root/drivers/media/i2c/ov7740.c
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2017 Microchip Corporation.

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <media/v4l2-ctrls.h>
#include <media/v4l2-event.h>
#include <media/v4l2-image-sizes.h>
#include <media/v4l2-subdev.h>

#define REG_OUTSIZE_LSB 0x34

/* OV7740 register tables */
#define REG_GAIN        0x00    /* Gain lower 8 bits (rest in vref) */
#define REG_BGAIN       0x01    /* blue gain */
#define REG_RGAIN       0x02    /* red gain */
#define REG_GGAIN       0x03    /* green gain */
#define REG_REG04       0x04    /* analog setting, don't change*/
#define REG_BAVG        0x05    /* b channel average */
#define REG_GAVG        0x06    /* g channel average */
#define REG_RAVG        0x07    /* r channel average */

#define REG_REG0C       0x0C    /* filp enable */
#define REG0C_IMG_FLIP          0x80
#define REG0C_IMG_MIRROR        0x40

#define REG_REG0E       0x0E    /* blc line */
#define REG_HAEC        0x0F    /* auto exposure cntrl */
#define REG_AEC         0x10    /* auto exposure cntrl */

#define REG_CLK         0x11    /* Clock control */
#define REG_REG55       0x55    /* Clock PLL DIV/PreDiv */

#define REG_REG12       0x12

#define REG_REG13       0x13    /* auto/manual AGC, AEC, Write Balance*/
#define REG13_AEC_EN    0x01
#define REG13_AGC_EN    0x04

#define REG_REG14       0x14
#define REG_CTRL15      0x15
#define REG15_GAIN_MSB  0x03

#define REG_REG16       0x16

#define REG_MIDH        0x1C    /* manufacture id byte */
#define REG_MIDL        0x1D    /* manufacture id byre */
#define REG_PIDH        0x0A    /* Product ID MSB */
#define REG_PIDL        0x0B    /* Product ID LSB */

#define REG_84          0x84    /* lots of stuff */
#define REG_REG38       0x38    /* sub-addr */

#define REG_AHSTART     0x17    /* Horiz start high bits */
#define REG_AHSIZE      0x18
#define REG_AVSTART     0x19    /* Vert start high bits */
#define REG_AVSIZE      0x1A
#define REG_PSHFT       0x1b    /* Pixel delay after HREF */

#define REG_HOUTSIZE    0x31
#define REG_VOUTSIZE    0x32
#define REG_HVSIZEOFF   0x33
#define REG_REG34       0x34    /* DSP output size H/V LSB*/

#define REG_ISP_CTRL00  0x80
#define ISPCTRL00_AWB_EN        0x10
#define ISPCTRL00_AWB_GAIN_EN   0x04

#define REG_YGAIN       0xE2    /* ygain for contrast control */

#define REG_YBRIGHT       0xE3
#define REG_SGNSET        0xE4
#define SGNSET_YBRIGHT_MASK       0x08

#define REG_USAT        0xDD
#define REG_VSAT        0xDE


struct ov7740 {
        struct v4l2_subdev subdev;
        struct media_pad pad;
        struct v4l2_mbus_framefmt format;
        const struct ov7740_pixfmt *fmt;  /* Current format */
        const struct ov7740_framesize *frmsize;
        struct regmap *regmap;
        struct clk *xvclk;
        struct v4l2_ctrl_handler ctrl_handler;
        struct {
                /* gain cluster */
                struct v4l2_ctrl *auto_gain;
                struct v4l2_ctrl *gain;
        };
        struct {
                struct v4l2_ctrl *auto_wb;
                struct v4l2_ctrl *blue_balance;
                struct v4l2_ctrl *red_balance;
        };
        struct {
                struct v4l2_ctrl *hflip;
                struct v4l2_ctrl *vflip;
        };
        struct {
                /* exposure cluster */
                struct v4l2_ctrl *auto_exposure;
                struct v4l2_ctrl *exposure;
        };
        struct {
                /* saturation/hue cluster */
                struct v4l2_ctrl *saturation;
                struct v4l2_ctrl *hue;
        };
        struct v4l2_ctrl *brightness;
        struct v4l2_ctrl *contrast;

        struct mutex mutex;     /* To serialize asynchronous callbacks */

        struct gpio_desc *resetb_gpio;
        struct gpio_desc *pwdn_gpio;
};

struct ov7740_pixfmt {
        u32 mbus_code;
        enum v4l2_colorspace colorspace;
        const struct reg_sequence *regs;
        u32 reg_num;
};

struct ov7740_framesize {
        u16 width;
        u16 height;
        const struct reg_sequence *regs;
        u32 reg_num;
};

static const struct reg_sequence ov7740_vga[] = {
        {0x55, 0x40},
        {0x11, 0x02},

        {0xd5, 0x10},
        {0x0c, 0x12},
        {0x0d, 0x34},
        {0x17, 0x25},
        {0x18, 0xa0},
        {0x19, 0x03},
        {0x1a, 0xf0},
        {0x1b, 0x89},
        {0x22, 0x03},
        {0x29, 0x18},
        {0x2b, 0xf8},
        {0x2c, 0x01},
        {REG_HOUTSIZE, 0xa0},
        {REG_VOUTSIZE, 0xf0},
        {0x33, 0xc4},
        {REG_OUTSIZE_LSB, 0x0},
        {0x35, 0x05},
        {0x04, 0x60},
        {0x27, 0x80},
        {0x3d, 0x0f},
        {0x3e, 0x80},
        {0x3f, 0x40},
        {0x40, 0x7f},
        {0x41, 0x6a},
        {0x42, 0x29},
        {0x44, 0x22},
        {0x45, 0x41},
        {0x47, 0x02},
        {0x49, 0x64},
        {0x4a, 0xa1},
        {0x4b, 0x40},
        {0x4c, 0x1a},
        {0x4d, 0x50},
        {0x4e, 0x13},
        {0x64, 0x00},
        {0x67, 0x88},
        {0x68, 0x1a},

        {0x14, 0x28},
        {0x24, 0x3c},
        {0x25, 0x30},
        {0x26, 0x72},
        {0x50, 0x97},
        {0x51, 0x1f},
        {0x52, 0x00},
        {0x53, 0x00},
        {0x20, 0x00},
        {0x21, 0xcf},
        {0x50, 0x4b},
        {0x38, 0x14},
        {0xe9, 0x00},
        {0x56, 0x55},
        {0x57, 0xff},
        {0x58, 0xff},
        {0x59, 0xff},
        {0x5f, 0x04},
        {0xec, 0x00},
        {0x13, 0xff},

        {0x81, 0x3f},
        {0x82, 0x32},
        {0x38, 0x11},
        {0x84, 0x70},
        {0x85, 0x00},
        {0x86, 0x03},
        {0x87, 0x01},
        {0x88, 0x05},
        {0x89, 0x30},
        {0x8d, 0x30},
        {0x8f, 0x85},
        {0x93, 0x30},
        {0x95, 0x85},
        {0x99, 0x30},
        {0x9b, 0x85},

        {0x9c, 0x08},
        {0x9d, 0x12},
        {0x9e, 0x23},
        {0x9f, 0x45},
        {0xa0, 0x55},
        {0xa1, 0x64},
        {0xa2, 0x72},
        {0xa3, 0x7f},
        {0xa4, 0x8b},
        {0xa5, 0x95},
        {0xa6, 0xa7},
        {0xa7, 0xb5},
        {0xa8, 0xcb},
        {0xa9, 0xdd},
        {0xaa, 0xec},
        {0xab, 0x1a},

        {0xce, 0x78},
        {0xcf, 0x6e},
        {0xd0, 0x0a},
        {0xd1, 0x0c},
        {0xd2, 0x84},
        {0xd3, 0x90},
        {0xd4, 0x1e},

        {0x5a, 0x24},
        {0x5b, 0x1f},
        {0x5c, 0x88},
        {0x5d, 0x60},

        {0xac, 0x6e},
        {0xbe, 0xff},
        {0xbf, 0x00},

        {0x0f, 0x1d},
        {0x0f, 0x1f},
};

static const struct ov7740_framesize ov7740_framesizes[] = {
        {
                .width          = VGA_WIDTH,
                .height         = VGA_HEIGHT,
                .regs           = ov7740_vga,
                .reg_num        = ARRAY_SIZE(ov7740_vga),
        },
};

#ifdef CONFIG_VIDEO_ADV_DEBUG
static int ov7740_get_register(struct v4l2_subdev *sd,
                               struct v4l2_dbg_register *reg)
{
        struct ov7740 *ov7740 = container_of(sd, struct ov7740, subdev);
        struct regmap *regmap = ov7740->regmap;
        unsigned int val = 0;
        int ret;

        ret = regmap_read(regmap, reg->reg & 0xff, &val);
        reg->val = val;
        reg->size = 1;

        return ret;
}

static int ov7740_set_register(struct v4l2_subdev *sd,
                               const struct v4l2_dbg_register *reg)
{
        struct ov7740 *ov7740 = container_of(sd, struct ov7740, subdev);
        struct regmap *regmap = ov7740->regmap;

        regmap_write(regmap, reg->reg & 0xff, reg->val & 0xff);

        return 0;
}
#endif

static int ov7740_set_power(struct ov7740 *ov7740, int on)
{
        int ret;

        if (on) {
                ret = clk_prepare_enable(ov7740->xvclk);
                if (ret)
                        return ret;

                if (ov7740->pwdn_gpio)
                        gpiod_direction_output(ov7740->pwdn_gpio, 0);

                if (ov7740->resetb_gpio) {
                        gpiod_set_value(ov7740->resetb_gpio, 1);
                        usleep_range(500, 1000);
                        gpiod_set_value(ov7740->resetb_gpio, 0);
                        usleep_range(3000, 5000);
                }
        } else {
                clk_disable_unprepare(ov7740->xvclk);

                if (ov7740->pwdn_gpio)
                        gpiod_direction_output(ov7740->pwdn_gpio, 0);
        }

        return 0;
}

static const struct v4l2_subdev_core_ops ov7740_subdev_core_ops = {
        .log_status = v4l2_ctrl_subdev_log_status,
#ifdef CONFIG_VIDEO_ADV_DEBUG
        .g_register = ov7740_get_register,
        .s_register = ov7740_set_register,
#endif
        .subscribe_event = v4l2_ctrl_subdev_subscribe_event,
        .unsubscribe_event = v4l2_event_subdev_unsubscribe,
};

static int ov7740_set_white_balance(struct ov7740 *ov7740, int awb)
{
        struct regmap *regmap = ov7740->regmap;
        unsigned int value;
        int ret;

        ret = regmap_read(regmap, REG_ISP_CTRL00, &value);
        if (!ret) {
                if (awb)
                        value |= (ISPCTRL00_AWB_EN | ISPCTRL00_AWB_GAIN_EN);
                else
                        value &= ~(ISPCTRL00_AWB_EN | ISPCTRL00_AWB_GAIN_EN);
                ret = regmap_write(regmap, REG_ISP_CTRL00, value);
                if (ret)
                        return ret;
        }

        if (!awb) {
                ret = regmap_write(regmap, REG_BGAIN,
                                   ov7740->blue_balance->val);
                if (ret)
                        return ret;

                ret = regmap_write(regmap, REG_RGAIN, ov7740->red_balance->val);
                if (ret)
                        return ret;
        }

        return 0;
}

static int ov7740_set_saturation(struct regmap *regmap, int value)
{
        int ret;

        ret = regmap_write(regmap, REG_USAT, (unsigned char)value);
        if (ret)
                return ret;

        return regmap_write(regmap, REG_VSAT, (unsigned char)value);
}

static int ov7740_set_gain(struct regmap *regmap, int value)
{
        int ret;

        ret = regmap_write(regmap, REG_GAIN, value & 0xff);
        if (ret)
                return ret;

        ret = regmap_update_bits(regmap, REG_CTRL15,
                                 REG15_GAIN_MSB, (value >> 8) & 0x3);
        if (!ret)
                ret = regmap_update_bits(regmap, REG_REG13, REG13_AGC_EN, 0);

        return ret;
}

static int ov7740_set_autogain(struct regmap *regmap, int value)
{
        unsigned int reg;
        int ret;

        ret = regmap_read(regmap, REG_REG13, &reg);
        if (ret)
                return ret;
        if (value)
                reg |= REG13_AGC_EN;
        else
                reg &= ~REG13_AGC_EN;
        return regmap_write(regmap, REG_REG13, reg);
}

static int ov7740_set_brightness(struct regmap *regmap, int value)
{
        /* Turn off AEC/AGC */
        regmap_update_bits(regmap, REG_REG13, REG13_AEC_EN, 0);
        regmap_update_bits(regmap, REG_REG13, REG13_AGC_EN, 0);

        if (value >= 0) {
                regmap_write(regmap, REG_YBRIGHT, (unsigned char)value);
                regmap_update_bits(regmap, REG_SGNSET, SGNSET_YBRIGHT_MASK, 0);
        } else{
                regmap_write(regmap, REG_YBRIGHT, (unsigned char)(-value));
                regmap_update_bits(regmap, REG_SGNSET, SGNSET_YBRIGHT_MASK, 1);
        }

        return 0;
}

static int ov7740_set_contrast(struct regmap *regmap, int value)
{
        return regmap_write(regmap, REG_YGAIN, (unsigned char)value);
}

static int ov7740_get_gain(struct ov7740 *ov7740, struct v4l2_ctrl *ctrl)
{
        struct regmap *regmap = ov7740->regmap;
        unsigned int value0, value1;
        int ret;

        if (!ctrl->val)
                return 0;

        ret = regmap_read(regmap, REG_GAIN, &value0);
        if (ret)
                return ret;
        ret = regmap_read(regmap, REG_CTRL15, &value1);
        if (ret)
                return ret;

        ov7740->gain->val = (value1 << 8) | (value0 & 0xff);

        return 0;
}

static int ov7740_get_exp(struct ov7740 *ov7740, struct v4l2_ctrl *ctrl)
{
        struct regmap *regmap = ov7740->regmap;
        unsigned int value0, value1;
        int ret;

        if (ctrl->val == V4L2_EXPOSURE_MANUAL)
                return 0;

        ret = regmap_read(regmap, REG_AEC, &value0);
        if (ret)
                return ret;
        ret = regmap_read(regmap, REG_HAEC, &value1);
        if (ret)
                return ret;

        ov7740->exposure->val = (value1 << 8) | (value0 & 0xff);

        return 0;
}

static int ov7740_set_exp(struct regmap *regmap, int value)
{
        int ret;

        /* Turn off AEC/AGC */
        ret = regmap_update_bits(regmap, REG_REG13,
                                 REG13_AEC_EN | REG13_AGC_EN, 0);
        if (ret)
                return ret;

        ret = regmap_write(regmap, REG_AEC, (unsigned char)value);
        if (ret)
                return ret;

        return regmap_write(regmap, REG_HAEC, (unsigned char)(value >> 8));
}

static int ov7740_set_autoexp(struct regmap *regmap,
                              enum v4l2_exposure_auto_type value)
{
        unsigned int reg;
        int ret;

        ret = regmap_read(regmap, REG_REG13, &reg);
        if (!ret) {
                if (value == V4L2_EXPOSURE_AUTO)
                        reg |= (REG13_AEC_EN | REG13_AGC_EN);
                else
                        reg &= ~(REG13_AEC_EN | REG13_AGC_EN);
                ret = regmap_write(regmap, REG_REG13, reg);
        }

        return ret;
}


static int ov7740_get_volatile_ctrl(struct v4l2_ctrl *ctrl)
{
        struct ov7740 *ov7740 = container_of(ctrl->handler,
                                             struct ov7740, ctrl_handler);
        int ret;

        switch (ctrl->id) {
        case V4L2_CID_AUTOGAIN:
                ret = ov7740_get_gain(ov7740, ctrl);
                break;
        case V4L2_CID_EXPOSURE_AUTO:
                ret = ov7740_get_exp(ov7740, ctrl);
                break;
        default:
                ret = -EINVAL;
                break;
        }
        return ret;
}

static int ov7740_set_ctrl(struct v4l2_ctrl *ctrl)
{
        struct ov7740 *ov7740 = container_of(ctrl->handler,
                                             struct ov7740, ctrl_handler);
        struct i2c_client *client = v4l2_get_subdevdata(&ov7740->subdev);
        struct regmap *regmap = ov7740->regmap;
        int ret;
        u8 val;

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

        switch (ctrl->id) {
        case V4L2_CID_AUTO_WHITE_BALANCE:
                ret = ov7740_set_white_balance(ov7740, ctrl->val);
                break;
        case V4L2_CID_SATURATION:
                ret = ov7740_set_saturation(regmap, ctrl->val);
                break;
        case V4L2_CID_BRIGHTNESS:
                ret = ov7740_set_brightness(regmap, ctrl->val);
                break;
        case V4L2_CID_CONTRAST:
                ret = ov7740_set_contrast(regmap, ctrl->val);
                break;
        case V4L2_CID_VFLIP:
                val = ctrl->val ? REG0C_IMG_FLIP : 0x00;
                ret = regmap_update_bits(regmap, REG_REG0C,
                                         REG0C_IMG_FLIP, val);
                break;
        case V4L2_CID_HFLIP:
                val = ctrl->val ? REG0C_IMG_MIRROR : 0x00;
                ret = regmap_update_bits(regmap, REG_REG0C,
                                         REG0C_IMG_MIRROR, val);
                break;
        case V4L2_CID_AUTOGAIN:
                if (!ctrl->val)
                        ret = ov7740_set_gain(regmap, ov7740->gain->val);
                else
                        ret = ov7740_set_autogain(regmap, ctrl->val);
                break;

        case V4L2_CID_EXPOSURE_AUTO:
                if (ctrl->val == V4L2_EXPOSURE_MANUAL)
                        ret = ov7740_set_exp(regmap, ov7740->exposure->val);
                else
                        ret = ov7740_set_autoexp(regmap, ctrl->val);
                break;
        default:
                ret = -EINVAL;
                break;
        }

        pm_runtime_put(&client->dev);

        return ret;
}

static const struct v4l2_ctrl_ops ov7740_ctrl_ops = {
        .g_volatile_ctrl = ov7740_get_volatile_ctrl,
        .s_ctrl = ov7740_set_ctrl,
};

static int ov7740_start_streaming(struct ov7740 *ov7740)
{
        int ret;

        if (ov7740->fmt) {
                ret = regmap_multi_reg_write(ov7740->regmap,
                                             ov7740->fmt->regs,
                                             ov7740->fmt->reg_num);
                if (ret)
                        return ret;
        }

        if (ov7740->frmsize) {
                ret = regmap_multi_reg_write(ov7740->regmap,
                                             ov7740->frmsize->regs,
                                             ov7740->frmsize->reg_num);
                if (ret)
                        return ret;
        }

        return __v4l2_ctrl_handler_setup(ov7740->subdev.ctrl_handler);
}

static int ov7740_set_stream(struct v4l2_subdev *sd, int enable)
{
        struct ov7740 *ov7740 = container_of(sd, struct ov7740, subdev);
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        int ret = 0;

        mutex_lock(&ov7740->mutex);

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

                ret = ov7740_start_streaming(ov7740);
                if (ret)
                        goto err_rpm_put;
        } else {
                pm_runtime_put(&client->dev);
        }

        mutex_unlock(&ov7740->mutex);
        return ret;

err_rpm_put:
        pm_runtime_put(&client->dev);
err_unlock:
        mutex_unlock(&ov7740->mutex);
        return ret;
}

static const struct v4l2_subdev_video_ops ov7740_subdev_video_ops = {
        .s_stream = ov7740_set_stream,
};

static const struct reg_sequence ov7740_format_yuyv[] = {
        {0x12, 0x00},
        {0x36, 0x3f},
        {0x80, 0x7f},
        {0x83, 0x01},
};

static const struct reg_sequence ov7740_format_bggr8[] = {
        {0x36, 0x2f},
        {0x80, 0x01},
        {0x83, 0x04},
};

static const struct ov7740_pixfmt ov7740_formats[] = {
        {
                .mbus_code = MEDIA_BUS_FMT_YUYV8_2X8,
                .colorspace = V4L2_COLORSPACE_SRGB,
                .regs = ov7740_format_yuyv,
                .reg_num = ARRAY_SIZE(ov7740_format_yuyv),
        },
        {
                .mbus_code = MEDIA_BUS_FMT_SBGGR8_1X8,
                .colorspace = V4L2_COLORSPACE_SRGB,
                .regs = ov7740_format_bggr8,
                .reg_num = ARRAY_SIZE(ov7740_format_bggr8),
        }
};
#define N_OV7740_FMTS ARRAY_SIZE(ov7740_formats)

static int ov7740_enum_mbus_code(struct v4l2_subdev *sd,
                                 struct v4l2_subdev_state *sd_state,
                                 struct v4l2_subdev_mbus_code_enum *code)
{
        if (code->pad || code->index >= N_OV7740_FMTS)
                return -EINVAL;

        code->code = ov7740_formats[code->index].mbus_code;

        return 0;
}

static int ov7740_enum_frame_interval(struct v4l2_subdev *sd,
                                struct v4l2_subdev_state *sd_state,
                                struct v4l2_subdev_frame_interval_enum *fie)
{
        if (fie->pad)
                return -EINVAL;

        if (fie->index >= 1)
                return -EINVAL;

        if ((fie->width != VGA_WIDTH) || (fie->height != VGA_HEIGHT))
                return -EINVAL;

        fie->interval.numerator = 1;
        fie->interval.denominator = 60;

        return 0;
}

static int ov7740_enum_frame_size(struct v4l2_subdev *sd,
                                  struct v4l2_subdev_state *sd_state,
                                  struct v4l2_subdev_frame_size_enum *fse)
{
        if (fse->pad)
                return -EINVAL;

        if (fse->index > 0)
                return -EINVAL;

        fse->min_width = fse->max_width = VGA_WIDTH;
        fse->min_height = fse->max_height = VGA_HEIGHT;

        return 0;
}

static int ov7740_try_fmt_internal(struct v4l2_subdev *sd,
                                   struct v4l2_mbus_framefmt *fmt,
                                   const struct ov7740_pixfmt **ret_fmt,
                                   const struct ov7740_framesize **ret_frmsize)
{
        struct ov7740 *ov7740 = container_of(sd, struct ov7740, subdev);
        const struct ov7740_framesize *fsize = &ov7740_framesizes[0];
        int index, i;

        for (index = 0; index < N_OV7740_FMTS; index++) {
                if (ov7740_formats[index].mbus_code == fmt->code)
                        break;
        }
        if (index >= N_OV7740_FMTS) {
                /* default to first format */
                index = 0;
                fmt->code = ov7740_formats[0].mbus_code;
        }
        if (ret_fmt != NULL)
                *ret_fmt = ov7740_formats + index;

        for (i = 0; i < ARRAY_SIZE(ov7740_framesizes); i++) {
                if ((fsize->width >= fmt->width) &&
                    (fsize->height >= fmt->height)) {
                        fmt->width = fsize->width;
                        fmt->height = fsize->height;
                        break;
                }

                fsize++;
        }
        if (i >= ARRAY_SIZE(ov7740_framesizes)) {
                fsize = &ov7740_framesizes[0];
                fmt->width = fsize->width;
                fmt->height = fsize->height;
        }
        if (ret_frmsize != NULL)
                *ret_frmsize = fsize;

        fmt->field = V4L2_FIELD_NONE;
        fmt->colorspace = ov7740_formats[index].colorspace;

        ov7740->format = *fmt;

        return 0;
}

static int ov7740_set_fmt(struct v4l2_subdev *sd,
                          struct v4l2_subdev_state *sd_state,
                          struct v4l2_subdev_format *format)
{
        struct ov7740 *ov7740 = container_of(sd, struct ov7740, subdev);
        const struct ov7740_pixfmt *ovfmt;
        const struct ov7740_framesize *fsize;
        struct v4l2_mbus_framefmt *mbus_fmt;
        int ret;

        mutex_lock(&ov7740->mutex);
        if (format->pad) {
                ret = -EINVAL;
                goto error;
        }

        if (format->which == V4L2_SUBDEV_FORMAT_TRY) {
                ret = ov7740_try_fmt_internal(sd, &format->format, NULL, NULL);
                if (ret)
                        goto error;

                mbus_fmt = v4l2_subdev_state_get_format(sd_state, format->pad);
                *mbus_fmt = format->format;
                mutex_unlock(&ov7740->mutex);
                return 0;
        }

        ret = ov7740_try_fmt_internal(sd, &format->format, &ovfmt, &fsize);
        if (ret)
                goto error;

        ov7740->fmt = ovfmt;
        ov7740->frmsize = fsize;

        mutex_unlock(&ov7740->mutex);
        return 0;

error:
        mutex_unlock(&ov7740->mutex);
        return ret;
}

static int ov7740_get_fmt(struct v4l2_subdev *sd,
                          struct v4l2_subdev_state *sd_state,
                          struct v4l2_subdev_format *format)
{
        struct ov7740 *ov7740 = container_of(sd, struct ov7740, subdev);
        struct v4l2_mbus_framefmt *mbus_fmt;

        mutex_lock(&ov7740->mutex);
        if (format->which == V4L2_SUBDEV_FORMAT_TRY) {
                mbus_fmt = v4l2_subdev_state_get_format(sd_state, 0);
                format->format = *mbus_fmt;
        } else {
                format->format = ov7740->format;
        }
        mutex_unlock(&ov7740->mutex);

        return 0;
}

static int ov7740_get_frame_interval(struct v4l2_subdev *sd,
                                     struct v4l2_subdev_state *sd_state,
                                     struct v4l2_subdev_frame_interval *ival)
{
        struct v4l2_fract *tpf = &ival->interval;

        tpf->numerator = 1;
        tpf->denominator = 60;

        return 0;
}

static const struct v4l2_subdev_pad_ops ov7740_subdev_pad_ops = {
        .enum_frame_interval = ov7740_enum_frame_interval,
        .enum_frame_size = ov7740_enum_frame_size,
        .enum_mbus_code = ov7740_enum_mbus_code,
        .get_fmt = ov7740_get_fmt,
        .set_fmt = ov7740_set_fmt,
        .get_frame_interval = ov7740_get_frame_interval,
        .set_frame_interval = ov7740_get_frame_interval,
};

static const struct v4l2_subdev_ops ov7740_subdev_ops = {
        .core   = &ov7740_subdev_core_ops,
        .video  = &ov7740_subdev_video_ops,
        .pad    = &ov7740_subdev_pad_ops,
};

static void ov7740_get_default_format(struct v4l2_subdev *sd,
                                      struct v4l2_mbus_framefmt *format)
{
        struct ov7740 *ov7740 = container_of(sd, struct ov7740, subdev);

        format->width = ov7740->frmsize->width;
        format->height = ov7740->frmsize->height;
        format->colorspace = ov7740->fmt->colorspace;
        format->code = ov7740->fmt->mbus_code;
        format->field = V4L2_FIELD_NONE;
}

static int ov7740_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
{
        struct ov7740 *ov7740 = container_of(sd, struct ov7740, subdev);
        struct v4l2_mbus_framefmt *format =
                                v4l2_subdev_state_get_format(fh->state, 0);

        mutex_lock(&ov7740->mutex);
        ov7740_get_default_format(sd, format);
        mutex_unlock(&ov7740->mutex);

        return 0;
}

static const struct v4l2_subdev_internal_ops ov7740_subdev_internal_ops = {
        .open = ov7740_open,
};

static int ov7740_probe_dt(struct i2c_client *client,
                           struct ov7740 *ov7740)
{
        ov7740->resetb_gpio = devm_gpiod_get_optional(&client->dev, "reset",
                        GPIOD_OUT_HIGH);
        if (IS_ERR(ov7740->resetb_gpio)) {
                dev_info(&client->dev, "can't get %s GPIO\n", "reset");
                return PTR_ERR(ov7740->resetb_gpio);
        }

        ov7740->pwdn_gpio = devm_gpiod_get_optional(&client->dev, "powerdown",
                        GPIOD_OUT_LOW);
        if (IS_ERR(ov7740->pwdn_gpio)) {
                dev_info(&client->dev, "can't get %s GPIO\n", "powerdown");
                return PTR_ERR(ov7740->pwdn_gpio);
        }

        return 0;
}

static int ov7740_detect(struct ov7740 *ov7740)
{
        struct regmap *regmap = ov7740->regmap;
        unsigned int midh, midl, pidh, pidl;
        int ret;

        ret = regmap_read(regmap, REG_MIDH, &midh);
        if (ret)
                return ret;
        if (midh != 0x7f)
                return -ENODEV;

        ret = regmap_read(regmap, REG_MIDL, &midl);
        if (ret)
                return ret;
        if (midl != 0xa2)
                return -ENODEV;

        ret = regmap_read(regmap, REG_PIDH, &pidh);
        if (ret)
                return ret;
        if (pidh != 0x77)
                return -ENODEV;

        ret = regmap_read(regmap, REG_PIDL, &pidl);
        if (ret)
                return ret;
        if ((pidl != 0x40) && (pidl != 0x41) && (pidl != 0x42))
                return -ENODEV;

        return 0;
}

static int ov7740_init_controls(struct ov7740 *ov7740)
{
        struct i2c_client *client = v4l2_get_subdevdata(&ov7740->subdev);
        struct v4l2_ctrl_handler *ctrl_hdlr = &ov7740->ctrl_handler;
        int ret;

        ret = v4l2_ctrl_handler_init(ctrl_hdlr, 12);
        if (ret < 0)
                return ret;

        ctrl_hdlr->lock = &ov7740->mutex;
        ov7740->auto_wb = v4l2_ctrl_new_std(ctrl_hdlr, &ov7740_ctrl_ops,
                                          V4L2_CID_AUTO_WHITE_BALANCE,
                                          0, 1, 1, 1);
        ov7740->blue_balance = v4l2_ctrl_new_std(ctrl_hdlr, &ov7740_ctrl_ops,
                                               V4L2_CID_BLUE_BALANCE,
                                               0, 0xff, 1, 0x80);
        ov7740->red_balance = v4l2_ctrl_new_std(ctrl_hdlr, &ov7740_ctrl_ops,
                                              V4L2_CID_RED_BALANCE,
                                              0, 0xff, 1, 0x80);

        ov7740->brightness = v4l2_ctrl_new_std(ctrl_hdlr, &ov7740_ctrl_ops,
                                             V4L2_CID_BRIGHTNESS,
                                             -255, 255, 1, 0);
        ov7740->contrast = v4l2_ctrl_new_std(ctrl_hdlr, &ov7740_ctrl_ops,
                                           V4L2_CID_CONTRAST,
                                           0, 127, 1, 0x20);
        ov7740->saturation = v4l2_ctrl_new_std(ctrl_hdlr, &ov7740_ctrl_ops,
                          V4L2_CID_SATURATION, 0, 256, 1, 0x80);
        ov7740->hflip = v4l2_ctrl_new_std(ctrl_hdlr, &ov7740_ctrl_ops,
                                        V4L2_CID_HFLIP, 0, 1, 1, 0);
        ov7740->vflip = v4l2_ctrl_new_std(ctrl_hdlr, &ov7740_ctrl_ops,
                                        V4L2_CID_VFLIP, 0, 1, 1, 0);

        ov7740->gain = v4l2_ctrl_new_std(ctrl_hdlr, &ov7740_ctrl_ops,
                                       V4L2_CID_GAIN, 0, 1023, 1, 500);

        ov7740->auto_gain = v4l2_ctrl_new_std(ctrl_hdlr, &ov7740_ctrl_ops,
                                            V4L2_CID_AUTOGAIN, 0, 1, 1, 1);

        ov7740->exposure = v4l2_ctrl_new_std(ctrl_hdlr, &ov7740_ctrl_ops,
                                           V4L2_CID_EXPOSURE, 0, 65535, 1, 500);

        ov7740->auto_exposure = v4l2_ctrl_new_std_menu(ctrl_hdlr,
                                        &ov7740_ctrl_ops,
                                        V4L2_CID_EXPOSURE_AUTO,
                                        V4L2_EXPOSURE_MANUAL, 0,
                                        V4L2_EXPOSURE_AUTO);

        v4l2_ctrl_auto_cluster(3, &ov7740->auto_wb, 0, false);
        v4l2_ctrl_auto_cluster(2, &ov7740->auto_gain, 0, true);
        v4l2_ctrl_auto_cluster(2, &ov7740->auto_exposure,
                               V4L2_EXPOSURE_MANUAL, true);

        if (ctrl_hdlr->error) {
                ret = ctrl_hdlr->error;
                dev_err(&client->dev, "controls initialisation failed (%d)\n",
                        ret);
                goto error;
        }

        ret = v4l2_ctrl_handler_setup(ctrl_hdlr);
        if (ret) {
                dev_err(&client->dev, "%s control init failed (%d)\n",
                        __func__, ret);
                goto error;
        }

        ov7740->subdev.ctrl_handler = ctrl_hdlr;
        return 0;

error:
        v4l2_ctrl_handler_free(ctrl_hdlr);
        mutex_destroy(&ov7740->mutex);
        return ret;
}

static void ov7740_free_controls(struct ov7740 *ov7740)
{
        v4l2_ctrl_handler_free(ov7740->subdev.ctrl_handler);
        mutex_destroy(&ov7740->mutex);
}

#define OV7740_MAX_REGISTER     0xff
static const struct regmap_config ov7740_regmap_config = {
        .reg_bits       = 8,
        .val_bits       = 8,
        .max_register   = OV7740_MAX_REGISTER,
};

static int ov7740_probe(struct i2c_client *client)
{
        struct ov7740 *ov7740;
        struct v4l2_subdev *sd;
        int ret;

        ov7740 = devm_kzalloc(&client->dev, sizeof(*ov7740), GFP_KERNEL);
        if (!ov7740)
                return -ENOMEM;

        ov7740->xvclk = devm_v4l2_sensor_clk_get(&client->dev, "xvclk");
        if (IS_ERR(ov7740->xvclk))
                return dev_err_probe(&client->dev, PTR_ERR(ov7740->xvclk),
                                     "OV7740: fail to get xvclk\n");

        ret = ov7740_probe_dt(client, ov7740);
        if (ret)
                return ret;

        ov7740->regmap = devm_regmap_init_sccb(client, &ov7740_regmap_config);
        if (IS_ERR(ov7740->regmap)) {
                ret = PTR_ERR(ov7740->regmap);
                dev_err(&client->dev, "Failed to allocate register map: %d\n",
                        ret);
                return ret;
        }

        sd = &ov7740->subdev;
        v4l2_i2c_subdev_init(sd, client, &ov7740_subdev_ops);

        sd->internal_ops = &ov7740_subdev_internal_ops;
        sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_HAS_EVENTS;

        ov7740->pad.flags = MEDIA_PAD_FL_SOURCE;
        sd->entity.function = MEDIA_ENT_F_CAM_SENSOR;
        ret = media_entity_pads_init(&sd->entity, 1, &ov7740->pad);
        if (ret)
                return ret;

        ret = ov7740_set_power(ov7740, 1);
        if (ret)
                return ret;

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

        ret = ov7740_detect(ov7740);
        if (ret)
                goto error_detect;

        mutex_init(&ov7740->mutex);

        ret = ov7740_init_controls(ov7740);
        if (ret)
                goto error_init_controls;

        v4l_info(client, "chip found @ 0x%02x (%s)\n",
                        client->addr << 1, client->adapter->name);

        ov7740->fmt = &ov7740_formats[0];
        ov7740->frmsize = &ov7740_framesizes[0];

        ov7740_get_default_format(sd, &ov7740->format);

        ret = v4l2_async_register_subdev(sd);
        if (ret)
                goto error_async_register;

        pm_runtime_idle(&client->dev);

        return 0;

error_async_register:
        v4l2_ctrl_handler_free(ov7740->subdev.ctrl_handler);
error_init_controls:
        ov7740_free_controls(ov7740);
error_detect:
        pm_runtime_disable(&client->dev);
        pm_runtime_set_suspended(&client->dev);
        ov7740_set_power(ov7740, 0);
        media_entity_cleanup(&ov7740->subdev.entity);

        return ret;
}

static void ov7740_remove(struct i2c_client *client)
{
        struct v4l2_subdev *sd = i2c_get_clientdata(client);
        struct ov7740 *ov7740 = container_of(sd, struct ov7740, subdev);

        mutex_destroy(&ov7740->mutex);
        v4l2_ctrl_handler_free(ov7740->subdev.ctrl_handler);
        media_entity_cleanup(&ov7740->subdev.entity);
        v4l2_async_unregister_subdev(sd);
        ov7740_free_controls(ov7740);

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

        ov7740_set_power(ov7740, 0);
}

static int __maybe_unused ov7740_runtime_suspend(struct device *dev)
{
        struct v4l2_subdev *sd = dev_get_drvdata(dev);
        struct ov7740 *ov7740 = container_of(sd, struct ov7740, subdev);

        ov7740_set_power(ov7740, 0);

        return 0;
}

static int __maybe_unused ov7740_runtime_resume(struct device *dev)
{
        struct v4l2_subdev *sd = dev_get_drvdata(dev);
        struct ov7740 *ov7740 = container_of(sd, struct ov7740, subdev);

        return ov7740_set_power(ov7740, 1);
}

static const struct i2c_device_id ov7740_id[] = {
        { "ov7740" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(i2c, ov7740_id);

static const struct dev_pm_ops ov7740_pm_ops = {
        SET_RUNTIME_PM_OPS(ov7740_runtime_suspend, ov7740_runtime_resume, NULL)
};

static const struct of_device_id ov7740_of_match[] = {
        {.compatible = "ovti,ov7740", },
        { /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, ov7740_of_match);

static struct i2c_driver ov7740_i2c_driver = {
        .driver = {
                .name = "ov7740",
                .pm = &ov7740_pm_ops,
                .of_match_table = ov7740_of_match,
        },
        .probe    = ov7740_probe,
        .remove   = ov7740_remove,
        .id_table = ov7740_id,
};
module_i2c_driver(ov7740_i2c_driver);

MODULE_DESCRIPTION("The V4L2 driver for Omnivision 7740 sensor");
MODULE_AUTHOR("Songjun Wu <songjun.wu@atmel.com>");
MODULE_LICENSE("GPL v2");