Difference between revisions of "I2cwrite.c"
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<source lang="c"> | <source lang="c"> | ||
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/* a simple program to write on i2c bus* | /* a simple program to write on i2c bus* | ||
* Fabien Marteau <fabien.marteau@armadeus.com> | * Fabien Marteau <fabien.marteau@armadeus.com> | ||
* | * | ||
− | * | + | * inspired from : |
+ | * ch7024: manage the Svideo controller CH7024 | ||
+ | * author: thom25@users.sourceforge.net | ||
+ | * | ||
+ | * | ||
+ | ** THE ARMADEUS PROJECT | ||
+ | ** | ||
+ | ** Copyright (C) year The source forge armadeus project team | ||
+ | ** | ||
+ | ** 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | ||
+ | ** | ||
*/ | */ | ||
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struct i2c_rdwr_ioctl_data rdwr = { &msg, 1 }; | struct i2c_rdwr_ioctl_data rdwr = { &msg, 1 }; | ||
− | |||
− | |||
− | |||
if ( ioctl( fd, I2C_RDWR, &rdwr ) < 0 ){ | if ( ioctl( fd, I2C_RDWR, &rdwr ) < 0 ){ | ||
printf("Write error\n"); | printf("Write error\n"); |
Latest revision as of 12:02, 3 April 2008
/* a simple program to write on i2c bus*
* Fabien Marteau <fabien.marteau@armadeus.com>
*
* inspired from :
* ch7024: manage the Svideo controller CH7024
* author: thom25@users.sourceforge.net
*
*
** THE ARMADEUS PROJECT
**
** Copyright (C) year The source forge armadeus project team
**
** 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
**
*/
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <linux/i2c.h>
#include <linux/i2c-dev.h>
#include <sys/ioctl.h>
int fd;
/* Write a byte on the I2C bus
@param fd: file descriptor of the device
@param reg: register to access
@param value: value to write
@return : -1 in case of error otherwise 0
*/
int write_byte(int fd,unsigned char addr, unsigned char reg, unsigned char value)
{
unsigned char buf[2] = {reg,value}; // initialise a data buffer with
// address and data
// create an I2C write message
struct i2c_msg msg = {addr, 0, sizeof(buf), buf };
// create a I2C IOCTL request
struct i2c_rdwr_ioctl_data rdwr = { &msg, 1 };
if ( ioctl( fd, I2C_RDWR, &rdwr ) < 0 ){
printf("Write error\n");
return -1;
}
return 0;
}
/* i2cwrite i2c-devfile addr value*/
int main(int argc, char **argv){
unsigned char buf;
unsigned char addr;
unsigned char subaddr;
unsigned char value;
if(argc != 5){
printf("wrong args numbers\nsyntaxe (value in hexa) :\ni2cwrite i2c-devfile addr subaddr value\n");
return -1;
}
fd = open(argv[1],O_RDWR);
if(fd < 0){
printf("can't open %s\n",argv[1]);
return -1;
}
addr = (unsigned char )strtol(argv[2], (char **)NULL, 16);
subaddr = (unsigned char )strtol(argv[3], (char **)NULL, 16);
buf = (unsigned char )strtol(argv[4], (char **)NULL, 16);
write_byte(fd,addr, subaddr, buf);
printf("Wrote component %02x at subaddress %02x -> %02x\n",addr,subaddr,buf);
return value;
}