rw_addr.c

来自「gpio+physaddr驱动例子」· C语言 代码 · 共 40 行

#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#define DEVICE	"/dev/phyaddrtest"
int main()
{
	int fd,ret;
	unsigned short val[4]={0x0028,0x0029,0x002A,0x002B};	
	unsigned short read_val=0;
	if((fd=open(DEVICE,O_RDWR | O_NONBLOCK))<0)
	{
		printf("open device: %s\n",DEVICE);
		perror("can not open device");
		exit(1);
	}
	
	ret=write(fd,&val[0],2);
	read(fd,&read_val,2);
	printf("read1=0x%02x\n",(unsigned char)(read_val&0xff));

	ret=write(fd,&val[1],2);
        read(fd,&read_val,2);
        printf("read2=0x%02x\n",(unsigned char)(read_val&0xff));

	ret=write(fd,&val[2],2);
        read(fd,&read_val,2);
        printf("read2=0x%02x\n",(unsigned char)(read_val&0xff));

	ret=write(fd,&val[3],2);
        read(fd,&read_val,2);
        printf("read3=0x%02x\n",(unsigned char)(read_val&0xff));

	return 0;
}