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源码压缩包
gpio.tar.gz
(6.46 KB, 下载次数: 11734)
包含源码、Makefile文件、镜像文件（使用arm-none-linux-gnueabi-gcc编译）
源码
[mw_shl_code=c,true]/********************************************************************
* copyright (C) 2014 all rights reserved
* @file: gpio.c
* @Created: 2014-8-6 15:00
* @Author: conway chen
* @Description: test gpios interrupt
* @Modify Date: 2014-8-6 15:00
*********************************************************************/
#include<stdio.h>
#include <stdlib.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<unistd.h>
#include<errno.h>
#include<string.h>
#include <poll.h>
#define SYSFS_GPIO_DIR "/sys/class/gpio"
#define GPIO_LED 41
#define MAX_BUF 60
#define POLL_TIMEOUT (3 * 1000) /* 3 seconds */
#define OUT 1
#define IN 0
/**
* brief: export the GPIO to user space
* @Param: gpio: the GPIO number
*/
int gpio_export(unsigned int gpio)
{
int fd ,len;
char buf[MAX_BUF];
fd = open(SYSFS_GPIO_DIR "/export" ,O_WRONLY);
if (fd < 0) {
perror("gpio/export");
return fd;
}
len = snprintf(buf ,sizeof(buf) ,"%d" ,gpio);
write(fd ,buf ,len);
close(fd);
return 0;
}
/**
* brief: unexport the GPIO to user space
* @Param: gpio: the GPIO number
*/
int gpio_unexport(unsigned int gpio)
{
int fd ,len;
char buf[MAX_BUF];
fd = open(SYSFS_GPIO_DIR "/unexport" ,O_WRONLY);
if (fd < 0) {
perror("gpio/unexport");
return fd;
}
len = snprintf(buf ,sizeof(buf) ,"%d" ,gpio);
write(fd ,buf ,len);
close(fd);
return 0;
}
/**
* brief: configure GPIO for input or output
* @Param: gpio: the GPIO number
* @Param: out_flag: the flag of output or input.It's value can be 1 or 0.
*/
int gpio_set_dir(unsigned int gpio ,int out_flag)
{
int fd ,len;
char buf[MAX_BUF];
len = snprintf(buf, sizeof(buf), SYSFS_GPIO_DIR "/gpio%d/direction", gpio);
fd = open(buf ,O_WRONLY);
if (fd < 0) {
perror(buf);
return fd;
}
if (out_flag)
write(fd ,"out" ,4);
else
write(fd ,"in" ,3);
close(fd);
return 0;
}
/**
* brief: Set the value of GPIO
* @Param: gpio: the GPIO number
* @Param: value: the value of GPIO. Supports values of 0 and 1.
*/
int gpio_set_value(unsigned int gpio, unsigned int value)
{
int fd, len;
char buf[MAX_BUF];
len = snprintf(buf, sizeof(buf), SYSFS_GPIO_DIR "/gpio%d/value", gpio);
fd = open(buf, O_WRONLY);
if (fd < 0) {
perror("gpio/set-value");
return fd;
}
if (value)
write(fd, "1", 2);
else
write(fd, "0", 2);
close(fd);
return 0;
}
/**
* brief: get the value of GPIO
* @Param: gpio: the GPIO number
* @Param: value: pointer to the value of GPIO
*/
int gpio_get_value(unsigned int gpio, unsigned int *value)
{
int fd, len;
char ch;
char buf[MAX_BUF];
len = snprintf(buf ,sizeof(buf), SYSFS_GPIO_DIR "/gpio%d/value" ,gpio);
fd = open(buf ,O_RDONLY);
if (fd < 0) {
perror("gpio_get_value");
return fd;
}
read(fd ,&ch ,1);
if (ch == '1')
*value = 1;
else if(ch == '0')
*value = 0;
close(fd);
return 0;
}
/**
* brief: set the edge that trigger interrupt
* @Param: gpio: the GPIO number
* @Param: edge: edge that trigger interrupt
*/
int gpio_set_edge(unsigned int gpio ,char *edge)
{
int fd ,len;
char buf[MAX_BUF];
len = snprintf(buf ,sizeof(buf) ,SYSFS_GPIO_DIR "/gpio%d/edge" ,gpio);
fd = open(buf ,O_WRONLY);
if (fd < 0) {
perror("gpio_set_edge");
return fd;
}
write(fd ,edge ,strlen(edge) + 1);
close(fd);
return 0;
}
/**
* brief: open gpio device and return the file descriptor
* @Param: gpio: the GPIO number
*/
int gpio_fd_open(unsigned int gpio)
{
int fd, len;
char buf[MAX_BUF];
len = snprintf(buf, sizeof(buf), SYSFS_GPIO_DIR "/gpio%d/value", gpio);
fd = open(buf, O_RDONLY | O_NONBLOCK );
if (fd < 0) {
perror("gpio/fd_open");
}
return fd;
}
/**
* brief: close gpio device
* @Param: fd: the file descriptor of gpio
*/
int gpio_fd_close(int fd)
{
return close(fd);
}
/**
* @brief: main function
* @Param: argc: number of parameters
* @Param: argv: parameters list
*/
int main(int argc, char **argv)
{
struct pollfd *fdset;
int nfds = 1;
int gpio_fd, timeout, rc;
char *buf[MAX_BUF];
unsigned int gpio;
int len;
char *cmd;
unsigned int value;
fdset = (struct pollfd*)malloc(sizeof(struct pollfd));
if (argc < 3) {
printf("Usage: %s <gpio-pin> <direction> [value]\n\n", argv[0]);
exit(-1);
}
cmd = argv[2];
gpio = atoi(argv[1]);
gpio_export(gpio);
if (strcmp(cmd, "interrupt") == 0) {
printf("\n**************************GPIO interrupt***************************\n");
gpio_set_dir(gpio, IN);
gpio_set_edge(gpio, "rising");
gpio_fd = gpio_fd_open(gpio);
/* GPIO_LED configure */
//gpio_export(GPIO_LED);
//gpio_set_dir(GPIO_LED, OUT);
timeout = POLL_TIMEOUT;
while (1) {
memset((void*)fdset, 0, sizeof(fdset));
fdset->fd = gpio_fd;
fdset->events = POLLPRI;
rc = poll(fdset, nfds, timeout);
if (rc < 0) {
printf("\npoll() failed!\n");
return -1;
}
if (rc == 0) {
printf(".");
/* LED off */
//gpio_set_value(GPIO_LED, 1);
}
if (fdset->revents & POLLPRI) {
len = read(fdset->fd, buf, MAX_BUF);
printf("\nGPIO %d interrupt occurred\n", gpio);
/* when GPIO interrupt occurred, LED turn on */
//gpio_set_value(GPIO_LED, 0);
}
fflush(stdout);
}
gpio_fd_close(gpio_fd);
} else if (strcmp(cmd, "out") == 0) {
gpio_set_dir(gpio, OUT);
if (argc = 4) {
gpio_set_value(gpio, atoi(argv[3]));
printf("gpio%d is set to %d\n", gpio, atoi(argv[3]));
}
} else if (strcmp(cmd, "in") == 0) {
gpio_set_dir(gpio, IN);
printf("\n");
while (1) {
gpio_get_value(gpio, &value);
printf("\rvalue:%d", value);
}
} else if (strcmp(cmd, "unexport") == 0) {
gpio_unexport(gpio);
}
else {
printf("Usage: %s <gpio-pin> <direction> [value]\n\n", argv[0]);
exit(-1);
}
return 0;
}
[/mw_shl_code]
测试
IM28X
执行以下命令配置开发板上的PD14引脚为中断功能，并给该引脚一个下降沿触发 ，程序检测到下降沿后将打印出相关信息。
[mw_shl_code=bash,true]root@freescale ~$ ./gpio 99 interrupt
****************************GPIO interrupt*****************************
GPIO 99 interrupt occurred
.......
GPIO 99 interrupt occurred[/mw_shl_code]
执行以下命令将gpio口配置为输出功能并设置对应值：
[mw_shl_code=bash,true]root@freescale ~$ ./gpio 99 out 0
gpio99 is set to 0
root@freescale ~$ ./gpio 99 out 1
gpio99 is set to 1[/mw_shl_code]
执行以下命令将gpio口配置为输入功能并获取输入值：
[mw_shl_code=bash,true]root@freescale ~$ ./gpio 99 in
value:1[/mw_shl_code]
执行以下命令导出gpio口：
[mw_shl_code=bash,true]root@freescale ~$ ./gpio 99 unexport[/mw_shl_code]
AM335X
执行以下命令配置开发板上的gpio3_5引脚为中断功能，并给该引脚一个下降沿触发 ，程序检测到下降沿后将打印出相关信息。
[mw_shl_code=bash,true]root@MYD-AM335X:~# ./gpio 101 interrupt
****************************GPIO interrupt*****************************
GPIO 101 interrupt occurred
....
GPIO 101 interrupt occurred[/mw_shl_code]
执行以下命令将gpio口配置为输出功能并设置对应值：
[mw_shl_code=bash,true]root@MYD-AM335X:~# ./gpio 101 out 0
gpio101 is set to 0
root@MYD-AM335X:~# ./gpio 101 out 1
gpio101 is set to 1[/mw_shl_code]
执行以下命令将gpio口配置为输入功能并获取输入值：
[mw_shl_code=bash,true]root@MYD-AM335X:~# ./gpio 101 in
value:0[/mw_shl_code]
执行以下命令导出gpio口：
[mw_shl_code=bash,true]root@MYD-AM335X:~# ./gpio 101 unexport[/mw_shl_code]
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