i2c_test.c

嵌入式LINUX 的驱动程序。采用2410的开发板全部可以通用（如使用引脚不同只要重新改脚定义）

/************************************
*  *GEC-2410-BOX
*  *eeprom at24c02 test program
************************************/
#include <stdio.h>
#include <fcntl.h>

#include <linux/i2c.h>
#include <linux/i2c-dev.h>

#define CHIP_ADDR 	0x50
#define PAGE_SIZE	0x08

#define I2C_DEV_PATH   "/dev/i2c/0"

static int read_eeprom(int fd, char buff[], int addr, int count)
{
	int res;
	if(write(fd, &addr, 1) != 1)
		return -1;

	res=read(fd, buff, count);
	printf("read %d byte at 0x%.2x\n", res, addr);

	return res;
}

static int write_eeprom(int fd, char  buff[], int addr, int count)
{
	int res;
	int i;
	char sendbuffer[PAGE_SIZE+1];

	memcpy(sendbuffer+1, buff, count);
	sendbuffer[0]=addr;

	 res= write(fd, sendbuffer, count+1);
	 printf("write %d byte at 0x%.2x\n", res ,addr);
}

int main(void)
{
	int fd, n, res;
	unsigned char buf[PAGE_SIZE];
	
	fd = open(I2C_DEV_PATH,  O_RDWR);
	if(fd < 0)
	{
		printf("####i2c test device open fail####\n");
		return (-1);
	}
	printf("success, i2c open file device %d \n",fd);
	

	res = ioctl(fd, I2C_TENBIT,0);							//do not use 10bit address mode
	res = ioctl(fd, I2C_SLAVE_FORCE, CHIP_ADDR);			//set slave device address
	printf("ioctl I2C_SLAVE_FORCE msg NO:%d\n",res);

	for(n=0; n<PAGE_SIZE; n++)
		buf[n]=n;

	write_eeprom(fd, buf, 0, sizeof(buf));
	read_eeprom(fd, buf, 0, sizeof(buf));

	for(n=0; n<sizeof(buf); n++) {
		printf("0x%.2x, ", buf[n]);
	}
	printf("\n");
	
	close(fd);
	return(0);
}