按键驱动测试程序

宝剑锋从磨砺出，梅花香自苦寒来。——《警世贤文》

上一篇分析了一波驱动程序的代码，虽然有一些部分还是不懂，但还是挤出来一个测试程序，不足之处，请各位告知：

#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>

#define KEY1 0x01
#define KEY2 0x02
#define KEY3 0x04
#define KEY4 0x08
#define PLATDRV_MAGIC   0x60
#define OFF _IO (PLATDRV_MAGIC,0x18)
#define ON _IO (PLATDRV_MAGIC,0X19)

int main (int argc, char **argv)
{
int button_fd;
int led_fd;
int ret_button;
int current_button;
int i;
int j;
int x;
int y;

button_fd = open("/dev/button",0);

if(button_fd<0)
{
printf("open button failed.\n");
exit(1);
}

while(1)
{
ret_button = read(button_fd,¤t_button,sizeof(4));
if(ret_button != sizeof(current_button))
{
printf("Read() button failed.\n");
}

else
{
if (current_button == KEY1)
{
led_fd = open("/dev/led0",O_RDWR,755);
switch(i%2)  
                {  
                case 0:   
                    ioctl(led_fd,OFF,0);  
                    i++;
printf("Turn led0 OFF.\n");
break;  
                case 1:   
                    ioctl(led_fd,ON,0);  
                    i++;
printf("Turn led0 ON.\n");
break;
}

}

else if (current_button == KEY2)
{
led_fd = open("/dev/led1",O_RDWR,755);
switch(j%2)  
                {  
                case 0:   
                    ioctl(led_fd,OFF,1);  
                    j++;
printf("Turn led1 OFF.\n");
break;  
                case 1:   
                    ioctl(led_fd,ON,1);  
                    j++;
printf("Turn led1 ON.\n");
break;
}

}

else if (current_button == KEY3)
{
led_fd = open("/dev/led2",O_RDWR,755);
switch(x%2)  
                {  
                case 0:   
                    ioctl(led_fd,OFF,2);  
                    x++;
printf("Turn led2 OFF.\n");
break;  
                case 1:   
                    ioctl(led_fd,ON,2);  
                    x++;
printf("Turn led2 ON.\n");
break;
}

}

else if (current_button == KEY4)
{
led_fd = open("/dev/led3",O_RDWR,755);
switch(y%2)  
                {  
                case 0:   
                    ioctl(led_fd,OFF,3);  
                    y++;
printf("Turn led3 OFF.\n");
break; 
                case 1:   
                    ioctl(led_fd,ON,3);  
                    y++;
printf("Turn led3 ON.\n");
break;
}

}
}

}
ioctl(led_fd,OFF);
close(led_fd);
close(button_fd);

return 0;
}

编译以后和前面LED操作一样，在开发板上安装led驱动和按键驱动。

执行后按奇数下亮，偶数下灭。

对于定时器还不是太理解，以后将进一步理解定时器。