linux下使用mmap控制GPIO

guitarhua 2011-12-24

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linux下使用mmap控制GPIO

2008-07-12 7:41

欢迎看看我的另一个小窝,说不定有意外的惊喜哦 ^_^ www.

如果没有/dev/mem,则执行

mknod /dev/mem c 1 1

编译下面的代码

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include<sys/mman.h>
#include<fcntl.h>
#include <asm/page.h>

#define GPIO_CTL_BASE 0x56000000
#define rGPBCON 0x10
#define rGPBDAT 0x14
#define rGPBUP 0x18

unsigned int *GPBCON,*GPBDAT,*GPBUP;

void Led_Display(int data)
{
*(volatile unsigned int *)GPBDAT= (~data & 0xf)<<7;//因为是第7-10位，且只有4位，故左移7
}

int main(int argc, char** argv)
{
int gpio_fd, ip=0, i=0;
unsigned char *gpio_map;

gpio_map = NULL;
GPBCON = NULL;
GPBDAT = NULL;
GPBUP = NULL;

gpio_fd =open("/dev/mem",O_RDWR);
if (gpio_fd == -1)
{
printf("can't open /dev/mem.\n");
return ;
}

gpio_map = (unsigned char *)mmap(0, 0xbc,PROT_READ | PROT_WRITE, MAP_SHARED,gpio_fd, GPIO_CTL_BASE);
GPBCON = (volatile unsigned int *) (gpio_map+rGPBCON);
GPBDAT = (volatile unsigned int *) (gpio_map+rGPBDAT);
GPBUP = (volatile unsigned int *) (gpio_map+rGPBUP);

//初始化io
*(volatile unsigned int *)GPBCON=0x154000;
*(volatile unsigned int *)GPBUP=0x7ff;

for(i=0;i<16;i++)
{
Led_Display(i);
sleep(1);
}

munmap(0, 0xbc);
if (gpio_fd != 0x0)
{
close(gpio_fd);
}

printf("GPIO Control Test end\n");

}