drivers/media/video/usbvision/usbvision-i2c.c - arm/linux-arm64-legacy - Git at Google

 /*
  * I2C_ALGO_USB.C
  *  i2c algorithm for USB-I2C Bridges
  *
  * Copyright (c) 1999-2005 Joerg Heckenbach <joerg@heckenbach-aw.de>
  *                         Dwaine Garden <dwainegarden@rogers.com>
  *
  * This module is part of usbvision driver project.
  * Updates to driver completed by Dwaine P. Garden
  *
  * 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
  * (at your option) 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., 675 Mass Ave, Cambridge, MA 02139, USA.
  */


 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/version.h>
 #include <linux/utsname.h>
 #include <linux/init.h>
 #include <asm/uaccess.h>
 #include <linux/ioport.h>
 #include <linux/errno.h>
 #include <linux/usb.h>
 #include <linux/i2c.h>
 #include "usbvision.h"

 #define DBG_I2C		1<<0
 #define DBG_ALGO	1<<1

 static int i2c_debug = 0;

 module_param (i2c_debug, int, 0644);			// debug_i2c_usb mode of the device driver
 MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");

 #define PDEBUG(level, fmt, args...) \
 		if (i2c_debug & (level)) info("[%s:%d] " fmt, __PRETTY_FUNCTION__, __LINE__ , ## args)

 static int usbvision_i2c_write(void *data, unsigned char addr, char *buf,
 			    short len);
 static int usbvision_i2c_read(void *data, unsigned char addr, char *buf,
 			   short len);

 static inline int try_write_address(struct i2c_adapter *i2c_adap,
 				    unsigned char addr, int retries)
 {
 	void *data;
 	int i, ret = -1;
 	char buf[4];

 	data = i2c_get_adapdata(i2c_adap);
 	buf[0] = 0x00;
 	for (i = 0; i <= retries; i++) {
 		ret = (usbvision_i2c_write(data, addr, buf, 1));
 		if (ret == 1)
 			break;	/* success! */
 		udelay(5);
 		if (i == retries)	/* no success */
 			break;
 		udelay(10);
 	}
 	if (i) {
 		PDEBUG(DBG_ALGO,"Needed %d retries for address %#2x", i, addr);
 		PDEBUG(DBG_ALGO,"Maybe there's no device at this address");
 	}
 	return ret;
 }

 static inline int try_read_address(struct i2c_adapter *i2c_adap,
 				   unsigned char addr, int retries)
 {
 	void *data;
 	int i, ret = -1;
 	char buf[4];

 	data = i2c_get_adapdata(i2c_adap);
 	for (i = 0; i <= retries; i++) {
 		ret = (usbvision_i2c_read(data, addr, buf, 1));
 		if (ret == 1)
 			break;	/* success! */
 		udelay(5);
 		if (i == retries)	/* no success */
 			break;
 		udelay(10);
 	}
 	if (i) {
 		PDEBUG(DBG_ALGO,"Needed %d retries for address %#2x", i, addr);
 		PDEBUG(DBG_ALGO,"Maybe there's no device at this address");
 	}
 	return ret;
 }

 static inline int usb_find_address(struct i2c_adapter *i2c_adap,
 				   struct i2c_msg *msg, int retries,
 				   unsigned char *add)
 {
 	unsigned short flags = msg->flags;

 	unsigned char addr;
 	int ret;
 	if ((flags & I2C_M_TEN)) {
 		/* a ten bit address */
 		addr = 0xf0 | ((msg->addr >> 7) & 0x03);
 		/* try extended address code... */
 		ret = try_write_address(i2c_adap, addr, retries);
 		if (ret != 1) {
 			err("died at extended address code, while writing");
 			return -EREMOTEIO;
 		}
 		add[0] = addr;
 		if (flags & I2C_M_RD) {
 			/* okay, now switch into reading mode */
 			addr |= 0x01;
 			ret = try_read_address(i2c_adap, addr, retries);
 			if (ret != 1) {
 				err("died at extended address code, while reading");
 				return -EREMOTEIO;
 			}
 		}

 	} else {		/* normal 7bit address  */
 		addr = (msg->addr << 1);
 		if (flags & I2C_M_RD)
 			addr |= 1;
 		if (flags & I2C_M_REV_DIR_ADDR)
 			addr ^= 1;

 		add[0] = addr;
 		if (flags & I2C_M_RD)
 			ret = try_read_address(i2c_adap, addr, retries);
 		else
 			ret = try_write_address(i2c_adap, addr, retries);

 		if (ret != 1) {
 			return -EREMOTEIO;
 		}
 	}
 	return 0;
 }

 static int
 usb_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[], int num)
 {
 	struct i2c_msg *pmsg;
 	void *data;
 	int i, ret;
 	unsigned char addr;

 	data = i2c_get_adapdata(i2c_adap);

 	for (i = 0; i < num; i++) {
 		pmsg = &msgs[i];
 		ret = usb_find_address(i2c_adap, pmsg, i2c_adap->retries, &addr);
 		if (ret != 0) {
 			PDEBUG(DBG_ALGO,"got NAK from device, message #%d", i);
 			return (ret < 0) ? ret : -EREMOTEIO;
 		}

 		if (pmsg->flags & I2C_M_RD) {
 			/* read bytes into buffer */
 			ret = (usbvision_i2c_read(data, addr, pmsg->buf, pmsg->len));
 			if (ret < pmsg->len) {
 				return (ret < 0) ? ret : -EREMOTEIO;
 			}
 		} else {
 			/* write bytes from buffer */
 			ret = (usbvision_i2c_write(data, addr, pmsg->buf, pmsg->len));
 			if (ret < pmsg->len) {
 				return (ret < 0) ? ret : -EREMOTEIO;
 			}
 		}
 	}
 	return num;
 }

 static int algo_control(struct i2c_adapter *adapter, unsigned int cmd, unsigned long arg)
 {
 	return 0;
 }

 static u32 usb_func(struct i2c_adapter *adap)
 {
 	return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
 }


 /* -----exported algorithm data: -------------------------------------	*/

 static struct i2c_algorithm i2c_usb_algo = {
 	.master_xfer   = usb_xfer,
 	.smbus_xfer    = NULL,
 	.algo_control  = algo_control,
 	.functionality = usb_func,
 };


 /*
  * registering functions to load algorithms at runtime
  */
 static int usbvision_i2c_usb_add_bus(struct i2c_adapter *adap)
 {
 	PDEBUG(DBG_I2C, "I2C   debugging is enabled [i2c]");
 	PDEBUG(DBG_ALGO, "ALGO   debugging is enabled [i2c]");

 	/* register new adapter to i2c module... */

 	adap->algo = &i2c_usb_algo;

 	adap->timeout = 100;	/* default values, should       */
 	adap->retries = 3;	/* be replaced by defines       */

 	i2c_add_adapter(adap);

 	PDEBUG(DBG_ALGO,"i2c bus for %s registered", adap->name);

 	return 0;
 }


 int usbvision_i2c_usb_del_bus(struct i2c_adapter *adap)
 {

 	i2c_del_adapter(adap);

 	PDEBUG(DBG_ALGO,"i2c bus for %s unregistered", adap->name);

 	return 0;
 }


 /* ----------------------------------------------------------------------- */
 /* usbvision specific I2C functions                                        */
 /* ----------------------------------------------------------------------- */
 static struct i2c_adapter i2c_adap_template;
 static struct i2c_client i2c_client_template;

 int usbvision_init_i2c(struct usb_usbvision *usbvision)
 {
 	memcpy(&usbvision->i2c_adap, &i2c_adap_template,
 	       sizeof(struct i2c_adapter));
 	memcpy(&usbvision->i2c_client, &i2c_client_template,
 	       sizeof(struct i2c_client));

 	sprintf(usbvision->i2c_adap.name + strlen(usbvision->i2c_adap.name),
 		" #%d", usbvision->vdev->minor & 0x1f);
 	PDEBUG(DBG_I2C,"Adaptername: %s", usbvision->i2c_adap.name);
 	usbvision->i2c_adap.dev.parent = &usbvision->dev->dev;

 	i2c_set_adapdata(&usbvision->i2c_adap, usbvision);
 	i2c_set_clientdata(&usbvision->i2c_client, usbvision);

 	usbvision->i2c_client.adapter = &usbvision->i2c_adap;

 	if (usbvision_write_reg(usbvision, USBVISION_SER_MODE, USBVISION_IIC_LRNACK) < 0) {
 		printk(KERN_ERR "usbvision_init_i2c: can't write reg\n");
 		return -EBUSY;
 	}

 #ifdef CONFIG_MODULES
 	/* Request the load of the i2c modules we need */
 	switch (usbvision_device_data[usbvision->DevModel].Codec) {
 	case CODEC_SAA7113:
 		request_module("saa7115");
 		break;
 	case CODEC_SAA7111:
 		request_module("saa7115");
 		break;
 	}
 	if (usbvision_device_data[usbvision->DevModel].Tuner == 1) {
 		request_module("tuner");
 	}
 #endif

 	return usbvision_i2c_usb_add_bus(&usbvision->i2c_adap);
 }

 void call_i2c_clients(struct usb_usbvision *usbvision, unsigned int cmd,
 		      void *arg)
 {
 	i2c_clients_command(&usbvision->i2c_adap, cmd, arg);
 }

 static int attach_inform(struct i2c_client *client)
 {
 	struct usb_usbvision *usbvision;

 	usbvision = (struct usb_usbvision *)i2c_get_adapdata(client->adapter);

 	switch (client->addr << 1) {
 		case 0x43:
 		case 0x4b:
 		{
 			struct tuner_setup tun_setup;

 			tun_setup.mode_mask = T_ANALOG_TV | T_RADIO;
 			tun_setup.type = TUNER_TDA9887;
 			tun_setup.addr = client->addr;

 			call_i2c_clients(usbvision, TUNER_SET_TYPE_ADDR, &tun_setup);

 			break;
 		}
 		case 0x42:
 			PDEBUG(DBG_I2C,"attach_inform: saa7114 detected.");
 			break;
 		case 0x4a:
 			PDEBUG(DBG_I2C,"attach_inform: saa7113 detected.");
 			break;
 		case 0x48:
 			PDEBUG(DBG_I2C,"attach_inform: saa7111 detected.");
 			break;
 		case 0xa0:
 			PDEBUG(DBG_I2C,"attach_inform: eeprom detected.");
 			break;

 		default:
 			{
 				struct tuner_setup tun_setup;

 				PDEBUG(DBG_I2C,"attach inform: detected I2C address %x", client->addr << 1);
 				usbvision->tuner_addr = client->addr;

 				if ((usbvision->have_tuner) && (usbvision->tuner_type != -1)) {
 					tun_setup.mode_mask = T_ANALOG_TV | T_RADIO;
 					tun_setup.type = usbvision->tuner_type;
 					tun_setup.addr = usbvision->tuner_addr;
 					call_i2c_clients(usbvision, TUNER_SET_TYPE_ADDR, &tun_setup);
 				}
 			}
 			break;
 	}
 	return 0;
 }

 static int detach_inform(struct i2c_client *client)
 {
 	struct usb_usbvision *usbvision;

 	usbvision = (struct usb_usbvision *)i2c_get_adapdata(client->adapter);

 	PDEBUG(DBG_I2C,"usbvision[%d] detaches %s", usbvision->nr, client->name);
 	return 0;
 }

 static int
 usbvision_i2c_read_max4(struct usb_usbvision *usbvision, unsigned char addr,
 		     char *buf, short len)
 {
 	int rc, retries;

 	for (retries = 5;;) {
 		rc = usbvision_write_reg(usbvision, USBVISION_SER_ADRS, addr);
 		if (rc < 0)
 			return rc;

 		/* Initiate byte read cycle                    */
 		/* USBVISION_SER_CONT <- d0-d2 n. of bytes to r/w */
 		/*                    d3 0=Wr 1=Rd             */
 		rc = usbvision_write_reg(usbvision, USBVISION_SER_CONT,
 				      (len & 0x07) | 0x18);
 		if (rc < 0)
 			return rc;

 		/* Test for Busy and ACK */
 		do {
 			/* USBVISION_SER_CONT -> d4 == 0 busy */
 			rc = usbvision_read_reg(usbvision, USBVISION_SER_CONT);
 		} while (rc > 0 && ((rc & 0x10) != 0));	/* Retry while busy */
 		if (rc < 0)
 			return rc;

 		/* USBVISION_SER_CONT -> d5 == 1 Not ack */
 		if ((rc & 0x20) == 0)	/* Ack? */
 			break;

 		/* I2C abort */
 		rc = usbvision_write_reg(usbvision, USBVISION_SER_CONT, 0x00);
 		if (rc < 0)
 			return rc;

 		if (--retries < 0)
 			return -1;
 	}

 	switch (len) {
 	case 4:
 		buf[3] = usbvision_read_reg(usbvision, USBVISION_SER_DAT4);
 	case 3:
 		buf[2] = usbvision_read_reg(usbvision, USBVISION_SER_DAT3);
 	case 2:
 		buf[1] = usbvision_read_reg(usbvision, USBVISION_SER_DAT2);
 	case 1:
 		buf[0] = usbvision_read_reg(usbvision, USBVISION_SER_DAT1);
 		break;
 	default:
 		printk(KERN_ERR
 		       "usbvision_i2c_read_max4: buffer length > 4\n");
 	}

 	if (i2c_debug & DBG_I2C) {
 		int idx;
 		for (idx = 0; idx < len; idx++) {
 			PDEBUG(DBG_I2C,"read %x from address %x", (unsigned char)buf[idx], addr);
 		}
 	}
 	return len;
 }


 static int usbvision_i2c_write_max4(struct usb_usbvision *usbvision,
 				 unsigned char addr, const char *buf,
 				 short len)
 {
 	int rc, retries;
 	int i;
 	unsigned char value[6];
 	unsigned char ser_cont;

 	ser_cont = (len & 0x07) | 0x10;

 	value[0] = addr;
 	value[1] = ser_cont;
 	for (i = 0; i < len; i++)
 		value[i + 2] = buf[i];

 	for (retries = 5;;) {
 		rc = usb_control_msg(usbvision->dev,
 				     usb_sndctrlpipe(usbvision->dev, 1),
 				     USBVISION_OP_CODE,
 				     USB_DIR_OUT | USB_TYPE_VENDOR |
 				     USB_RECIP_ENDPOINT, 0,
 				     (__u16) USBVISION_SER_ADRS, value,
 				     len + 2, HZ);

 		if (rc < 0)
 			return rc;

 		rc = usbvision_write_reg(usbvision, USBVISION_SER_CONT,
 				      (len & 0x07) | 0x10);
 		if (rc < 0)
 			return rc;

 		/* Test for Busy and ACK */
 		do {
 			rc = usbvision_read_reg(usbvision, USBVISION_SER_CONT);
 		} while (rc > 0 && ((rc & 0x10) != 0));	/* Retry while busy */
 		if (rc < 0)
 			return rc;

 		if ((rc & 0x20) == 0)	/* Ack? */
 			break;

 		/* I2C abort */
 		usbvision_write_reg(usbvision, USBVISION_SER_CONT, 0x00);

 		if (--retries < 0)
 			return -1;

 	}

 	if (i2c_debug & DBG_I2C) {
 		int idx;
 		for (idx = 0; idx < len; idx++) {
 			PDEBUG(DBG_I2C,"wrote %x at address %x", (unsigned char)buf[idx], addr);
 		}
 	}
 	return len;
 }

 static int usbvision_i2c_write(void *data, unsigned char addr, char *buf,
 			    short len)
 {
 	char *bufPtr = buf;
 	int retval;
 	int wrcount = 0;
 	int count;
 	int maxLen = 4;
 	struct usb_usbvision *usbvision = (struct usb_usbvision *) data;

 	while (len > 0) {
 		count = (len > maxLen) ? maxLen : len;
 		retval = usbvision_i2c_write_max4(usbvision, addr, bufPtr, count);
 		if (retval > 0) {
 			len -= count;
 			bufPtr += count;
 			wrcount += count;
 		} else
 			return (retval < 0) ? retval : -EFAULT;
 	}
 	return wrcount;
 }

 static int usbvision_i2c_read(void *data, unsigned char addr, char *buf,
 			   short len)
 {
 	char temp[4];
 	int retval, i;
 	int rdcount = 0;
 	int count;
 	struct usb_usbvision *usbvision = (struct usb_usbvision *) data;

 	while (len > 0) {
 		count = (len > 3) ? 4 : len;
 		retval = usbvision_i2c_read_max4(usbvision, addr, temp, count);
 		if (retval > 0) {
 			for (i = 0; i < len; i++)
 				buf[rdcount + i] = temp[i];
 			len -= count;
 			rdcount += count;
 		} else
 			return (retval < 0) ? retval : -EFAULT;
 	}
 	return rdcount;
 }

 static struct i2c_adapter i2c_adap_template = {
 	.owner = THIS_MODULE,
 	.name              = "usbvision",
 	.id                = I2C_HW_B_BT848, /* FIXME */
 	.client_register   = attach_inform,
 	.client_unregister = detach_inform,
 #ifdef I2C_ADAP_CLASS_TV_ANALOG
 	.class             = I2C_ADAP_CLASS_TV_ANALOG,
 #else
 	.class		   = I2C_CLASS_TV_ANALOG,
 #endif
 };

 static struct i2c_client i2c_client_template = {
 	.name		= "usbvision internal",
 };

 /*
  * Overrides for Emacs so that we follow Linus's tabbing style.
  * ---------------------------------------------------------------------------
  * Local variables:
  * c-basic-offset: 8
  * End:
  */
	/*
	* I2C_ALGO_USB.C
	* i2c algorithm for USB-I2C Bridges
	*
	* Copyright (c) 1999-2005 Joerg Heckenbach <joerg@heckenbach-aw.de>
	* Dwaine Garden <dwainegarden@rogers.com>
	*
	* This module is part of usbvision driver project.
	* Updates to driver completed by Dwaine P. Garden
	*
	* 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
	* (at your option) 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., 675 Mass Ave, Cambridge, MA 02139, USA.
	*/


	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/delay.h>
	#include <linux/slab.h>
	#include <linux/version.h>
	#include <linux/utsname.h>
	#include <linux/init.h>
	#include <asm/uaccess.h>
	#include <linux/ioport.h>
	#include <linux/errno.h>
	#include <linux/usb.h>
	#include <linux/i2c.h>
	#include "usbvision.h"

	#define DBG_I2C 1<<0
	#define DBG_ALGO 1<<1

	static int i2c_debug = 0;

	module_param (i2c_debug, int, 0644); // debug_i2c_usb mode of the device driver
	MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");

	#define PDEBUG(level, fmt, args...) \
	if (i2c_debug & (level)) info("[%s:%d] " fmt, __PRETTY_FUNCTION__, __LINE__ , ## args)

	static int usbvision_i2c_write(void data, unsigned char addr, char buf,
	short len);
	static int usbvision_i2c_read(void data, unsigned char addr, char buf,
	short len);

	static inline int try_write_address(struct i2c_adapter *i2c_adap,
	unsigned char addr, int retries)
	{
	void *data;
	int i, ret = -1;
	char buf[4];

	data = i2c_get_adapdata(i2c_adap);
	buf[0] = 0x00;
	for (i = 0; i <= retries; i++) {
	ret = (usbvision_i2c_write(data, addr, buf, 1));
	if (ret == 1)
	break; /* success! */
	udelay(5);
	if (i == retries) /* no success */
	break;
	udelay(10);
	}
	if (i) {
	PDEBUG(DBG_ALGO,"Needed %d retries for address %#2x", i, addr);
	PDEBUG(DBG_ALGO,"Maybe there's no device at this address");
	}
	return ret;
	}

	static inline int try_read_address(struct i2c_adapter *i2c_adap,
	unsigned char addr, int retries)
	{
	void *data;
	int i, ret = -1;
	char buf[4];

	data = i2c_get_adapdata(i2c_adap);
	for (i = 0; i <= retries; i++) {
	ret = (usbvision_i2c_read(data, addr, buf, 1));
	if (ret == 1)
	break; /* success! */
	udelay(5);
	if (i == retries) /* no success */
	break;
	udelay(10);
	}
	if (i) {
	PDEBUG(DBG_ALGO,"Needed %d retries for address %#2x", i, addr);
	PDEBUG(DBG_ALGO,"Maybe there's no device at this address");
	}
	return ret;
	}

	static inline int usb_find_address(struct i2c_adapter *i2c_adap,
	struct i2c_msg *msg, int retries,
	unsigned char *add)
	{
	unsigned short flags = msg->flags;

	unsigned char addr;
	int ret;
	if ((flags & I2C_M_TEN)) {
	/* a ten bit address */
	addr = 0xf0 \| ((msg->addr >> 7) & 0x03);
	/* try extended address code... */
	ret = try_write_address(i2c_adap, addr, retries);
	if (ret != 1) {
	err("died at extended address code, while writing");
	return -EREMOTEIO;
	}
	add[0] = addr;
	if (flags & I2C_M_RD) {
	/* okay, now switch into reading mode */
	addr \|= 0x01;
	ret = try_read_address(i2c_adap, addr, retries);
	if (ret != 1) {
	err("died at extended address code, while reading");
	return -EREMOTEIO;
	}
	}

	} else { /* normal 7bit address */
	addr = (msg->addr << 1);
	if (flags & I2C_M_RD)
	addr \|= 1;
	if (flags & I2C_M_REV_DIR_ADDR)
	addr ^= 1;

	add[0] = addr;
	if (flags & I2C_M_RD)
	ret = try_read_address(i2c_adap, addr, retries);
	else
	ret = try_write_address(i2c_adap, addr, retries);

	if (ret != 1) {
	return -EREMOTEIO;
	}
	}
	return 0;
	}

	static int
	usb_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[], int num)
	{
	struct i2c_msg *pmsg;
	void *data;
	int i, ret;
	unsigned char addr;

	data = i2c_get_adapdata(i2c_adap);

	for (i = 0; i < num; i++) {
	pmsg = &msgs[i];
	ret = usb_find_address(i2c_adap, pmsg, i2c_adap->retries, &addr);
	if (ret != 0) {
	PDEBUG(DBG_ALGO,"got NAK from device, message #%d", i);
	return (ret < 0) ? ret : -EREMOTEIO;
	}

	if (pmsg->flags & I2C_M_RD) {
	/* read bytes into buffer */
	ret = (usbvision_i2c_read(data, addr, pmsg->buf, pmsg->len));
	if (ret < pmsg->len) {
	return (ret < 0) ? ret : -EREMOTEIO;
	}
	} else {
	/* write bytes from buffer */
	ret = (usbvision_i2c_write(data, addr, pmsg->buf, pmsg->len));
	if (ret < pmsg->len) {
	return (ret < 0) ? ret : -EREMOTEIO;
	}
	}
	}
	return num;
	}

	static int algo_control(struct i2c_adapter *adapter, unsigned int cmd, unsigned long arg)
	{
	return 0;
	}

	static u32 usb_func(struct i2c_adapter *adap)
	{
	return I2C_FUNC_SMBUS_EMUL \| I2C_FUNC_10BIT_ADDR \| I2C_FUNC_PROTOCOL_MANGLING;
	}


	/* -----exported algorithm data: ------------------------------------- */

	static struct i2c_algorithm i2c_usb_algo = {
	.master_xfer = usb_xfer,
	.smbus_xfer = NULL,
	.algo_control = algo_control,
	.functionality = usb_func,
	};


	/*
	* registering functions to load algorithms at runtime
	*/
	static int usbvision_i2c_usb_add_bus(struct i2c_adapter *adap)
	{
	PDEBUG(DBG_I2C, "I2C debugging is enabled [i2c]");
	PDEBUG(DBG_ALGO, "ALGO debugging is enabled [i2c]");

	/* register new adapter to i2c module... */

	adap->algo = &i2c_usb_algo;

	adap->timeout = 100; /* default values, should */
	adap->retries = 3; /* be replaced by defines */

	i2c_add_adapter(adap);

	PDEBUG(DBG_ALGO,"i2c bus for %s registered", adap->name);

	return 0;
	}


	int usbvision_i2c_usb_del_bus(struct i2c_adapter *adap)
	{

	i2c_del_adapter(adap);

	PDEBUG(DBG_ALGO,"i2c bus for %s unregistered", adap->name);

	return 0;
	}


	/* ----------------------------------------------------------------------- */
	/* usbvision specific I2C functions */
	/* ----------------------------------------------------------------------- */
	static struct i2c_adapter i2c_adap_template;
	static struct i2c_client i2c_client_template;

	int usbvision_init_i2c(struct usb_usbvision *usbvision)
	{
	memcpy(&usbvision->i2c_adap, &i2c_adap_template,
	sizeof(struct i2c_adapter));
	memcpy(&usbvision->i2c_client, &i2c_client_template,
	sizeof(struct i2c_client));

	sprintf(usbvision->i2c_adap.name + strlen(usbvision->i2c_adap.name),
	" #%d", usbvision->vdev->minor & 0x1f);
	PDEBUG(DBG_I2C,"Adaptername: %s", usbvision->i2c_adap.name);
	usbvision->i2c_adap.dev.parent = &usbvision->dev->dev;

	i2c_set_adapdata(&usbvision->i2c_adap, usbvision);
	i2c_set_clientdata(&usbvision->i2c_client, usbvision);

	usbvision->i2c_client.adapter = &usbvision->i2c_adap;

	if (usbvision_write_reg(usbvision, USBVISION_SER_MODE, USBVISION_IIC_LRNACK) < 0) {
	printk(KERN_ERR "usbvision_init_i2c: can't write reg\n");
	return -EBUSY;
	}

	#ifdef CONFIG_MODULES
	/* Request the load of the i2c modules we need */
	switch (usbvision_device_data[usbvision->DevModel].Codec) {
	case CODEC_SAA7113:
	request_module("saa7115");
	break;
	case CODEC_SAA7111:
	request_module("saa7115");
	break;
	}
	if (usbvision_device_data[usbvision->DevModel].Tuner == 1) {
	request_module("tuner");
	}
	#endif

	return usbvision_i2c_usb_add_bus(&usbvision->i2c_adap);
	}

	void call_i2c_clients(struct usb_usbvision *usbvision, unsigned int cmd,
	void *arg)
	{
	i2c_clients_command(&usbvision->i2c_adap, cmd, arg);
	}

	static int attach_inform(struct i2c_client *client)
	{
	struct usb_usbvision *usbvision;

	usbvision = (struct usb_usbvision *)i2c_get_adapdata(client->adapter);

	switch (client->addr << 1) {
	case 0x43:
	case 0x4b:
	{
	struct tuner_setup tun_setup;

	tun_setup.mode_mask = T_ANALOG_TV \| T_RADIO;
	tun_setup.type = TUNER_TDA9887;
	tun_setup.addr = client->addr;

	call_i2c_clients(usbvision, TUNER_SET_TYPE_ADDR, &tun_setup);

	break;
	}
	case 0x42:
	PDEBUG(DBG_I2C,"attach_inform: saa7114 detected.");
	break;
	case 0x4a:
	PDEBUG(DBG_I2C,"attach_inform: saa7113 detected.");
	break;
	case 0x48:
	PDEBUG(DBG_I2C,"attach_inform: saa7111 detected.");
	break;
	case 0xa0:
	PDEBUG(DBG_I2C,"attach_inform: eeprom detected.");
	break;

	default:
	{
	struct tuner_setup tun_setup;

	PDEBUG(DBG_I2C,"attach inform: detected I2C address %x", client->addr << 1);
	usbvision->tuner_addr = client->addr;

	if ((usbvision->have_tuner) && (usbvision->tuner_type != -1)) {
	tun_setup.mode_mask = T_ANALOG_TV \| T_RADIO;
	tun_setup.type = usbvision->tuner_type;
	tun_setup.addr = usbvision->tuner_addr;
	call_i2c_clients(usbvision, TUNER_SET_TYPE_ADDR, &tun_setup);
	}
	}
	break;
	}
	return 0;
	}

	static int detach_inform(struct i2c_client *client)
	{
	struct usb_usbvision *usbvision;

	usbvision = (struct usb_usbvision *)i2c_get_adapdata(client->adapter);

	PDEBUG(DBG_I2C,"usbvision[%d] detaches %s", usbvision->nr, client->name);
	return 0;
	}

	static int
	usbvision_i2c_read_max4(struct usb_usbvision *usbvision, unsigned char addr,
	char *buf, short len)
	{
	int rc, retries;

	for (retries = 5;;) {
	rc = usbvision_write_reg(usbvision, USBVISION_SER_ADRS, addr);
	if (rc < 0)
	return rc;

	/* Initiate byte read cycle */
	/* USBVISION_SER_CONT <- d0-d2 n. of bytes to r/w */
	/* d3 0=Wr 1=Rd */
	rc = usbvision_write_reg(usbvision, USBVISION_SER_CONT,
	(len & 0x07) \| 0x18);
	if (rc < 0)
	return rc;

	/* Test for Busy and ACK */
	do {
	/* USBVISION_SER_CONT -> d4 == 0 busy */
	rc = usbvision_read_reg(usbvision, USBVISION_SER_CONT);
	} while (rc > 0 && ((rc & 0x10) != 0)); /* Retry while busy */
	if (rc < 0)
	return rc;

	/* USBVISION_SER_CONT -> d5 == 1 Not ack */
	if ((rc & 0x20) == 0) /* Ack? */
	break;

	/* I2C abort */
	rc = usbvision_write_reg(usbvision, USBVISION_SER_CONT, 0x00);
	if (rc < 0)
	return rc;

	if (--retries < 0)
	return -1;
	}

	switch (len) {
	case 4:
	buf[3] = usbvision_read_reg(usbvision, USBVISION_SER_DAT4);
	case 3:
	buf[2] = usbvision_read_reg(usbvision, USBVISION_SER_DAT3);
	case 2:
	buf[1] = usbvision_read_reg(usbvision, USBVISION_SER_DAT2);
	case 1:
	buf[0] = usbvision_read_reg(usbvision, USBVISION_SER_DAT1);
	break;
	default:
	printk(KERN_ERR
	"usbvision_i2c_read_max4: buffer length > 4\n");
	}

	if (i2c_debug & DBG_I2C) {
	int idx;
	for (idx = 0; idx < len; idx++) {
	PDEBUG(DBG_I2C,"read %x from address %x", (unsigned char)buf[idx], addr);
	}
	}
	return len;
	}


	static int usbvision_i2c_write_max4(struct usb_usbvision *usbvision,
	unsigned char addr, const char *buf,
	short len)
	{
	int rc, retries;
	int i;
	unsigned char value[6];
	unsigned char ser_cont;

	ser_cont = (len & 0x07) \| 0x10;

	value[0] = addr;
	value[1] = ser_cont;
	for (i = 0; i < len; i++)
	value[i + 2] = buf[i];

	for (retries = 5;;) {
	rc = usb_control_msg(usbvision->dev,
	usb_sndctrlpipe(usbvision->dev, 1),
	USBVISION_OP_CODE,
	USB_DIR_OUT \| USB_TYPE_VENDOR \|
	USB_RECIP_ENDPOINT, 0,
	(__u16) USBVISION_SER_ADRS, value,
	len + 2, HZ);

	if (rc < 0)
	return rc;

	rc = usbvision_write_reg(usbvision, USBVISION_SER_CONT,
	(len & 0x07) \| 0x10);
	if (rc < 0)
	return rc;

	/* Test for Busy and ACK */
	do {
	rc = usbvision_read_reg(usbvision, USBVISION_SER_CONT);
	} while (rc > 0 && ((rc & 0x10) != 0)); /* Retry while busy */
	if (rc < 0)
	return rc;

	if ((rc & 0x20) == 0) /* Ack? */
	break;

	/* I2C abort */
	usbvision_write_reg(usbvision, USBVISION_SER_CONT, 0x00);

	if (--retries < 0)
	return -1;

	}

	if (i2c_debug & DBG_I2C) {
	int idx;
	for (idx = 0; idx < len; idx++) {
	PDEBUG(DBG_I2C,"wrote %x at address %x", (unsigned char)buf[idx], addr);
	}
	}
	return len;
	}

	static int usbvision_i2c_write(void data, unsigned char addr, char buf,
	short len)
	{
	char *bufPtr = buf;
	int retval;
	int wrcount = 0;
	int count;
	int maxLen = 4;
	struct usb_usbvision usbvision = (struct usb_usbvision ) data;

	while (len > 0) {
	count = (len > maxLen) ? maxLen : len;
	retval = usbvision_i2c_write_max4(usbvision, addr, bufPtr, count);
	if (retval > 0) {
	len -= count;
	bufPtr += count;
	wrcount += count;
	} else
	return (retval < 0) ? retval : -EFAULT;
	}
	return wrcount;
	}

	static int usbvision_i2c_read(void data, unsigned char addr, char buf,
	short len)
	{
	char temp[4];
	int retval, i;
	int rdcount = 0;
	int count;
	struct usb_usbvision usbvision = (struct usb_usbvision ) data;

	while (len > 0) {
	count = (len > 3) ? 4 : len;
	retval = usbvision_i2c_read_max4(usbvision, addr, temp, count);
	if (retval > 0) {
	for (i = 0; i < len; i++)
	buf[rdcount + i] = temp[i];
	len -= count;
	rdcount += count;
	} else
	return (retval < 0) ? retval : -EFAULT;
	}
	return rdcount;
	}

	static struct i2c_adapter i2c_adap_template = {
	.owner = THIS_MODULE,
	.name = "usbvision",
	.id = I2C_HW_B_BT848, /* FIXME */
	.client_register = attach_inform,
	.client_unregister = detach_inform,
	#ifdef I2C_ADAP_CLASS_TV_ANALOG
	.class = I2C_ADAP_CLASS_TV_ANALOG,
	#else
	.class = I2C_CLASS_TV_ANALOG,
	#endif
	};

	static struct i2c_client i2c_client_template = {
	.name = "usbvision internal",
	};

	/*
	* Overrides for Emacs so that we follow Linus's tabbing style.
	* ---------------------------------------------------------------------------
	* Local variables:
	* c-basic-offset: 8
	* End:
	*/