/*
 * Pixart PAC7302 driver
 *
 * Copyright (C) 2008-2012 Jean-Francois Moine <http://moinejf.free.fr>
 * Copyright (C) 2005 Thomas Kaiser thomas@kaiser-linux.li
 *
 * Separated from Pixart PAC7311 library by Márton Németh
 * Camera button input handling by Márton Németh <nm127@freemail.hu>
 * Copyright (C) 2009-2010 Márton Németh <nm127@freemail.hu>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

/*
 * Some documentation about various registers as determined by trial and error.
 *
 * Register page 1:
 *
 * Address	Description
 * 0x78		Global control, bit 6 controls the LED (inverted)
 * 0x80		Compression balance, 2 interesting settings:
 *		0x0f Default
 *		0x50 Values >= this switch the camera to a lower compression,
 *		     using the same table for both luminance and chrominance.
 *		     This gives a sharper picture. Only usable when running
 *		     at < 15 fps! Note currently the driver does not use this
 *		     as the quality gain is small and the generated JPG-s are
 *		     only understood by v4l-utils >= 0.8.9
 *
 * Register page 3:
 *
 * Address	Description
 * 0x02		Clock divider 3-63, fps = 90 / val. Must be a multiple of 3 on
 *		the 7302, so one of 3, 6, 9, ..., except when between 6 and 12?
 * 0x03		Variable framerate ctrl reg2==3: 0 -> ~30 fps, 255 -> ~22fps
 * 0x04		Another var framerate ctrl reg2==3, reg3==0: 0 -> ~30 fps,
 *		63 -> ~27 fps, the 2 msb's must always be 1 !!
 * 0x05		Another var framerate ctrl reg2==3, reg3==0, reg4==0xc0:
 *		1 -> ~30 fps, 2 -> ~20 fps
 * 0x0e		Exposure bits 0-7, 0-448, 0 = use full frame time
 * 0x0f		Exposure bit 8, 0-448, 448 = no exposure at all
 * 0x10		Gain 0-31
 * 0x12		Another gain 0-31, unlike 0x10 this one seems to start with an
 *		amplification value of 1 rather then 0 at its lowest setting
 * 0x21		Bitfield: 0-1 unused, 2-3 vflip/hflip, 4-5 unknown, 6-7 unused
 * 0x80		Another framerate control, best left at 1, moving it from 1 to
 *		2 causes the framerate to become 3/4th of what it was, and
 *		also seems to cause pixel averaging, resulting in an effective
 *		resolution of 320x240 and thus a much blockier image
 *
 * The registers are accessed in the following functions:
 *
 * Page | Register   | Function
 * -----+------------+---------------------------------------------------
 *  0   | 0x0f..0x20 | setcolors()
 *  0   | 0xa2..0xab | setbrightcont()
 *  0   | 0xc5       | setredbalance()
 *  0   | 0xc6       | setwhitebalance()
 *  0   | 0xc7       | setbluebalance()
 *  0   | 0xdc       | setbrightcont(), setcolors()
 *  3   | 0x02       | setexposure()
 *  3   | 0x10, 0x12 | setgain()
 *  3   | 0x11       | setcolors(), setgain(), setexposure(), sethvflip()
 *  3   | 0x21       | sethvflip()
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/input.h>
#include <media/v4l2-chip-ident.h>
#include "gspca.h"
/* Include pac common sof detection functions */
#include "pac_common.h"

MODULE_AUTHOR("Jean-Francois Moine <http://moinejf.free.fr>, "
		"Thomas Kaiser thomas@kaiser-linux.li");
MODULE_DESCRIPTION("Pixart PAC7302");
MODULE_LICENSE("GPL");

enum e_ctrl {
	BRIGHTNESS,
	CONTRAST,
	COLORS,
	WHITE_BALANCE,
	RED_BALANCE,
	BLUE_BALANCE,
	GAIN,
	AUTOGAIN,
	EXPOSURE,
	VFLIP,
	HFLIP,
	NCTRLS		/* number of controls */
};

struct sd {
	struct gspca_dev gspca_dev;		/* !! must be the first item */

	struct gspca_ctrl ctrls[NCTRLS];

	u8 flags;
#define FL_HFLIP 0x01		/* mirrored by default */
#define FL_VFLIP 0x02		/* vertical flipped by default */

	u8 sof_read;
	s8 autogain_ignore_frames;

	atomic_t avg_lum;
};

/* V4L2 controls supported by the driver */
static void setbrightcont(struct gspca_dev *gspca_dev);
static void setcolors(struct gspca_dev *gspca_dev);
static void setwhitebalance(struct gspca_dev *gspca_dev);
static void setredbalance(struct gspca_dev *gspca_dev);
static void setbluebalance(struct gspca_dev *gspca_dev);
static void setgain(struct gspca_dev *gspca_dev);
static void setexposure(struct gspca_dev *gspca_dev);
static void setautogain(struct gspca_dev *gspca_dev);
static void sethvflip(struct gspca_dev *gspca_dev);

static const struct ctrl sd_ctrls[] = {
[BRIGHTNESS] = {
	    {
		.id      = V4L2_CID_BRIGHTNESS,
		.type    = V4L2_CTRL_TYPE_INTEGER,
		.name    = "Brightness",
		.minimum = 0,
#define BRIGHTNESS_MAX 0x20
		.maximum = BRIGHTNESS_MAX,
		.step    = 1,
		.default_value = 0x10,
	    },
	    .set_control = setbrightcont
	},
[CONTRAST] = {
	    {
		.id      = V4L2_CID_CONTRAST,
		.type    = V4L2_CTRL_TYPE_INTEGER,
		.name    = "Contrast",
		.minimum = 0,
#define CONTRAST_MAX 255
		.maximum = CONTRAST_MAX,
		.step    = 1,
		.default_value = 127,
	    },
	    .set_control = setbrightcont
	},
[COLORS] = {
	    {
		.id      = V4L2_CID_SATURATION,
		.type    = V4L2_CTRL_TYPE_INTEGER,
		.name    = "Saturation",
		.minimum = 0,
#define COLOR_MAX 255
		.maximum = COLOR_MAX,
		.step    = 1,
		.default_value = 127
	    },
	    .set_control = setcolors
	},
[WHITE_BALANCE] = {
	    {
		.id      = V4L2_CID_WHITE_BALANCE_TEMPERATURE,
		.type    = V4L2_CTRL_TYPE_INTEGER,
		.name    = "White Balance",
		.minimum = 0,
		.maximum = 255,
		.step    = 1,
		.default_value = 4,
	    },
	    .set_control = setwhitebalance
	},
[RED_BALANCE] = {
	    {
		.id      = V4L2_CID_RED_BALANCE,
		.type    = V4L2_CTRL_TYPE_INTEGER,
		.name    = "Red",
		.minimum = 0,
		.maximum = 3,
		.step    = 1,
		.default_value = 1,
	    },
	    .set_control = setredbalance
	},
[BLUE_BALANCE] = {
	    {
		.id      = V4L2_CID_BLUE_BALANCE,
		.type    = V4L2_CTRL_TYPE_INTEGER,
		.name    = "Blue",
		.minimum = 0,
		.maximum = 3,
		.step    = 1,
		.default_value = 1,
	    },
	    .set_control = setbluebalance
	},
[GAIN] = {
	    {
		.id      = V4L2_CID_GAIN,
		.type    = V4L2_CTRL_TYPE_INTEGER,
		.name    = "Gain",
		.minimum = 0,
		.maximum = 62,
		.step    = 1,
#define GAIN_DEF 15
#define GAIN_KNEE 46
		.default_value = GAIN_DEF,
	    },
	    .set_control = setgain
	},
[EXPOSURE] = {
	    {
		.id      = V4L2_CID_EXPOSURE,
		.type    = V4L2_CTRL_TYPE_INTEGER,
		.name    = "Exposure",
		.minimum = 0,
		.maximum = 1023,
		.step    = 1,
#define EXPOSURE_DEF  66  /*  33 ms / 30 fps */
#define EXPOSURE_KNEE 133 /*  66 ms / 15 fps */
		.default_value = EXPOSURE_DEF,
	    },
	    .set_control = setexposure
	},
[AUTOGAIN] = {
	    {
		.id      = V4L2_CID_AUTOGAIN,
		.type    = V4L2_CTRL_TYPE_BOOLEAN,
		.name    = "Auto Gain",
		.minimum = 0,
		.maximum = 1,
		.step    = 1,
#define AUTOGAIN_DEF 1
		.default_value = AUTOGAIN_DEF,
	    },
	    .set_control = setautogain,
	},
[HFLIP] = {
	    {
		.id      = V4L2_CID_HFLIP,
		.type    = V4L2_CTRL_TYPE_BOOLEAN,
		.name    = "Mirror",
		.minimum = 0,
		.maximum = 1,
		.step    = 1,
		.default_value = 0,
	    },
	    .set_control = sethvflip,
	},
[VFLIP] = {
	    {
		.id      = V4L2_CID_VFLIP,
		.type    = V4L2_CTRL_TYPE_BOOLEAN,
		.name    = "Vflip",
		.minimum = 0,
		.maximum = 1,
		.step    = 1,
		.default_value = 0,
	    },
	    .set_control = sethvflip
	},
};

static const struct v4l2_pix_format vga_mode[] = {
	{640, 480, V4L2_PIX_FMT_PJPG, V4L2_FIELD_NONE,
		.bytesperline = 640,
		.sizeimage = 640 * 480 * 3 / 8 + 590,
		.colorspace = V4L2_COLORSPACE_JPEG,
	},
};

#define LOAD_PAGE3		255
#define END_OF_SEQUENCE		0

static const u8 init_7302[] = {
/*	index,value */
	0xff, 0x01,		/* page 1 */
	0x78, 0x00,		/* deactivate */
	0xff, 0x01,
	0x78, 0x40,		/* led off */
};
static const u8 start_7302[] = {
/*	index, len, [value]* */
	0xff, 1,	0x00,		/* page 0 */
	0x00, 12,	0x01, 0x40, 0x40, 0x40, 0x01, 0xe0, 0x02, 0x80,
			0x00, 0x00, 0x00, 0x00,
	0x0d, 24,	0x03, 0x01, 0x00, 0xb5, 0x07, 0xcb, 0x00, 0x00,
			0x07, 0xc8, 0x00, 0xea, 0x07, 0xcf, 0x07, 0xf7,
			0x07, 0x7e, 0x01, 0x0b, 0x00, 0x00, 0x00, 0x11,
	0x26, 2,	0xaa, 0xaa,
	0x2e, 1,	0x31,
	0x38, 1,	0x01,
	0x3a, 3,	0x14, 0xff, 0x5a,
	0x43, 11,	0x00, 0x0a, 0x18, 0x11, 0x01, 0x2c, 0x88, 0x11,
			0x00, 0x54, 0x11,
	0x55, 1,	0x00,
	0x62, 4,	0x10, 0x1e, 0x1e, 0x18,
	0x6b, 1,	0x00,
	0x6e, 3,	0x08, 0x06, 0x00,
	0x72, 3,	0x00, 0xff, 0x00,
	0x7d, 23,	0x01, 0x01, 0x58, 0x46, 0x50, 0x3c, 0x50, 0x3c,
			0x54, 0x46, 0x54, 0x56, 0x52, 0x50, 0x52, 0x50,
			0x56, 0x64, 0xa4, 0x00, 0xda, 0x00, 0x00,
	0xa2, 10,	0x22, 0x2c, 0x3c, 0x54, 0x69, 0x7c, 0x9c, 0xb9,
			0xd2, 0xeb,
	0xaf, 1,	0x02,
	0xb5, 2,	0x08, 0x08,
	0xb8, 2,	0x08, 0x88,
	0xc4, 4,	0xae, 0x01, 0x04, 0x01,
	0xcc, 1,	0x00,
	0xd1, 11,	0x01, 0x30, 0x49, 0x5e, 0x6f, 0x7f, 0x8e, 0xa9,
			0xc1, 0xd7, 0xec,
	0xdc, 1,	0x01,
	0xff, 1,	0x01,		/* page 1 */
	0x12, 3,	0x02, 0x00, 0x01,
	0x3e, 2,	0x00, 0x00,
	0x76, 5,	0x01, 0x20, 0x40, 0x00, 0xf2,
	0x7c, 1,	0x00,
	0x7f, 10,	0x4b, 0x0f, 0x01, 0x2c, 0x02, 0x58, 0x03, 0x20,
			0x02, 0x00,
	0x96, 5,	0x01, 0x10, 0x04, 0x01, 0x04,
	0xc8, 14,	0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0x00, 0x00,
			0x07, 0x00, 0x01, 0x07, 0x04, 0x01,
	0xd8, 1,	0x01,
	0xdb, 2,	0x00, 0x01,
	0xde, 7,	0x00, 0x01, 0x04, 0x04, 0x00, 0x00, 0x00,
	0xe6, 4,	0x00, 0x00, 0x00, 0x01,
	0xeb, 1,	0x00,
	0xff, 1,	0x02,		/* page 2 */
	0x22, 1,	0x00,
	0xff, 1,	0x03,		/* page 3 */
	0, LOAD_PAGE3,			/* load the page 3 */
	0x11, 1,	0x01,
	0xff, 1,	0x02,		/* page 2 */
	0x13, 1,	0x00,
	0x22, 4,	0x1f, 0xa4, 0xf0, 0x96,
	0x27, 2,	0x14, 0x0c,
	0x2a, 5,	0xc8, 0x00, 0x18, 0x12, 0x22,
	0x64, 8,	0x00, 0x00, 0xf0, 0x01, 0x14, 0x44, 0x44, 0x44,
	0x6e, 1,	0x08,
	0xff, 1,	0x01,		/* page 1 */
	0x78, 1,	0x00,
	0, END_OF_SEQUENCE		/* end of sequence */
};

#define SKIP		0xaa
/* page 3 - the value SKIP says skip the index - see reg_w_page() */
static const u8 page3_7302[] = {
	0x90, 0x40, 0x03, 0x00, 0xc0, 0x01, 0x14, 0x16,
	0x14, 0x12, 0x00, 0x00, 0x00, 0x02, 0x33, 0x00,
	0x0f, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x47, 0x01, 0xb3, 0x01, 0x00,
	0x00, 0x08, 0x00, 0x00, 0x0d, 0x00, 0x00, 0x21,
	0x00, 0x00, 0x00, 0x54, 0xf4, 0x02, 0x52, 0x54,
	0xa4, 0xb8, 0xe0, 0x2a, 0xf6, 0x00, 0x00, 0x00,
	0x00, 0x1e, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0xfc, 0x00, 0xf2, 0x1f, 0x04, 0x00, 0x00,
	SKIP, 0x00, 0x00, 0xc0, 0xc0, 0x10, 0x00, 0x00,
	0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x40, 0xff, 0x03, 0x19, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0xc8, 0xc8, 0xc8,
	0xc8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x50,
	0x08, 0x10, 0x24, 0x40, 0x00, 0x00, 0x00, 0x00,
	0x01, 0x00, 0x02, 0x47, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x02, 0xfa, 0x00, 0x64, 0x5a, 0x28, 0x00,
	0x00
};

static void reg_w_buf(struct gspca_dev *gspca_dev,
		u8 index,
		  const u8 *buffer, int len)
{
	int ret;

	if (gspca_dev->usb_err < 0)
		return;
	memcpy(gspca_dev->usb_buf, buffer, len);
	ret = usb_control_msg(gspca_dev->dev,
			usb_sndctrlpipe(gspca_dev->dev, 0),
			0,		/* request */
			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
			0,		/* value */
			index, gspca_dev->usb_buf, len,
			500);
	if (ret < 0) {
		pr_err("reg_w_buf failed i: %02x error %d\n",
		       index, ret);
		gspca_dev->usb_err = ret;
	}
}


static void reg_w(struct gspca_dev *gspca_dev,
		u8 index,
		u8 value)
{
	int ret;

	if (gspca_dev->usb_err < 0)
		return;
	gspca_dev->usb_buf[0] = value;
	ret = usb_control_msg(gspca_dev->dev,
			usb_sndctrlpipe(gspca_dev->dev, 0),
			0,			/* request */
			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
			0, index, gspca_dev->usb_buf, 1,
			500);
	if (ret < 0) {
		pr_err("reg_w() failed i: %02x v: %02x error %d\n",
		       index, value, ret);
		gspca_dev->usb_err = ret;
	}
}

static void reg_w_seq(struct gspca_dev *gspca_dev,
		const u8 *seq, int len)
{
	while (--len >= 0) {
		reg_w(gspca_dev, seq[0], seq[1]);
		seq += 2;
	}
}

/* load the beginning of a page */
static void reg_w_page(struct gspca_dev *gspca_dev,
			const u8 *page, int len)
{
	int index;
	int ret = 0;

	if (gspca_dev->usb_err < 0)
		return;
	for (index = 0; index < len; index++) {
		if (page[index] == SKIP)		/* skip this index */
			continue;
		gspca_dev->usb_buf[0] = page[index];
		ret = usb_control_msg(gspca_dev->dev,
				usb_sndctrlpipe(gspca_dev->dev, 0),
				0,			/* request */
			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
				0, index, gspca_dev->usb_buf, 1,
				500);
		if (ret < 0) {
			pr_err("reg_w_page() failed i: %02x v: %02x error %d\n",
			       index, page[index], ret);
			gspca_dev->usb_err = ret;
			break;
		}
	}
}

/* output a variable sequence */
static void reg_w_var(struct gspca_dev *gspca_dev,
			const u8 *seq,
			const u8 *page3, unsigned int page3_len)
{
	int index, len;

	for (;;) {
		index = *seq++;
		len = *seq++;
		switch (len) {
		case END_OF_SEQUENCE:
			return;
		case LOAD_PAGE3:
			reg_w_page(gspca_dev, page3, page3_len);
			break;
		default:
#ifdef GSPCA_DEBUG
			if (len > USB_BUF_SZ) {
				PDEBUG(D_ERR|D_STREAM,
					"Incorrect variable sequence");
				return;
			}
#endif
			while (len > 0) {
				if (len < 8) {
					reg_w_buf(gspca_dev,
						index, seq, len);
					seq += len;
					break;
				}
				reg_w_buf(gspca_dev, index, seq, 8);
				seq += 8;
				index += 8;
				len -= 8;
			}
		}
	}
	/* not reached */
}

/* this function is called at probe time for pac7302 */
static int sd_config(struct gspca_dev *gspca_dev,
			const struct usb_device_id *id)
{
	struct sd *sd = (struct sd *) gspca_dev;
	struct cam *cam;

	cam = &gspca_dev->cam;

	cam->cam_mode = vga_mode;	/* only 640x480 */
	cam->nmodes = ARRAY_SIZE(vga_mode);

	gspca_dev->cam.ctrls = sd->ctrls;

	sd->flags = id->driver_info;
	return 0;
}

static void setbrightcont(struct gspca_dev *gspca_dev)
{
	struct sd *sd = (struct sd *) gspca_dev;
	int i, v;
	static const u8 max[10] =
		{0x29, 0x33, 0x42, 0x5a, 0x6e, 0x80, 0x9f, 0xbb,
		 0xd4, 0xec};
	static const u8 delta[10] =
		{0x35, 0x33, 0x33, 0x2f, 0x2a, 0x25, 0x1e, 0x17,
		 0x11, 0x0b};

	reg_w(gspca_dev, 0xff, 0x00);		/* page 0 */
	for (i = 0; i < 10; i++) {
		v = max[i];
		v += (sd->ctrls[BRIGHTNESS].val - BRIGHTNESS_MAX)
			* 150 / BRIGHTNESS_MAX;		/* 200 ? */
		v -= delta[i] * sd->ctrls[CONTRAST].val / CONTRAST_MAX;
		if (v < 0)
			v = 0;
		else if (v > 0xff)
			v = 0xff;
		reg_w(gspca_dev, 0xa2 + i, v);
	}
	reg_w(gspca_dev, 0xdc, 0x01);
}

static void setcolors(struct gspca_dev *gspca_dev)
{
	struct sd *sd = (struct sd *) gspca_dev;
	int i, v;
	static const int a[9] =
		{217, -212, 0, -101, 170, -67, -38, -315, 355};
	static const int b[9] =
		{19, 106, 0, 19, 106, 1, 19, 106, 1};

	reg_w(gspca_dev, 0xff, 0x03);			/* page 3 */
	reg_w(gspca_dev, 0x11, 0x01);
	reg_w(gspca_dev, 0xff, 0x00);			/* page 0 */
	for (i = 0; i < 9; i++) {
		v = a[i] * sd->ctrls[COLORS].val / COLOR_MAX + b[i];
		reg_w(gspca_dev, 0x0f + 2 * i, (v >> 8) & 0x07);
		reg_w(gspca_dev, 0x0f + 2 * i + 1, v);
	}
	reg_w(gspca_dev, 0xdc, 0x01);
}

static void setwhitebalance(struct gspca_dev *gspca_dev)
{
	struct sd *sd = (struct sd *) gspca_dev;

	reg_w(gspca_dev, 0xff, 0x00);		/* page 0 */
	reg_w(gspca_dev, 0xc6, sd->ctrls[WHITE_BALANCE].val);

	reg_w(gspca_dev, 0xdc, 0x01);
}

static void setredbalance(struct gspca_dev *gspca_dev)
{
	struct sd *sd = (struct sd *) gspca_dev;

	reg_w(gspca_dev, 0xff, 0x00);		/* page 0 */
	reg_w(gspca_dev, 0xc5, sd->ctrls[RED_BALANCE].val);

	reg_w(gspca_dev, 0xdc, 0x01);
}

static void setbluebalance(struct gspca_dev *gspca_dev)
{
	struct sd *sd = (struct sd *) gspca_dev;

	reg_w(gspca_dev, 0xff, 0x00);			/* page 0 */
	reg_w(gspca_dev, 0xc7, sd->ctrls[BLUE_BALANCE].val);

	reg_w(gspca_dev, 0xdc, 0x01);
}

static void setgain(struct gspca_dev *gspca_dev)
{
	struct sd *sd = (struct sd *) gspca_dev;
	u8 reg10, reg12;

	if (sd->ctrls[GAIN].val < 32) {
		reg10 = sd->ctrls[GAIN].val;
		reg12 = 0;
	} else {
		reg10 = 31;
		reg12 = sd->ctrls[GAIN].val - 31;
	}

	reg_w(gspca_dev, 0xff, 0x03);			/* page 3 */
	reg_w(gspca_dev, 0x10, reg10);
	reg_w(gspca_dev, 0x12, reg12);

	/* load registers to sensor (Bit 0, auto clear) */
	reg_w(gspca_dev, 0x11, 0x01);
}

static void setexposure(struct gspca_dev *gspca_dev)
{
	struct sd *sd = (struct sd *) gspca_dev;
	u8 clockdiv;
	u16 exposure;

	/*
	 * Register 2 of frame 3 contains the clock divider configuring the
	 * no fps according to the formula: 90 / reg. sd->exposure is the
	 * desired exposure time in 0.5 ms.
	 */
	clockdiv = (90 * sd->ctrls[EXPOSURE].val + 1999) / 2000;

	/*
	 * Note clockdiv = 3 also works, but when running at 30 fps, depending
	 * on the scene being recorded, the camera switches to another
	 * quantization table for certain JPEG blocks, and we don't know how
	 * to decompress these blocks. So we cap the framerate at 15 fps.
	 */
	if (clockdiv < 6)
		clockdiv = 6;
	else if (clockdiv > 63)
		clockdiv = 63;

	/*
	 * Register 2 MUST be a multiple of 3, except when between 6 and 12?
	 * Always round up, otherwise we cannot get the desired frametime
	 * using the partial frame time exposure control.
	 */
	if (clockdiv < 6 || clockdiv > 12)
		clockdiv = ((clockdiv + 2) / 3) * 3;

	/*
	 * frame exposure time in ms = 1000 * clockdiv / 90    ->
	 * exposure = (sd->exposure / 2) * 448 / (1000 * clockdiv / 90)
	 */
	exposure = (sd->ctrls[EXPOSURE].val * 45 * 448) / (1000 * clockdiv);
	/* 0 = use full frametime, 448 = no exposure, reverse it */
	exposure = 448 - exposure;

	reg_w(gspca_dev, 0xff, 0x03);			/* page 3 */
	reg_w(gspca_dev, 0x02, clockdiv);
	reg_w(gspca_dev, 0x0e, exposure & 0xff);
	reg_w(gspca_dev, 0x0f, exposure >> 8);

	/* load registers to sensor (Bit 0, auto clear) */
	reg_w(gspca_dev, 0x11, 0x01);
}

static void setautogain(struct gspca_dev *gspca_dev)
{
	struct sd *sd = (struct sd *) gspca_dev;

	/*
	 * When switching to autogain set defaults to make sure
	 * we are on a valid point of the autogain gain /
	 * exposure knee graph, and give this change time to
	 * take effect before doing autogain.
	 */
	if (sd->ctrls[AUTOGAIN].val) {
		sd->ctrls[EXPOSURE].val = EXPOSURE_DEF;
		sd->ctrls[GAIN].val = GAIN_DEF;
		sd->autogain_ignore_frames =
				PAC_AUTOGAIN_IGNORE_FRAMES;
	} else {
		sd->autogain_ignore_frames = -1;
	}
	setexposure(gspca_dev);
	setgain(gspca_dev);
}

static void sethvflip(struct gspca_dev *gspca_dev)
{
	struct sd *sd = (struct sd *) gspca_dev;
	u8 data, hflip, vflip;

	hflip = sd->ctrls[HFLIP].val;
	if (sd->flags & FL_HFLIP)
		hflip = !hflip;
	vflip = sd->ctrls[VFLIP].val;
	if (sd->flags & FL_VFLIP)
		vflip = !vflip;

	reg_w(gspca_dev, 0xff, 0x03);			/* page 3 */
	data = (hflip ? 0x08 : 0x00) | (vflip ? 0x04 : 0x00);
	reg_w(gspca_dev, 0x21, data);

	/* load registers to sensor (Bit 0, auto clear) */
	reg_w(gspca_dev, 0x11, 0x01);
}

/* this function is called at probe and resume time for pac7302 */
static int sd_init(struct gspca_dev *gspca_dev)
{
	reg_w_seq(gspca_dev, init_7302, sizeof(init_7302)/2);
	return gspca_dev->usb_err;
}

static int sd_start(struct gspca_dev *gspca_dev)
{
	struct sd *sd = (struct sd *) gspca_dev;

	reg_w_var(gspca_dev, start_7302,
		page3_7302, sizeof(page3_7302));
	setbrightcont(gspca_dev);
	setcolors(gspca_dev);
	setwhitebalance(gspca_dev);
	setredbalance(gspca_dev);
	setbluebalance(gspca_dev);
	setautogain(gspca_dev);
	sethvflip(gspca_dev);

	sd->sof_read = 0;
	atomic_set(&sd->avg_lum, 270 + sd->ctrls[BRIGHTNESS].val);

	/* start stream */
	reg_w(gspca_dev, 0xff, 0x01);
	reg_w(gspca_dev, 0x78, 0x01);

	return gspca_dev->usb_err;
}

static void sd_stopN(struct gspca_dev *gspca_dev)
{

	/* stop stream */
	reg_w(gspca_dev, 0xff, 0x01);
	reg_w(gspca_dev, 0x78, 0x00);
}

/* called on streamoff with alt 0 and on disconnect for pac7302 */
static void sd_stop0(struct gspca_dev *gspca_dev)
{
	if (!gspca_dev->present)
		return;
	reg_w(gspca_dev, 0xff, 0x01);
	reg_w(gspca_dev, 0x78, 0x40);
}

#define WANT_REGULAR_AUTOGAIN
#include "autogain_functions.h"

static void do_autogain(struct gspca_dev *gspca_dev)
{
	struct sd *sd = (struct sd *) gspca_dev;
	int avg_lum = atomic_read(&sd->avg_lum);
	int desired_lum;
	const int deadzone = 30;

	if (sd->autogain_ignore_frames < 0)
		return;

	if (sd->autogain_ignore_frames > 0) {
		sd->autogain_ignore_frames--;
	} else {
		desired_lum = 270 + sd->ctrls[BRIGHTNESS].val;

		auto_gain_n_exposure(gspca_dev, avg_lum, desired_lum,
				deadzone, GAIN_KNEE, EXPOSURE_KNEE);
		sd->autogain_ignore_frames = PAC_AUTOGAIN_IGNORE_FRAMES;
	}
}

/* JPEG header */
static const u8 jpeg_header[] = {
	0xff, 0xd8,	/* SOI: Start of Image */

	0xff, 0xc0,	/* SOF0: Start of Frame (Baseline DCT) */
	0x00, 0x11,	/* length = 17 bytes (including this length field) */
	0x08,		/* Precision: 8 */
	0x02, 0x80,	/* height = 640 (image rotated) */
	0x01, 0xe0,	/* width = 480 */
	0x03,		/* Number of image components: 3 */
	0x01, 0x21, 0x00, /* ID=1, Subsampling 1x1, Quantization table: 0 */
	0x02, 0x11, 0x01, /* ID=2, Subsampling 2x1, Quantization table: 1 */
	0x03, 0x11, 0x01, /* ID=3, Subsampling 2x1, Quantization table: 1 */

	0xff, 0xda,	/* SOS: Start Of Scan */
	0x00, 0x0c,	/* length = 12 bytes (including this length field) */
	0x03,		/* number of components: 3 */
	0x01, 0x00,	/* selector 1, table 0x00 */
	0x02, 0x11,	/* selector 2, table 0x11 */
	0x03, 0x11,	/* selector 3, table 0x11 */
	0x00, 0x3f,	/* Spectral selection: 0 .. 63 */
	0x00		/* Successive approximation: 0 */
};

/* this function is run at interrupt level */
static void sd_pkt_scan(struct gspca_dev *gspca_dev,
			u8 *data,			/* isoc packet */
			int len)			/* iso packet length */
{
	struct sd *sd = (struct sd *) gspca_dev;
	u8 *image;
	u8 *sof;

	sof = pac_find_sof(&sd->sof_read, data, len);
	if (sof) {
		int n, lum_offset, footer_length;

		/*
		 * 6 bytes after the FF D9 EOF marker a number of lumination
		 * bytes are send corresponding to different parts of the
		 * image, the 14th and 15th byte after the EOF seem to
		 * correspond to the center of the image.
		 */
		lum_offset = 61 + sizeof pac_sof_marker;
		footer_length = 74;

		/* Finish decoding current frame */
		n = (sof - data) - (footer_length + sizeof pac_sof_marker);
		if (n < 0) {
			gspca_dev->image_len += n;
			n = 0;
		} else {
			gspca_frame_add(gspca_dev, INTER_PACKET, data, n);
		}

		image = gspca_dev->image;
		if (image != NULL
		 && image[gspca_dev->image_len - 2] == 0xff
		 && image[gspca_dev->image_len - 1] == 0xd9)
			gspca_frame_add(gspca_dev, LAST_PACKET, NULL, 0);

		n = sof - data;
		len -= n;
		data = sof;

		/* Get average lumination */
		if (gspca_dev->last_packet_type == LAST_PACKET &&
				n >= lum_offset)
			atomic_set(&sd->avg_lum, data[-lum_offset] +
						data[-lum_offset + 1]);

		/* Start the new frame with the jpeg header */
		/* The PAC7302 has the image rotated 90 degrees */
		gspca_frame_add(gspca_dev, FIRST_PACKET,
				jpeg_header, sizeof jpeg_header);
	}
	gspca_frame_add(gspca_dev, INTER_PACKET, data, len);
}

#ifdef CONFIG_VIDEO_ADV_DEBUG
static int sd_dbg_s_register(struct gspca_dev *gspca_dev,
			struct v4l2_dbg_register *reg)
{
	u8 index;
	u8 value;

	/*
	 * reg->reg: bit0..15: reserved for register index (wIndex is 16bit
	 *		       long on the USB bus)
	 */
	if (reg->match.type == V4L2_CHIP_MATCH_HOST &&
	    reg->match.addr == 0 &&
	    (reg->reg < 0x000000ff) &&
	    (reg->val <= 0x000000ff)
	) {
		/* Currently writing to page 0 is only supported. */
		/* reg_w() only supports 8bit index */
		index = reg->reg;
		value = reg->val;

		/*
		 * Note that there shall be no access to other page
		 * by any other function between the page switch and
		 * the actual register write.
		 */
		reg_w(gspca_dev, 0xff, 0x00);		/* page 0 */
		reg_w(gspca_dev, index, value);

		reg_w(gspca_dev, 0xdc, 0x01);
	}
	return gspca_dev->usb_err;
}

static int sd_chip_ident(struct gspca_dev *gspca_dev,
			struct v4l2_dbg_chip_ident *chip)
{
	int ret = -EINVAL;

	if (chip->match.type == V4L2_CHIP_MATCH_HOST &&
	    chip->match.addr == 0) {
		chip->revision = 0;
		chip->ident = V4L2_IDENT_UNKNOWN;
		ret = 0;
	}
	return ret;
}
#endif

#if defined(CONFIG_INPUT) || defined(CONFIG_INPUT_MODULE)
static int sd_int_pkt_scan(struct gspca_dev *gspca_dev,
			u8 *data,		/* interrupt packet data */
			int len)		/* interrput packet length */
{
	int ret = -EINVAL;
	u8 data0, data1;

	if (len == 2) {
		data0 = data[0];
		data1 = data[1];
		if ((data0 == 0x00 && data1 == 0x11) ||
		    (data0 == 0x22 && data1 == 0x33) ||
		    (data0 == 0x44 && data1 == 0x55) ||
		    (data0 == 0x66 && data1 == 0x77) ||
		    (data0 == 0x88 && data1 == 0x99) ||
		    (data0 == 0xaa && data1 == 0xbb) ||
		    (data0 == 0xcc && data1 == 0xdd) ||
		    (data0 == 0xee && data1 == 0xff)) {
			input_report_key(gspca_dev->input_dev, KEY_CAMERA, 1);
			input_sync(gspca_dev->input_dev);
			input_report_key(gspca_dev->input_dev, KEY_CAMERA, 0);
			input_sync(gspca_dev->input_dev);
			ret = 0;
		}
	}

	return ret;
}
#endif

/* sub-driver description for pac7302 */
static const struct sd_desc sd_desc = {
	.name = KBUILD_MODNAME,
	.ctrls = sd_ctrls,
	.nctrls = ARRAY_SIZE(sd_ctrls),
	.config = sd_config,
	.init = sd_init,
	.start = sd_start,
	.stopN = sd_stopN,
	.stop0 = sd_stop0,
	.pkt_scan = sd_pkt_scan,
	.dq_callback = do_autogain,
#ifdef CONFIG_VIDEO_ADV_DEBUG
	.set_register = sd_dbg_s_register,
	.get_chip_ident = sd_chip_ident,
#endif
#if defined(CONFIG_INPUT) || defined(CONFIG_INPUT_MODULE)
	.int_pkt_scan = sd_int_pkt_scan,
#endif
};

/* -- module initialisation -- */
static const struct usb_device_id device_table[] = {
	{USB_DEVICE(0x06f8, 0x3009)},
	{USB_DEVICE(0x06f8, 0x301b)},
	{USB_DEVICE(0x093a, 0x2620)},
	{USB_DEVICE(0x093a, 0x2621)},
	{USB_DEVICE(0x093a, 0x2622), .driver_info = FL_VFLIP},
	{USB_DEVICE(0x093a, 0x2624), .driver_info = FL_VFLIP},
	{USB_DEVICE(0x093a, 0x2625)},
	{USB_DEVICE(0x093a, 0x2626)},
	{USB_DEVICE(0x093a, 0x2627), .driver_info = FL_VFLIP},
	{USB_DEVICE(0x093a, 0x2628)},
	{USB_DEVICE(0x093a, 0x2629), .driver_info = FL_VFLIP},
	{USB_DEVICE(0x093a, 0x262a)},
	{USB_DEVICE(0x093a, 0x262c)},
	{USB_DEVICE(0x145f, 0x013c)},
	{}
};
MODULE_DEVICE_TABLE(usb, device_table);

/* -- device connect -- */
static int sd_probe(struct usb_interface *intf,
			const struct usb_device_id *id)
{
	return gspca_dev_probe(intf, id, &sd_desc, sizeof(struct sd),
				THIS_MODULE);
}

static struct usb_driver sd_driver = {
	.name = KBUILD_MODNAME,
	.id_table = device_table,
	.probe = sd_probe,
	.disconnect = gspca_disconnect,
#ifdef CONFIG_PM
	.suspend = gspca_suspend,
	.resume = gspca_resume,
#endif
};

module_usb_driver(sd_driver);