GPIO编程2：使用GPIO监听中断完整程序

一个完整的使用GPIO捕捉中断的程序：

#include<stdlib.h>
#include<stdio.h>
#include<string.h>
#include<unistd.h>
#include<fcntl.h>
#include<poll.h>

#define MSG(args...) printf(args) 

//函数声明
static int gpio_export(int pin);
static int gpio_unexport(int pin);
static int gpio_direction(int pin, int dir);
static int gpio_write(int pin, int value);
static int gpio_read(int pin);
static int gpio_edge(int pin, int edge);

static int gpio_export(int pin)
{
    ];
    int len;
    int fd;  

    fd = open("/sys/class/gpio/export", O_WRONLY);
    )
    {
        MSG("Failed to open export for writing!\n");
        );
    }  

    len = snprintf(buffer, sizeof(buffer), "%d", pin);
    printf("%s,%d,%d\n",buffer,sizeof(buffer),len);
    )
    {
        MSG("Failed to export gpio!");
        ;
    }  

    close(fd);
    ;
}
static int gpio_unexport(int pin)
{
    ];
    int len;
    int fd;  

    fd = open("/sys/class/gpio/unexport", O_WRONLY);
    )
    {
        MSG("Failed to open unexport for writing!\n");
        ;
    }  

    len = snprintf(buffer, sizeof(buffer), "%d", pin);
    )
    {
        MSG("Failed to unexport gpio!");
        ;
    }  

    close(fd);
    ;
}
//dir: 0-->IN, 1-->OUT
static int gpio_direction(int pin, int dir)
{
    static const char dir_str[] = "in\0out";
    ];
    int fd;  

    snprintf(path, sizeof(path), "/sys/class/gpio/gpio%d/direction", pin);
    fd = open(path, O_WRONLY);
    )
    {
        MSG("Failed to open gpio direction for writing!\n");
        ;
    }  

     ?  : ], dir ==  ?  : ) < )
    {
        MSG("Failed to set direction!\n");
        ;
    }  

    close(fd);
    ;
}
//value: 0-->LOW, 1-->HIGH
static int gpio_write(int pin, int value)
{
    ";
    ];
    int fd;  

    snprintf(path, sizeof(path), "/sys/class/gpio/gpio%d/value", pin);
    fd = open(path, O_WRONLY);
    )
    {
        MSG("Failed to open gpio value for writing!\n");
        ;
    }  

     ?  : ], ) < )
    {
        MSG("Failed to write value!\n");
        ;
    }  

    close(fd);
    ;
}
static int gpio_read(int pin)
{
    ];
    ];
    int fd;  

    snprintf(path, sizeof(path), "/sys/class/gpio/gpio%d/value", pin);
    fd = open(path, O_RDONLY);
    )
    {
        MSG("Failed to open gpio value for reading!\n");
        ;
    }  

    ) < )
    {
        MSG("Failed to read value!\n");
        ;
    }  

    close(fd);
    return (atoi(value_str));
}
// none表示引脚为输入，不是中断引脚
// rising表示引脚为中断输入，上升沿触发
// falling表示引脚为中断输入，下降沿触发
// both表示引脚为中断输入，边沿触发
// 0-->none, 1-->rising, 2-->falling, 3-->both
static int gpio_edge(int pin, int edge)
{
const char dir_str[] = "none\0rising\0falling\0both";
char ptr;
];
    int fd;
switch(edge)
{
    :
        ptr = ;
        break;
    :
        ptr = ;
        break;
    :
        ptr = ;
        break;
    :
        ptr = ;
        break;
    default:
        ptr = ;
} 

    snprintf(path, sizeof(path), "/sys/class/gpio/gpio%d/edge", pin);
    fd = open(path, O_WRONLY);
    )
    {
        MSG("Failed to open gpio edge for writing!\n");
        ;
    }  

    )
    {
        MSG("Failed to set edge!\n");
        ;
    }  

    close(fd);
    ;
}
//GPIO1_17
int main()
{
    int gpio_fd, ret;
    ];
    ];
    unsigned ;

    gpio_unexport();
    gpio_unexport();

    //p8_12 init
    gpio_export();
    gpio_direction(, );//output out
    gpio_write(, );

    //p8_11 init
    gpio_export();
    gpio_direction(, );//input in
    gpio_edge(,);
    gpio_fd = open("/sys/class/gpio/gpio45/value",O_RDONLY);
    )
    {
        MSG("Failed to open value!\n");
        ;
    }
    fds[].fd = gpio_fd;
    fds[].events  = POLLPRI;

    )
    {
        ret = read(gpio_fd,buff,);
         )
        MSG("read\n");

        ret = poll(fds,,);
         )
        MSG("poll\n");
        ].revents & POLLPRI)
        {
            ret = lseek(gpio_fd,,SEEK_SET);
             )
            MSG("lseek\n");

            //gpio_write(44, cnt++%2);
            printf("**********************************\n");
        }
        usleep();
    }
    ;
}