rtc.c

The source code example of ARM9 development board from Artila (M-501 starter kit). The source code c

/*
 *	Description: 
 *		example for rtc.
 *	
 *		What is shown in this example:
 *		1. How to open rtc
 *		2. How to get rtc
 *		3. How to set new hour to rtc
 *
 *	Usage:
 *		rtc.o [new hour]
 *		e.g
 *		rtc.o 23	change hour to 23
 */
#include <stdio.h>
#include <linux/rtc.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/ioctl.h>

int
main(argc, argv)
	int	argc;
	char	*argv[];
{
	int	fd, new_hour;
	struct rtc_time	org_time, set_time, rd_time;

	/*open rtc*/
	fd = open("/dev/rtc",O_RDWR);
	if (fd == -1) {
		printf("open Failed. errno: %d\r\n", errno);
		return;
	}
	
	/*get current time*/
	ioctl(fd, RTC_RD_TIME, &org_time);
	printf("local time: %d/%d/%d: %d:%d:%d\r\n", 
		org_time.tm_year+1900, org_time.tm_mon, org_time.tm_mday, 
		org_time.tm_hour, org_time.tm_min, org_time.tm_sec);

	if (argc == 2) {
		new_hour = atoi(argv[1]);	
		if ((new_hour < 0) || (new_hour > 23)) {
			printf("Usage: rtc.o 15....change new hour to 15");
			return;
		}
		/*set new time*/
		set_time = org_time;
		set_time.tm_hour = new_hour;
		ioctl(fd, RTC_SET_TIME, &set_time);
		/*get new time*/
		ioctl(fd, RTC_RD_TIME, &rd_time);
		printf("new time: %d/%d/%d: %d:%d:%d\r\n", 
			rd_time.tm_year+1900, rd_time.tm_mon, rd_time.tm_mday, 
			rd_time.tm_hour, rd_time.tm_min, rd_time.tm_sec);
	}

	close(fd);
}