C++ / ubuntu_GPIO触发 | Zichuan365' Blog

解决方法链接：https://stackoverflow.com/questions/30938991/access-gpio-sys-class-gpio-as-non-root/30940526

硬件获取触发权限、开放对应端口

//1.开放权限
gedit /etc/udev/rules.d/99-galaxy-u3v.rules
##添加
SUBSYSTEM=="gpio*", PROGRAM="/bin/sh -c 'chown -R root:gpio /sys/class/gpio && chmod -R 770 /sys/class/gpio'"

//2.设置触发
gedit /etc/rc.local
##添加
sudo chmod 770 /sys/class/gpio/unexport /sys/class/gpio/export
sudo echo 246 > /sys/class/gpio/export
sudo chmod -R 777 /sys/class/gpio/gpio246
sudo echo out > /sys/class/gpio/gpio246/direcion
sudo echo 0 > /sys/class/gpio/gpio246/value

C++具体实现
gpioset.h

#ifndef GPIOSET
#define GPIOSET

#define SYSFS_GPIO_DIR "/sys/class/gpio"
#define POLL_TIMEOUT (3 * 1000) /* 3 seconds */
#define MAX_BUF 64
//int keepgoing = 1;

enum PIN_DIRECTION
{
    INPUT_PIN=0,
    OUTPUT_PIN=1
};

enum PIN_VALUE
{
    LOW = 0,
    HIGH = 1
};
/*****************************************/
/* gpio export */
int gpio_export(unsigned int gpio);
/* gpio unexport */
int gpio_unexport(unsigned int gpio);
/* gpio set dir */
int gpio_set_dir(unsigned int gpio, const char *dir);
/* gpio set value */
int gpio_set_value(unsigned int gpio, unsigned int value);
/* gpio get value */
int gpio_get_value(unsigned int gpio, unsigned int *value);

/* gpio set edge
控制中断触发模式:引脚被配置为中断后可以使用poll()函数监听引脚
非中断引脚:echo "none" >edge
上升沿触发:rising
下降沿触发:falling
边沿触发:both
*/
int gpio_set_edge(unsigned int gpio, const char *edge);
/* gpio fd open */
int gpio_fd_open(unsigned int gpio, unsigned int dir);
/* gpio fd close */
int gpio_fd_close(int fd);
/*// Callback called when SIGINT is sent to the process (Ctrl-C)
void signal_handler(int sig);*/

#endif // GPIOSET

gpioset.cpp

#include "gpioset.h"
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <poll.h>
#include <stdlib.h>
#include <errno.h>
#include <signal.h>
#include <sys/epoll.h>

/* gpio export */
int gpio_export(unsigned int gpio)
{
    int fd, len;
    char buf[MAX_BUF];

    fd = open(SYSFS_GPIO_DIR "/export", O_WRONLY);
    if (fd < 0)
    {
        printf ("\nFailed export GPIO-%d\n", gpio);
        return fd;
    }

    len = snprintf(buf, sizeof(buf), "%d", gpio);
    write(fd, buf, len);
    close(fd);
    printf ("\nSucessfully export GPIO-%d\n", gpio);
    return 1;
}
/* gpio unexport */
int gpio_unexport(unsigned int gpio)
{
    int fd, len;
    char buf[MAX_BUF];

    fd = open(SYSFS_GPIO_DIR "/unexport", O_WRONLY);
    if (fd < 0)
    {
        printf ("\nFailed unexport GPIO-%d\n", gpio);
        return fd;
    }

    len = snprintf(buf, sizeof(buf), "%d", gpio);
    write(fd, buf, len);
    close(fd);
    printf ("\nSucessfully unexport GPIO-%d\n", gpio);
    return 1;
}
/* gpio set dir */
int gpio_set_dir(unsigned int gpio, const char *dir)
{
    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)
    {
        printf ("\nFailed set GPIO-%d direction\n", gpio);
        return fd;
    }

    write(fd, dir, strlen(dir)+1);
    close(fd);
    printf ("\nSucessfully set GPIO-%d direction\n", gpio);
    return 1;
}
/* gpio set value */
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)
    {
        printf ("\nFailed set GPIO-%d value\n", gpio);
        return fd;
    }

    if (value!=0)
    {
        int i = write(fd, "1", 2);
        printf ("\nGPIO-%d value set high\n", gpio);
    }
    else
    {
        write(fd, "0", 2);
        printf ("\nGPIO-%d value set low\n", gpio);
    }

    close(fd);
    printf ("\nSucessfully set GPIO-%d value\n", gpio);
    return 1;
}
/* gpio get value */
int gpio_get_value(unsigned int gpio, unsigned int *value)
{
    int fd, len;
    char buf[MAX_BUF];
    char ch;

    len = snprintf(buf, sizeof(buf), SYSFS_GPIO_DIR "/gpio%d/value", gpio);

    fd = open(buf, O_RDONLY);
    if (fd < 0)
    {
        printf ("\nFailed get GPIO-%d value\n", gpio);
        return fd;
    }

    read(fd, &ch, 1);

    if (ch != '0')
    {
        *value = 1;
    } else
    {
        *value = 0;
    }

    close(fd);
    printf ("\nSucessfully get GPIO-%d value\n", gpio);
    return 0;
}
/* gpio set edge */
int gpio_set_edge(unsigned int gpio, const 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)
    {
        printf ("\nFailed set GPIO-%d edge\n", gpio);
        return fd;
    }

    write(fd, edge, strlen(edge) + 1);
    close(fd);
    return 0;
}
/* gpio fd open */
int gpio_fd_open(unsigned int gpio, unsigned int dir)
{
    int fd, len;
    char buf[MAX_BUF];

    len = snprintf(buf, sizeof(buf), SYSFS_GPIO_DIR "/gpio%d/value", gpio);

    fd = open(buf, dir | O_NONBLOCK );
    if (fd < 0)
    {
        perror("gpio/fd_open");
    }
    return fd;
}
/* gpio fd close */
int gpio_fd_close(int fd)
{
    return close(fd);
}

// Callback called when SIGINT is sent to the process (Ctrl-C)
/*void signal_handler(int sig)
{
    printf( "Ctrl-C pressed, cleaning up and exiting..\n" );
    keepgoing = 0;
}*/

main.cpp / 具体调用

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gpio_set_dir(246,"out");
gpio_set_value(246,0);
gpio_set_value(246,1);