/*
 * OmniVision OV9740 Camera Driver
 *
 * Copyright (C) 2011 NVIDIA Corporation
 *
 * Based on ov9640 camera driver. 
 *
 * 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/init.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/v4l2-mediabus.h>

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

#define to_ov9740(sd)		container_of(sd, struct ov9740_priv, subdev)

/* General Status Registers */
#define OV9740_MODEL_ID_HI		0x0000
#define OV9740_MODEL_ID_LO		0x0001
#define OV9740_REVISION_NUMBER		0x0002
#define OV9740_MANUFACTURER_ID		0x0003
#define OV9740_SMIA_VERSION		0x0004

/* General Setup Registers */
#define OV9740_MODE_SELECT		0x0100
#define OV9740_IMAGE_ORT		0x0101
#define OV9740_SOFTWARE_RESET		0x0103
#define OV9740_GRP_PARAM_HOLD		0x0104
#define OV9740_MSK_CORRUP_FM		0x0105

/* Timing Setting */
#define OV9740_FRM_LENGTH_LN_HI		0x0340 /* VTS */
#define OV9740_FRM_LENGTH_LN_LO		0x0341 /* VTS */
#define OV9740_LN_LENGTH_PCK_HI		0x0342 /* HTS */
#define OV9740_LN_LENGTH_PCK_LO		0x0343 /* HTS */
#define OV9740_X_ADDR_START_HI		0x0344
#define OV9740_X_ADDR_START_LO		0x0345
#define OV9740_Y_ADDR_START_HI		0x0346
#define OV9740_Y_ADDR_START_LO		0x0347
#define OV9740_X_ADDR_END_HI		0x0348
#define OV9740_X_ADDR_END_LO		0x0349
#define OV9740_Y_ADDR_END_HI		0x034a
#define OV9740_Y_ADDR_END_LO		0x034b
#define OV9740_X_OUTPUT_SIZE_HI		0x034c
#define OV9740_X_OUTPUT_SIZE_LO		0x034d
#define OV9740_Y_OUTPUT_SIZE_HI		0x034e
#define OV9740_Y_OUTPUT_SIZE_LO		0x034f

/* IO Control Registers */
#define OV9740_IO_CREL00		0x3002
#define OV9740_IO_CREL01		0x3004
#define OV9740_IO_CREL02		0x3005
#define OV9740_IO_OUTPUT_SEL01		0x3026
#define OV9740_IO_OUTPUT_SEL02		0x3027

/* AWB Registers */
#define OV9740_AWB_MANUAL_CTRL		0x3406

/* Analog Control Registers */
#define OV9740_ANALOG_CTRL01		0x3601
#define OV9740_ANALOG_CTRL02		0x3602
#define OV9740_ANALOG_CTRL03		0x3603
#define OV9740_ANALOG_CTRL04		0x3604
#define OV9740_ANALOG_CTRL10		0x3610
#define OV9740_ANALOG_CTRL12		0x3612
#define OV9740_ANALOG_CTRL15		0x3615
#define OV9740_ANALOG_CTRL20		0x3620
#define OV9740_ANALOG_CTRL21		0x3621
#define OV9740_ANALOG_CTRL22		0x3622
#define OV9740_ANALOG_CTRL30		0x3630
#define OV9740_ANALOG_CTRL31		0x3631
#define OV9740_ANALOG_CTRL32		0x3632
#define OV9740_ANALOG_CTRL33		0x3633

/* Sensor Control */
#define OV9740_SENSOR_CTRL03		0x3703
#define OV9740_SENSOR_CTRL04		0x3704
#define OV9740_SENSOR_CTRL05		0x3705
#define OV9740_SENSOR_CTRL07		0x3707

/* Timing Control */
#define OV9740_TIMING_CTRL17		0x3817
#define OV9740_TIMING_CTRL19		0x3819
#define OV9740_TIMING_CTRL33		0x3833
#define OV9740_TIMING_CTRL35		0x3835

/* Banding Filter */
#define OV9740_AEC_MAXEXPO_60_H		0x3a02
#define OV9740_AEC_MAXEXPO_60_L		0x3a03
#define OV9740_AEC_B50_STEP_HI		0x3a08
#define OV9740_AEC_B50_STEP_LO		0x3a09
#define OV9740_AEC_B60_STEP_HI		0x3a0a
#define OV9740_AEC_B60_STEP_LO		0x3a0b
#define OV9740_AEC_CTRL0D		0x3a0d
#define OV9740_AEC_CTRL0E		0x3a0e
#define OV9740_AEC_MAXEXPO_50_H		0x3a14
#define OV9740_AEC_MAXEXPO_50_L		0x3a15

/* AEC/AGC Control */
#define OV9740_AEC_ENABLE		0x3503
#define OV9740_GAIN_CEILING_01		0x3a18
#define OV9740_GAIN_CEILING_02		0x3a19
#define OV9740_AEC_HI_THRESHOLD		0x3a11
#define OV9740_AEC_3A1A			0x3a1a
#define OV9740_AEC_CTRL1B_WPT2		0x3a1b
#define OV9740_AEC_CTRL0F_WPT		0x3a0f
#define OV9740_AEC_CTRL10_BPT		0x3a10
#define OV9740_AEC_CTRL1E_BPT2		0x3a1e
#define OV9740_AEC_LO_THRESHOLD		0x3a1f

/* BLC Control */
#define OV9740_BLC_AUTO_ENABLE		0x4002
#define OV9740_BLC_MODE			0x4005

/* VFIFO */
#define OV9740_VFIFO_READ_START_HI	0x4608
#define OV9740_VFIFO_READ_START_LO	0x4609

/* DVP Control */
#define OV9740_DVP_VSYNC_CTRL02		0x4702
#define OV9740_DVP_VSYNC_MODE		0x4704
#define OV9740_DVP_VSYNC_CTRL06		0x4706

/* PLL Setting */
#define OV9740_PLL_MODE_CTRL01		0x3104
#define OV9740_PRE_PLL_CLK_DIV		0x0305
#define OV9740_PLL_MULTIPLIER		0x0307
#define OV9740_VT_SYS_CLK_DIV		0x0303
#define OV9740_VT_PIX_CLK_DIV		0x0301
#define OV9740_PLL_CTRL3010		0x3010
#define OV9740_VFIFO_CTRL00		0x460e

/* ISP Control */
#define OV9740_ISP_CTRL00		0x5000
#define OV9740_ISP_CTRL01		0x5001
#define OV9740_ISP_CTRL03		0x5003
#define OV9740_ISP_CTRL05		0x5005
#define OV9740_ISP_CTRL12		0x5012
#define OV9740_ISP_CTRL19		0x5019
#define OV9740_ISP_CTRL1A		0x501a
#define OV9740_ISP_CTRL1E		0x501e
#define OV9740_ISP_CTRL1F		0x501f
#define OV9740_ISP_CTRL20		0x5020
#define OV9740_ISP_CTRL21		0x5021

/* AWB */
#define OV9740_AWB_CTRL00		0x5180
#define OV9740_AWB_CTRL01		0x5181
#define OV9740_AWB_CTRL02		0x5182
#define OV9740_AWB_CTRL03		0x5183
#define OV9740_AWB_ADV_CTRL01		0x5184
#define OV9740_AWB_ADV_CTRL02		0x5185
#define OV9740_AWB_ADV_CTRL03		0x5186
#define OV9740_AWB_ADV_CTRL04		0x5187
#define OV9740_AWB_ADV_CTRL05		0x5188
#define OV9740_AWB_ADV_CTRL06		0x5189
#define OV9740_AWB_ADV_CTRL07		0x518a
#define OV9740_AWB_ADV_CTRL08		0x518b
#define OV9740_AWB_ADV_CTRL09		0x518c
#define OV9740_AWB_ADV_CTRL10		0x518d
#define OV9740_AWB_ADV_CTRL11		0x518e
#define OV9740_AWB_CTRL0F		0x518f
#define OV9740_AWB_CTRL10		0x5190
#define OV9740_AWB_CTRL11		0x5191
#define OV9740_AWB_CTRL12		0x5192
#define OV9740_AWB_CTRL13		0x5193
#define OV9740_AWB_CTRL14		0x5194

/* MIPI Control */
#define OV9740_MIPI_CTRL00		0x4800
#define OV9740_MIPI_3837		0x3837
#define OV9740_MIPI_CTRL01		0x4801
#define OV9740_MIPI_CTRL03		0x4803
#define OV9740_MIPI_CTRL05		0x4805
#define OV9740_VFIFO_RD_CTRL		0x4601
#define OV9740_MIPI_CTRL_3012		0x3012
#define OV9740_SC_CMMM_MIPI_CTR		0x3014

#define OV9740_MAX_WIDTH		1280
#define OV9740_MAX_HEIGHT		720

/* Misc.  structures */
struct ov9740_reg {
	u16				reg;
	u8				val;
};

struct ov9740_priv {
	struct v4l2_subdev		subdev;
	struct v4l2_ctrl_handler	hdl;

	int				ident;
	u16				model;
	u8				revision;
	u8				manid;
	u8				smiaver;

	bool				flag_vflip;
	bool				flag_hflip;

	/* For suspend/resume. */ 
	struct v4l2_mbus_framefmt	current_mf;
	bool				current_enable;
};

static const struct ov9740_reg ov9740_defaults[] = {
	/* Software Reset */
	{ OV9740_SOFTWARE_RESET,	0x01 },

	/* Banding Filter */
	{ OV9740_AEC_B50_STEP_HI,	0x00 },
	{ OV9740_AEC_B50_STEP_LO,	0xe8 },
	{ OV9740_AEC_CTRL0E,		0x03 },
	{ OV9740_AEC_MAXEXPO_50_H,	0x15 },
	{ OV9740_AEC_MAXEXPO_50_L,	0xc6 },
	{ OV9740_AEC_B60_STEP_HI,	0x00 },
	{ OV9740_AEC_B60_STEP_LO,	0xc0 },
	{ OV9740_AEC_CTRL0D,		0x04 },
	{ OV9740_AEC_MAXEXPO_60_H,	0x18 },
	{ OV9740_AEC_MAXEXPO_60_L,	0x20 },

	/* LC */
	{ 0x5842, 0x02 }, { 0x5843, 0x5e }, { 0x5844, 0x04 }, { 0x5845, 0x32 },
	{ 0x5846, 0x03 }, { 0x5847, 0x29 }, { 0x5848, 0x02 }, { 0x5849, 0xcc },

	/* Un-documented OV9740 registers */
	{ 0x5800, 0x29 }, { 0x5801, 0x25 }, { 0x5802, 0x20 }, { 0x5803, 0x21 },
	{ 0x5804, 0x26 }, { 0x5805, 0x2e }, { 0x5806, 0x11 }, { 0x5807, 0x0c },
	{ 0x5808, 0x09 }, { 0x5809, 0x0a }, { 0x580a, 0x0e }, { 0x580b, 0x16 },
	{ 0x580c, 0x06 }, { 0x580d, 0x02 }, { 0x580e, 0x00 }, { 0x580f, 0x00 },
	{ 0x5810, 0x04 }, { 0x5811, 0x0a }, { 0x5812, 0x05 }, { 0x5813, 0x02 },
	{ 0x5814, 0x00 }, { 0x5815, 0x00 }, { 0x5816, 0x03 }, { 0x5817, 0x09 },
	{ 0x5818, 0x0f }, { 0x5819, 0x0a }, { 0x581a, 0x07 }, { 0x581b, 0x08 },
	{ 0x581c, 0x0b }, { 0x581d, 0x14 }, { 0x581e, 0x28 }, { 0x581f, 0x23 },
	{ 0x5820, 0x1d }, { 0x5821, 0x1e }, { 0x5822, 0x24 }, { 0x5823, 0x2a },
	{ 0x5824, 0x4f }, { 0x5825, 0x6f }, { 0x5826, 0x5f }, { 0x5827, 0x7f },
	{ 0x5828, 0x9f }, { 0x5829, 0x5f }, { 0x582a, 0x8f }, { 0x582b, 0x9e },
	{ 0x582c, 0x8f }, { 0x582d, 0x9f }, { 0x582e, 0x4f }, { 0x582f, 0x87 },
	{ 0x5830, 0x86 }, { 0x5831, 0x97 }, { 0x5832, 0xae }, { 0x5833, 0x3f },
	{ 0x5834, 0x8e }, { 0x5835, 0x7c }, { 0x5836, 0x7e }, { 0x5837, 0xaf },
	{ 0x5838, 0x8f }, { 0x5839, 0x8f }, { 0x583a, 0x9f }, { 0x583b, 0x7f },
	{ 0x583c, 0x5f },

	/* Y Gamma */
	{ 0x5480, 0x07 }, { 0x5481, 0x18 }, { 0x5482, 0x2c }, { 0x5483, 0x4e },
	{ 0x5484, 0x5e }, { 0x5485, 0x6b }, { 0x5486, 0x77 }, { 0x5487, 0x82 },
	{ 0x5488, 0x8c }, { 0x5489, 0x95 }, { 0x548a, 0xa4 }, { 0x548b, 0xb1 },
	{ 0x548c, 0xc6 }, { 0x548d, 0xd8 }, { 0x548e, 0xe9 },

	/* UV Gamma */
	{ 0x5490, 0x0f }, { 0x5491, 0xff }, { 0x5492, 0x0d }, { 0x5493, 0x05 },
	{ 0x5494, 0x07 }, { 0x5495, 0x1a }, { 0x5496, 0x04 }, { 0x5497, 0x01 },
	{ 0x5498, 0x03 }, { 0x5499, 0x53 }, { 0x549a, 0x02 }, { 0x549b, 0xeb },
	{ 0x549c, 0x02 }, { 0x549d, 0xa0 }, { 0x549e, 0x02 }, { 0x549f, 0x67 },
	{ 0x54a0, 0x02 }, { 0x54a1, 0x3b }, { 0x54a2, 0x02 }, { 0x54a3, 0x18 },
	{ 0x54a4, 0x01 }, { 0x54a5, 0xe7 }, { 0x54a6, 0x01 }, { 0x54a7, 0xc3 },
	{ 0x54a8, 0x01 }, { 0x54a9, 0x94 }, { 0x54aa, 0x01 }, { 0x54ab, 0x72 },
	{ 0x54ac, 0x01 }, { 0x54ad, 0x57 },

	/* AWB */
	{ OV9740_AWB_CTRL00,		0xf0 },
	{ OV9740_AWB_CTRL01,		0x00 },
	{ OV9740_AWB_CTRL02,		0x41 },
	{ OV9740_AWB_CTRL03,		0x42 },
	{ OV9740_AWB_ADV_CTRL01,	0x8a },
	{ OV9740_AWB_ADV_CTRL02,	0x61 },
	{ OV9740_AWB_ADV_CTRL03,	0xce },
	{ OV9740_AWB_ADV_CTRL04,	0xa8 },
	{ OV9740_AWB_ADV_CTRL05,	0x17 },
	{ OV9740_AWB_ADV_CTRL06,	0x1f },
	{ OV9740_AWB_ADV_CTRL07,	0x27 },
	{ OV9740_AWB_ADV_CTRL08,	0x41 },
	{ OV9740_AWB_ADV_CTRL09,	0x34 },
	{ OV9740_AWB_ADV_CTRL10,	0xf0 },
	{ OV9740_AWB_ADV_CTRL11,	0x10 },
	{ OV9740_AWB_CTRL0F,		0xff },
	{ OV9740_AWB_CTRL10,		0x00 },
	{ OV9740_AWB_CTRL11,		0xff },
	{ OV9740_AWB_CTRL12,		0x00 },
	{ OV9740_AWB_CTRL13,		0xff },
	{ OV9740_AWB_CTRL14,		0x00 },

	/* CIP */
	{ 0x530d, 0x12 },

	/* CMX */
	{ 0x5380, 0x01 }, { 0x5381, 0x00 }, { 0x5382, 0x00 }, { 0x5383, 0x17 },
	{ 0x5384, 0x00 }, { 0x5385, 0x01 }, { 0x5386, 0x00 }, { 0x5387, 0x00 },
	{ 0x5388, 0x00 }, { 0x5389, 0xe0 }, { 0x538a, 0x00 }, { 0x538b, 0x20 },
	{ 0x538c, 0x00 }, { 0x538d, 0x00 }, { 0x538e, 0x00 }, { 0x538f, 0x16 },
	{ 0x5390, 0x00 }, { 0x5391, 0x9c }, { 0x5392, 0x00 }, { 0x5393, 0xa0 },
	{ 0x5394, 0x18 },

	/* 50/60 Detection */
	{ 0x3c0a, 0x9c }, { 0x3c0b, 0x3f },

	/* Output Select */
	{ OV9740_IO_OUTPUT_SEL01,	0x00 },
	{ OV9740_IO_OUTPUT_SEL02,	0x00 },
	{ OV9740_IO_CREL00,		0x00 },
	{ OV9740_IO_CREL01,		0x00 },
	{ OV9740_IO_CREL02,		0x00 },

	/* AWB Control */
	{ OV9740_AWB_MANUAL_CTRL,	0x00 },

	/* Analog Control */
	{ OV9740_ANALOG_CTRL03,		0xaa },
	{ OV9740_ANALOG_CTRL32,		0x2f },
	{ OV9740_ANALOG_CTRL20,		0x66 },
	{ OV9740_ANALOG_CTRL21,		0xc0 },
	{ OV9740_ANALOG_CTRL31,		0x52 },
	{ OV9740_ANALOG_CTRL33,		0x50 },
	{ OV9740_ANALOG_CTRL30,		0xca },
	{ OV9740_ANALOG_CTRL04,		0x0c },
	{ OV9740_ANALOG_CTRL01,		0x40 },
	{ OV9740_ANALOG_CTRL02,		0x16 },
	{ OV9740_ANALOG_CTRL10,		0xa1 },
	{ OV9740_ANALOG_CTRL12,		0x24 },
	{ OV9740_ANALOG_CTRL22,		0x9f },
	{ OV9740_ANALOG_CTRL15,		0xf0 },

	/* Sensor Control */
	{ OV9740_SENSOR_CTRL03,		0x42 },
	{ OV9740_SENSOR_CTRL04,		0x10 },
	{ OV9740_SENSOR_CTRL05,		0x45 },
	{ OV9740_SENSOR_CTRL07,		0x14 },

	/* Timing Control */
	{ OV9740_TIMING_CTRL33,		0x04 },
	{ OV9740_TIMING_CTRL35,		0x02 },
	{ OV9740_TIMING_CTRL19,		0x6e },
	{ OV9740_TIMING_CTRL17,		0x94 },

	/* AEC/AGC Control */
	{ OV9740_AEC_ENABLE,		0x10 },
	{ OV9740_GAIN_CEILING_01,	0x00 },
	{ OV9740_GAIN_CEILING_02,	0x7f },
	{ OV9740_AEC_HI_THRESHOLD,	0xa0 },
	{ OV9740_AEC_3A1A,		0x05 },
	{ OV9740_AEC_CTRL1B_WPT2,	0x50 },
	{ OV9740_AEC_CTRL0F_WPT,	0x50 },
	{ OV9740_AEC_CTRL10_BPT,	0x4c },
	{ OV9740_AEC_CTRL1E_BPT2,	0x4c },
	{ OV9740_AEC_LO_THRESHOLD,	0x26 },

	/* BLC Control */
	{ OV9740_BLC_AUTO_ENABLE,	0x45 },
	{ OV9740_BLC_MODE,		0x18 },

	/* DVP Control */
	{ OV9740_DVP_VSYNC_CTRL02,	0x04 },
	{ OV9740_DVP_VSYNC_MODE,	0x00 },
	{ OV9740_DVP_VSYNC_CTRL06,	0x08 },

	/* PLL Setting */
	{ OV9740_PLL_MODE_CTRL01,	0x20 },
	{ OV9740_PRE_PLL_CLK_DIV,	0x03 },
	{ OV9740_PLL_MULTIPLIER,	0x4c },
	{ OV9740_VT_SYS_CLK_DIV,	0x01 },
	{ OV9740_VT_PIX_CLK_DIV,	0x08 },
	{ OV9740_PLL_CTRL3010,		0x01 },
	{ OV9740_VFIFO_CTRL00,		0x82 },

	/* Timing Setting */
	/* VTS */
	{ OV9740_FRM_LENGTH_LN_HI,	0x03 },
	{ OV9740_FRM_LENGTH_LN_LO,	0x07 },
	/* HTS */
	{ OV9740_LN_LENGTH_PCK_HI,	0x06 },
	{ OV9740_LN_LENGTH_PCK_LO,	0x62 },

	/* MIPI Control */
	{ OV9740_MIPI_CTRL00,		0x44 }, /* 0x64 for discontinuous clk */
	{ OV9740_MIPI_3837,		0x01 },
	{ OV9740_MIPI_CTRL01,		0x0f },
	{ OV9740_MIPI_CTRL03,		0x05 },
	{ OV9740_MIPI_CTRL05,		0x10 },
	{ OV9740_VFIFO_RD_CTRL,		0x16 },
	{ OV9740_MIPI_CTRL_3012,	0x70 },
	{ OV9740_SC_CMMM_MIPI_CTR,	0x01 },

	/* YUYV order */
	{ OV9740_ISP_CTRL19,		0x02 },
};

static enum v4l2_mbus_pixelcode ov9740_codes[] = {
	V4L2_MBUS_FMT_YUYV8_2X8,
};

/* read a register */
static int ov9740_reg_read(struct i2c_client *client, u16 reg, u8 *val)
{
	int ret;
	struct i2c_msg msg[] = {
		{
			.addr	= client->addr,
			.flags	= 0,
			.len	= 2,
			.buf	= (u8 *)&reg,
		},
		{
			.addr	= client->addr,
			.flags	= I2C_M_RD,
			.len	= 1,
			.buf	= val,
		},
	};

	reg = swab16(reg);

	ret = i2c_transfer(client->adapter, msg, 2);
	if (ret < 0) {
		dev_err(&client->dev, "Failed reading register 0x%04x!\n", reg);
		return ret;
	}

	return 0;
}

/* write a register */
static int ov9740_reg_write(struct i2c_client *client, u16 reg, u8 val)
{
	struct i2c_msg msg;
	struct {
		u16 reg;
		u8 val;
	} __packed buf;
	int ret;

	reg = swab16(reg);

	buf.reg = reg;
	buf.val = val;

	msg.addr	= client->addr;
	msg.flags	= 0;
	msg.len		= 3;
	msg.buf		= (u8 *)&buf;

	ret = i2c_transfer(client->adapter, &msg, 1);
	if (ret < 0) {
		dev_err(&client->dev, "Failed writing register 0x%04x!\n", reg);
		return ret;
	}

	return 0;
}


/* Read a register, alter its bits, write it back */
static int ov9740_reg_rmw(struct i2c_client *client, u16 reg, u8 set, u8 unset)
{
	u8 val;
	int ret;

	ret = ov9740_reg_read(client, reg, &val);
	if (ret < 0) {
		dev_err(&client->dev,
			"[Read]-Modify-Write of register 0x%04x failed!\n",
			reg);
		return ret;
	}

	val |= set;
	val &= ~unset;

	ret = ov9740_reg_write(client, reg, val);
	if (ret < 0) {
		dev_err(&client->dev,
			"Read-Modify-[Write] of register 0x%04x failed!\n",
			reg);
		return ret;
	}

	return 0;
}

static int ov9740_reg_write_array(struct i2c_client *client,
				  const struct ov9740_reg *regarray,
				  int regarraylen)
{
	int i;
	int ret;

	for (i = 0; i < regarraylen; i++) {
		ret = ov9740_reg_write(client,
				       regarray[i].reg, regarray[i].val);
		if (ret < 0)
			return ret;
	}

	return 0;
}

/* Start/Stop streaming from the device */
static int ov9740_s_stream(struct v4l2_subdev *sd, int enable)
{
	struct i2c_client *client = v4l2_get_subdevdata(sd);
	struct ov9740_priv *priv = to_ov9740(sd);
	int ret;

	/* Program orientation register. */ 
	if (priv->flag_vflip)
		ret = ov9740_reg_rmw(client, OV9740_IMAGE_ORT, 0x2, 0);
	else
		ret = ov9740_reg_rmw(client, OV9740_IMAGE_ORT, 0, 0x2);
	if (ret < 0)
		return ret;

	if (priv->flag_hflip)
		ret = ov9740_reg_rmw(client, OV9740_IMAGE_ORT, 0x1, 0);
	else
		ret = ov9740_reg_rmw(client, OV9740_IMAGE_ORT, 0, 0x1);
	if (ret < 0)
		return ret;

	if (enable) {
		dev_dbg(&client->dev, "Enabling Streaming\n");
		/* Start Streaming */
		ret = ov9740_reg_write(client, OV9740_MODE_SELECT, 0x01);

	} else {
		dev_dbg(&client->dev, "Disabling Streaming\n");
		/* Software Reset */
		ret = ov9740_reg_write(client, OV9740_SOFTWARE_RESET, 0x01);
		if (! ret)
			/* Setting Streaming to Standby */
			ret = ov9740_reg_write(client, OV9740_MODE_SELECT,
					       0x00);
	}

	priv->current_enable = enable;

	return ret;
}

/* select nearest higher resolution for capture */
static void ov9740_res_roundup(u32 *width, u32 *height)
{
	/* Width must be a multiple of 4 pixels. */ 
	*width = ALIGN(*width, 4);

	/* Max resolution is 1280x720 (720p). */ 
	if (*width > OV9740_MAX_WIDTH)
		*width = OV9740_MAX_WIDTH;

	if (*height > OV9740_MAX_HEIGHT)
		*height = OV9740_MAX_HEIGHT;
}

/* Setup registers according to resolution and color encoding */
static int ov9740_set_res(struct i2c_client *client, u32 width, u32 height)
{
	u32 x_start;
	u32 y_start;
	u32 x_end;
	u32 y_end;
	bool scaling = 0;
	u32 scale_input_x;
	u32 scale_input_y;
	int ret;

	if ((width ! = OV9740_MAX_WIDTH) || (height ! = OV9740_MAX_HEIGHT))
		scaling = 1;

	/*
	 * Try to use as much of the sensor area as possible when supporting
	 * smaller resolutions.   Depending on the aspect ratio of the
	 * chosen resolution, we can either use the full width of the sensor,
	 * or the full height of the sensor (or both if the aspect ratio is
	 * the same as 1280x720. 
	 */
	if ((OV9740_MAX_WIDTH * height) > (OV9740_MAX_HEIGHT * width)) {
		scale_input_x = (OV9740_MAX_HEIGHT * width) / height;
		scale_input_y = OV9740_MAX_HEIGHT;
	} else {
		scale_input_x = OV9740_MAX_WIDTH;
		scale_input_y = (OV9740_MAX_WIDTH * height) / width;
	}

	/* These describe the area of the sensor to use. */ 
	x_start = (OV9740_MAX_WIDTH - scale_input_x) / 2;
	y_start = (OV9740_MAX_HEIGHT - scale_input_y) / 2;
	x_end = x_start + scale_input_x - 1;
	y_end = y_start + scale_input_y - 1;

	ret = ov9740_reg_write(client, OV9740_X_ADDR_START_HI, x_start >> 8);
	if (ret)
		goto done;
	ret = ov9740_reg_write(client, OV9740_X_ADDR_START_LO, x_start & 0xff);
	if (ret)
		goto done;
	ret = ov9740_reg_write(client, OV9740_Y_ADDR_START_HI, y_start >> 8);
	if (ret)
		goto done;
	ret = ov9740_reg_write(client, OV9740_Y_ADDR_START_LO, y_start & 0xff);
	if (ret)
		goto done;

	ret = ov9740_reg_write(client, OV9740_X_ADDR_END_HI, x_end >> 8);
	if (ret)
		goto done;
	ret = ov9740_reg_write(client, OV9740_X_ADDR_END_LO, x_end & 0xff);
	if (ret)
		goto done;
	ret = ov9740_reg_write(client, OV9740_Y_ADDR_END_HI, y_end >> 8);
	if (ret)
		goto done;
	ret = ov9740_reg_write(client, OV9740_Y_ADDR_END_LO, y_end & 0xff);
	if (ret)
		goto done;

	ret = ov9740_reg_write(client, OV9740_X_OUTPUT_SIZE_HI, width >> 8);
	if (ret)
		goto done;
	ret = ov9740_reg_write(client, OV9740_X_OUTPUT_SIZE_LO, width & 0xff);
	if (ret)
		goto done;
	ret = ov9740_reg_write(client, OV9740_Y_OUTPUT_SIZE_HI, height >> 8);
	if (ret)
		goto done;
	ret = ov9740_reg_write(client, OV9740_Y_OUTPUT_SIZE_LO, height & 0xff);
	if (ret)
		goto done;

	ret = ov9740_reg_write(client, OV9740_ISP_CTRL1E, scale_input_x >> 8);
	if (ret)
		goto done;
	ret = ov9740_reg_write(client, OV9740_ISP_CTRL1F, scale_input_x & 0xff);
	if (ret)
		goto done;
	ret = ov9740_reg_write(client, OV9740_ISP_CTRL20, scale_input_y >> 8);
	if (ret)
		goto done;
	ret = ov9740_reg_write(client, OV9740_ISP_CTRL21, scale_input_y & 0xff);
	if (ret)
		goto done;

	ret = ov9740_reg_write(client, OV9740_VFIFO_READ_START_HI,
			       (scale_input_x - width) >> 8);
	if (ret)
		goto done;
	ret = ov9740_reg_write(client, OV9740_VFIFO_READ_START_LO,
			       (scale_input_x - width) & 0xff);
	if (ret)
		goto done;

	ret = ov9740_reg_write(client, OV9740_ISP_CTRL00, 0xff);
	if (ret)
		goto done;
	ret = ov9740_reg_write(client, OV9740_ISP_CTRL01, 0xef |
							  (scaling << 4));
	if (ret)
		goto done;
	ret = ov9740_reg_write(client, OV9740_ISP_CTRL03, 0xff);

done:
	return ret;
}

/* set the format we will capture in */
static int ov9740_s_fmt(struct v4l2_subdev *sd,
			struct v4l2_mbus_framefmt *mf)
{
	struct i2c_client *client = v4l2_get_subdevdata(sd);
	struct ov9740_priv *priv = to_ov9740(sd);
	enum v4l2_colorspace cspace;
	enum v4l2_mbus_pixelcode code = mf->code;
	int ret;

	ov9740_res_roundup(&mf->width, &mf->height);

	switch (code) {
	case V4L2_MBUS_FMT_YUYV8_2X8:
		cspace = V4L2_COLORSPACE_SRGB;
		break;
	default:
		return -EINVAL;
	}

	ret = ov9740_reg_write_array(client, ov9740_defaults,
				     ARRAY_SIZE(ov9740_defaults));
	if (ret < 0)
		return ret;

	ret = ov9740_set_res(client, mf->width, mf->height);
	if (ret < 0)
		return ret;

	mf->code	= code;
	mf->colorspace	= cspace;

	memcpy(&priv->current_mf, mf, sizeof(struct v4l2_mbus_framefmt));

	return ret;
}

static int ov9740_try_fmt(struct v4l2_subdev *sd,
			  struct v4l2_mbus_framefmt *mf)
{
	ov9740_res_roundup(&mf->width, &mf->height);

	mf->field = V4L2_FIELD_NONE;
	mf->code = V4L2_MBUS_FMT_YUYV8_2X8;
	mf->colorspace = V4L2_COLORSPACE_SRGB;

	return 0;
}

static int ov9740_enum_fmt(struct v4l2_subdev *sd, unsigned int index,
			   enum v4l2_mbus_pixelcode *code)
{
	if (index >= ARRAY_SIZE(ov9740_codes))
		return -EINVAL;

	*code = ov9740_codes[index];

	return 0;
}

static int ov9740_cropcap(struct v4l2_subdev *sd, struct v4l2_cropcap *a)
{
	a->bounds.left		= 0;
	a->bounds.top		= 0;
	a->bounds.width		= OV9740_MAX_WIDTH;
	a->bounds.height	= OV9740_MAX_HEIGHT;
	a->defrect		= a->bounds;
	a->type			= V4L2_BUF_TYPE_VIDEO_CAPTURE;
	a->pixelaspect.numerator	= 1;
	a->pixelaspect.denominator	= 1;

	return 0;
}

static int ov9740_g_crop(struct v4l2_subdev *sd, struct v4l2_crop *a)
{
	a->c.left		= 0;
	a->c.top		= 0;
	a->c.width		= OV9740_MAX_WIDTH;
	a->c.height		= OV9740_MAX_HEIGHT;
	a->type			= V4L2_BUF_TYPE_VIDEO_CAPTURE;

	return 0;
}

/* Set status of additional camera capabilities */
static int ov9740_s_ctrl(struct v4l2_ctrl *ctrl)
{
	struct ov9740_priv *priv =
		container_of(ctrl->handler, struct ov9740_priv, hdl);

	switch (ctrl->id) {
	case V4L2_CID_VFLIP:
		priv->flag_vflip = ctrl->val;
		break;
	case V4L2_CID_HFLIP:
		priv->flag_hflip = ctrl->val;
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

/* Get chip identification */
static int ov9740_g_chip_ident(struct v4l2_subdev *sd,
			       struct v4l2_dbg_chip_ident *id)
{
	struct ov9740_priv *priv = to_ov9740(sd);

	id->ident = priv->ident;
	id->revision = priv->revision;

	return 0;
}

static int ov9740_s_power(struct v4l2_subdev *sd, int on)
{
	struct ov9740_priv *priv = to_ov9740(sd);

	if (! priv->current_enable)
		return 0;

	if (on) {
		ov9740_s_fmt(sd, &priv->current_mf);
		ov9740_s_stream(sd, priv->current_enable);
	} else {
		ov9740_s_stream(sd, 0);
		priv->current_enable = true;
	}

	return 0;
}

#ifdef CONFIG_VIDEO_ADV_DEBUG
static int ov9740_get_register(struct v4l2_subdev *sd,
			       struct v4l2_dbg_register *reg)
{
	struct i2c_client *client = v4l2_get_subdevdata(sd);
	int ret;
	u8 val;

	if (reg->reg & ~0xffff)
		return -EINVAL;

	reg->size = 2;

	ret = ov9740_reg_read(client, reg->reg, &val);
	if (ret)
		return ret;

	reg->val = (__u64)val;

	return ret;
}

static int ov9740_set_register(struct v4l2_subdev *sd,
			       struct v4l2_dbg_register *reg)
{
	struct i2c_client *client = v4l2_get_subdevdata(sd);

	if (reg->reg & ~0xffff || reg->val & ~0xff)
		return -EINVAL;

	return ov9740_reg_write(client, reg->reg, reg->val);
}
#endif

static int ov9740_video_probe(struct i2c_client *client)
{
	struct v4l2_subdev *sd = i2c_get_clientdata(client);
	struct ov9740_priv *priv = to_ov9740(sd);
	u8 modelhi, modello;
	int ret;

	/*
	 * check and show product ID and manufacturer ID
	 */
	ret = ov9740_reg_read(client, OV9740_MODEL_ID_HI, &modelhi);
	if (ret < 0)
		goto err;

	ret = ov9740_reg_read(client, OV9740_MODEL_ID_LO, &modello);
	if (ret < 0)
		goto err;

	priv->model = (modelhi << 8) | modello;

	ret = ov9740_reg_read(client, OV9740_REVISION_NUMBER, &priv->revision);
	if (ret < 0)
		goto err;

	ret = ov9740_reg_read(client, OV9740_MANUFACTURER_ID, &priv->manid);
	if (ret < 0)
		goto err;

	ret = ov9740_reg_read(client, OV9740_SMIA_VERSION, &priv->smiaver);
	if (ret < 0)
		goto err;

	if (priv->model ! = 0x9740) {
		ret = -ENODEV;
		goto err;
	}

	priv->ident = V4L2_IDENT_OV9740;

	dev_info(&client->dev, "ov9740 Model ID 0x%04x, Revision 0x%02x, "
		 "Manufacturer 0x%02x, SMIA Version 0x%02x\n",
		 priv->model, priv->revision, priv->manid, priv->smiaver);

err:
	return ret;
}

/* Request bus settings on camera side */
static int ov9740_g_mbus_config(struct v4l2_subdev *sd,
				struct v4l2_mbus_config *cfg)
{
	struct i2c_client *client = v4l2_get_subdevdata(sd);
	struct soc_camera_link *icl = soc_camera_i2c_to_link(client);

	cfg->flags = V4L2_MBUS_PCLK_SAMPLE_RISING | V4L2_MBUS_MASTER |
		V4L2_MBUS_VSYNC_ACTIVE_HIGH | V4L2_MBUS_HSYNC_ACTIVE_HIGH |
		V4L2_MBUS_DATA_ACTIVE_HIGH;
	cfg->type = V4L2_MBUS_PARALLEL;
	cfg->flags = soc_camera_apply_board_flags(icl, cfg);

	return 0;
}

static struct v4l2_subdev_video_ops ov9740_video_ops = {
	.s_stream	= ov9740_s_stream,
	.s_mbus_fmt	= ov9740_s_fmt,
	.try_mbus_fmt	= ov9740_try_fmt,
	.enum_mbus_fmt	= ov9740_enum_fmt,
	.cropcap	= ov9740_cropcap,
	.g_crop		= ov9740_g_crop,
	.g_mbus_config	= ov9740_g_mbus_config,
};

static struct v4l2_subdev_core_ops ov9740_core_ops = {
	.g_chip_ident		= ov9740_g_chip_ident,
	.s_power		= ov9740_s_power,
#ifdef CONFIG_VIDEO_ADV_DEBUG
	.g_register		= ov9740_get_register,
	.s_register		= ov9740_set_register,
#endif
};

static struct v4l2_subdev_ops ov9740_subdev_ops = {
	.core			= &ov9740_core_ops,
	.video			= &ov9740_video_ops,
};

static const struct v4l2_ctrl_ops ov9740_ctrl_ops = {
	.s_ctrl = ov9740_s_ctrl,
};

/*
 * i2c_driver function
 */
static int ov9740_probe(struct i2c_client *client,
			const struct i2c_device_id *did)
{
	struct ov9740_priv *priv;
	struct soc_camera_link *icl = soc_camera_i2c_to_link(client);
	int ret;

	if (! icl) {
		dev_err(&client->dev, "Missing platform_data for driver\n");
		return -EINVAL;
	}

	priv = kzalloc(sizeof(struct ov9740_priv), GFP_KERNEL);
	if (! priv) {
		dev_err(&client->dev, "Failed to allocate private data!\n");
		return -ENOMEM;
	}

	v4l2_i2c_subdev_init(&priv->subdev, client, &ov9740_subdev_ops);
	v4l2_ctrl_handler_init(&priv->hdl, 13);
	v4l2_ctrl_new_std(&priv->hdl, &ov9740_ctrl_ops,
			V4L2_CID_VFLIP, 0, 1, 1, 0);
	v4l2_ctrl_new_std(&priv->hdl, &ov9740_ctrl_ops,
			V4L2_CID_HFLIP, 0, 1, 1, 0);
	priv->subdev.ctrl_handler = &priv->hdl;
	if (priv->hdl.error) {
		int err = priv->hdl.error;

		kfree(priv);
		return err;
	}

	ret = ov9740_video_probe(client);
	if (! ret)
		ret = v4l2_ctrl_handler_setup(&priv->hdl);
	if (ret < 0) {
		v4l2_ctrl_handler_free(&priv->hdl);
		kfree(priv);
	}

	return ret;
}

static int ov9740_remove(struct i2c_client *client)
{
	struct ov9740_priv *priv = i2c_get_clientdata(client);

	v4l2_device_unregister_subdev(&priv->subdev);
	v4l2_ctrl_handler_free(&priv->hdl);
	kfree(priv);
	return 0;
}

static const struct i2c_device_id ov9740_id[] = {
	{ "ov9740", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ov9740_id);

static struct i2c_driver ov9740_i2c_driver = {
	.driver = {
		.name = "ov9740",
	},
	.probe    = ov9740_probe,
	.remove   = ov9740_remove,
	.id_table = ov9740_id,
};

module_i2c_driver(ov9740_i2c_driver);

MODULE_DESCRIPTION("SoC Camera driver for OmniVision OV9740");
MODULE_AUTHOR("Andrew Chew <achew@nvidia.com>");
MODULE_LICENSE("GPL v2");
