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|
/*
* usbvision_i2c.c
* i2c algorithm for USB-I2C Bridges
*
* Copyright (c) 1999-2007 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/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
static int i2c_debug;
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)) \
printk(KERN_INFO KBUILD_MODNAME ":[%s:%d] " fmt, \
__func__, __LINE__ , ## args); \
}
static int usbvision_i2c_write(struct usb_usbvision *usbvision, unsigned char addr, char *buf,
short len);
static int usbvision_i2c_read(struct usb_usbvision *usbvision, unsigned char addr, char *buf,
short len);
static inline int try_write_address(struct i2c_adapter *i2c_adap,
unsigned char addr, int retries)
{
struct usb_usbvision *usbvision;
int i, ret = -1;
char buf[4];
usbvision = (struct usb_usbvision *)i2c_get_adapdata(i2c_adap);
buf[0] = 0x00;
for (i = 0; i <= retries; i++) {
ret = (usbvision_i2c_write(usbvision, addr, buf, 1));
if (ret == 1)
break; /* success! */
udelay(5);
if (i == retries) /* no success */
break;
udelay(10);
}
if (i) {
PDEBUG(DBG_I2C,"Needed %d retries for address %#2x", i, addr);
PDEBUG(DBG_I2C,"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)
{
struct usb_usbvision *usbvision;
int i, ret = -1;
char buf[4];
usbvision = (struct usb_usbvision *)i2c_get_adapdata(i2c_adap);
for (i = 0; i <= retries; i++) {
ret = (usbvision_i2c_read(usbvision, addr, buf, 1));
if (ret == 1)
break; /* success! */
udelay(5);
if (i == retries) /* no success */
break;
udelay(10);
}
if (i) {
PDEBUG(DBG_I2C,"Needed %d retries for address %#2x", i, addr);
PDEBUG(DBG_I2C,"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) {
dev_err(&i2c_adap->dev,
"died at extended address code, while writing\n");
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) {
dev_err(&i2c_adap->dev,
"died at extended address code, while reading\n");
return -EREMOTEIO;
}
}
} else { /* normal 7bit address */
addr = (msg->addr << 1);
if (flags & I2C_M_RD)
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
usbvision_i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[], int num)
{
struct i2c_msg *pmsg;
struct usb_usbvision *usbvision;
int i, ret;
unsigned char addr = 0;
usbvision = (struct usb_usbvision *)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_I2C,"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(usbvision, addr, pmsg->buf, pmsg->len));
if (ret < pmsg->len) {
return (ret < 0) ? ret : -EREMOTEIO;
}
} else {
/* write bytes from buffer */
ret = (usbvision_i2c_write(usbvision, addr, pmsg->buf, pmsg->len));
if (ret < pmsg->len) {
return (ret < 0) ? ret : -EREMOTEIO;
}
}
}
return num;
}
static u32 functionality(struct i2c_adapter *adap)
{
return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
}
/* -----exported algorithm data: ------------------------------------- */
static struct i2c_algorithm usbvision_algo = {
.master_xfer = usbvision_i2c_xfer,
.smbus_xfer = NULL,
.functionality = functionality,
};
/* ----------------------------------------------------------------------- */
/* usbvision specific I2C functions */
/* ----------------------------------------------------------------------- */
static struct i2c_adapter i2c_adap_template;
int usbvision_i2c_register(struct usb_usbvision *usbvision)
{
static unsigned short saa711x_addrs[] = {
0x4a >> 1, 0x48 >> 1, /* SAA7111, SAA7111A and SAA7113 */
0x42 >> 1, 0x40 >> 1, /* SAA7114, SAA7115 and SAA7118 */
I2C_CLIENT_END };
if (usbvision->registered_i2c)
return 0;
memcpy(&usbvision->i2c_adap, &i2c_adap_template,
sizeof(struct i2c_adapter));
sprintf(usbvision->i2c_adap.name, "%s-%d-%s", i2c_adap_template.name,
usbvision->dev->bus->busnum, usbvision->dev->devpath);
PDEBUG(DBG_I2C,"Adaptername: %s", usbvision->i2c_adap.name);
usbvision->i2c_adap.dev.parent = &usbvision->dev->dev;
i2c_set_adapdata(&
|