key_test.c

来自「嵌入式linux 开发板驱动程序」· C语言 代码 · 共 54 行

/**********************************************
* *single key driver test function
*  *date : created at 2007-09-19 by baijb
**********************************************/

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

#define PATH "/dev/key/0"	//device file

int main(void)
{
	int fd;
	int result;
	int key_value;
	int times = 0;

	fd = open(PATH, 0);
	if (fd < 0) {
		printf("Failed to open key_driver\n");
		exit(1);
	}
	
	do {
		result = read(fd, &key_value, sizeof(key_value)) == sizeof(key_value);
		if (!result) {
			if (errno == EINVAL)
				printf("Wrong size!\n");
			goto failed;	
		}

		if(key_value == 1) {
			printf("key-19 or key-20 pressed!\n");
			printf("pressed %d times\n", ++times);
		}
		else if(key_value == 2) {
			printf("key-17 or key-18 pressed!\n");
			printf("pressed %d times\n", ++times);
		}

	}while(times < 10);
	
failed:
	close(fd);
	
	return 0;
}