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/*
* 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/sched.h>
#include <linux/usb.h>
#include <linux/i2c.h>
#include "usbvision-i2c.h"
static int debug = 0;
#if defined(module_param) // Showing parameters under SYSFS
module_param (debug, int, 0444); // debug mode of the device driver
#else
MODULE_PARM(debug, "i"); // debug mode of the device driver
#endif
MODULE_AUTHOR("Joerg Heckenbach");
MODULE_DESCRIPTION("I2C algorithm for USB-I2C-bridges");
MODULE_LICENSE("GPL");
static inline int try_write_address(struct i2c_adapter *i2c_adap,
unsigned char addr, int retries)
{
struct i2c_algo_usb_data *adap = i2c_adap->algo_data;
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 = (adap->outb(data, addr, buf, 1));
if (ret == 1)
break; /* success! */
udelay(5 /*adap->udelay */ );
if (i == retries) /* no success */
break;
udelay(adap->udelay);
}
if (debug) {
if (i) {
info("%s: Needed %d retries for address %#2x", __FUNCTION__, i, addr);
info("%s: Maybe there's no device at this address", __FUNCTION__);
}
}
return ret;
}
static inline int try_read_address(struct i2c_adapter *i2c_adap,
unsigned char addr, int retries)
{
struct i2c_algo_usb_data *adap = i2c_adap->algo_data;
void *data;
int i, ret = -1;
char buf[4];
data = i2c_get_adapdata(i2c_adap);
for (i = 0; i <= retries; i++) {
ret = (adap->inb(data, addr, buf, 1));
if (ret == 1)
break; /* success! */
udelay(5 /*adap->udelay */ );
if (i == retries) /* no success */
break;
udelay(adap->udelay);
}
if (debug) {
if (i) {
info("%s: Needed %d retries for address %#2x", __FUNCTION__, i, addr);
info("%s: Maybe there's no device at this address", __FUNCTION__);
}
}
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;
struct i2c_algo_usb_data *adap = i2c_adap->algo_data;
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) {
if (debug) {
info("%s: got NAK from device, message #%d\n", __FUNCTION__, i);
}
return (ret < 0) ? ret : -EREMOTEIO;
}
if (pmsg->flags & I2C_M_RD) {
/* read bytes into buffer */
ret = (adap->inb(data, addr, pmsg->buf, pmsg->len));
if (ret < pmsg->len) {
return (ret < 0) ? ret : -EREMOTEIO;
}
} else {
/* write bytes from buffer */
ret = (adap->outb(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,
.slave_send = NULL,
.slave_recv = NULL,
.algo_control = algo_control,
.functionality = usb_func,
};
/*
* registering functions to load algorithms at runtime
*/
int usbvision_i2c_usb_add_bus(struct i2c_adapter *adap)
{
/* register new adapter to i2c module... */
adap->algo = &i2c_usb_algo;
adap->timeout = 100; /* default values, should */
adap->retries = 3; /* be replaced by defines */
#ifdef MODULE
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 4, 21)
MOD_INC_USE_COUNT;
#endif
#endif
i2c_add_adapter(adap);
if (debug) {
info("i2c bus for %s registered", adap->name);
}
return 0;
}
int usbvision_i2c_usb_del_bus(struct i2c_adapter *adap)
{
i2c_del_adapter(adap);
if (debug) {
info("i2c bus for %s unregistered", adap->name);
}
#ifdef MODULE
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 4, 21)
MOD_DEC_USE_COUNT;
#endif
#endif
return 0;
}
EXPORT_SYMBOL(usbvision_i2c_usb_add_bus);
EXPORT_SYMBOL(usbvision_i2c_usb_del_bus);
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