2_CID_EXPOSURE_AUTO, 1, 0,
            V4L2_EXPOSURE_AUTO);
    mt9m001->subdev.ctrl_handler = &mt9m001->hdl;
    if (mt9m001->hdl.error) {
        int err = mt9m001->hdl.error;

        kfree(mt9m001);
        return err;
    }
    v4l2_ctrl_auto_cluster(2, &mt9m001->autoexposure,
                    V4L2_EXPOSURE_MANUAL, true);

    /* Second stage probe - when a capture adapter is there */
    mt9m001->y_skip_top = 0;
    mt9m001->rect.left  = MT9M001_COLUMN_SKIP;
    mt9m001->rect.top   = MT9M001_ROW_SKIP;
    mt9m001->rect.width = MT9M001_MAX_WIDTH;
    mt9m001->rect.height    = MT9M001_MAX_HEIGHT;

    ret = mt9m001_video_probe(icl, client);
    if (ret) {
        v4l2_ctrl_handler_free(&mt9m001->hdl);
        kfree(mt9m001);
    }

    return ret;
}

static int mt9m001_remove(struct i2c_client *client)
{
    struct mt9m001 *mt9m001 = to_mt9m001(client);
    struct soc_camera_link *icl = soc_camera_i2c_to_link(client);

    v4l2_device_unregister_subdev(&mt9m001->subdev);
    v4l2_ctrl_handler_free(&mt9m001->hdl);
    mt9m001_video_remove(icl);
    kfree(mt9m001);

    return 0;
}

static const struct i2c_device_id mt9m001_id[] = {
    { "mt9m001", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, mt9m001_id);

static struct i2c_driver mt9m001_i2c_driver = {
    .driver = {
        .name = "mt9m001",
    },
    .probe      = mt9m001_probe,
    .remove     = mt9m001_remove,
    .id_table   = mt9m001_id,
};

module_i2c_driver(mt9m001_i2c_driver);

MODULE_DESCRIPTION("Micron MT9M001 Camera driver");
MODULE_AUTHOR("Guennadi Liakhovetski <[email protected]>");
MODULE_LICENSE("GPL");