drivers/staging/media/easycap/easycap_low.c

/*****************************************************************************
*                                                                            *
*                                                                            *
*  easycap_low.c                                                             *
*                                                                            *
*                                                                            *
*****************************************************************************/
/*
 *
 *  Copyright (C) 2010 R.M. Thomas  <rmthomas@sciolus.org>
 *
 *
 *  This 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
 *  (at your option) any later version.
 *
 *  The software 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 software; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
*/
/*****************************************************************************/
/*
 *  ACKNOWLEGEMENTS AND REFERENCES
 *  ------------------------------
 *  This driver makes use of register information contained in the Syntek
 *  Semicon DC-1125 driver hosted at
 *               http://sourceforge.net/projects/syntekdriver/.
 *  Particularly useful has been a patch to the latter driver provided by
 *  Ivor Hewitt in January 2009.  The NTSC implementation is taken from the
 *  work of Ben Trask.
*/
/****************************************************************************/

#include "easycap.h"


#define GET(X, Y, Z) do { \
	int __rc; \
	*(Z) = (u16)0; \
	__rc = regget(X, Y, Z, sizeof(u8)); \
	if (0 > __rc) { \
		JOT(8, ":-(%i\n", __LINE__);  return __rc; \
	} \
} while (0)

#define SET(X, Y, Z) do { \
	int __rc; \
	__rc = regset(X, Y, Z); \
	if (0 > __rc) { \
		JOT(8, ":-(%i\n", __LINE__);  return __rc; \
	} \
} while (0)

/*--------------------------------------------------------------------------*/
static const struct stk1160config {
	u16 reg;
	u16 set;
} stk1160configPAL[] = {
		{0x000, 0x0098},
		{0x002, 0x0093},

		{0x001, 0x0003},
		{0x003, 0x0080},
		{0x00D, 0x0000},
		{0x00F, 0x0002},
		{0x018, 0x0010},
		{0x019, 0x0000},
		{0x01A, 0x0014},
		{0x01B, 0x000E},
		{0x01C, 0x0046},

		{0x100, 0x0033},
		{0x103, 0x0000},
		{0x104, 0x0000},
		{0x105, 0x0000},
		{0x106, 0x0000},

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/*
 *  RESOLUTION 640x480
*/
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
		{0x110, 0x0008},
		{0x111, 0x0000},
		{0x112, 0x0020},
		{0x113, 0x0000},
		{0x114, 0x0508},
		{0x115, 0x0005},
		{0x116, 0x0110},
		{0x117, 0x0001},
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

		{0x202, 0x000F},
		{0x203, 0x004A},
		{0x2FF, 0x0000},

		{0xFFF, 0xFFFF}
};
/*--------------------------------------------------------------------------*/
static const struct stk1160config stk1160configNTSC[] = {
		{0x000, 0x0098},
		{0x002, 0x0093},

		{0x001, 0x0003},
		{0x003, 0x0080},
		{0x00D, 0x0000},
		{0x00F, 0x0002},
		{0x018, 0x0010},
		{0x019, 0x0000},
		{0x01A, 0x0014},
		{0x01B, 0x000E},
		{0x01C, 0x0046},

		{0x100, 0x0033},
		{0x103, 0x0000},
		{0x104, 0x0000},
		{0x105, 0x0000},
		{0x106, 0x0000},

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/*
 *  RESOLUTION 640x480
*/
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
		{0x110, 0x0008},
		{0x111, 0x0000},
		{0x112, 0x0003},
		{0x113, 0x0000},
		{0x114, 0x0508},
		{0x115, 0x0005},
		{0x116, 0x00F3},
		{0x117, 0x0000},
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

		{0x202, 0x000F},
		{0x203, 0x004A},
		{0x2FF, 0x0000},

		{0xFFF, 0xFFFF}
};
/*--------------------------------------------------------------------------*/
static const struct saa7113config {
	u8 reg;
	u8 set;
} saa7113configPAL[] = {
		{0x01, 0x08},
		{0x02, 0x80},
		{0x03, 0x33},
		{0x04, 0x00},
		{0x05, 0x00},
		{0x06, 0xE9},
		{0x07, 0x0D},
		{0x08, 0x38},
		{0x09, 0x00},
		{0x0A, SAA_0A_DEFAULT},
		{0x0B, SAA_0B_DEFAULT},
		{0x0C, SAA_0C_DEFAULT},
		{0x0D, SAA_0D_DEFAULT},
		{0x0E, 0x01},
		{0x0F, 0x36},
		{0x10, 0x00},
		{0x11, 0x0C},
		{0x12, 0xE7},
		{0x13, 0x00},
		{0x15, 0x00},
		{0x16, 0x00},
		{0x40, 0x02},
		{0x41, 0xFF},
		{0x42, 0xFF},
		{0x43, 0xFF},
		{0x44, 0xFF},
		{0x45, 0xFF},
		{0x46, 0xFF},
		{0x47, 0xFF},
		{0x48, 0xFF},
		{0x49, 0xFF},
		{0x4A, 0xFF},
		{0x4B, 0xFF},
		{0x4C, 0xFF},
		{0x4D, 0xFF},
		{0x4E, 0xFF},
		{0x4F, 0xFF},
		{0x50, 0xFF},
		{0x51, 0xFF},
		{0x52, 0xFF},
		{0x53, 0xFF},
		{0x54, 0xFF},
		{0x55, 0xFF},
		{0x56, 0xFF},
		{0x57, 0xFF},
		{0x58, 0x40},
		{0x59, 0x54},
		{0x5A, 0x07},
		{0x5B, 0x83},

		{0xFF, 0xFF}
};
/*--------------------------------------------------------------------------*/
static const struct saa7113config saa7113configNTSC[] = {
		{0x01, 0x08},
		{0x02, 0x80},
		{0x03, 0x33},
		{0x04, 0x00},
		{0x05, 0x00},
		{0x06, 0xE9},
		{0x07, 0x0D},
		{0x08, 0x78},
		{0x09, 0x00},
		{0x0A, SAA_0A_DEFAULT},
		{0x0B, SAA_0B_DEFAULT},
		{0x0C, SAA_0C_DEFAULT},
		{0x0D, SAA_0D_DEFAULT},
		{0x0E, 0x01},
		{0x0F, 0x36},
		{0x10, 0x00},
		{0x11, 0x0C},
		{0x12, 0xE7},
		{0x13, 0x00},
		{0x15, 0x00},
		{0x16, 0x00},
		{0x40, 0x82},
		{0x41, 0xFF},
		{0x42, 0xFF},
		{0x43, 0xFF},
		{0x44, 0xFF},
		{0x45, 0xFF},
		{0x46, 0xFF},
		{0x47, 0xFF},
		{0x48, 0xFF},
		{0x49, 0xFF},
		{0x4A, 0xFF},
		{0x4B, 0xFF},
		{0x4C, 0xFF},
		{0x4D, 0xFF},
		{0x4E, 0xFF},
		{0x4F, 0xFF},
		{0x50, 0xFF},
		{0x51, 0xFF},
		{0x52, 0xFF},
		{0x53, 0xFF},
		{0x54, 0xFF},
		{0x55, 0xFF},
		{0x56, 0xFF},
		{0x57, 0xFF},
		{0x58, 0x40},
		{0x59, 0x54},
		{0x5A, 0x0A},
		{0x5B, 0x83},

		{0xFF, 0xFF}
};

static int regget(struct usb_device *pusb_device,
		u16 index, void *reg, int reg_size)
{
	int rc;

	if (!pusb_device)
		return -ENODEV;

	rc = usb_control_msg(pusb_device, usb_rcvctrlpipe(pusb_device, 0),
			0x00,
			(USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE),
			0x00,
			index, reg, reg_size, 50000);

	return rc;
}

static int regset(struct usb_device *pusb_device, u16 index, u16 value)
{
	int rc;

	if (!pusb_device)
		return -ENODEV;

	rc = usb_control_msg(pusb_device, usb_sndctrlpipe(pusb_device, 0),
			0x01,
			(USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE),
			value, index, NULL, 0, 500);

	if (rc < 0)
		return rc;

	if (easycap_readback) {
		u16 igot = 0;
		rc = regget(pusb_device, index, &igot, sizeof(igot));
		igot = 0xFF & igot;
		switch (index) {
		case 0x000:
		case 0x500:
		case 0x502:
		case 0x503:
		case 0x504:
		case 0x506:
		case 0x507:
			break;

		case 0x204:
		case 0x205:
		case 0x350:
		case 0x351:
			if (igot)
				JOT(8, "unexpected 0x%02X "
					"for STK register 0x%03X\n",
					igot, index);
			break;

		default:
			if ((0xFF & value) != igot)
				JOT(8, "unexpected 0x%02X != 0x%02X "
					"for STK register 0x%03X\n",
						igot, value, index);
			break;
		}
	}

	return rc;
}
/*--------------------------------------------------------------------------*/
/*
 *  FUNCTION wait_i2c() RETURNS 0 ON SUCCESS
*/
/*--------------------------------------------------------------------------*/
static int wait_i2c(struct usb_device *p)
{
	u16 get0;
	u8 igot;
	const int max = 2;
	int k;

	if (!p)
		return -ENODEV;

	for (k = 0;  k < max;  k++) {
		GET(p, 0x0201, &igot);  get0 = igot;
		switch (get0) {
		case 0x04:
		case 0x01:
			return 0;
		case 0x00:
			msleep(20);
			continue;
		default:
			return get0 - 1;
		}
	}
	return -1;
}

/****************************************************************************/
int write_saa(struct usb_device *p, u16 reg0, u16 set0)
{
	if (!p)
		return -ENODEV;
	SET(p, 0x200, 0x00);
	SET(p, 0x204, reg0);
	SET(p, 0x205, set0);
	SET(p, 0x200, 0x01);
	return wait_i2c(p);
}
/****************************************************************************/
/*--------------------------------------------------------------------------*/
/*
 *  REGISTER 500:  SETTING VALUE TO 0x008B READS FROM VT1612A (?)
 *  REGISTER 500:  SETTING VALUE TO 0x008C WRITES TO  VT1612A
 *  REGISTER 502:  LEAST SIGNIFICANT BYTE OF VALUE TO SET
 *  REGISTER 503:  MOST SIGNIFICANT BYTE OF VALUE TO SET
 *  REGISTER 504:  TARGET ADDRESS ON VT1612A
 */
/*--------------------------------------------------------------------------*/
static int write_vt(struct usb_device *p, u16 reg0, u16 set0)
{
	u8 igot;
	u16 got502, got503;
	u16 set502, set503;

	if (!p)
		return -ENODEV;
	SET(p, 0x0504, reg0);
	SET(p, 0x0500, 0x008B);

	GET(p, 0x0502, &igot);  got502 = (0xFF & igot);
	GET(p, 0x0503, &igot);  got503 = (0xFF & igot);

	JOT(16, "write_vt(., 0x%04X, 0x%04X): was 0x%04X\n",
				reg0, set0, ((got503 << 8) | got502));

	set502 =  (0x00FF & set0);
	set503 = ((0xFF00 & set0) >> 8);

	SET(p, 0x0504, reg0);
	SET(p, 0x0502, set502);
	SET(p, 0x0503, set503);
	SET(p, 0x0500, 0x008C);

	return 0;
}
/****************************************************************************/
/*--------------------------------------------------------------------------*/
/*
 *  REGISTER 500:  SETTING VALUE TO 0x008B READS FROM VT1612A (?)
 *  REGISTER 500:  SETTING VALUE TO 0x008C WRITES TO  VT1612A
 *  REGISTER 502:  LEAST SIGNIFICANT BYTE OF VALUE TO GET
 *  REGISTER 503:  MOST SIGNIFICANT BYTE OF VALUE TO GET
 *  REGISTER 504:  TARGET ADDRESS ON VT1612A
 */
/*--------------------------------------------------------------------------*/
static int read_vt(struct usb_device *p, u16 reg0)
{
	u8 igot;
	u16 got502, got503;

	if (!p)
		return -ENODEV;
	SET(p, 0x0504, reg0);
	SET(p, 0x0500, 0x008B);

	GET(p, 0x0502, &igot);  got502 = (0xFF & igot);
	GET(p, 0x0503, &igot);  got503 = (0xFF & igot);

	JOT(16, "read_vt(., 0x%04X): has 0x%04X\n",
			reg0, ((got503 << 8) | got502));

	return (got503 << 8) | got502;
}
/****************************************************************************/
/*--------------------------------------------------------------------------*/
/*
 *  THESE APPEAR TO HAVE NO EFFECT ON EITHER VIDEO OR AUDIO.
 */
/*--------------------------------------------------------------------------*/
static int write_300(struct usb_device *p)
{
	if (!p)
		return -ENODEV;
	SET(p, 0x300, 0x0012);
	SET(p, 0x350, 0x002D);
	SET(p, 0x351, 0x0001);
	SET(p, 0x352, 0x0000);
	SET(p, 0x353, 0x0000);
	SET(p, 0x300, 0x0080);
	return 0;
}
/****************************************************************************/
/****************************************************************************/
int setup_stk(struct usb_device *p, bool ntsc)
{
	int i;
	const struct stk1160config *cfg;
	if (!p)
		return -ENODEV;
	cfg = (ntsc) ? stk1160configNTSC : stk1160configPAL;
	for (i = 0; cfg[i].reg != 0xFFF; i++)
		SET(p, cfg[i].reg, cfg[i].set);

	write_300(p);

	return 0;
}
/****************************************************************************/
int setup_saa(struct usb_device *p, bool ntsc)
{
	int i, rc;
	const struct saa7113config *cfg;
	if (!p)
		return -ENODEV;
	cfg = (ntsc) ?  saa7113configNTSC : saa7113configPAL;
	for (i = 0; cfg[i].reg != 0xFF; i++) {
		rc = write_saa(p, cfg[i].reg, cfg[i].set);
		if (rc)
			dev_err(&p->dev,
				"Failed to set SAA register %d", cfg[i].reg);
	}
	return 0;
}
/****************************************************************************/
int merit_saa(struct usb_device *p)
{
	int rc;

	if (!p)
		return -ENODEV;
	rc = read_saa(p, 0x1F);
	return ((0 > rc) || (0x02 & rc)) ? 1 : 0;
}
/****************************************************************************/
int ready_saa(struct usb_device *p)
{
	int j, rc, rate;
	const int max = 5, marktime = PATIENCE/5;
/*--------------------------------------------------------------------------*/
/*
 *   RETURNS    0     FOR INTERLACED       50 Hz
 *              1     FOR NON-INTERLACED   50 Hz
 *              2     FOR INTERLACED       60 Hz
 *              3     FOR NON-INTERLACED   60 Hz
*/
/*--------------------------------------------------------------------------*/
	if (!p)
		return -ENODEV;
	j = 0;
	while (max > j) {
		rc = read_saa(p, 0x1F);
		if (0 <= rc) {
			if (0 == (0x40 & rc))
				break;
			if (1 == (0x01 & rc))
				break;
		}
		msleep(marktime);
		j++;
	}

	if (max == j)
		return -1;

	if (0x20 & rc) {
		rate = 2;
		JOT(8, "hardware detects 60 Hz\n");
	} else {
		rate = 0;
		JOT(8, "hardware detects 50 Hz\n");
	}
	if (0x80 & rc)
		JOT(8, "hardware detects interlacing\n");
	else {
		rate++;
		JOT(8, "hardware detects no interlacing\n");
	}
	return 0;
}
/****************************************************************************/
int read_saa(struct usb_device *p, u16 reg0)
{
	u8 igot;

	if (!p)
		return -ENODEV;
	SET(p, 0x208, reg0);
	SET(p, 0x200, 0x20);
	if (0 != wait_i2c(p))
		return -1;
	igot = 0;
	GET(p, 0x0209, &igot);
	return igot;
}
/****************************************************************************/
static int read_stk(struct usb_device *p, u32 reg0)
{
	u8 igot;

	if (!p)
		return -ENODEV;
	igot = 0;
	GET(p, reg0, &igot);
	return igot;
}
int select_input(struct usb_device *p, int input, int mode)
{
	int ir;

	if (!p)
		return -ENODEV;
	stop_100(p);
	switch (input) {
	case 0:
	case 1: {
		if (0 != write_saa(p, 0x02, 0x80))
			SAY("ERROR: failed to set SAA register 0x02 "
						"for input %i\n", input);

		SET(p, 0x0000, 0x0098);
		SET(p, 0x0002, 0x0078);
		break;
	}
	case 2: {
		if (0 != write_saa(p, 0x02, 0x80))
			SAY("ERROR: failed to set SAA register 0x02 "
						"for input %i\n", input);

		SET(p, 0x0000, 0x0090);
		SET(p, 0x0002, 0x0078);
		break;
	}
	case 3: {
		if (0 != write_saa(p, 0x02, 0x80))
			SAY("ERROR: failed to set SAA register 0x02 "
					" for input %i\n", input);

		SET(p, 0x0000, 0x0088);
		SET(p, 0x0002, 0x0078);
		break;
	}
	case 4: {
		if (0 != write_saa(p, 0x02, 0x80)) {
			SAY("ERROR: failed to set SAA register 0x02 "
						"for input %i\n", input);
		}
		SET(p, 0x0000, 0x0080);
		SET(p, 0x0002, 0x0078);
		break;
	}
	case 5: {
		if (9 != mode)
			mode = 7;
		switch (mode) {
		case 7: {
			if (0 != write_saa(p, 0x02, 0x87))
				SAY("ERROR: failed to set SAA register 0x02 "
						"for input %i\n", input);

			if (0 != write_saa(p, 0x05, 0xFF))
				SAY("ERROR: failed to set SAA register 0x05 "
						"for input %i\n", input);

			break;
		}
		case 9: {
			if (0 != write_saa(p, 0x02, 0x89))
				SAY("ERROR: failed to set SAA register 0x02 "
						"for input %i\n", input);

			if (0 != write_saa(p, 0x05, 0x00))
				SAY("ERROR: failed to set SAA register 0x05 "
						"for input %i\n", input);

			break;
		}
		default:
			SAY("MISTAKE:  bad mode: %i\n", mode);
			return -1;
		}

		if (0 != write_saa(p, 0x04, 0x00))
			SAY("ERROR: failed to set SAA register 0x04 "
					"for input %i\n", input);

		if (0 != write_saa(p, 0x09, 0x80))
			SAY("ERROR: failed to set SAA register 0x09 "
						"for input %i\n", input);

		SET(p, 0x0002, 0x0093);
		break;
	}
	default:
		SAY("ERROR:  bad input: %i\n", input);
		return -1;
	}

	ir = read_stk(p, 0x00);
	JOT(8, "STK register 0x00 has 0x%02X\n", ir);
	ir = read_saa(p, 0x02);
	JOT(8, "SAA register 0x02 has 0x%02X\n", ir);

	start_100(p);

	return 0;
}
/****************************************************************************/
int set_resolution(struct usb_device *p,
		   u16 set0, u16 set1, u16 set2, u16 set3)
{
	u16 u0x0111, u0x0113, u0x0115, u0x0117;

	if (!p)
		return -ENODEV;
	u0x0111 = ((0xFF00 & set0) >> 8);
	u0x0113 = ((0xFF00 & set1) >> 8);
	u0x0115 = ((0xFF00 & set2) >> 8);
	u0x0117 = ((0xFF00 & set3) >> 8);

	SET(p, 0x0110, (0x00FF & set0));
	SET(p, 0x0111, u0x0111);
	SET(p, 0x0112, (0x00FF & set1));
	SET(p, 0x0113, u0x0113);
	SET(p, 0x0114, (0x00FF & set2));
	SET(p, 0x0115, u0x0115);
	SET(p, 0x0116, (0x00FF & set3));
	SET(p, 0x0117, u0x0117);

	return 0;
}
/****************************************************************************/
int start_100(struct usb_device *p)
{
	u16 get116, get117, get0;
	u8 igot116, igot117, igot;

	if (!p)
		return -ENODEV;
	GET(p, 0x0116, &igot116);
	get116 = igot116;
	GET(p, 0x0117, &igot117);
	get117 = igot117;
	SET(p, 0x0116, 0x0000);
	SET(p, 0x0117, 0x0000);

	GET(p, 0x0100, &igot);
	get0 = igot;
	SET(p, 0x0100, (0x80 | get0));

	SET(p, 0x0116, get116);
	SET(p, 0x0117, get117);

	return 0;
}
/****************************************************************************/
int stop_100(struct usb_device *p)
{
	u16 get0;
	u8 igot;

	if (!p)
		return -ENODEV;
	GET(p, 0x0100, &igot);
	get0 = igot;
	SET(p, 0x0100, (0x7F & get0));
	return 0;
}
/****************************************************************************/
/****************************************************************************/
/*****************************************************************************/
int easycap_wakeup_device(struct usb_device *pusb_device)
{
	if (!pusb_device)
		return -ENODEV;

	return usb_control_msg(pusb_device, usb_sndctrlpipe(pusb_device, 0),
			USB_REQ_SET_FEATURE,
			USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
			USB_DEVICE_REMOTE_WAKEUP,
			0, NULL, 0, 50000);
}
/*****************************************************************************/
int easycap_audio_setup(struct easycap *peasycap)
{
	struct usb_device *pusb_device;
	u8 buffer[1];
	int rc, id1, id2;
/*---------------------------------------------------------------------------*/
/*
 *                                IMPORTANT:
 *  THE MESSAGE OF TYPE (USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE)
 *  CAUSES MUTING IF THE VALUE 0x0100 IS SENT.
 *  TO ENABLE AUDIO  THE VALUE 0x0200 MUST BE SENT.
 */
/*---------------------------------------------------------------------------*/
	const u8 request = 0x01;
	const u8 requesttype = USB_DIR_OUT |
			       USB_TYPE_CLASS |
			       USB_RECIP_INTERFACE;
	const u16 value_unmute = 0x0200;
	const u16 index = 0x0301;
	const u16 length = 1;

	if (!peasycap)
		return -EFAULT;

	pusb_device = peasycap->pusb_device;
	if (!pusb_device)
		return -ENODEV;

	JOM(8, "%02X %02X %02X %02X %02X %02X %02X %02X\n",
				requesttype, request,
				(0x00FF & value_unmute),
				(0xFF00 & value_unmute) >> 8,
				(0x00FF & index),
				(0xFF00 & index) >> 8,
				(0x00FF & length),
				(0xFF00 & length) >> 8);

	buffer[0] = 0x01;

	rc = usb_control_msg(pusb_device, usb_sndctrlpipe(pusb_device, 0),
				request, requesttype, value_unmute,
				index, &buffer[0], length, 50000);

	JOT(8, "0x%02X=buffer\n", buffer[0]);
	if (rc != (int)length) {
		switch (rc) {
		case -EPIPE:
			SAY("usb_control_msg returned -EPIPE\n");
			break;
		default:
			SAY("ERROR: usb_control_msg returned %i\n", rc);
			break;
		}
	}
/*--------------------------------------------------------------------------*/
/*
 *  REGISTER 500:  SETTING VALUE TO 0x0094 RESETS AUDIO CONFIGURATION ???
 *  REGISTER 506:  ANALOGUE AUDIO ATTENTUATOR ???
 *                 FOR THE CVBS+S-VIDEO HARDWARE:
 *                    SETTING VALUE TO 0x0000 GIVES QUIET SOUND.
 *                    THE UPPER BYTE SEEMS TO HAVE NO EFFECT.
 *                 FOR THE FOUR-CVBS HARDWARE:
 *                    SETTING VALUE TO 0x0000 SEEMS TO HAVE NO EFFECT.
 *  REGISTER 507:  ANALOGUE AUDIO PREAMPLIFIER ON/OFF ???
 *                 FOR THE CVBS-S-VIDEO HARDWARE:
 *                    SETTING VALUE TO 0x0001 GIVES VERY LOUD, DISTORTED SOUND.
 *                    THE UPPER BYTE SEEMS TO HAVE NO EFFECT.
 */
/*--------------------------------------------------------------------------*/
	SET(pusb_device, 0x0500, 0x0094);
	SET(pusb_device, 0x0500, 0x008C);
	SET(pusb_device, 0x0506, 0x0001);
	SET(pusb_device, 0x0507, 0x0000);
	id1 = read_vt(pusb_device, 0x007C);
	id2 = read_vt(pusb_device, 0x007E);
	SAM("0x%04X:0x%04X is audio vendor id\n", id1, id2);
/*---------------------------------------------------------------------------*/
/*
 *  SELECT AUDIO SOURCE "LINE IN" AND SET THE AUDIO GAIN.
*/
/*---------------------------------------------------------------------------*/
	if (easycap_audio_gainset(pusb_device, peasycap->gain))
		SAY("ERROR: audio_gainset() failed\n");
	check_vt(pusb_device);
	return 0;
}
/*****************************************************************************/
int check_vt(struct usb_device *pusb_device)
{
	int igot;

	if (!pusb_device)
		return -ENODEV;
	igot = read_vt(pusb_device, 0x0002);
	if (0 > igot)
		SAY("ERROR: failed to read VT1612A register 0x02\n");
	if (0x8000 & igot)
		SAY("register 0x%02X muted\n", 0x02);

	igot = read_vt(pusb_device, 0x000E);
	if (0 > igot)
		SAY("ERROR: failed to read VT1612A register 0x0E\n");
	if (0x8000 & igot)
		SAY("register 0x%02X muted\n", 0x0E);

	igot = read_vt(pusb_device, 0x0010);
	if (0 > igot)
		SAY("ERROR: failed to read VT1612A register 0x10\n");
	if (0x8000 & igot)
		SAY("register 0x%02X muted\n", 0x10);

	igot = read_vt(pusb_device, 0x0012);
	if (0 > igot)
		SAY("ERROR: failed to read VT1612A register 0x12\n");
	if (0x8000 & igot)
		SAY("register 0x%02X muted\n", 0x12);

	igot = read_vt(pusb_device, 0x0014);
	if (0 > igot)
		SAY("ERROR: failed to read VT1612A register 0x14\n");
	if (0x8000 & igot)
		SAY("register 0x%02X muted\n", 0x14);

	igot = read_vt(pusb_device, 0x0016);
	if (0 > igot)
		SAY("ERROR: failed to read VT1612A register 0x16\n");
	if (0x8000 & igot)
		SAY("register 0x%02X muted\n", 0x16);

	igot = read_vt(pusb_device, 0x0018);
	if (0 > igot)
		SAY("ERROR: failed to read VT1612A register 0x18\n");
	if (0x8000 & igot)
		SAY("register 0x%02X muted\n", 0x18);

	igot = read_vt(pusb_device, 0x001C);
	if (0 > igot)
		SAY("ERROR: failed to read VT1612A register 0x1C\n");
	if (0x8000 & igot)
		SAY("register 0x%02X muted\n", 0x1C);

	return 0;
}
/*****************************************************************************/
/*---------------------------------------------------------------------------*/
/*  NOTE:  THIS DOES INCREASE THE VOLUME DRAMATICALLY:
 *                      audio_gainset(pusb_device, 0x000F);
 *
 *       loud        dB  register 0x10      dB register 0x1C    dB total
 *         0               -34.5                   0             -34.5
 *        ..                ....                   .              ....
 *        15                10.5                   0              10.5
 *        16                12.0                   0              12.0
 *        17                12.0                   1.5            13.5
 *        ..                ....                  ....            ....
 *        31                12.0                  22.5            34.5
*/
/*---------------------------------------------------------------------------*/
int easycap_audio_gainset(struct usb_device *pusb_device, s8 loud)
{
	int igot;
	u8 tmp;
	u16 mute;

	if (!pusb_device)
		return -ENODEV;
	if (0 > loud)
		loud = 0;
	if (31 < loud)
		loud = 31;

	write_vt(pusb_device, 0x0002, 0x8000);
/*---------------------------------------------------------------------------*/
	igot = read_vt(pusb_device, 0x000E);
	if (0 > igot) {
		SAY("ERROR: failed to read VT1612A register 0x0E\n");
		mute = 0x0000;
	} else
		mute = 0x8000 & ((unsigned int)igot);
	mute = 0;

	if (16 > loud)
		tmp = 0x01 | (0x001F & (((u8)(15 - loud)) << 1));
	else
		tmp = 0;

	JOT(8, "0x%04X=(mute|tmp) for VT1612A register 0x0E\n", mute | tmp);
	write_vt(pusb_device, 0x000E, (mute | tmp));
/*---------------------------------------------------------------------------*/
	igot = read_vt(pusb_device, 0x0010);
	if (0 > igot) {
		SAY("ERROR: failed to read VT1612A register 0x10\n");
		mute = 0x0000;
	} else
		mute = 0x8000 & ((unsigned int)igot);
	mute = 0;

	JOT(8, "0x%04X=(mute|tmp|(tmp<<8)) for VT1612A register 0x10,...0x18\n",
						mute | tmp | (tmp << 8));
	write_vt(pusb_device, 0x0010, (mute | tmp | (tmp << 8)));
	write_vt(pusb_device, 0x0012, (mute | tmp | (tmp << 8)));
	write_vt(pusb_device, 0x0014, (mute | tmp | (tmp << 8)));
	write_vt(pusb_device, 0x0016, (mute | tmp | (tmp << 8)));
	write_vt(pusb_device, 0x0018, (mute | tmp | (tmp << 8)));
/*---------------------------------------------------------------------------*/
	igot = read_vt(pusb_device, 0x001C);
	if (0 > igot) {
		SAY("ERROR: failed to read VT1612A register 0x1C\n");
		mute = 0x0000;
	} else
		mute = 0x8000 & ((unsigned int)igot);
	mute = 0;

	if (16 <= loud)
		tmp = 0x000F & (u8)(loud - 16);
	else
		tmp = 0;

	JOT(8, "0x%04X=(mute|tmp|(tmp<<8)) for VT1612A register 0x1C\n",
						mute | tmp | (tmp << 8));
	write_vt(pusb_device, 0x001C, (mute | tmp | (tmp << 8)));
	write_vt(pusb_device, 0x001A, 0x0404);
	write_vt(pusb_device, 0x0002, 0x0000);
	return 0;
}
/*****************************************************************************/