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/***************************************************************************
copyright : (C) by 2002-2003 Stefano Barbato
email : stefano@codesink.org
***************************************************************************/
/***************************************************************************
* *
* 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. *
* *
***************************************************************************/
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <linux/fs.h>
#include <linux/i2c.h>
#include <linux/i2c-dev.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <assert.h>
#include <string.h>
#include <i2c/smbus.h>
#include "24cXX.h"
/*
* EEPROMs need some time to process writes
* Ideally this value should either be settable with a command line parameter,
* or "guessed" at runtime using a retry loop.
*/
#define WRITE_DELAY_US 5000
static int i2c_write_1b(struct eeprom *e, __u8 buf)
{
int r;
// we must simulate a plain I2C byte write with SMBus functions
r = i2c_smbus_write_byte(e->fd, buf);
if(r < 0)
fprintf(stderr, "Error i2c_write_1b: %s\n", strerror(errno));
usleep(WRITE_DELAY_US);
return r;
}
static int i2c_write_2b(struct eeprom *e, __u8 buf[2])
{
int r;
// we must simulate a plain I2C byte write with SMBus functions
r = i2c_smbus_write_byte_data(e->fd, buf[0], buf[1]);
if(r < 0)
fprintf(stderr, "Error i2c_write_2b: %s\n", strerror(errno));
usleep(WRITE_DELAY_US);
return r;
}
static int i2c_write_3b(struct eeprom *e, __u8 buf[3])
{
int r;
// we must simulate a plain I2C byte write with SMBus functions
// the __u16 data field will be byte swapped by the SMBus protocol
r = i2c_smbus_write_word_data(e->fd, buf[0], buf[2] << 8 | buf[1]);
if(r < 0)
fprintf(stderr, "Error i2c_write_3b: %s\n", strerror(errno));
usleep(WRITE_DELAY_US);
return r;
}
#define CHECK_I2C_FUNC( var, label ) \
do { if(0 == (var & label)) { \
fprintf(stderr, "\nError: " \
#label " function is required. Program halted.\n\n"); \
exit(1); } \
} while(0);
int eeprom_open(char *dev_fqn, int addr, int type, struct eeprom* e)
{
int fd, r;
unsigned long funcs;
e->fd = e->addr = 0;
e->dev = 0;
fd = open(dev_fqn, O_RDWR);
if(fd <= 0)
return -1;
// get funcs list
r = ioctl(fd, I2C_FUNCS, &funcs);
if (r < 0)
return r;
// check for req funcs
CHECK_I2C_FUNC( funcs, I2C_FUNC_SMBUS_READ_BYTE );
CHECK_I2C_FUNC( funcs, I2C_FUNC_SMBUS_WRITE_BYTE );
CHECK_I2C_FUNC( funcs, I2C_FUNC_SMBUS_READ_BYTE_DATA );
CHECK_I2C_FUNC( funcs, I2C_FUNC_SMBUS_WRITE_BYTE_DATA );
CHECK_I2C_FUNC( funcs, I2C_FUNC_SMBUS_READ_WORD_DATA );
CHECK_I2C_FUNC( funcs, I2C_FUNC_SMBUS_WRITE_WORD_DATA );
// set working device
r = ioctl(fd, I2C_SLAVE, addr);
if (r < 0)
return r;
e->fd = fd;
e->addr = addr;
e->dev = dev_fqn;
e->type = type;
return 0;
}
int eeprom_close(struct eeprom *e)
{
close(e->fd);
e->fd = -1;
e->dev = 0;
e->type = EEPROM_TYPE_UNKNOWN;
return 0;
}
#if 0
int eeprom_24c32_write_byte(struct eeprom *e, __u16 mem_addr, __u8 data)
{
__u8 buf[3] = { (mem_addr >> 8) & 0x00ff, mem_addr & 0x00ff, data };
return i2c_write_3b(e, buf);
}
int eeprom_24c32_read_current_byte(struct eeprom* e)
{
ioctl(e->fd, BLKFLSBUF); // clear kernel read buffer
return i2c_smbus_read_byte(e->fd);
}
int eeprom_24c32_read_byte(struct eeprom* e, __u16 mem_addr)
{
int r;
ioctl(e->fd, BLKFLSBUF); // clear kernel read buffer
__u8 buf[2] = { (mem_addr >> 8) & 0x0ff, mem_addr & 0x0ff };
r = i2c_write_2b(e, buf);
if (r < 0)
return r;
r = i2c_smbus_read_byte(e->fd);
return r;
}
#endif
int eeprom_read_current_byte(struct eeprom* e)
{
ioctl(e->fd, BLKFLSBUF); // clear kernel read buffer
return i2c_smbus_read_byte(e->fd);
}
int eeprom_read_byte(struct eeprom* e, __u16 mem_addr)
{
int r;
ioctl(e->fd, BLKFLSBUF); // clear kernel read buffer
if(e->type == EEPROM_TYPE_8BIT_ADDR)
{
__u8 buf = mem_addr & 0x0ff;
r = i2c_write_1b(e, buf);
} else if(e->type == EEPROM_TYPE_16BIT_ADDR) {
__u8 buf[2] = { (mem_addr >> 8) & 0x0ff, mem_addr & 0x0ff };
r = i2c_write_2b(e, buf);
} else {
fprintf(stderr, "ERR: unknown eeprom type\n");
return -1;
}
if (r < 0)
return r;
r = i2c_smbus_read_byte(e->fd);
return r;
}
int eeprom_write_byte(struct eeprom *e, __u16 mem_addr, __u8 data)
{
if(e->type == EEPROM_TYPE_8BIT_ADDR) {
__u8 buf[2] = { mem_addr & 0x00ff, data };
return i2c_write_2b(e, buf);
} else if(e->type == EEPROM_TYPE_16BIT_ADDR) {
__u8 buf[3] =
{ (mem_addr >> 8) & 0x00ff, mem_addr & 0x00ff, data };
return i2c_write_3b(e, buf);
} else {
fprintf(stderr, "ERR: unknown eeprom type\n");
return -1;
}
}
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