/*
 * Omnivision OV9650/OV9652 CMOS Image Sensor driver
 *
 * Copyright (C) 2013, Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
 *
 * Register definitions and initial settings based on a driver written
 * by Vladimir Fonov.
 * Copyright (c) 2010, Vladimir Fonov
 *
 * 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/clk.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/media.h>
#include <linux/module.h>
#include <linux/ratelimit.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/videodev2.h>

#include <media/media-entity.h>
#include <media/v4l2-async.h>
#include <media/v4l2-ctrls.h>
#include <media/v4l2-device.h>
#include <media/v4l2-event.h>
#include <media/v4l2-image-sizes.h>
#include <media/v4l2-subdev.h>
#include <media/v4l2-mediabus.h>
#include <media/i2c/ov9650.h>

static int debug;
module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "Debug level (0-2)");

#define DRIVER_NAME "OV9650"

/*
 * OV9650/OV9652 register definitions
 */
#define REG_GAIN                0x00    /* Gain control, AGC[7:0] */
#define REG_BLUE                0x01    /* AWB - Blue chanel gain */
#define REG_RED                 0x02    /* AWB - Red chanel gain */
#define REG_VREF                0x03    /* [7:6] - AGC[9:8], [5:3]/[2:0] */
#define  VREF_GAIN_MASK         0xc0    /* - VREF end/start low 3 bits */
#define REG_COM1                0x04
#define  COM1_CCIR656           0x40
#define REG_B_AVE               0x05
#define REG_GB_AVE              0x06
#define REG_GR_AVE              0x07
#define REG_R_AVE               0x08
#define REG_COM2                0x09
#define REG_PID                 0x0a    /* Product ID MSB */
#define REG_VER                 0x0b    /* Product ID LSB */
#define REG_COM3                0x0c
#define  COM3_SWAP              0x40
#define  COM3_VARIOPIXEL1       0x04
#define REG_COM4                0x0d    /* Vario Pixels  */
#define  COM4_VARIOPIXEL2       0x80
#define REG_COM5                0x0e    /* System clock options */
#define  COM5_SLAVE_MODE        0x10
#define  COM5_SYSTEMCLOCK48MHZ  0x80
#define REG_COM6                0x0f    /* HREF & ADBLC options */
#define REG_AECH                0x10    /* Exposure value, AEC[9:2] */
#define REG_CLKRC               0x11    /* Clock control */
#define  CLK_EXT                0x40    /* Use external clock directly */
#define  CLK_SCALE              0x3f    /* Mask for internal clock scale */
#define REG_COM7                0x12    /* SCCB reset, output format */
#define  COM7_RESET             0x80
#define  COM7_FMT_MASK          0x38
#define  COM7_FMT_VGA           0x40
#define  COM7_FMT_CIF           0x20
#define  COM7_FMT_QVGA          0x10
#define  COM7_FMT_QCIF          0x08
#define  COM7_RGB               0x04
#define  COM7_YUV               0x00
#define  COM7_BAYER             0x01
#define  COM7_PBAYER            0x05
#define REG_COM8                0x13    /* AGC/AEC options */
#define  COM8_FASTAEC           0x80    /* Enable fast AGC/AEC */
#define  COM8_AECSTEP           0x40    /* Unlimited AEC step size */
#define  COM8_BFILT             0x20    /* Band filter enable */
#define  COM8_AGC               0x04    /* Auto gain enable */
#define  COM8_AWB               0x02    /* White balance enable */
#define  COM8_AEC               0x01    /* Auto exposure enable */
#define REG_COM9                0x14    /* Gain ceiling */
#define  COM9_GAIN_CEIL_MASK    0x70    /* */
#define REG_COM10               0x15    /* PCLK, HREF, HSYNC signals polarity */
#define  COM10_HSYNC            0x40    /* HSYNC instead of HREF */
#define  COM10_PCLK_HB          0x20    /* Suppress PCLK on horiz blank */
#define  COM10_HREF_REV         0x08    /* Reverse HREF */
#define  COM10_VS_LEAD          0x04    /* VSYNC on clock leading edge */
#define  COM10_VS_NEG           0x02    /* VSYNC negative */
#define  COM10_HS_NEG           0x01    /* HSYNC negative */
#define REG_HSTART              0x17    /* Horiz start high bits */
#define REG_HSTOP               0x18    /* Horiz stop high bits */
#define REG_VSTART              0x19    /* Vert start high bits */
#define REG_VSTOP               0x1a    /* Vert stop high bits */
#define REG_PSHFT               0x1b    /* Pixel delay after HREF */
#define REG_MIDH                0x1c    /* Manufacturer ID MSB */
#define REG_MIDL                0x1d    /* Manufufacturer ID LSB */
#define REG_MVFP                0x1e    /* Image mirror/flip */
#define  MVFP_MIRROR            0x20    /* Mirror image */
#define  MVFP_FLIP              0x10    /* Vertical flip */
#define REG_BOS                 0x20    /* B channel Offset */
#define REG_GBOS                0x21    /* Gb channel Offset */
#define REG_GROS                0x22    /* Gr channel Offset */
#define REG_ROS                 0x23    /* R channel Offset */
#define REG_AEW                 0x24    /* AGC upper limit */
#define REG_AEB                 0x25    /* AGC lower limit */
#define REG_VPT                 0x26    /* AGC/AEC fast mode op region */
#define REG_BBIAS               0x27    /* B channel output bias */
#define REG_GBBIAS              0x28    /* Gb channel output bias */
#define REG_GRCOM               0x29    /* Analog BLC & regulator */
#define REG_EXHCH               0x2a    /* Dummy pixel insert MSB */
#define REG_EXHCL               0x2b    /* Dummy pixel insert LSB */
#define REG_RBIAS               0x2c    /* R channel output bias */
#define REG_ADVFL               0x2d    /* LSB of dummy line insert */
#define REG_ADVFH               0x2e    /* MSB of dummy line insert */
#define REG_YAVE                0x2f    /* Y/G channel average value */
#define REG_HSYST               0x30    /* HSYNC rising edge delay LSB*/
#define REG_HSYEN               0x31    /* HSYNC falling edge delay LSB*/
#define REG_HREF                0x32    /* HREF pieces */
#define REG_CHLF                0x33    /* reserved */
#define REG_ADC                 0x37    /* reserved */
#define REG_ACOM                0x38    /* reserved */
#define REG_OFON                0x39    /* Power down register */
#define  OFON_PWRDN             0x08    /* Power down bit */
#define REG_TSLB                0x3a    /* YUVU format */
#define  TSLB_YUYV_MASK         0x0c    /* UYVY or VYUY - see com13 */
#define REG_COM11               0x3b    /* Night mode, banding filter enable */
#define  COM11_NIGHT            0x80    /* Night mode enable */
#define  COM11_NMFR             0x60    /* Two bit NM frame rate */
#define  COM11_BANDING          0x01    /* Banding filter */
#define  COM11_AEC_REF_MASK     0x18    /* AEC reference area selection */
#define REG_COM12               0x3c    /* HREF option, UV average */
#define  COM12_HREF             0x80    /* HREF always */
#define REG_COM13               0x3d    /* Gamma selection, Color matrix en. */
#define  COM13_GAMMA            0x80    /* Gamma enable */
#define  COM13_UVSAT            0x40    /* UV saturation auto adjustment */
#define  COM13_UVSWAP           0x01    /* V before U - w/TSLB */
#define REG_COM14               0x3e    /* Edge enhancement options */
#define  COM14_EDGE_EN          0x02
#define  COM14_EEF_X2           0x01
#define REG_EDGE                0x3f    /* Edge enhancement factor */
#define  EDGE_FACTOR_MASK       0x0f
#define REG_COM15               0x40    /* Output range, RGB 555/565 */
#define  COM15_R10F0            0x00    /* Data range 10 to F0 */
#define  COM15_R01FE            0x80    /* 01 to FE */
#define  COM15_R00FF            0xc0    /* 00 to FF */
#define  COM15_RGB565           0x10    /* RGB565 output */
#define  COM15_RGB555           0x30    /* RGB555 output */
#define  COM15_SWAPRB           0x04    /* Swap R&B */
#define REG_COM16               0x41    /* Color matrix coeff options */
#define REG_COM17               0x42    /* Single frame out, banding filter */
/* n = 1...9, 0x4f..0x57 */
#define REG_MTX(__n)            (0x4f + (__n) - 1)
#define REG_MTXS                0x58
/* Lens Correction Option 1...5, __n = 0...5 */
#define REG_LCC(__n)            (0x62 + (__n) - 1)
#define  LCC5_LCC_ENABLE        0x01    /* LCC5, enable lens correction */
#define  LCC5_LCC_COLOR         0x04
#define REG_MANU                0x67    /* Manual U value */
#define REG_MANV                0x68    /* Manual V value */
#define REG_HV                  0x69    /* Manual banding filter MSB */
#define REG_MBD                 0x6a    /* Manual banding filter value */
#define REG_DBLV                0x6b    /* reserved */
#define REG_GSP                 0x6c    /* Gamma curve */
#define  GSP_LEN                15
#define REG_GST                 0x7c    /* Gamma curve */
#define  GST_LEN                15
#define REG_COM21               0x8b
#define REG_COM22               0x8c    /* Edge enhancement, denoising */
#define  COM22_WHTPCOR          0x02    /* White pixel correction enable */
#define  COM22_WHTPCOROPT       0x01    /* White pixel correction option */
#define  COM22_DENOISE          0x10    /* White pixel correction option */
#define REG_COM23               0x8d    /* Color bar test, color gain */
#define  COM23_TEST_MODE        0x10
#define REG_DBLC1               0x8f    /* Digital BLC */
#define REG_DBLC_B              0x90    /* Digital BLC B channel offset */
#define REG_DBLC_R              0x91    /* Digital BLC R channel offset */
#define REG_DM_LNL              0x92    /* Dummy line low 8 bits */
#define REG_DM_LNH              0x93    /* Dummy line high 8 bits */
#define REG_LCCFB               0x9d    /* Lens Correction B channel */
#define REG_LCCFR               0x9e    /* Lens Correction R channel */
#define REG_DBLC_GB             0x9f    /* Digital BLC GB chan offset */
#define REG_DBLC_GR             0xa0    /* Digital BLC GR chan offset */
#define REG_AECHM               0xa1    /* Exposure value - bits AEC[15:10] */
#define REG_BD50ST              0xa2    /* Banding filter value for 50Hz */
#define REG_BD60ST              0xa3    /* Banding filter value for 60Hz */
#define REG_NULL                0xff    /* Array end token */

#define DEF_CLKRC               0x80

#define OV965X_ID(_msb, _lsb)   ((_msb) << 8 | (_lsb))
#define OV9650_ID               0x9650
#define OV9652_ID               0x9652

struct ov965x_ctrls {
        struct v4l2_ctrl_handler handler;
        struct {
                struct v4l2_ctrl *auto_exp;
                struct v4l2_ctrl *exposure;
        };
        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 {
                struct v4l2_ctrl *auto_gain;
                struct v4l2_ctrl *gain;
        };
        struct v4l2_ctrl *brightness;
        struct v4l2_ctrl *saturation;
        struct v4l2_ctrl *sharpness;
        struct v4l2_ctrl *light_freq;
        u8 update;
};

struct ov965x_framesize {
        u16 width;
        u16 height;
        u16 max_exp_lines;
        const u8 *regs;
};

struct ov965x_interval {
        struct v4l2_fract interval;
        /* Maximum resolution for this interval */
        struct v4l2_frmsize_discrete size;
        u8 clkrc_div;
};

enum gpio_id {
        GPIO_PWDN,
        GPIO_RST,
        NUM_GPIOS,
};

struct ov965x {
        struct v4l2_subdev sd;
        struct media_pad pad;
        enum v4l2_mbus_type bus_type;
        struct gpio_desc *gpios[NUM_GPIOS];
        /* External master clock frequency */
        unsigned long mclk_frequency;
        struct clk *clk;

        /* Protects the struct fields below */
        struct mutex lock;

        struct i2c_client *client;

        /* Exposure row interval in us */
        unsigned int exp_row_interval;

        unsigned short id;
        const struct ov965x_framesize *frame_size;
        /* YUYV sequence (pixel format) control register */
        u8 tslb_reg;
        struct v4l2_mbus_framefmt format;

        struct ov965x_ctrls ctrls;
        /* Pointer to frame rate control data structure */
        const struct ov965x_interval *fiv;

        int streaming;
        int power;

        u8 apply_frame_fmt;
};

struct i2c_rv {
        u8 addr;
        u8 value;
};

static const struct i2c_rv ov965x_init_regs[] = {
        { REG_COM2, 0x10 },     /* Set soft sleep mode */
        { REG_COM5, 0x00 },     /* System clock options */
        { REG_COM2, 0x01 },     /* Output drive, soft sleep mode */
        { REG_COM10, 0x00 },    /* Slave mode, HREF vs HSYNC, signals negate */
        { REG_EDGE, 0xa6 },     /* Edge enhancement treshhold and factor */
        { REG_COM16, 0x02 },    /* Color matrix coeff double option */
        { REG_COM17, 0x08 },    /* Single frame out, banding filter */
        { 0x16, 0x06 },
        { REG_CHLF, 0xc0 },     /* Reserved  */
        { 0x34, 0xbf },
        { 0xa8, 0x80 },
        { 0x96, 0x04 },
        { 0x8e, 0x00 },
        { REG_COM12, 0x77 },    /* HREF option, UV average  */
        { 0x8b, 0x06 },
        { 0x35, 0x91 },
        { 0x94, 0x88 },
        { 0x95, 0x88 },
        { REG_COM15, 0xc1 },    /* Output range, RGB 555/565 */
        { REG_GRCOM, 0x2f },    /* Analog BLC & regulator */
        { REG_COM6, 0x43 },     /* HREF & ADBLC options */
        { REG_COM8, 0xe5 },     /* AGC/AEC options */
        { REG_COM13, 0x90 },    /* Gamma selection, colour matrix, UV delay */
        { REG_HV, 0x80 },       /* Manual banding filter MSB  */
        { 0x5c, 0x96 },         /* Reserved up to 0xa5 */
        { 0x5d, 0x96 },
        { 0x5e, 0x10 },
        { 0x59, 0xeb },
        { 0x5a, 0x9c },
        { 0x5b, 0x55 },
        { 0x43, 0xf0 },
        { 0x44, 0x10 },
        { 0x45, 0x55 },
        { 0x46, 0x86 },
        { 0x47, 0x64 },
        { 0x48, 0x86 },
        { 0x5f, 0xe0 },
        { 0x60, 0x8c },
        { 0x61, 0x20 },
        { 0xa5, 0xd9 },
        { 0xa4, 0x74 },         /* reserved */
        { REG_COM23, 0x02 },    /* Color gain analog/_digital_ */
        { REG_COM8, 0xe7 },     /* Enable AEC, AWB, AEC */
        { REG_COM22, 0x23 },    /* Edge enhancement, denoising */
        { 0xa9, 0xb8 },
        { 0xaa, 0x92 },
        { 0xab, 0x0a },
        { REG_DBLC1, 0xdf },    /* Digital BLC */
        { REG_DBLC_B, 0x00 },   /* Digital BLC B chan offset */
        { REG_DBLC_R, 0x00 },   /* Digital BLC R chan offset */
        { REG_DBLC_GB, 0x00 },  /* Digital BLC GB chan offset */
        { REG_DBLC_GR, 0x00 },
        { REG_COM9, 0x3a },     /* Gain ceiling 16x */
        { REG_NULL, 0 }
};

#define NUM_FMT_REGS 14
/*
 * COM7,  COM3,  COM4, HSTART, HSTOP, HREF, VSTART, VSTOP, VREF,
 * EXHCH, EXHCL, ADC,  OCOM,   OFON
 */
static const u8 frame_size_reg_addr[NUM_FMT_REGS] = {
        0x12, 0x0c, 0x0d, 0x17, 0x18, 0x32, 0x19, 0x1a, 0x03,
        0x2a, 0x2b, 0x37, 0x38, 0x39,
};

static const u8 ov965x_sxga_regs[NUM_FMT_REGS] = {
        0x00, 0x00, 0x00, 0x1e, 0xbe, 0xbf, 0x01, 0x81, 0x12,
        0x10, 0x34, 0x81, 0x93, 0x51,
};

static const u8 ov965x_vga_regs[NUM_FMT_REGS] = {
        0x40, 0x04, 0x80, 0x26, 0xc6, 0xed, 0x01, 0x3d, 0x00,
        0x10, 0x40, 0x91, 0x12, 0x43,
};

/* Determined empirically. */
static const u8 ov965x_qvga_regs[NUM_FMT_REGS] = {
        0x10, 0x04, 0x80, 0x25, 0xc5, 0xbf, 0x00, 0x80, 0x12,
        0x10, 0x40, 0x91, 0x12, 0x43,
};

static const struct ov965x_framesize ov965x_framesizes[] = {
        {
                .width          = SXGA_WIDTH,
                .height         = SXGA_HEIGHT,
                .regs           = ov965x_sxga_regs,
                .max_exp_lines  = 1048,
        }, {
                .width          = VGA_WIDTH,
                .height         = VGA_HEIGHT,
                .regs           = ov965x_vga_regs,
                .max_exp_lines  = 498,
        }, {
                .width          = QVGA_WIDTH,
                .height         = QVGA_HEIGHT,
                .regs           = ov965x_qvga_regs,
                .max_exp_lines  = 248,
        },
};

struct ov965x_pixfmt {
        u32 code;
        u32 colorspace;
        /* REG_TSLB value, only bits [3:2] may be set. */
        u8 tslb_reg;
};

static const struct ov965x_pixfmt ov965x_formats[] = {
        { MEDIA_BUS_FMT_YUYV8_2X8, V4L2_COLORSPACE_JPEG, 0x00},
        { MEDIA_BUS_FMT_YVYU8_2X8, V4L2_COLORSPACE_JPEG, 0x04},
        { MEDIA_BUS_FMT_UYVY8_2X8, V4L2_COLORSPACE_JPEG, 0x0c},
        { MEDIA_BUS_FMT_VYUY8_2X8, V4L2_COLORSPACE_JPEG, 0x08},
};

/*
 * This table specifies possible frame resolution and interval
 * combinations. Default CLKRC[5:0] divider values are valid
 * only for 24 MHz external clock frequency.
 */
static struct ov965x_interval ov965x_intervals[] = {
        {{ 100, 625 }, { SXGA_WIDTH, SXGA_HEIGHT }, 0 },  /* 6.25 fps */
        {{ 10,  125 }, { VGA_WIDTH, VGA_HEIGHT },   1 },  /* 12.5 fps */
        {{ 10,  125 }, { QVGA_WIDTH, QVGA_HEIGHT }, 3 },  /* 12.5 fps */
        {{ 1,   25  }, { VGA_WIDTH, VGA_HEIGHT },   0 },  /* 25 fps */
        {{ 1,   25  }, { QVGA_WIDTH, QVGA_HEIGHT }, 1 },  /* 25 fps */
};

static inline struct v4l2_subdev *ctrl_to_sd(struct v4l2_ctrl *ctrl)
{
        return &container_of(ctrl->handler, struct ov965x, ctrls.handler)->sd;
}

static inline struct ov965x *to_ov965x(struct v4l2_subdev *sd)
{
        return container_of(sd, struct ov965x, sd);
}

static int ov965x_read(struct i2c_client *client, u8 addr, u8 *val)
{
        u8 buf = addr;
        struct i2c_msg msg = {
                .addr = client->addr,
                .flags = 0,
                .len = 1,
                .buf = &buf
        };
        int ret;

        ret = i2c_transfer(client->adapter, &msg, 1);
        if (ret == 1) {
                msg.flags = I2C_M_RD;
                ret = i2c_transfer(client->adapter, &msg, 1);

                if (ret == 1)
                        *val = buf;
        }

        v4l2_dbg(2, debug, client, "%s: 0x%02x @ 0x%02x. (%d)\n",
                 __func__, *val, addr, ret);

        return ret == 1 ? 0 : ret;
}

static int ov965x_write(struct i2c_client *client, u8 addr, u8 val)
{
        u8 buf[2] = { addr, val };

        int ret = i2c_master_send(client, buf, 2);

        v4l2_dbg(2, debug, client, "%s: 0x%02x @ 0x%02X (%d)\n",
                 __func__, val, addr, ret);

        return ret == 2 ? 0 : ret;
}

static int ov965x_write_array(struct i2c_client *client,
                              const struct i2c_rv *regs)
{
        int i, ret = 0;

        for (i = 0; ret == 0 && regs[i].addr != REG_NULL; i++)
                ret = ov965x_write(client, regs[i].addr, regs[i].value);

        return ret;
}

static int ov965x_set_default_gamma_curve(struct ov965x *ov965x)
{
        static const u8 gamma_curve[] = {
                /* Values taken from OV application note. */
                0x40, 0x30, 0x4b, 0x60, 0x70, 0x70, 0x70, 0x70,
                0x60, 0x60, 0x50, 0x48, 0x3a, 0x2e, 0x28, 0x22,
                0x04, 0x07, 0x10, 0x28, 0x36, 0x44, 0x52, 0x60,
                0x6c, 0x78, 0x8c, 0x9e, 0xbb, 0xd2, 0xe6
        };
        u8 addr = REG_GSP;
        unsigned int i;

        for (i = 0; i < ARRAY_SIZE(gamma_curve); i++) {
                int ret = ov965x_write(ov965x->client, addr, gamma_curve[i]);

                if (ret < 0)
                        return ret;
                addr++;
        }

        return 0;
};

static int ov965x_set_color_matrix(struct ov965x *ov965x)
{
        static const u8 mtx[] = {
                /* MTX1..MTX9, MTXS */
                0x3a, 0x3d, 0x03, 0x12, 0x26, 0x38, 0x40, 0x40, 0x40, 0x0d
        };
        u8 addr = REG_MTX(1);
        unsigned int i;

        for (i = 0; i < ARRAY_SIZE(mtx); i++) {
                int ret = ov965x_write(ov965x->client, addr, mtx[i]);

                if (ret < 0)
                        return ret;
                addr++;
        }

        return 0;
}

static int __ov965x_set_power(struct ov965x *ov965x, int on)
{
        if (on) {
                int ret = clk_prepare_enable(ov965x->clk);

                if (ret)
                        return ret;

                gpiod_set_value_cansleep(ov965x->gpios[GPIO_PWDN], 0);
                gpiod_set_value_cansleep(ov965x->gpios[GPIO_RST], 0);
                msleep(25);
        } else {
                gpiod_set_value_cansleep(ov965x->gpios[GPIO_RST], 1);
                gpiod_set_value_cansleep(ov965x->gpios[GPIO_PWDN], 1);

                clk_disable_unprepare(ov965x->clk);
        }

        ov965x->streaming = 0;

        return 0;
}

static int ov965x_s_power(struct v4l2_subdev *sd, int on)
{
        struct ov965x *ov965x = to_ov965x(sd);
        struct i2c_client *client = ov965x->client;
        int ret = 0;

        v4l2_dbg(1, debug, client, "%s: on: %d\n", __func__, on);

        mutex_lock(&ov965x->lock);
        if (ov965x->power == !on) {
                ret = __ov965x_set_power(ov965x, on);
                if (!ret && on) {
                        ret = ov965x_write_array(client,
                                                 ov965x_init_regs);
                        ov965x->apply_frame_fmt = 1;
                        ov965x->ctrls.update = 1;
                }
        }
        if (!ret)
                ov965x->power += on ? 1 : -1;

        WARN_ON(ov965x->power < 0);
        mutex_unlock(&ov965x->lock);
        return ret;
}

/*
 * V4L2 controls
 */

static void ov965x_update_exposure_ctrl(struct ov965x *ov965x)
{
        struct v4l2_ctrl *ctrl = ov965x->ctrls.exposure;
        unsigned long fint, trow;
        int min, max, def;
        u8 clkrc;

        mutex_lock(&ov965x->lock);
        if (WARN_ON(!ctrl || !ov965x->frame_size)) {
                mutex_unlock(&ov965x->lock);
                return;
        }
        clkrc = DEF_CLKRC + ov965x->fiv->clkrc_div;
        /* Calculate internal clock frequency */
        fint = ov965x->mclk_frequency * ((clkrc >> 7) + 1) /
                                ((2 * ((clkrc & 0x3f) + 1)));
        /* and the row interval (in us). */
        trow = (2 * 1520 * 1000000UL) / fint;
        max = ov965x->frame_size->max_exp_lines * trow;
        ov965x->exp_row_interval = trow;
        mutex_unlock(&ov965x->lock);

        v4l2_dbg(1, debug, &ov965x->sd, "clkrc: %#x, fi: %lu, tr: %lu, %d\n",
                 clkrc, fint, trow, max);

        /* Update exposure time range to match current frame format. */
        min = (trow + 100) / 100;
        max = (max - 100) / 100;
        def = min + (max - min) / 2;

        if (v4l2_ctrl_modify_range(ctrl, min, max, 1, def))
                v4l2_err(&ov965x->sd, "Exposure ctrl range update failed\n");
}

static int ov965x_set_banding_filter(struct ov965x *ov965x, int value)
{
        unsigned long mbd, light_freq;
        int ret;
        u8 reg;

        ret = ov965x_read(ov965x->client, REG_COM8, &reg);
        if (!ret) {
                if (value == V4L2_CID_POWER_LINE_FREQUENCY_DISABLED)
                        reg &= ~COM8_BFILT;
                else
                        reg |= COM8_BFILT;
                ret = ov965x_write(ov965x->client, REG_COM8, reg);
        }
        if (value == V4L2_CID_POWER_LINE_FREQUENCY_DISABLED)
                return 0;
        if (WARN_ON(!ov965x->fiv))
                return -EINVAL;
        /* Set minimal exposure time for 50/60 HZ lighting */
        if (value == V4L2_CID_POWER_LINE_FREQUENCY_50HZ)
                light_freq = 50;
        else
                light_freq = 60;
        mbd = (1000UL * ov965x->fiv->interval.denominator *
               ov965x->frame_size->max_exp_lines) /
               ov965x->fiv->interval.numerator;
        mbd = ((mbd / (light_freq * 2)) + 500) / 1000UL;

        return ov965x_write(ov965x->client, REG_MBD, mbd);
}

static int ov965x_set_white_balance(struct ov965x *ov965x, int awb)
{
        int ret;
        u8 reg;

        ret = ov965x_read(ov965x->client, REG_COM8, &reg);
        if (!ret) {
                reg = awb ? reg | REG_COM8 : reg & ~REG_COM8;
                ret = ov965x_write(ov965x->client, REG_COM8, reg);
        }
        if (!ret && !awb) {
                ret = ov965x_write(ov965x->client, REG_BLUE,
                                   ov965x->ctrls.blue_balance->val);
                if (ret < 0)
                        return ret;
                ret = ov965x_write(ov965x->client, REG_RED,
                                   ov965x->ctrls.red_balance->val);
        }
        return ret;
}

#define NUM_BR_LEVELS   7
#define NUM_BR_REGS     3

static int ov965x_set_brightness(struct ov965x *ov965x, int val)
{
        static const u8 regs[NUM_BR_LEVELS + 1][NUM_BR_REGS] = {
                { REG_AEW, REG_AEB, REG_VPT },
                { 0x1c, 0x12, 0x50 }, /* -3 */
                { 0x3d, 0x30, 0x71 }, /* -2 */
                { 0x50, 0x44, 0x92 }, /* -1 */
                { 0x70, 0x64, 0xc3 }, /*  0 */
                { 0x90, 0x84, 0xd4 }, /* +1 */
                { 0xc4, 0xbf, 0xf9 }, /* +2 */
                { 0xd8, 0xd0, 0xfa }, /* +3 */
        };
        int i, ret = 0;

        val += (NUM_BR_LEVELS / 2 + 1);
        if (val > NUM_BR_LEVELS)
                return -EINVAL;

        for (i = 0; i < NUM_BR_REGS && !ret; i++)
                ret = ov965x_write(ov965x->client, regs[0][i],
                                   regs[val][i]);
        return ret;
}

static int ov965x_set_gain(struct ov965x *ov965x, int auto_gain)
{
        struct i2c_client *client = ov965x->client;
        struct ov965x_ctrls *ctrls = &ov965x->ctrls;
        int ret = 0;
        u8 reg;
        /*
         * For manual mode we need to disable AGC first, so
         * gain value in REG_VREF, REG_GAIN is not overwritten.
         */
        if (ctrls->auto_gain->is_new) {
                ret = ov965x_read(client, REG_COM8, &reg);
                if (ret < 0)
                        return ret;
                if (ctrls->auto_gain->val)
                        reg |= COM8_AGC;
                else
                        reg &= ~COM8_AGC;
                ret = ov965x_write(client, REG_COM8, reg);
                if (ret < 0)
                        return ret;
        }

        if (ctrls->gain->is_new && !auto_gain) {
                unsigned int gain = ctrls->gain->val;
                unsigned int rgain;
                int m;
                /*
                 * Convert gain control value to the sensor's gain
                 * registers (VREF[7:6], GAIN[7:0]) format.
                 */
                for (m = 6; m >= 0; m--)
                        if (gain >= (1 << m) * 16)
                                break;
                rgain = (gain - ((1 << m) * 16)) / (1 << m);
                rgain |= (((1 << m) - 1) << 4);

                ret = ov965x_write(client, REG_GAIN, rgain & 0xff);
                if (ret < 0)
                        return ret;
                ret = ov965x_read(client, REG_VREF, &reg);
                if (ret < 0)
                        return ret;
                reg &= ~VREF_GAIN_MASK;
                reg |= (((rgain >> 8) & 0x3) << 6);
                ret = ov965x_write(client, REG_VREF, reg);
                if (ret < 0)
                        return ret;
                /* Return updated control's value to userspace */
                ctrls->gain->val = (1 << m) * (16 + (rgain & 0xf));
        }

        return ret;
}

static int ov965x_set_sharpness(struct ov965x *ov965x, unsigned int value)
{
        u8 com14, edge;
        int ret;

        ret = ov965x_read(ov965x->client, REG_COM14, &com14);
        if (ret < 0)
                return ret;
        ret = ov965x_read(ov965x->client, REG_EDGE, &edge);
        if (ret < 0)
                return ret;
        com14 = value ? com14 | COM14_EDGE_EN : com14 & ~COM14_EDGE_EN;
        value--;
        if (value > 0x0f) {
                com14 |= COM14_EEF_X2;
                value >>= 1;
        } else {
                com14 &= ~COM14_EEF_X2;
        }
        ret = ov965x_write(ov965x->client, REG_COM14, com14);
        if (ret < 0)
                return ret;

        edge &= ~EDGE_FACTOR_MASK;
        edge |= ((u8)value & 0x0f);

        return ov965x_write(ov965x->client, REG_EDGE, edge);
}

static int ov965x_set_exposure(struct ov965x *ov965x, int exp)
{
        struct i2c_client *client = ov965x->client;
        struct ov965x_ctrls *ctrls = &ov965x->ctrls;
        bool auto_exposure = (exp == V4L2_EXPOSURE_AUTO);
        int ret;
        u8 reg;

        if (ctrls->auto_exp->is_new) {
                ret = ov965x_read(client, REG_COM8, &reg);
                if (ret < 0)
                        return ret;
                if (auto_exposure)
                        reg |= (COM8_AEC | COM8_AGC);
                else
                        reg &= ~(COM8_AEC | COM8_AGC);
                ret = ov965x_write(client, REG_COM8, reg);
                if (ret < 0)
                        return ret;
        }

        if (!auto_exposure && ctrls->exposure->is_new) {
                unsigned int exposure = (ctrls->exposure->val * 100)
                                         / ov965x->exp_row_interval;
                /*
                 * Manual exposure value
                 * [b15:b0] - AECHM (b15:b10), AECH (b9:b2), COM1 (b1:b0)
                 */
                ret = ov965x_write(client, REG_COM1, exposure & 0x3);
                if (!ret)
                        ret = ov965x_write(client, REG_AECH,
                                           (exposure >> 2) & 0xff);
                if (!ret)
                        ret = ov965x_write(client, REG_AECHM,
                                           (exposure >> 10) & 0x3f);
                /* Update the value to minimize rounding errors */
                ctrls->exposure->val = ((exposure * ov965x->exp_row_interval)
                                                        + 50) / 100;
                if (ret < 0)
                        return ret;
        }

        v4l2_ctrl_activate(ov965x->ctrls.brightness, !exp);
        return 0;
}

static int ov965x_set_flip(struct ov965x *ov965x)
{
        u8 mvfp = 0;

        if (ov965x->ctrls.hflip->val)
                mvfp |= MVFP_MIRROR;

        if (ov965x->ctrls.vflip->val)
                mvfp |= MVFP_FLIP;

        return ov965x_write(ov965x->client, REG_MVFP, mvfp);
}

#define NUM_SAT_LEVELS  5
#define NUM_SAT_REGS    6

static int ov965x_set_saturation(struct ov965x *ov965x, int val)
{
        static const u8 regs[NUM_SAT_LEVELS][NUM_SAT_REGS] = {
                /* MTX(1)...MTX(6) */
                { 0x1d, 0x1f, 0x02, 0x09, 0x13, 0x1c }, /* -2 */
                { 0x2e, 0x31, 0x02, 0x0e, 0x1e, 0x2d }, /* -1 */
                { 0x3a, 0x3d, 0x03, 0x12, 0x26, 0x38 }, /*  0 */
                { 0x46, 0x49, 0x04, 0x16, 0x2e, 0x43 }, /* +1 */
                { 0x57, 0x5c, 0x05, 0x1b, 0x39, 0x54 }, /* +2 */
        };
        u8 addr = REG_MTX(1);
        int i, ret = 0;

        val += (NUM_SAT_LEVELS / 2);
        if (val >= NUM_SAT_LEVELS)
                return -EINVAL;

        for (i = 0; i < NUM_SAT_REGS && !ret; i++)
                ret = ov965x_write(ov965x->client, addr + i, regs[val][i]);

        return ret;
}

static int ov965x_set_test_pattern(struct ov965x *ov965x, int value)
{
        int ret;
        u8 reg;

        ret = ov965x_read(ov965x->client, REG_COM23, &reg);
        if (ret < 0)
                return ret;
        reg = value ? reg | COM23_TEST_MODE : reg & ~COM23_TEST_MODE;
        return ov965x_write(ov965x->client, REG_COM23, reg);
}

static int __g_volatile_ctrl(struct ov965x *ov965x, struct v4l2_ctrl *ctrl)
{
        struct i2c_client *client = ov965x->client;
        unsigned int exposure, gain, m;
        u8 reg0, reg1, reg2;
        int ret;

        if (!ov965x->power)
                return 0;

        switch (ctrl->id) {
        case V4L2_CID_AUTOGAIN:
                if (!ctrl->val)
                        return 0;
                ret = ov965x_read(client, REG_GAIN, &reg0);
                if (ret < 0)
                        return ret;
                ret = ov965x_read(client, REG_VREF, &reg1);
                if (ret < 0)
                        return ret;
                gain = ((reg1 >> 6) << 8) | reg0;
                m = 0x01 << fls(gain >> 4);
                ov965x->ctrls.gain->val = m * (16 + (gain & 0xf));
                break;

        case V4L2_CID_EXPOSURE_AUTO:
                if (ctrl->val == V4L2_EXPOSURE_MANUAL)
                        return 0;
                ret = ov965x_read(client, REG_COM1, &reg0);
                if (ret < 0)
                        return ret;
                ret = ov965x_read(client, REG_AECH, &reg1);
                if (ret < 0)
                        return ret;
                ret = ov965x_read(client, REG_AECHM, &reg2);
                if (ret < 0)
                        return ret;
                exposure = ((reg2 & 0x3f) << 10) | (reg1 << 2) |
                                                (reg0 & 0x3);
                ov965x->ctrls.exposure->val = ((exposure *
                                ov965x->exp_row_interval) + 50) / 100;
                break;
        }

        return 0;
}

static int ov965x_g_volatile_ctrl(struct v4l2_ctrl *ctrl)
{
        struct v4l2_subdev *sd = ctrl_to_sd(ctrl);
        struct ov965x *ov965x = to_ov965x(sd);
        int ret;

        v4l2_dbg(1, debug, sd, "g_ctrl: %s\n", ctrl->name);

        mutex_lock(&ov965x->lock);
        ret = __g_volatile_ctrl(ov965x, ctrl);
        mutex_unlock(&ov965x->lock);
        return ret;
}

static int ov965x_s_ctrl(struct v4l2_ctrl *ctrl)
{
        struct v4l2_subdev *sd = ctrl_to_sd(ctrl);
        struct ov965x *ov965x = to_ov965x(sd);
        int ret = -EINVAL;

        v4l2_dbg(1, debug, sd, "s_ctrl: %s, value: %d. power: %d\n",
                 ctrl->name, ctrl->val, ov965x->power);

        mutex_lock(&ov965x->lock);
        /*
         * If the device is not powered up now postpone applying control's
         * value to the hardware, until it is ready to accept commands.
         */
        if (ov965x->power == 0) {
                mutex_unlock(&ov965x->lock);
                return 0;
        }

        switch (ctrl->id) {
        case V4L2_CID_AUTO_WHITE_BALANCE:
                ret = ov965x_set_white_balance(ov965x, ctrl->val);
                break;

        case V4L2_CID_BRIGHTNESS:
                ret = ov965x_set_brightness(ov965x, ctrl->val);
                break;

        case V4L2_CID_EXPOSURE_AUTO:
                ret = ov965x_set_exposure(ov965x, ctrl->val);
                break;

        case V4L2_CID_AUTOGAIN:
                ret = ov965x_set_gain(ov965x, ctrl->val);
                break;

        case V4L2_CID_HFLIP:
                ret = ov965x_set_flip(ov965x);
                break;

        case V4L2_CID_POWER_LINE_FREQUENCY:
                ret = ov965x_set_banding_filter(ov965x, ctrl->val);
                break;

        case V4L2_CID_SATURATION:
                ret = ov965x_set_saturation(ov965x, ctrl->val);
                break;

        case V4L2_CID_SHARPNESS:
                ret = ov965x_set_sharpness(ov965x, ctrl->val);
                break;

        case V4L2_CID_TEST_PATTERN:
                ret = ov965x_set_test_pattern(ov965x, ctrl->val);
                break;
        }

        mutex_unlock(&ov965x->lock);
        return ret;
}

static const struct v4l2_ctrl_ops ov965x_ctrl_ops = {
        .g_volatile_ctrl = ov965x_g_volatile_ctrl,
        .s_ctrl = ov965x_s_ctrl,
};

static const char * const test_pattern_menu[] = {
        "Disabled",
        "Color bars",
};

static int ov965x_initialize_controls(struct ov965x *ov965x)
{
        const struct v4l2_ctrl_ops *ops = &ov965x_ctrl_ops;

        struct ov965x_ctrls *ctrls = &ov965x->ctrls;
        struct v4l2_ctrl_handler *hdl = &ctrls->handler;
        int ret;

        ret = v4l2_ctrl_handler_init(hdl, 16);
        if (ret < 0)
                return ret;

        /* Auto/manual white balance */
        ctrls->auto_wb = v4l2_ctrl_new_std(hdl, ops,
                                           V4L2_CID_AUTO_WHITE_BALANCE,
                                           0, 1, 1, 1);
        ctrls->blue_balance = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_BLUE_BALANCE,
                                                0, 0xff, 1, 0x80);
        ctrls->red_balance = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_RED_BALANCE,
                                               0, 0xff, 1, 0x80);
        /* Auto/manual exposure */
        ctrls->auto_exp =
                v4l2_ctrl_new_std_menu(hdl, ops,
                                       V4L2_CID_EXPOSURE_AUTO,
                                       V4L2_EXPOSURE_MANUAL, 0,
                                       V4L2_EXPOSURE_AUTO);
        /* Exposure time, in 100 us units. min/max is updated dynamically. */
        ctrls->exposure = v4l2_ctrl_new_std(hdl, ops,
                                            V4L2_CID_EXPOSURE_ABSOLUTE,
                                            2, 1500, 1, 500);
        /* Auto/manual gain */
        ctrls->auto_gain = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_AUTOGAIN,
                                             0, 1, 1, 1);
        ctrls->gain = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_GAIN,
                                        16, 64 * (16 + 15), 1, 64 * 16);

        ctrls->saturation = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_SATURATION,
                                              -2, 2, 1, 0);
        ctrls->brightness = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_BRIGHTNESS,
                                              -3, 3, 1, 0);
        ctrls->sharpness = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_SHARPNESS,
                                             0, 32, 1, 6);

        ctrls->hflip = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_HFLIP, 0, 1, 1, 0);
        ctrls->vflip = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_VFLIP, 0, 1, 1, 0);

        ctrls->light_freq =
                v4l2_ctrl_new_std_menu(hdl, ops,
                                       V4L2_CID_POWER_LINE_FREQUENCY,
                                       V4L2_CID_POWER_LINE_FREQUENCY_60HZ, ~0x7,
                                       V4L2_CID_POWER_LINE_FREQUENCY_50HZ);

        v4l2_ctrl_new_std_menu_items(hdl, ops, V4L2_CID_TEST_PATTERN,
                                     ARRAY_SIZE(test_pattern_menu) - 1, 0, 0,
                                     test_pattern_menu);
        if (hdl->error) {
                ret = hdl->error;
                v4l2_ctrl_handler_free(hdl);
                return ret;
        }

        ctrls->gain->flags |= V4L2_CTRL_FLAG_VOLATILE;
        ctrls->exposure->flags |= V4L2_CTRL_FLAG_VOLATILE;

        v4l2_ctrl_auto_cluster(3, &ctrls->auto_wb, 0, false);
        v4l2_ctrl_auto_cluster(2, &ctrls->auto_gain, 0, true);
        v4l2_ctrl_auto_cluster(2, &ctrls->auto_exp, 1, true);
        v4l2_ctrl_cluster(2, &ctrls->hflip);

        ov965x->sd.ctrl_handler = hdl;
        return 0;
}

/*
 * V4L2 subdev video and pad level operations
 */
static void ov965x_get_default_format(struct v4l2_mbus_framefmt *mf)
{
        mf->width = ov965x_framesizes[0].width;
        mf->height = ov965x_framesizes[0].height;
        mf->colorspace = ov965x_formats[0].colorspace;
        mf->code = ov965x_formats[0].code;
        mf->field = V4L2_FIELD_NONE;
}

static int ov965x_enum_mbus_code(struct v4l2_subdev *sd,
                                 struct v4l2_subdev_pad_config *cfg,
                                 struct v4l2_subdev_mbus_code_enum *code)
{
        if (code->index >= ARRAY_SIZE(ov965x_formats))
                return -EINVAL;

        code->code = ov965x_formats[code->index].code;
        return 0;
}

static int ov965x_enum_frame_sizes(struct v4l2_subdev *sd,
                                   struct v4l2_subdev_pad_config *cfg,
                                   struct v4l2_subdev_frame_size_enum *fse)
{
        int i = ARRAY_SIZE(ov965x_formats);

        if (fse->index >= ARRAY_SIZE(ov965x_framesizes))
                return -EINVAL;

        while (--i)
                if (fse->code == ov965x_formats[i].code)
                        break;

        fse->code = ov965x_formats[i].code;

        fse->min_width  = ov965x_framesizes[fse->index].width;
        fse->max_width  = fse->min_width;
        fse->max_height = ov965x_framesizes[fse->index].height;
        fse->min_height = fse->max_height;

        return 0;
}

static int ov965x_g_frame_interval(struct v4l2_subdev *sd,
                                   struct v4l2_subdev_frame_interval *fi)
{
        struct ov965x *ov965x = to_ov965x(sd);

        mutex_lock(&ov965x->lock);
        fi->interval = ov965x->fiv->interval;
        mutex_unlock(&ov965x->lock);

        return 0;
}

static int __ov965x_set_frame_interval(struct ov965x *ov965x,
                                       struct v4l2_subdev_frame_interval *fi)
{
        struct v4l2_mbus_framefmt *mbus_fmt = &ov965x->format;
        const struct ov965x_interval *fiv = &ov965x_intervals[0];
        u64 req_int, err, min_err = ~0ULL;
        unsigned int i;

        if (fi->interval.denominator == 0)
                return -EINVAL;

        req_int = (u64)fi->interval.numerator * 10000;
        do_div(req_int, fi->interval.denominator);

        for (i = 0; i < ARRAY_SIZE(ov965x_intervals); i++) {
                const struct ov965x_interval *iv = &ov965x_intervals[i];

                if (mbus_fmt->width != iv->size.width ||
                    mbus_fmt->height != iv->size.height)
                        continue;
                err = abs((u64)(iv->interval.numerator * 10000) /
                            iv->interval.denominator - req_int);
                if (err < min_err) {
                        fiv = iv;
                        min_err = err;
                }
        }
        ov965x->fiv = fiv;

        v4l2_dbg(1, debug, &ov965x->sd, "Changed frame interval to %u us\n",
                 fiv->interval.numerator * 1000000 / fiv->interval.denominator);

        return 0;
}

static int ov965x_s_frame_interval(struct v4l2_subdev *sd,
                                   struct v4l2_subdev_frame_interval *fi)
{
        struct ov965x *ov965x = to_ov965x(sd);
        int ret;

        v4l2_dbg(1, debug, sd, "Setting %d/%d frame interval\n",
                 fi->interval.numerator, fi->interval.denominator);

        mutex_lock(&ov965x->lock);
        ret = __ov965x_set_frame_interval(ov965x, fi);
        ov965x->apply_frame_fmt = 1;
        mutex_unlock(&ov965x->lock);
        return ret;
}

static int ov965x_get_fmt(struct v4l2_subdev *sd,
                          struct v4l2_subdev_pad_config *cfg,
                          struct v4l2_subdev_format *fmt)
{
        struct ov965x *ov965x = to_ov965x(sd);
        struct v4l2_mbus_framefmt *mf;

        if (fmt->which == V4L2_SUBDEV_FORMAT_TRY) {
                mf = v4l2_subdev_get_try_format(sd, cfg, 0);
                fmt->format = *mf;
                return 0;
        }

        mutex_lock(&ov965x->lock);
        fmt->format = ov965x->format;
        mutex_unlock(&ov965x->lock);

        return 0;
}

static void __ov965x_try_frame_size(struct v4l2_mbus_framefmt *mf,
                                    const struct ov965x_framesize **size)
{
        const struct ov965x_framesize *fsize = &ov965x_framesizes[0],
                *match = NULL;
        int i = ARRAY_SIZE(ov965x_framesizes);
        unsigned int min_err = UINT_MAX;

        while (i--) {
                int err = abs(fsize->width - mf->width)
                                + abs(fsize->height - mf->height);
                if (err < min_err) {
                        min_err = err;
                        match = fsize;
                }
                fsize++;
        }
        if (!match)
                match = &ov965x_framesizes[0];
        mf->width  = match->width;
        mf->height = match->height;
        if (size)
                *size = match;
}

static int ov965x_set_fmt(struct v4l2_subdev *sd,
                          struct v4l2_subdev_pad_config *cfg,
                          struct v4l2_subdev_format *fmt)
{
        unsigned int index = ARRAY_SIZE(ov965x_formats);
        struct v4l2_mbus_framefmt *mf = &fmt->format;
        struct ov965x *ov965x = to_ov965x(sd);
        const struct ov965x_framesize *size = NULL;
        int ret = 0;

        __ov965x_try_frame_size(mf, &size);

        while (--index)
                if (ov965x_formats[index].code == mf->code)
                        break;

        mf->colorspace  = V4L2_COLORSPACE_JPEG;
        mf->code        = ov965x_formats[index].code;
        mf->field       = V4L2_FIELD_NONE;

        mutex_lock(&ov965x->lock);

        if (fmt->which == V4L2_SUBDEV_FORMAT_TRY) {
                if (cfg) {
                        mf = v4l2_subdev_get_try_format(sd, cfg, fmt->pad);
                        *mf = fmt->format;
                }
        } else {
                if (ov965x->streaming) {
                        ret = -EBUSY;
                } else {
                        ov965x->frame_size = size;
                        ov965x->format = fmt->format;
                        ov965x->tslb_reg = ov965x_formats[index].tslb_reg;
                        ov965x->apply_frame_fmt = 1;
                }
        }

        if (!ret && fmt->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
                struct v4l2_subdev_frame_interval fiv = {
                        .interval = { 0, 1 }
                };
                /* Reset to minimum possible frame interval */
                __ov965x_set_frame_interval(ov965x, &fiv);
        }
        mutex_unlock(&ov965x->lock);

        if (!ret)
                ov965x_update_exposure_ctrl(ov965x);

        return ret;
}

static int ov965x_set_frame_size(struct ov965x *ov965x)
{
        int i, ret = 0;

        for (i = 0; ret == 0 && i < NUM_FMT_REGS; i++)
                ret = ov965x_write(ov965x->client, frame_size_reg_addr[i],
                                   ov965x->frame_size->regs[i]);
        return ret;
}

static int __ov965x_set_params(struct ov965x *ov965x)
{
        struct i2c_client *client = ov965x->client;
        struct ov965x_ctrls *ctrls = &ov965x->ctrls;
        int ret = 0;
        u8 reg;

        if (ov965x->apply_frame_fmt) {
                reg = DEF_CLKRC + ov965x->fiv->clkrc_div;
                ret = ov965x_write(client, REG_CLKRC, reg);
                if (ret < 0)
                        return ret;
                ret = ov965x_set_frame_size(ov965x);
                if (ret < 0)
                        return ret;
                ret = ov965x_read(client, REG_TSLB, &reg);
                if (ret < 0)
                        return ret;
                reg &= ~TSLB_YUYV_MASK;
                reg |= ov965x->tslb_reg;
                ret = ov965x_write(client, REG_TSLB, reg);
                if (ret < 0)
                        return ret;
        }
        ret = ov965x_set_default_gamma_curve(ov965x);
        if (ret < 0)
                return ret;
        ret = ov965x_set_color_matrix(ov965x);
        if (ret < 0)
                return ret;
        /*
         * Select manual banding filter, the filter will
         * be enabled further if required.
         */
        ret = ov965x_read(client, REG_COM11, &reg);
        if (!ret)
                reg |= COM11_BANDING;
        ret = ov965x_write(client, REG_COM11, reg);
        if (ret < 0)
                return ret;
        /*
         * Banding filter (REG_MBD value) needs to match selected
         * resolution and frame rate, so it's always updated here.
         */
        return ov965x_set_banding_filter(ov965x, ctrls->light_freq->val);
}

static int ov965x_s_stream(struct v4l2_subdev *sd, int on)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct ov965x *ov965x = to_ov965x(sd);
        struct ov965x_ctrls *ctrls = &ov965x->ctrls;
        int ret = 0;

        v4l2_dbg(1, debug, client, "%s: on: %d\n", __func__, on);

        mutex_lock(&ov965x->lock);
        if (ov965x->streaming == !on) {
                if (on)
                        ret = __ov965x_set_params(ov965x);

                if (!ret && ctrls->update) {
                        /*
                         * ov965x_s_ctrl callback takes the mutex
                         * so it needs to be released here.
                         */
                        mutex_unlock(&ov965x->lock);
                        ret = v4l2_ctrl_handler_setup(&ctrls->handler);

                        mutex_lock(&ov965x->lock);
                        if (!ret)
                                ctrls->update = 0;
                }
                if (!ret)
                        ret = ov965x_write(client, REG_COM2,
                                           on ? 0x01 : 0x11);
        }
        if (!ret)
                ov965x->streaming += on ? 1 : -1;

        WARN_ON(ov965x->streaming < 0);
        mutex_unlock(&ov965x->lock);

        return ret;
}

/*
 * V4L2 subdev internal operations
 */
static int ov965x_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
{
        struct v4l2_mbus_framefmt *mf =
                v4l2_subdev_get_try_format(sd, fh->pad, 0);

        ov965x_get_default_format(mf);
        return 0;
}

static const struct v4l2_subdev_pad_ops ov965x_pad_ops = {
        .enum_mbus_code = ov965x_enum_mbus_code,
        .enum_frame_size = ov965x_enum_frame_sizes,
        .get_fmt = ov965x_get_fmt,
        .set_fmt = ov965x_set_fmt,
};

static const struct v4l2_subdev_video_ops ov965x_video_ops = {
        .s_stream = ov965x_s_stream,
        .g_frame_interval = ov965x_g_frame_interval,
        .s_frame_interval = ov965x_s_frame_interval,

};

static const struct v4l2_subdev_internal_ops ov965x_sd_internal_ops = {
        .open = ov965x_open,
};

static const struct v4l2_subdev_core_ops ov965x_core_ops = {
        .s_power = ov965x_s_power,
        .log_status = v4l2_ctrl_subdev_log_status,
        .subscribe_event = v4l2_ctrl_subdev_subscribe_event,
        .unsubscribe_event = v4l2_event_subdev_unsubscribe,
};

static const struct v4l2_subdev_ops ov965x_subdev_ops = {
        .core = &ov965x_core_ops,
        .pad = &ov965x_pad_ops,
        .video = &ov965x_video_ops,
};

/*
 * Reset and power down GPIOs configuration
 */
static int ov965x_configure_gpios_pdata(struct ov965x *ov965x,
                                const struct ov9650_platform_data *pdata)
{
        int ret, i;
        int gpios[NUM_GPIOS];

        gpios[GPIO_PWDN] = pdata->gpio_pwdn;
        gpios[GPIO_RST]  = pdata->gpio_reset;

        for (i = 0; i < ARRAY_SIZE(ov965x->gpios); i++) {
                int gpio = gpios[i];

                if (!gpio_is_valid(gpio))
                        continue;
                ret = devm_gpio_request_one(&ov965x->client->dev, gpio,
                                            GPIOF_OUT_INIT_HIGH, "OV965X");
                if (ret < 0)
                        return ret;
                v4l2_dbg(1, debug, &ov965x->sd, "set gpio %d to 1\n", gpio);

                gpio_set_value_cansleep(gpio, 1);
                gpio_export(gpio, 0);
                ov965x->gpios[i] = gpio_to_desc(gpio);
        }

        return 0;
}

static int ov965x_configure_gpios(struct ov965x *ov965x)
{
        struct device *dev = &ov965x->client->dev;

        ov965x->gpios[GPIO_PWDN] = devm_gpiod_get_optional(dev, "powerdown",
                                                        GPIOD_OUT_HIGH);
        if (IS_ERR(ov965x->gpios[GPIO_PWDN])) {
                dev_info(dev, "can't get %s GPIO\n", "powerdown");
                return PTR_ERR(ov965x->gpios[GPIO_PWDN]);
        }

        ov965x->gpios[GPIO_RST] = devm_gpiod_get_optional(dev, "reset",
                                                        GPIOD_OUT_HIGH);
        if (IS_ERR(ov965x->gpios[GPIO_RST])) {
                dev_info(dev, "can't get %s GPIO\n", "reset");
                return PTR_ERR(ov965x->gpios[GPIO_RST]);
        }

        return 0;
}

static int ov965x_detect_sensor(struct v4l2_subdev *sd)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct ov965x *ov965x = to_ov965x(sd);
        u8 pid, ver;
        int ret;

        mutex_lock(&ov965x->lock);
        ret = __ov965x_set_power(ov965x, 1);
        if (ret)
                goto out;

        msleep(25);

        /* Check sensor revision */
        ret = ov965x_read(client, REG_PID, &pid);
        if (!ret)
                ret = ov965x_read(client, REG_VER, &ver);

        __ov965x_set_power(ov965x, 0);

        if (!ret) {
                ov965x->id = OV965X_ID(pid, ver);
                if (ov965x->id == OV9650_ID || ov965x->id == OV9652_ID) {
                        v4l2_info(sd, "Found OV%04X sensor\n", ov965x->id);
                } else {
                        v4l2_err(sd, "Sensor detection failed (%04X, %d)\n",
                                 ov965x->id, ret);
                        ret = -ENODEV;
                }
        }
out:
        mutex_unlock(&ov965x->lock);

        return ret;
}

static int ov965x_probe(struct i2c_client *client,
                        const struct i2c_device_id *id)
{
        const struct ov9650_platform_data *pdata = client->dev.platform_data;
        struct v4l2_subdev *sd;
        struct ov965x *ov965x;
        int ret;

        ov965x = devm_kzalloc(&client->dev, sizeof(*ov965x), GFP_KERNEL);
        if (!ov965x)
                return -ENOMEM;

        ov965x->client = client;

        if (pdata) {
                if (pdata->mclk_frequency == 0) {
                        dev_err(&client->dev, "MCLK frequency not specified\n");
                        return -EINVAL;
                }
                ov965x->mclk_frequency = pdata->mclk_frequency;

                ret = ov965x_configure_gpios_pdata(ov965x, pdata);
                if (ret < 0)
                        return ret;
        } else if (dev_fwnode(&client->dev)) {
                ov965x->clk = devm_clk_get(&ov965x->client->dev, NULL);
                if (IS_ERR(ov965x->clk))
                        return PTR_ERR(ov965x->clk);
                ov965x->mclk_frequency = clk_get_rate(ov965x->clk);

                ret = ov965x_configure_gpios(ov965x);
                if (ret < 0)
                        return ret;
        } else {
                dev_err(&client->dev,
                        "Neither platform data nor device property specified\n");

                return -EINVAL;
        }

        mutex_init(&ov965x->lock);

        sd = &ov965x->sd;
        v4l2_i2c_subdev_init(sd, client, &ov965x_subdev_ops);
        strlcpy(sd->name, DRIVER_NAME, sizeof(sd->name));

        sd->internal_ops = &ov965x_sd_internal_ops;
        sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE |
                     V4L2_SUBDEV_FL_HAS_EVENTS;

        ov965x->pad.flags = MEDIA_PAD_FL_SOURCE;
        sd->entity.function = MEDIA_ENT_F_CAM_SENSOR;
        ret = media_entity_pads_init(&sd->entity, 1, &ov965x->pad);
        if (ret < 0)
                goto err_mutex;

        ret = ov965x_initialize_controls(ov965x);
        if (ret < 0)
                goto err_me;

        ov965x_get_default_format(&ov965x->format);
        ov965x->frame_size = &ov965x_framesizes[0];
        ov965x->fiv = &ov965x_intervals[0];

        ret = ov965x_detect_sensor(sd);
        if (ret < 0)
                goto err_ctrls;

        /* Update exposure time min/max to match frame format */
        ov965x_update_exposure_ctrl(ov965x);

        ret = v4l2_async_register_subdev(sd);
        if (ret < 0)
                goto err_ctrls;

        return 0;
err_ctrls:
        v4l2_ctrl_handler_free(sd->ctrl_handler);
err_me:
        media_entity_cleanup(&sd->entity);
err_mutex:
        mutex_destroy(&ov965x->lock);
        return ret;
}

static int ov965x_remove(struct i2c_client *client)
{
        struct v4l2_subdev *sd = i2c_get_clientdata(client);
        struct ov965x *ov965x = to_ov965x(sd);

        v4l2_async_unregister_subdev(sd);
        v4l2_ctrl_handler_free(sd->ctrl_handler);
        media_entity_cleanup(&sd->entity);
        mutex_destroy(&ov965x->lock);

        return 0;
}

static const struct i2c_device_id ov965x_id[] = {
        { "OV9650", 0 },
        { "OV9652", 0 },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(i2c, ov965x_id);

#if IS_ENABLED(CONFIG_OF)
static const struct of_device_id ov965x_of_match[] = {
        { .compatible = "ovti,ov9650", },
        { .compatible = "ovti,ov9652", },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, ov965x_of_match);
#endif

static struct i2c_driver ov965x_i2c_driver = {
        .driver = {
                .name   = DRIVER_NAME,
                .of_match_table = of_match_ptr(ov965x_of_match),
        },
        .probe          = ov965x_probe,
        .remove         = ov965x_remove,
        .id_table       = ov965x_id,
};

module_i2c_driver(ov965x_i2c_driver);

MODULE_AUTHOR("Sylwester Nawrocki <sylvester.nawrocki@gmail.com>");
MODULE_DESCRIPTION("OV9650/OV9652 CMOS Image Sensor driver");
MODULE_LICENSE("GPL");