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gpio.c
/************************************************************/
// gpio.c
/************************************************************/
#include "gpio.h"
#define SYS_GPIO_PFX "/sys/class/gpio/"
int fd = -1;
//gpio init
uint8 gpio_init(int _pin)
{
DIR *dp;
char fpath[100];
int port,num;
port = _pin/8;
num = _pin%8;
printf("port=%d, num=%d \n",port,num);
sprintf(fpath, SYS_GPIO_PFX"P%d_0%d", port, num);
if(!(dp=opendir(fpath)))
{
FILE *fp;
if((fp = fopen(SYS_GPIO_PFX"export", "w")) == NULL) return(-1);
fprintf(fp, "%d", _pin);
fclose(fp);
}
else
{
closedir(dp);
}
return(0);
}
uint8 gpio_read(int _pin)
{
char ret, ss[2];
char fpath[100];
int port,num;
port = _pin/8;
num = _pin%8;
sprintf(fpath, SYS_GPIO_PFX"P%d_0%d/value", port, num);
printf("fpath=%s \n", fpath);
fd = open(fpath, O_RDWR); // open file and enable read and write
if(fd < 0)
{
perror("Can't open gpio file \n"); // open i2c dev file fail
exit(1);
}
printf("open gpio file success !\n"); // open i2c dev file succes
ret = read(fd, ss, 1);
close(fd);
if(ret < 0) return(0);
return((ss[0] == '0'?0:1));
}
uint8 gpio_write(int _pin, int _val)
{
int ret;
char x[2];
char fpath[100];
int port,num;
port = _pin/8;
num = _pin%8;
sprintf(fpath, SYS_GPIO_PFX"P%d_0%d/value", port, num);
printf("fpath=%s \n", fpath);
fd = open(fpath, O_RDWR); // open file and enable read and write
if(fd < 0)
{
perror("Can't open gpio file \n"); // open i2c dev file fail
exit(1);
}
printf("open gpio file success !\n"); // open i2c dev file succes
x[1] = '\0';
x[0] = (_val>0 ? '1':'0');
ret = write(fd, x, 1);
close(fd);
return(ret);
}
uint8 gpio_dir_get(int _pin)
{
static char ss[2];
char fpath[100];
int ret,port,num;
port = _pin/8;
num = _pin%8;
sprintf(fpath, SYS_GPIO_PFX"P%d_0%d/direction", port, num);
printf("fpath=%s \n", fpath);
fd = open(fpath, O_RDWR); // open file and enable read and write
if(fd < 0)
{
perror("Can't open gpio file \n"); // open i2c dev file fail
exit(1);
}
printf("open gpio file success !\n"); // open i2c dev file succes
ret = read(fd, ss, 2);
close(fd);
if(ret < 0) return(0);
return((ss[0] == 'i'? PIN_DIR_I:PIN_DIR_O));
}
uint8 gpio_dir_set(int _pin, int _dir)
{
int ret=0;
const char *ss="in";
char fpath[100];
int port,num;
port = _pin/8;
num = _pin%8;
sprintf(fpath, SYS_GPIO_PFX"P%d_0%d/direction", port, num);
printf("fpath=%s \n", fpath);
fd = open(fpath, O_RDWR); // open file and enable read and write
if(fd < 0)
{
perror("Can't open gpio file \n"); // open i2c dev file fail
exit(1);
}
printf("open gpio file success !\n"); // open i2c dev file succes
if(_dir == PIN_DIR_O) ss="out";
ret = write(fd, ss, strlen(ss)*sizeof(char));
close(fd);
return((ret<2 ? -1:0));
}
gpio.h
/************************************************************/
// gpio.h
/************************************************************/
#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<sys/ioctl.h>
#include<fcntl.h>
#include<dirent.h>
#include<string.h>
#define PIN_DIR_I 0
#define PIN_DIR_O 1
typedef unsigned char uint8;
uint8 gpio_init(int);
uint8 gpio_read(int);
uint8 gpio_write(int,int);
uint8 gpio_dir_get(int);
uint8 gpio_dir_set(int,int);
main.c
/************************************************************/
// main.c
/************************************************************/
#include "gpio.h"
// main
int main(int argc, char *argv[])
{
int pinnum1,pinnum2;
printf("GPIO test main start \n");
pinnum1 = 22; //mean GPIO_P2_6=MX[22]
pinnum2 = 24; //mean GPIO_P3_0=MX[24]
gpio_init(pinnum1);
gpio_init(pinnum2);
gpio_dir_set(pinnum1,PIN_DIR_O);
gpio_dir_set(pinnum2,PIN_DIR_O);
gpio_write(pinnum1,1);
gpio_write(pinnum2,0);
usleep(3000*1000);
while(1)
{
gpio_write(pinnum1,1);
gpio_write(pinnum2,0);
usleep(1000*1000);
gpio_write(pinnum1,0);
gpio_write(pinnum2,1);
usleep(1000*1000);
}
}
3.Makefile
/******************************/
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