// SPDX-License-Identifier: GPL-2.0
/*
 * mt9t112 Camera Driver
 *
 * Copyright (C) 2018 Jacopo Mondi <jacopo+renesas@jmondi.org>
 *
 * Copyright (C) 2009 Renesas Solutions Corp.
 * Kuninori Morimoto <morimoto.kuninori@renesas.com>
 *
 * Based on ov772x driver, mt9m111 driver,
 *
 * Copyright (C) 2008 Kuninori Morimoto <morimoto.kuninori@renesas.com>
 * Copyright (C) 2008, Robert Jarzmik <robert.jarzmik@free.fr>
 * Copyright 2006-7 Jonathan Corbet <corbet@lwn.net>
 * Copyright (C) 2008 Magnus Damm
 * Copyright (C) 2008, Guennadi Liakhovetski <kernel@pengutronix.de>
 *
 * TODO: This driver lacks support for frame rate control due to missing
 *       register level documentation and suitable hardware for testing.
 *       v4l-utils compliance tools will report errors.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/v4l2-mediabus.h>
#include <linux/videodev2.h>

#include <media/i2c/mt9t112.h>
#include <media/v4l2-common.h>
#include <media/v4l2-image-sizes.h>
#include <media/v4l2-subdev.h>

/* you can check PLL/clock info */
/* #define EXT_CLOCK 24000000 */

/************************************************************************
 *                      macro
 ***********************************************************************/
/*
 * frame size
 */
#define MAX_WIDTH   2048
#define MAX_HEIGHT  1536

/*
 * macro of read/write
 */
#define ECHECKER(ret, x)                \
        do {                            \
                (ret) = (x);            \
                if ((ret) < 0)          \
                        return (ret);   \
        } while (0)

#define mt9t112_reg_write(ret, client, a, b) \
        ECHECKER(ret, __mt9t112_reg_write(client, a, b))
#define mt9t112_mcu_write(ret, client, a, b) \
        ECHECKER(ret, __mt9t112_mcu_write(client, a, b))

#define mt9t112_reg_mask_set(ret, client, a, b, c) \
        ECHECKER(ret, __mt9t112_reg_mask_set(client, a, b, c))
#define mt9t112_mcu_mask_set(ret, client, a, b, c) \
        ECHECKER(ret, __mt9t112_mcu_mask_set(client, a, b, c))

#define mt9t112_reg_read(ret, client, a) \
        ECHECKER(ret, __mt9t112_reg_read(client, a))

/*
 * Logical address
 */
#define _VAR(id, offset, base)  (base | (id & 0x1f) << 10 | (offset & 0x3ff))
#define VAR(id, offset)  _VAR(id, offset, 0x0000)
#define VAR8(id, offset) _VAR(id, offset, 0x8000)

/************************************************************************
 *                      struct
 ***********************************************************************/
struct mt9t112_format {
        u32 code;
        enum v4l2_colorspace colorspace;
        u16 fmt;
        u16 order;
};

struct mt9t112_priv {
        struct v4l2_subdev               subdev;
        struct mt9t112_platform_data    *info;
        struct i2c_client               *client;
        struct v4l2_rect                 frame;
        struct clk                      *clk;
        struct gpio_desc                *standby_gpio;
        const struct mt9t112_format     *format;
        int                              num_formats;
        bool                             init_done;
};

/************************************************************************
 *                      supported format
 ***********************************************************************/

static const struct mt9t112_format mt9t112_cfmts[] = {
        {
                .code           = MEDIA_BUS_FMT_UYVY8_2X8,
                .colorspace     = V4L2_COLORSPACE_SRGB,
                .fmt            = 1,
                .order          = 0,
        }, {
                .code           = MEDIA_BUS_FMT_VYUY8_2X8,
                .colorspace     = V4L2_COLORSPACE_SRGB,
                .fmt            = 1,
                .order          = 1,
        }, {
                .code           = MEDIA_BUS_FMT_YUYV8_2X8,
                .colorspace     = V4L2_COLORSPACE_SRGB,
                .fmt            = 1,
                .order          = 2,
        }, {
                .code           = MEDIA_BUS_FMT_YVYU8_2X8,
                .colorspace     = V4L2_COLORSPACE_SRGB,
                .fmt            = 1,
                .order          = 3,
        }, {
                .code           = MEDIA_BUS_FMT_RGB555_2X8_PADHI_LE,
                .colorspace     = V4L2_COLORSPACE_SRGB,
                .fmt            = 8,
                .order          = 2,
        }, {
                .code           = MEDIA_BUS_FMT_RGB565_2X8_LE,
                .colorspace     = V4L2_COLORSPACE_SRGB,
                .fmt            = 4,
                .order          = 2,
        },
};

/************************************************************************
 *                      general function
 ***********************************************************************/
static struct mt9t112_priv *to_mt9t112(const struct i2c_client *client)
{
        return container_of(i2c_get_clientdata(client),
                            struct mt9t112_priv,
                            subdev);
}

static int __mt9t112_reg_read(const struct i2c_client *client, u16 command)
{
        struct i2c_msg msg[2];
        u8 buf[2];
        int ret;

        command = swab16(command);

        msg[0].addr  = client->addr;
        msg[0].flags = 0;
        msg[0].len   = 2;
        msg[0].buf   = (u8 *)&command;

        msg[1].addr  = client->addr;
        msg[1].flags = I2C_M_RD;
        msg[1].len   = 2;
        msg[1].buf   = buf;

        /*
         * If return value of this function is < 0, it means error, else,
         * below 16bit is valid data.
         */
        ret = i2c_transfer(client->adapter, msg, 2);
        if (ret < 0)
                return ret;

        memcpy(&ret, buf, 2);

        return swab16(ret);
}

static int __mt9t112_reg_write(const struct i2c_client *client,
                               u16 command, u16 data)
{
        struct i2c_msg msg;
        u8 buf[4];
        int ret;

        command = swab16(command);
        data = swab16(data);

        memcpy(buf + 0, &command, 2);
        memcpy(buf + 2, &data,    2);

        msg.addr  = client->addr;
        msg.flags = 0;
        msg.len   = 4;
        msg.buf   = buf;

        /*
         * i2c_transfer return message length, but this function should
         * return 0 if correct case.
         */
        ret = i2c_transfer(client->adapter, &msg, 1);

        return ret >= 0 ? 0 : ret;
}

static int __mt9t112_reg_mask_set(const struct i2c_client *client,
                                  u16  command, u16  mask, u16  set)
{
        int val = __mt9t112_reg_read(client, command);

        if (val < 0)
                return val;

        val &= ~mask;
        val |= set & mask;

        return __mt9t112_reg_write(client, command, val);
}

/* mcu access */
static int __mt9t112_mcu_read(const struct i2c_client *client, u16 command)
{
        int ret;

        ret = __mt9t112_reg_write(client, 0x098E, command);
        if (ret < 0)
                return ret;

        return __mt9t112_reg_read(client, 0x0990);
}

static int __mt9t112_mcu_write(const struct i2c_client *client,
                               u16 command, u16 data)
{
        int ret;

        ret = __mt9t112_reg_write(client, 0x098E, command);
        if (ret < 0)
                return ret;

        return __mt9t112_reg_write(client, 0x0990, data);
}

static int __mt9t112_mcu_mask_set(const struct i2c_client *client,
                                  u16  command, u16  mask, u16  set)
{
        int val = __mt9t112_mcu_read(client, command);

        if (val < 0)
                return val;

        val &= ~mask;
        val |= set & mask;

        return __mt9t112_mcu_write(client, command, val);
}

static int mt9t112_reset(const struct i2c_client *client)
{
        int ret;

        mt9t112_reg_mask_set(ret, client, 0x001a, 0x0001, 0x0001);
        usleep_range(1000, 5000);
        mt9t112_reg_mask_set(ret, client, 0x001a, 0x0001, 0x0000);

        return ret;
}

#ifndef EXT_CLOCK
#define CLOCK_INFO(a, b)
#else
#define CLOCK_INFO(a, b) mt9t112_clock_info(a, b)
static int mt9t112_clock_info(const struct i2c_client *client, u32 ext)
{
        int m, n, p1, p2, p3, p4, p5, p6, p7;
        u32 vco, clk;
        char *enable;

        ext /= 1000; /* kbyte order */

        mt9t112_reg_read(n, client, 0x0012);
        p1 = n & 0x000f;
        n = n >> 4;
        p2 = n & 0x000f;
        n = n >> 4;
        p3 = n & 0x000f;

        mt9t112_reg_read(n, client, 0x002a);
        p4 = n & 0x000f;
        n = n >> 4;
        p5 = n & 0x000f;
        n = n >> 4;
        p6 = n & 0x000f;

        mt9t112_reg_read(n, client, 0x002c);
        p7 = n & 0x000f;

        mt9t112_reg_read(n, client, 0x0010);
        m = n & 0x00ff;
        n = (n >> 8) & 0x003f;

        enable = ((ext < 6000) || (ext > 54000)) ? "X" : "";
        dev_dbg(&client->dev, "EXTCLK          : %10u K %s\n", ext, enable);

        vco = 2 * m * ext / (n + 1);
        enable = ((vco < 384000) || (vco > 768000)) ? "X" : "";
        dev_dbg(&client->dev, "VCO             : %10u K %s\n", vco, enable);

        clk = vco / (p1 + 1) / (p2 + 1);
        enable = (clk > 96000) ? "X" : "";
        dev_dbg(&client->dev, "PIXCLK          : %10u K %s\n", clk, enable);

        clk = vco / (p3 + 1);
        enable = (clk > 768000) ? "X" : "";
        dev_dbg(&client->dev, "MIPICLK         : %10u K %s\n", clk, enable);

        clk = vco / (p6 + 1);
        enable = (clk > 96000) ? "X" : "";
        dev_dbg(&client->dev, "MCU CLK         : %10u K %s\n", clk, enable);

        clk = vco / (p5 + 1);
        enable = (clk > 54000) ? "X" : "";
        dev_dbg(&client->dev, "SOC CLK         : %10u K %s\n", clk, enable);

        clk = vco / (p4 + 1);
        enable = (clk > 70000) ? "X" : "";
        dev_dbg(&client->dev, "Sensor CLK      : %10u K %s\n", clk, enable);

        clk = vco / (p7 + 1);
        dev_dbg(&client->dev, "External sensor : %10u K\n", clk);

        clk = ext / (n + 1);
        enable = ((clk < 2000) || (clk > 24000)) ? "X" : "";
        dev_dbg(&client->dev, "PFD             : %10u K %s\n", clk, enable);

        return 0;
}
#endif

static int mt9t112_set_a_frame_size(const struct i2c_client *client,
                                    u16 width, u16 height)
{
        int ret;
        u16 wstart = (MAX_WIDTH - width) / 2;
        u16 hstart = (MAX_HEIGHT - height) / 2;

        /* (Context A) Image Width/Height. */
        mt9t112_mcu_write(ret, client, VAR(26, 0), width);
        mt9t112_mcu_write(ret, client, VAR(26, 2), height);

        /* (Context A) Output Width/Height. */
        mt9t112_mcu_write(ret, client, VAR(18, 43), 8 + width);
        mt9t112_mcu_write(ret, client, VAR(18, 45), 8 + height);

        /* (Context A) Start Row/Column. */
        mt9t112_mcu_write(ret, client, VAR(18, 2), 4 + hstart);
        mt9t112_mcu_write(ret, client, VAR(18, 4), 4 + wstart);

        /* (Context A) End Row/Column. */
        mt9t112_mcu_write(ret, client, VAR(18, 6), 11 + height + hstart);
        mt9t112_mcu_write(ret, client, VAR(18, 8), 11 + width  + wstart);

        mt9t112_mcu_write(ret, client, VAR8(1, 0), 0x06);

        return ret;
}

static int mt9t112_set_pll_dividers(const struct i2c_client *client,
                                    u8 m, u8 n, u8 p1, u8 p2, u8 p3, u8 p4,
                                    u8 p5, u8 p6, u8 p7)
{
        int ret;
        u16 val;

        /* N/M */
        val = (n << 8) | (m << 0);
        mt9t112_reg_mask_set(ret, client, 0x0010, 0x3fff, val);

        /* P1/P2/P3 */
        val = ((p3 & 0x0F) << 8) | ((p2 & 0x0F) << 4) | ((p1 & 0x0F) << 0);
        mt9t112_reg_mask_set(ret, client, 0x0012, 0x0fff, val);

        /* P4/P5/P6 */
        val = (0x7 << 12) | ((p6 & 0x0F) <<  8) | ((p5 & 0x0F) <<  4) |
              ((p4 & 0x0F) <<  0);
        mt9t112_reg_mask_set(ret, client, 0x002A, 0x7fff, val);

        /* P7 */
        val = (0x1 << 12) | ((p7 & 0x0F) <<  0);
        mt9t112_reg_mask_set(ret, client, 0x002C, 0x100f, val);

        return ret;
}

static int mt9t112_init_pll(const struct i2c_client *client)
{
        struct mt9t112_priv *priv = to_mt9t112(client);
        int data, i, ret;

        mt9t112_reg_mask_set(ret, client, 0x0014, 0x003, 0x0001);

        /* PLL control: BYPASS PLL = 8517. */
        mt9t112_reg_write(ret, client, 0x0014, 0x2145);

        /* Replace these registers when new timing parameters are generated. */
        mt9t112_set_pll_dividers(client,
                                 priv->info->divider.m, priv->info->divider.n,
                                 priv->info->divider.p1, priv->info->divider.p2,
                                 priv->info->divider.p3, priv->info->divider.p4,
                                 priv->info->divider.p5, priv->info->divider.p6,
                                 priv->info->divider.p7);

        /*
         * TEST_BYPASS  on
         * PLL_ENABLE   on
         * SEL_LOCK_DET on
         * TEST_BYPASS  off
         */
        mt9t112_reg_write(ret, client, 0x0014, 0x2525);
        mt9t112_reg_write(ret, client, 0x0014, 0x2527);
        mt9t112_reg_write(ret, client, 0x0014, 0x3427);
        mt9t112_reg_write(ret, client, 0x0014, 0x3027);

        mdelay(10);

        /*
         * PLL_BYPASS off
         * Reference clock count
         * I2C Master Clock Divider
         */
        mt9t112_reg_write(ret, client, 0x0014, 0x3046);
        /* JPEG initialization workaround */
        mt9t112_reg_write(ret, client, 0x0016, 0x0400);
        mt9t112_reg_write(ret, client, 0x0022, 0x0190);
        mt9t112_reg_write(ret, client, 0x3B84, 0x0212);

        /* External sensor clock is PLL bypass. */
        mt9t112_reg_write(ret, client, 0x002E, 0x0500);

        mt9t112_reg_mask_set(ret, client, 0x0018, 0x0002, 0x0002);
        mt9t112_reg_mask_set(ret, client, 0x3B82, 0x0004, 0x0004);

        /* MCU disabled. */
        mt9t112_reg_mask_set(ret, client, 0x0018, 0x0004, 0x0004);

        /* Out of standby. */
        mt9t112_reg_mask_set(ret, client, 0x0018, 0x0001, 0);

        mdelay(50);

        /*
         * Standby Workaround
         * Disable Secondary I2C Pads
         */
        mt9t112_reg_write(ret, client, 0x0614, 0x0001);
        mdelay(1);
        mt9t112_reg_write(ret, client, 0x0614, 0x0001);
        mdelay(1);
        mt9t112_reg_write(ret, client, 0x0614, 0x0001);
        mdelay(1);
        mt9t112_reg_write(ret, client, 0x0614, 0x0001);
        mdelay(1);
        mt9t112_reg_write(ret, client, 0x0614, 0x0001);
        mdelay(1);
        mt9t112_reg_write(ret, client, 0x0614, 0x0001);
        mdelay(1);

        /* Poll to verify out of standby. Must Poll this bit. */
        for (i = 0; i < 100; i++) {
                mt9t112_reg_read(data, client, 0x0018);
                if (!(data & 0x4000))
                        break;

                mdelay(10);
        }

        return ret;
}

static int mt9t112_init_setting(const struct i2c_client *client)
{
        int ret;

        /* Adaptive Output Clock (A) */
        mt9t112_mcu_mask_set(ret, client, VAR(26, 160), 0x0040, 0x0000);

        /* Read Mode (A) */
        mt9t112_mcu_write(ret, client, VAR(18, 12), 0x0024);

        /* Fine Correction (A) */
        mt9t112_mcu_write(ret, client, VAR(18, 15), 0x00CC);

        /* Fine IT Min (A) */
        mt9t112_mcu_write(ret, client, VAR(18, 17), 0x01f1);

        /* Fine IT Max Margin (A) */
        mt9t112_mcu_write(ret, client, VAR(18, 19), 0x00fF);

        /* Base Frame Lines (A) */
        mt9t112_mcu_write(ret, client, VAR(18, 29), 0x032D);

        /* Min Line Length (A) */
        mt9t112_mcu_write(ret, client, VAR(18, 31), 0x073a);

        /* Line Length (A) */
        mt9t112_mcu_write(ret, client, VAR(18, 37), 0x07d0);

        /* Adaptive Output Clock (B) */
        mt9t112_mcu_mask_set(ret, client, VAR(27, 160), 0x0040, 0x0000);

        /* Row Start (B) */
        mt9t112_mcu_write(ret, client, VAR(18, 74), 0x004);

        /* Column Start (B) */
        mt9t112_mcu_write(ret, client, VAR(18, 76), 0x004);

        /* Row End (B) */
        mt9t112_mcu_write(ret, client, VAR(18, 78), 0x60B);

        /* Column End (B) */
        mt9t112_mcu_write(ret, client, VAR(18, 80), 0x80B);

        /* Fine Correction (B) */
        mt9t112_mcu_write(ret, client, VAR(18, 87), 0x008C);

        /* Fine IT Min (B) */
        mt9t112_mcu_write(ret, client, VAR(18, 89), 0x01F1);

        /* Fine IT Max Margin (B) */
        mt9t112_mcu_write(ret, client, VAR(18, 91), 0x00FF);

        /* Base Frame Lines (B) */
        mt9t112_mcu_write(ret, client, VAR(18, 101), 0x0668);

        /* Min Line Length (B) */
        mt9t112_mcu_write(ret, client, VAR(18, 103), 0x0AF0);

        /* Line Length (B) */
        mt9t112_mcu_write(ret, client, VAR(18, 109), 0x0AF0);

        /*
         * Flicker Detection registers.
         * This section should be replaced whenever new timing file is
         * generated. All the following registers need to be replaced.
         * Following registers are generated from Register Wizard but user can
         * modify them. For detail see auto flicker detection tuning.
         */

        /* FD_FDPERIOD_SELECT */
        mt9t112_mcu_write(ret, client, VAR8(8, 5), 0x01);

        /* PRI_B_CONFIG_FD_ALGO_RUN */
        mt9t112_mcu_write(ret, client, VAR(27, 17), 0x0003);

        /* PRI_A_CONFIG_FD_ALGO_RUN */
        mt9t112_mcu_write(ret, client, VAR(26, 17), 0x0003);

        /*
         * AFD range detection tuning registers.
         */

        /* Search_f1_50 */
        mt9t112_mcu_write(ret, client, VAR8(18, 165), 0x25);

        /* Search_f2_50 */
        mt9t112_mcu_write(ret, client, VAR8(18, 166), 0x28);

        /* Search_f1_60 */
        mt9t112_mcu_write(ret, client, VAR8(18, 167), 0x2C);

        /* Search_f2_60 */
        mt9t112_mcu_write(ret, client, VAR8(18, 168), 0x2F);

        /* Period_50Hz (A) */
        mt9t112_mcu_write(ret, client, VAR8(18, 68), 0xBA);

        /* Secret register by Aptina. */
        /* Period_50Hz (A MSB) */
        mt9t112_mcu_write(ret, client, VAR8(18, 303), 0x00);

        /* Period_60Hz (A) */
        mt9t112_mcu_write(ret, client, VAR8(18, 69), 0x9B);

        /* Secret register by Aptina. */
        /* Period_60Hz (A MSB) */
        mt9t112_mcu_write(ret, client, VAR8(18, 301), 0x00);

        /* Period_50Hz (B) */
        mt9t112_mcu_write(ret, client, VAR8(18, 140), 0x82);

        /* Secret register by Aptina. */
        /* Period_50Hz (B) MSB */
        mt9t112_mcu_write(ret, client, VAR8(18, 304), 0x00);

        /* Period_60Hz (B) */
        mt9t112_mcu_write(ret, client, VAR8(18, 141), 0x6D);

        /* Secret register by Aptina. */
        /* Period_60Hz (B) MSB */
        mt9t112_mcu_write(ret, client, VAR8(18, 302), 0x00);

        /* FD Mode */
        mt9t112_mcu_write(ret, client, VAR8(8, 2), 0x10);

        /* Stat_min */
        mt9t112_mcu_write(ret, client, VAR8(8, 9), 0x02);

        /* Stat_max */
        mt9t112_mcu_write(ret, client, VAR8(8, 10), 0x03);

        /* Min_amplitude */
        mt9t112_mcu_write(ret, client, VAR8(8, 12), 0x0A);

        /* RX FIFO Watermark (A) */
        mt9t112_mcu_write(ret, client, VAR(18, 70), 0x0014);

        /* RX FIFO Watermark (B) */
        mt9t112_mcu_write(ret, client, VAR(18, 142), 0x0014);

        /* MCLK: 16MHz
         * PCLK: 73MHz
         * CorePixCLK: 36.5 MHz
         */
        mt9t112_mcu_write(ret, client, VAR8(18, 0x0044), 133);
        mt9t112_mcu_write(ret, client, VAR8(18, 0x0045), 110);
        mt9t112_mcu_write(ret, client, VAR8(18, 0x008c), 130);
        mt9t112_mcu_write(ret, client, VAR8(18, 0x008d), 108);

        mt9t112_mcu_write(ret, client, VAR8(18, 0x00A5), 27);
        mt9t112_mcu_write(ret, client, VAR8(18, 0x00a6), 30);
        mt9t112_mcu_write(ret, client, VAR8(18, 0x00a7), 32);
        mt9t112_mcu_write(ret, client, VAR8(18, 0x00a8), 35);

        return ret;
}

static int mt9t112_auto_focus_setting(const struct i2c_client *client)
{
        int ret;

        mt9t112_mcu_write(ret, client, VAR(12, 13),     0x000F);
        mt9t112_mcu_write(ret, client, VAR(12, 23),     0x0F0F);
        mt9t112_mcu_write(ret, client, VAR8(1, 0),      0x06);

        mt9t112_reg_write(ret, client, 0x0614, 0x0000);

        mt9t112_mcu_write(ret, client, VAR8(1, 0),      0x05);
        mt9t112_mcu_write(ret, client, VAR8(12, 2),     0x02);
        mt9t112_mcu_write(ret, client, VAR(12, 3),      0x0002);
        mt9t112_mcu_write(ret, client, VAR(17, 3),      0x8001);
        mt9t112_mcu_write(ret, client, VAR(17, 11),     0x0025);
        mt9t112_mcu_write(ret, client, VAR(17, 13),     0x0193);
        mt9t112_mcu_write(ret, client, VAR8(17, 33),    0x18);
        mt9t112_mcu_write(ret, client, VAR8(1, 0),      0x05);

        return ret;
}

static int mt9t112_auto_focus_trigger(const struct i2c_client *client)
{
        int ret;

        mt9t112_mcu_write(ret, client, VAR8(12, 25), 0x01);

        return ret;
}

static int mt9t112_init_camera(const struct i2c_client *client)
{
        int ret;

        ECHECKER(ret, mt9t112_reset(client));
        ECHECKER(ret, mt9t112_init_pll(client));
        ECHECKER(ret, mt9t112_init_setting(client));
        ECHECKER(ret, mt9t112_auto_focus_setting(client));

        mt9t112_reg_mask_set(ret, client, 0x0018, 0x0004, 0);

        /* Analog setting B.*/
        mt9t112_reg_write(ret, client, 0x3084, 0x2409);
        mt9t112_reg_write(ret, client, 0x3092, 0x0A49);
        mt9t112_reg_write(ret, client, 0x3094, 0x4949);
        mt9t112_reg_write(ret, client, 0x3096, 0x4950);

        /*
         * Disable adaptive clock.
         * PRI_A_CONFIG_JPEG_OB_TX_CONTROL_VAR
         * PRI_B_CONFIG_JPEG_OB_TX_CONTROL_VAR
         */
        mt9t112_mcu_write(ret, client, VAR(26, 160), 0x0A2E);
        mt9t112_mcu_write(ret, client, VAR(27, 160), 0x0A2E);

        /*
         * Configure Status in Status_before_length Format and enable header.
         * PRI_B_CONFIG_JPEG_OB_TX_CONTROL_VAR
         */
        mt9t112_mcu_write(ret, client, VAR(27, 144), 0x0CB4);

        /*
         * Enable JPEG in context B.
         * PRI_B_CONFIG_JPEG_OB_TX_CONTROL_VAR
         */
        mt9t112_mcu_write(ret, client, VAR8(27, 142), 0x01);

        /* Disable Dac_TXLO. */
        mt9t112_reg_write(ret, client, 0x316C, 0x350F);

        /* Set max slew rates. */
        mt9t112_reg_write(ret, client, 0x1E, 0x777);

        return ret;
}

/************************************************************************
 *                      v4l2_subdev_core_ops
 ***********************************************************************/

#ifdef CONFIG_VIDEO_ADV_DEBUG
static int mt9t112_g_register(struct v4l2_subdev *sd,
                              struct v4l2_dbg_register *reg)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        int                ret;

        reg->size = 2;
        mt9t112_reg_read(ret, client, reg->reg);

        reg->val = (__u64)ret;

        return 0;
}

static int mt9t112_s_register(struct v4l2_subdev *sd,
                              const struct v4l2_dbg_register *reg)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        int ret;

        mt9t112_reg_write(ret, client, reg->reg, reg->val);

        return ret;
}
#endif

static int mt9t112_power_on(struct mt9t112_priv *priv)
{
        int ret;

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

        if (priv->standby_gpio) {
                gpiod_set_value(priv->standby_gpio, 0);
                msleep(100);
        }

        return 0;
}

static int mt9t112_power_off(struct mt9t112_priv *priv)
{
        clk_disable_unprepare(priv->clk);
        if (priv->standby_gpio) {
                gpiod_set_value(priv->standby_gpio, 1);
                msleep(100);
        }

        return 0;
}

static int mt9t112_s_power(struct v4l2_subdev *sd, int on)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9t112_priv *priv = to_mt9t112(client);

        return on ? mt9t112_power_on(priv) :
                    mt9t112_power_off(priv);
}

static const struct v4l2_subdev_core_ops mt9t112_subdev_core_ops = {
#ifdef CONFIG_VIDEO_ADV_DEBUG
        .g_register     = mt9t112_g_register,
        .s_register     = mt9t112_s_register,
#endif
        .s_power        = mt9t112_s_power,
};

/************************************************************************
 *                      v4l2_subdev_video_ops
 **********************************************************************/
static int mt9t112_s_stream(struct v4l2_subdev *sd, int enable)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9t112_priv *priv = to_mt9t112(client);
        int ret = 0;

        if (!enable) {
                /* FIXME
                 *
                 * If user selected large output size, and used it long time,
                 * mt9t112 camera will be very warm.
                 *
                 * But current driver can not stop mt9t112 camera.
                 * So, set small size here to solve this problem.
                 */
                mt9t112_set_a_frame_size(client, VGA_WIDTH, VGA_HEIGHT);
                return ret;
        }

        if (!priv->init_done) {
                u16 param = MT9T112_FLAG_PCLK_RISING_EDGE & priv->info->flags ?
                            0x0001 : 0x0000;

                ECHECKER(ret, mt9t112_init_camera(client));

                /* Invert PCLK (Data sampled on falling edge of pixclk). */
                mt9t112_reg_write(ret, client, 0x3C20, param);

                mdelay(5);

                priv->init_done = true;
        }

        mt9t112_mcu_write(ret, client, VAR(26, 7), priv->format->fmt);
        mt9t112_mcu_write(ret, client, VAR(26, 9), priv->format->order);
        mt9t112_mcu_write(ret, client, VAR8(1, 0), 0x06);

        mt9t112_set_a_frame_size(client, priv->frame.width, priv->frame.height);

        ECHECKER(ret, mt9t112_auto_focus_trigger(client));

        dev_dbg(&client->dev, "format : %d\n", priv->format->code);
        dev_dbg(&client->dev, "size   : %d x %d\n",
                priv->frame.width,
                priv->frame.height);

        CLOCK_INFO(client, EXT_CLOCK);

        return ret;
}

static int mt9t112_set_params(struct mt9t112_priv *priv,
                              const struct v4l2_rect *rect,
                              u32 code)
{
        int i;

        /*
         * get color format
         */
        for (i = 0; i < priv->num_formats; i++)
                if (mt9t112_cfmts[i].code == code)
                        break;

        if (i == priv->num_formats)
                return -EINVAL;

        priv->frame = *rect;

        /*
         * frame size check
         */
        v4l_bound_align_image(&priv->frame.width, 0, MAX_WIDTH, 0,
                              &priv->frame.height, 0, MAX_HEIGHT, 0, 0);

        priv->format = mt9t112_cfmts + i;

        return 0;
}

static int mt9t112_get_selection(struct v4l2_subdev *sd,
                                 struct v4l2_subdev_state *sd_state,
                                 struct v4l2_subdev_selection *sel)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9t112_priv *priv = to_mt9t112(client);

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

        switch (sel->target) {
        case V4L2_SEL_TGT_CROP_BOUNDS:
                sel->r.left = 0;
                sel->r.top = 0;
                sel->r.width = MAX_WIDTH;
                sel->r.height = MAX_HEIGHT;
                return 0;
        case V4L2_SEL_TGT_CROP:
                sel->r = priv->frame;
                return 0;
        default:
                return -EINVAL;
        }
}

static int mt9t112_set_selection(struct v4l2_subdev *sd,
                                 struct v4l2_subdev_state *sd_state,
                                 struct v4l2_subdev_selection *sel)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9t112_priv *priv = to_mt9t112(client);
        const struct v4l2_rect *rect = &sel->r;

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

        return mt9t112_set_params(priv, rect, priv->format->code);
}

static int mt9t112_get_fmt(struct v4l2_subdev *sd,
                           struct v4l2_subdev_state *sd_state,
                           struct v4l2_subdev_format *format)
{
        struct v4l2_mbus_framefmt *mf = &format->format;
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9t112_priv *priv = to_mt9t112(client);

        if (format->pad)
                return -EINVAL;

        mf->width       = priv->frame.width;
        mf->height      = priv->frame.height;
        mf->colorspace  = priv->format->colorspace;
        mf->code        = priv->format->code;
        mf->field       = V4L2_FIELD_NONE;

        return 0;
}

static int mt9t112_s_fmt(struct v4l2_subdev *sd,
                         struct v4l2_mbus_framefmt *mf)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9t112_priv *priv = to_mt9t112(client);
        struct v4l2_rect rect = {
                .width = mf->width,
                .height = mf->height,
                .left = priv->frame.left,
                .top = priv->frame.top,
        };
        int ret;

        ret = mt9t112_set_params(priv, &rect, mf->code);

        if (!ret)
                mf->colorspace = priv->format->colorspace;

        return ret;
}

static int mt9t112_set_fmt(struct v4l2_subdev *sd,
                           struct v4l2_subdev_state *sd_state,
                           struct v4l2_subdev_format *format)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct v4l2_mbus_framefmt *mf = &format->format;
        struct mt9t112_priv *priv = to_mt9t112(client);
        int i;

        if (format->pad)
                return -EINVAL;

        for (i = 0; i < priv->num_formats; i++)
                if (mt9t112_cfmts[i].code == mf->code)
                        break;

        if (i == priv->num_formats) {
                mf->code = MEDIA_BUS_FMT_UYVY8_2X8;
                mf->colorspace = V4L2_COLORSPACE_JPEG;
        } else {
                mf->colorspace = mt9t112_cfmts[i].colorspace;
        }

        v4l_bound_align_image(&mf->width, 0, MAX_WIDTH, 0,
                              &mf->height, 0, MAX_HEIGHT, 0, 0);

        mf->field = V4L2_FIELD_NONE;

        if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE)
                return mt9t112_s_fmt(sd, mf);

        return 0;
}

static int mt9t112_enum_mbus_code(struct v4l2_subdev *sd,
                                  struct v4l2_subdev_state *sd_state,
                                  struct v4l2_subdev_mbus_code_enum *code)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct mt9t112_priv *priv = to_mt9t112(client);

        if (code->pad || code->index >= priv->num_formats)
                return -EINVAL;

        code->code = mt9t112_cfmts[code->index].code;

        return 0;
}

static const struct v4l2_subdev_video_ops mt9t112_subdev_video_ops = {
        .s_stream       = mt9t112_s_stream,
};

static const struct v4l2_subdev_pad_ops mt9t112_subdev_pad_ops = {
        .enum_mbus_code = mt9t112_enum_mbus_code,
        .get_selection  = mt9t112_get_selection,
        .set_selection  = mt9t112_set_selection,
        .get_fmt        = mt9t112_get_fmt,
        .set_fmt        = mt9t112_set_fmt,
};

/************************************************************************
 *                      i2c driver
 ***********************************************************************/
static const struct v4l2_subdev_ops mt9t112_subdev_ops = {
        .core   = &mt9t112_subdev_core_ops,
        .video  = &mt9t112_subdev_video_ops,
        .pad    = &mt9t112_subdev_pad_ops,
};

static int mt9t112_camera_probe(struct i2c_client *client)
{
        struct mt9t112_priv *priv = to_mt9t112(client);
        const char          *devname;
        int                  chipid;
        int                  ret;

        ret = mt9t112_s_power(&priv->subdev, 1);
        if (ret < 0)
                return ret;

        /* Check and show chip ID. */
        mt9t112_reg_read(chipid, client, 0x0000);

        switch (chipid) {
        case 0x2680:
                devname = "mt9t111";
                priv->num_formats = 1;
                break;
        case 0x2682:
                devname = "mt9t112";
                priv->num_formats = ARRAY_SIZE(mt9t112_cfmts);
                break;
        default:
                dev_err(&client->dev, "Product ID error %04x\n", chipid);
                ret = -ENODEV;
                goto done;
        }

        dev_info(&client->dev, "%s chip ID %04x\n", devname, chipid);

done:
        mt9t112_s_power(&priv->subdev, 0);

        return ret;
}

static int mt9t112_probe(struct i2c_client *client)
{
        struct mt9t112_priv *priv;
        int ret;

        if (!client->dev.platform_data) {
                dev_err(&client->dev, "mt9t112: missing platform data!\n");
                return -EINVAL;
        }

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

        priv->info = client->dev.platform_data;
        priv->init_done = false;

        v4l2_i2c_subdev_init(&priv->subdev, client, &mt9t112_subdev_ops);

        priv->clk = devm_v4l2_sensor_clk_get(&client->dev, "extclk");
        if (PTR_ERR(priv->clk) == -ENOENT)
                priv->clk = NULL;
        else if (IS_ERR(priv->clk))
                return dev_err_probe(&client->dev, PTR_ERR(priv->clk),
                                     "Unable to get clock \"extclk\"\n");

        priv->standby_gpio = devm_gpiod_get_optional(&client->dev, "standby",
                                                     GPIOD_OUT_HIGH);
        if (IS_ERR(priv->standby_gpio)) {
                dev_err(&client->dev, "Unable to get gpio \"standby\"\n");
                return PTR_ERR(priv->standby_gpio);
        }

        ret = mt9t112_camera_probe(client);
        if (ret)
                return ret;

        return v4l2_async_register_subdev(&priv->subdev);
}

static void mt9t112_remove(struct i2c_client *client)
{
        struct mt9t112_priv *priv = to_mt9t112(client);

        clk_disable_unprepare(priv->clk);
        v4l2_async_unregister_subdev(&priv->subdev);
}

static const struct i2c_device_id mt9t112_id[] = {
        { "mt9t112" },
        { }
};
MODULE_DEVICE_TABLE(i2c, mt9t112_id);

static struct i2c_driver mt9t112_i2c_driver = {
        .driver = {
                .name = "mt9t112",
        },
        .probe    = mt9t112_probe,
        .remove   = mt9t112_remove,
        .id_table = mt9t112_id,
};

module_i2c_driver(mt9t112_i2c_driver);

MODULE_DESCRIPTION("V4L2 driver for MT9T111/MT9T112 camera sensor");
MODULE_AUTHOR("Kuninori Morimoto");
MODULE_LICENSE("GPL v2");