// SPDX-License-Identifier: GPL-2.0
/*
 * Driver for MT9M001 CMOS Image Sensor from Micron
 *
 * Copyright (C) 2008, Guennadi Liakhovetski <kernel@pengutronix.de>
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/log2.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/videodev2.h>

#include <media/v4l2-ctrls.h>
#include <media/v4l2-device.h>
#include <media/v4l2-event.h>
#include <media/v4l2-subdev.h>

/*
 * mt9m001 i2c address 0x5d
 */

/* 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
#define MT9M001_DEFAULT_HBLANK          9
#define MT9M001_DEFAULT_VBLANK          25

/* MT9M001 has only one fixed colorspace per pixelcode */
struct mt9m001_datafmt {
        u32     code;
        enum v4l2_colorspace            colorspace;
};

/* Find a data format by a pixel code in an array */
static const struct mt9m001_datafmt *mt9m001_find_datafmt(
        u32 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
         */
        {MEDIA_BUS_FMT_SBGGR10_1X10, V4L2_COLORSPACE_SRGB},
        {MEDIA_BUS_FMT_SBGGR8_1X8, V4L2_COLORSPACE_SRGB},
};

static const struct mt9m001_datafmt mt9m001_monochrome_fmts[] = {
        /* Order important - see above */
        {MEDIA_BUS_FMT_Y10_1X10, V4L2_COLORSPACE_JPEG},
        {MEDIA_BUS_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 mutex mutex;
        struct v4l2_rect rect;  /* Sensor window */
        struct clk *clk;
        struct gpio_desc *standby_gpio;
        struct gpio_desc *reset_gpio;
        const struct mt9m001_datafmt *fmt;
        const struct mt9m001_datafmt *fmts;
        int num_fmts;
        unsigned int total_h;
        unsigned short y_skip_top;      /* Lines to skip at the top */
        struct media_pad pad;
};

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);
}

struct mt9m001_reg {
        u8 reg;
        u16 data;
};

static int multi_reg_write(struct i2c_client *client,
                           const struct mt9m001_reg *regs, int num)
{
        int i;

        for (i = 0; i < num; i++) {
                int ret = reg_write(client, regs[i].reg, regs[i].data);

                if (ret)
                        return ret;
        }

        return 0;
}

static int mt9m001_init(struct i2c_client *client)
{
        static const struct mt9m001_reg init_regs[] = {
                /*
                 * Issue a soft reset. This returns all registers to their
                 * default values.
                 */
                { MT9M001_RESET, 1 },
                { MT9M001_RESET, 0 },
                /* Disable chip, synchronous option update */
                { MT9M001_OUTPUT_CONTROL, 0 }
        };

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

        return multi_reg_write(client, init_regs, ARRAY_SIZE(init_regs));
}

static int mt9m001_apply_selection(struct v4l2_subdev *sd)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9m001 *mt9m001 = to_mt9m001(client);
        const struct mt9m001_reg regs[] = {
                /* Blanking and start values - default... */
                { MT9M001_HORIZONTAL_BLANKING, MT9M001_DEFAULT_HBLANK },
                { MT9M001_VERTICAL_BLANKING, MT9M001_DEFAULT_VBLANK },
                /*
                 * The caller provides a supported format, as verified per
                 * call to .set_fmt(FORMAT_TRY).
                 */
                { MT9M001_COLUMN_START, mt9m001->rect.left },
                { MT9M001_ROW_START, mt9m001->rect.top },
                { MT9M001_WINDOW_WIDTH, mt9m001->rect.width - 1 },
                { MT9M001_WINDOW_HEIGHT,
                        mt9m001->rect.height + mt9m001->y_skip_top - 1 },
        };

        return multi_reg_write(client, regs, ARRAY_SIZE(regs));
}

static int mt9m001_s_stream(struct v4l2_subdev *sd, int enable)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9m001 *mt9m001 = to_mt9m001(client);
        int ret = 0;

        mutex_lock(&mt9m001->mutex);

        if (enable) {
                ret = pm_runtime_resume_and_get(&client->dev);
                if (ret < 0)
                        goto unlock;

                ret = mt9m001_apply_selection(sd);
                if (ret)
                        goto put_unlock;

                ret = __v4l2_ctrl_handler_setup(&mt9m001->hdl);
                if (ret)
                        goto put_unlock;

                /* Switch to master "normal" mode */
                ret = reg_write(client, MT9M001_OUTPUT_CONTROL, 2);
                if (ret < 0)
                        goto put_unlock;
        } else {
                /* Switch to master stop sensor readout */
                reg_write(client, MT9M001_OUTPUT_CONTROL, 0);
                pm_runtime_put(&client->dev);
        }

        mutex_unlock(&mt9m001->mutex);

        return 0;

put_unlock:
        pm_runtime_put(&client->dev);
unlock:
        mutex_unlock(&mt9m001->mutex);

        return ret;
}

static int mt9m001_set_selection(struct v4l2_subdev *sd,
                struct v4l2_subdev_state *sd_state,
                struct v4l2_subdev_selection *sel)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9m001 *mt9m001 = to_mt9m001(client);
        struct v4l2_rect rect = sel->r;

        if (sel->which != V4L2_SUBDEV_FORMAT_ACTIVE ||
            sel->target != V4L2_SEL_TGT_CROP)
                return -EINVAL;

        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);

        rect.width = clamp_t(u32, rect.width, MT9M001_MIN_WIDTH,
                        MT9M001_MAX_WIDTH);
        rect.left = clamp_t(u32, rect.left, MT9M001_COLUMN_SKIP,
                        MT9M001_COLUMN_SKIP + MT9M001_MAX_WIDTH - rect.width);

        rect.height = clamp_t(u32, rect.height, MT9M001_MIN_HEIGHT,
                        MT9M001_MAX_HEIGHT);
        rect.top = clamp_t(u32, rect.top, MT9M001_ROW_SKIP,
                        MT9M001_ROW_SKIP + MT9M001_MAX_HEIGHT - rect.height);

        mt9m001->total_h = rect.height + mt9m001->y_skip_top +
                           MT9M001_DEFAULT_VBLANK;

        mt9m001->rect = rect;

        return 0;
}

static int mt9m001_get_selection(struct v4l2_subdev *sd,
                struct v4l2_subdev_state *sd_state,
                struct v4l2_subdev_selection *sel)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9m001 *mt9m001 = to_mt9m001(client);

        if (sel->which != V4L2_SUBDEV_FORMAT_ACTIVE)
                return -EINVAL;

        switch (sel->target) {
        case V4L2_SEL_TGT_CROP_BOUNDS:
                sel->r.left = MT9M001_COLUMN_SKIP;
                sel->r.top = MT9M001_ROW_SKIP;
                sel->r.width = MT9M001_MAX_WIDTH;
                sel->r.height = MT9M001_MAX_HEIGHT;
                return 0;
        case V4L2_SEL_TGT_CROP:
                sel->r = mt9m001->rect;
                return 0;
        default:
                return -EINVAL;
        }
}

static int mt9m001_get_fmt(struct v4l2_subdev *sd,
                struct v4l2_subdev_state *sd_state,
                struct v4l2_subdev_format *format)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9m001 *mt9m001 = to_mt9m001(client);
        struct v4l2_mbus_framefmt *mf = &format->format;

        if (format->pad)
                return -EINVAL;

        if (format->which == V4L2_SUBDEV_FORMAT_TRY) {
                mf = v4l2_subdev_state_get_format(sd_state, 0);
                format->format = *mf;
                return 0;
        }

        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;
        mf->ycbcr_enc   = V4L2_YCBCR_ENC_DEFAULT;
        mf->quantization = V4L2_QUANTIZATION_DEFAULT;
        mf->xfer_func   = V4L2_XFER_FUNC_DEFAULT;

        return 0;
}

static int mt9m001_s_fmt(struct v4l2_subdev *sd,
                         const struct mt9m001_datafmt *fmt,
                         struct v4l2_mbus_framefmt *mf)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9m001 *mt9m001 = to_mt9m001(client);
        struct v4l2_subdev_selection sel = {
                .which = V4L2_SUBDEV_FORMAT_ACTIVE,
                .target = V4L2_SEL_TGT_CROP,
                .r.left = mt9m001->rect.left,
                .r.top = mt9m001->rect.top,
                .r.width = mf->width,
                .r.height = mf->height,
        };
        int ret;

        /* No support for scaling so far, just crop. TODO: use skipping */
        ret = mt9m001_set_selection(sd, NULL, &sel);
        if (!ret) {
                mf->width       = mt9m001->rect.width;
                mf->height      = mt9m001->rect.height;
                mt9m001->fmt    = fmt;
                mf->colorspace  = fmt->colorspace;
        }

        return ret;
}

static int mt9m001_set_fmt(struct v4l2_subdev *sd,
                struct v4l2_subdev_state *sd_state,
                struct v4l2_subdev_format *format)
{
        struct v4l2_mbus_framefmt *mf = &format->format;
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9m001 *mt9m001 = to_mt9m001(client);
        const struct mt9m001_datafmt *fmt;

        if (format->pad)
                return -EINVAL;

        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;
        mf->field       = V4L2_FIELD_NONE;
        mf->ycbcr_enc   = V4L2_YCBCR_ENC_DEFAULT;
        mf->quantization = V4L2_QUANTIZATION_DEFAULT;
        mf->xfer_func   = V4L2_XFER_FUNC_DEFAULT;

        if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE)
                return mt9m001_s_fmt(sd, fmt, mf);
        *v4l2_subdev_state_get_format(sd_state, 0) = *mf;
        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->reg > 0xff)
                return -EINVAL;

        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,
                              const struct v4l2_dbg_register *reg)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);

        if (reg->reg > 0xff)
                return -EINVAL;

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

        return 0;
}
#endif

static int mt9m001_power_on(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct mt9m001 *mt9m001 = to_mt9m001(client);
        int ret;

        ret = clk_prepare_enable(mt9m001->clk);
        if (ret)
                return ret;

        if (mt9m001->standby_gpio) {
                gpiod_set_value_cansleep(mt9m001->standby_gpio, 0);
                usleep_range(1000, 2000);
        }

        if (mt9m001->reset_gpio) {
                gpiod_set_value_cansleep(mt9m001->reset_gpio, 1);
                usleep_range(1000, 2000);
                gpiod_set_value_cansleep(mt9m001->reset_gpio, 0);
                usleep_range(1000, 2000);
        }

        return 0;
}

static int mt9m001_power_off(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct mt9m001 *mt9m001 = to_mt9m001(client);

        gpiod_set_value_cansleep(mt9m001->standby_gpio, 1);
        clk_disable_unprepare(mt9m001->clk);

        return 0;
}

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;
        int ret;

        if (!pm_runtime_get_if_in_use(&client->dev))
                return 0;

        switch (ctrl->id) {
        case V4L2_CID_VFLIP:
                if (ctrl->val)
                        ret = reg_set(client, MT9M001_READ_OPTIONS2, 0x8000);
                else
                        ret = reg_clear(client, MT9M001_READ_OPTIONS2, 0x8000);
                break;

        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 - (s32)ctrl->minimum) * 8 + range / 2) / range;

                        dev_dbg(&client->dev, "Setting gain %d\n", data);
                        ret = reg_write(client, MT9M001_GLOBAL_GAIN, data);
                } 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 - (s32)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);
                        ret = reg_write(client, MT9M001_GLOBAL_GAIN, data);
                }
                break;

        case V4L2_CID_EXPOSURE_AUTO:
                if (ctrl->val == V4L2_EXPOSURE_MANUAL) {
                        unsigned long range = exp->maximum - exp->minimum;
                        unsigned long shutter = ((exp->val - (s32)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);
                        ret = reg_write(client, MT9M001_SHUTTER_WIDTH, shutter);
                } else {
                        mt9m001->total_h = mt9m001->rect.height +
                                mt9m001->y_skip_top + MT9M001_DEFAULT_VBLANK;
                        ret = reg_write(client, MT9M001_SHUTTER_WIDTH,
                                        mt9m001->total_h);
                }
                break;
        default:
                ret = -EINVAL;
                break;
        }

        pm_runtime_put(&client->dev);

        return ret;
}

/*
 * 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 i2c_client *client)
{
        struct mt9m001 *mt9m001 = to_mt9m001(client);
        s32 data;
        int 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->fmts = mt9m001_colour_fmts;
                mt9m001->num_fmts = ARRAY_SIZE(mt9m001_colour_fmts);
                break;
        case 0x8431:
                mt9m001->fmts = mt9m001_monochrome_fmts;
                mt9m001->num_fmts = ARRAY_SIZE(mt9m001_monochrome_fmts);
                break;
        default:
                dev_err(&client->dev,
                        "No MT9M001 chip detected, register read %x\n", data);
                ret = -ENODEV;
                goto done;
        }

        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:
        return ret;
}

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 const struct v4l2_subdev_core_ops mt9m001_subdev_core_ops = {
        .log_status = v4l2_ctrl_subdev_log_status,
        .subscribe_event = v4l2_ctrl_subdev_subscribe_event,
        .unsubscribe_event = v4l2_event_subdev_unsubscribe,
#ifdef CONFIG_VIDEO_ADV_DEBUG
        .g_register     = mt9m001_g_register,
        .s_register     = mt9m001_s_register,
#endif
};

static int mt9m001_init_state(struct v4l2_subdev *sd,
                              struct v4l2_subdev_state *sd_state)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9m001 *mt9m001 = to_mt9m001(client);
        struct v4l2_mbus_framefmt *try_fmt =
                v4l2_subdev_state_get_format(sd_state, 0);

        try_fmt->width          = MT9M001_MAX_WIDTH;
        try_fmt->height         = MT9M001_MAX_HEIGHT;
        try_fmt->code           = mt9m001->fmts[0].code;
        try_fmt->colorspace     = mt9m001->fmts[0].colorspace;
        try_fmt->field          = V4L2_FIELD_NONE;
        try_fmt->ycbcr_enc      = V4L2_YCBCR_ENC_DEFAULT;
        try_fmt->quantization   = V4L2_QUANTIZATION_DEFAULT;
        try_fmt->xfer_func      = V4L2_XFER_FUNC_DEFAULT;

        return 0;
}

static int mt9m001_enum_mbus_code(struct v4l2_subdev *sd,
                struct v4l2_subdev_state *sd_state,
                struct v4l2_subdev_mbus_code_enum *code)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9m001 *mt9m001 = to_mt9m001(client);

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

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

static int mt9m001_get_mbus_config(struct v4l2_subdev *sd,
                                   unsigned int pad,
                                   struct v4l2_mbus_config *cfg)
{
        /* MT9M001 has all capture_format parameters fixed */
        cfg->type = V4L2_MBUS_PARALLEL;
        cfg->bus.parallel.flags = V4L2_MBUS_PCLK_SAMPLE_FALLING |
                                  V4L2_MBUS_HSYNC_ACTIVE_HIGH |
                                  V4L2_MBUS_VSYNC_ACTIVE_HIGH |
                                  V4L2_MBUS_DATA_ACTIVE_HIGH |
                                  V4L2_MBUS_MASTER;

        return 0;
}

static const struct v4l2_subdev_video_ops mt9m001_subdev_video_ops = {
        .s_stream       = mt9m001_s_stream,
};

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

static const struct v4l2_subdev_pad_ops mt9m001_subdev_pad_ops = {
        .enum_mbus_code = mt9m001_enum_mbus_code,
        .get_selection  = mt9m001_get_selection,
        .set_selection  = mt9m001_set_selection,
        .get_fmt        = mt9m001_get_fmt,
        .set_fmt        = mt9m001_set_fmt,
        .get_mbus_config = mt9m001_get_mbus_config,
};

static const struct v4l2_subdev_ops mt9m001_subdev_ops = {
        .core   = &mt9m001_subdev_core_ops,
        .video  = &mt9m001_subdev_video_ops,
        .sensor = &mt9m001_subdev_sensor_ops,
        .pad    = &mt9m001_subdev_pad_ops,
};

static const struct v4l2_subdev_internal_ops mt9m001_internal_ops = {
        .init_state     = mt9m001_init_state,
};

static int mt9m001_probe(struct i2c_client *client)
{
        struct mt9m001 *mt9m001;
        struct i2c_adapter *adapter = client->adapter;
        int ret;

        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 = devm_kzalloc(&client->dev, sizeof(*mt9m001), GFP_KERNEL);
        if (!mt9m001)
                return -ENOMEM;

        mt9m001->clk = devm_v4l2_sensor_clk_get(&client->dev, NULL);
        if (IS_ERR(mt9m001->clk))
                return dev_err_probe(&client->dev, PTR_ERR(mt9m001->clk),
                                     "failed to get the clock\n");

        mt9m001->standby_gpio = devm_gpiod_get_optional(&client->dev, "standby",
                                                        GPIOD_OUT_LOW);
        if (IS_ERR(mt9m001->standby_gpio))
                return PTR_ERR(mt9m001->standby_gpio);

        mt9m001->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
                                                      GPIOD_OUT_LOW);
        if (IS_ERR(mt9m001->reset_gpio))
                return PTR_ERR(mt9m001->reset_gpio);

        v4l2_i2c_subdev_init(&mt9m001->subdev, client, &mt9m001_subdev_ops);
        mt9m001->subdev.internal_ops = &mt9m001_internal_ops;
        mt9m001->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE |
                                 V4L2_SUBDEV_FL_HAS_EVENTS;
        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)
                return mt9m001->hdl.error;

        v4l2_ctrl_auto_cluster(2, &mt9m001->autoexposure,
                                        V4L2_EXPOSURE_MANUAL, true);

        mutex_init(&mt9m001->mutex);
        mt9m001->hdl.lock = &mt9m001->mutex;

        /* 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_power_on(&client->dev);
        if (ret)
                goto error_hdl_free;

        pm_runtime_set_active(&client->dev);
        pm_runtime_enable(&client->dev);

        ret = mt9m001_video_probe(client);
        if (ret)
                goto error_power_off;

        mt9m001->pad.flags = MEDIA_PAD_FL_SOURCE;
        mt9m001->subdev.entity.function = MEDIA_ENT_F_CAM_SENSOR;
        ret = media_entity_pads_init(&mt9m001->subdev.entity, 1, &mt9m001->pad);
        if (ret)
                goto error_power_off;

        ret = v4l2_async_register_subdev(&mt9m001->subdev);
        if (ret)
                goto error_entity_cleanup;

        pm_runtime_idle(&client->dev);

        return 0;

error_entity_cleanup:
        media_entity_cleanup(&mt9m001->subdev.entity);
error_power_off:
        pm_runtime_disable(&client->dev);
        pm_runtime_set_suspended(&client->dev);
        mt9m001_power_off(&client->dev);

error_hdl_free:
        v4l2_ctrl_handler_free(&mt9m001->hdl);
        mutex_destroy(&mt9m001->mutex);

        return ret;
}

static void mt9m001_remove(struct i2c_client *client)
{
        struct mt9m001 *mt9m001 = to_mt9m001(client);

        /*
         * As it increments RPM usage_count even on errors, we don't need to
         * check the returned code here.
         */
        pm_runtime_get_sync(&client->dev);

        v4l2_async_unregister_subdev(&mt9m001->subdev);
        media_entity_cleanup(&mt9m001->subdev.entity);

        pm_runtime_disable(&client->dev);
        pm_runtime_set_suspended(&client->dev);
        pm_runtime_put_noidle(&client->dev);
        mt9m001_power_off(&client->dev);

        v4l2_ctrl_handler_free(&mt9m001->hdl);
        mutex_destroy(&mt9m001->mutex);
}

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

static const struct dev_pm_ops mt9m001_pm_ops = {
        SET_RUNTIME_PM_OPS(mt9m001_power_off, mt9m001_power_on, NULL)
};

static const struct of_device_id mt9m001_of_match[] = {
        { .compatible = "onnn,mt9m001", },
        { /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, mt9m001_of_match);

static struct i2c_driver mt9m001_i2c_driver = {
        .driver = {
                .name = "mt9m001",
                .pm = &mt9m001_pm_ops,
                .of_match_table = mt9m001_of_match,
        },
        .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 <kernel@pengutronix.de>");
MODULE_LICENSE("GPL v2");