test.c

Linux 2.6.24通过SMBUS总线（也类似于i2c总线）读写内存上的SPD信息。里面包含驱动和测试程序。再PC机上反复测试过

/*
 
 This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2007, 2010 fengGuojin([e-mail])
 */
#include	<sys/types.h>
#include	<unistd.h>
#include	<fcntl.h>
#include	<linux/rtc.h>
#include	<linux/ioctl.h>
#include	<stdio.h>
#include	<stdlib.h>
#define		COUNT  (100)

int main(void)
{
	int fd;
	int i,result;
	unsigned char buf[COUNT];

	for(i=0;i<COUNT;i++)
		buf[i] = 0x00;

  	fd=open("/dev/spd",O_RDWR);
  	if(fd==-1)
  	{
		perror("  #### i2c test device open failed #### \n");
     	return -1;
  	}
 	//printf("  open /dev/spd successfully\n");

/*	while(chr != '9'){
		chr = getchar();
		if(chr != 10)
			printf("%x ",chr);
	}
	getchar();
*/
	result = read(fd,&buf,COUNT);
	if(result < 0)
	{
		perror("   #### read data form smbus failed #### \n");
		goto out;
	}
	for(i=0; i<COUNT;i++)
	{
		printf("   buf[%d]=%2x",i,buf[i]);
		if(i%5 == 0)  printf("\n");
	}
	printf("\n");
out:
	close(fd);
	return result;
}