/* * rtc and date/time utility functions * * Copyright (C) 2005-06 Tower Technologies * Author: Alessandro Zummo <a.zummo@towertech.it> * * based on arch/arm/common/rtctime.c and other bits * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation.*/ #include <linux/module.h>#include <linux/rtc.h> static const unsigned char rtc_days_in_month[] = {	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; #define LEAPS_THRU_END_OF(y) ((y)/4 - (y)/100 + (y)/400)#define LEAP_YEAR(year) ((!(year % 4) && (year % 100)) || !(year % 400)) int rtc_month_days(unsigned int month, unsigned int year){	return rtc_days_in_month[month] + (LEAP_YEAR(year) && month == 1);}EXPORT_SYMBOL(rtc_month_days); /* * Convert seconds since 01-01-1970 00:00:00 to Gregorian date. */void rtc_time_to_tm(unsigned long time, struct rtc_time *tm){	register int days, month, year; 	days = time / 86400;	time -= days * 86400; 	/* day of the week, 1970-01-01 was a Thursday */	tm->tm_wday = (days + 4) % 7; 	year = 1970 + days / 365;	days -= (year - 1970) * 365		+ LEAPS_THRU_END_OF(year - 1)		- LEAPS_THRU_END_OF(1970 - 1);	if (days < 0) {		year -= 1;		days += 365 + LEAP_YEAR(year);	}	tm->tm_year = year - 1900;	tm->tm_yday = days + 1; 	for (month = 0; month < 11; month++) {		int newdays; 		newdays = days - rtc_month_days(month, year);		if (newdays < 0)			break;		days = newdays;	}	tm->tm_mon = month;	tm->tm_mday = days + 1; 	tm->tm_hour = time / 3600;	time -= tm->tm_hour * 3600;	tm->tm_min = time / 60;	tm->tm_sec = time - tm->tm_min * 60;}EXPORT_SYMBOL(rtc_time_to_tm); /* * Does the rtc_time represent a valid date/time? */int rtc_valid_tm(struct rtc_time *tm){	if (tm->tm_year < 70		|| tm->tm_mon >= 12		|| tm->tm_mday < 1		|| tm->tm_mday > rtc_month_days(tm->tm_mon, tm->tm_year + 1900)		|| tm->tm_hour >= 24		|| tm->tm_min >= 60		|| tm->tm_sec >= 60)		return -EINVAL; 	return 0;}EXPORT_SYMBOL(rtc_valid_tm); /* * Convert Gregorian date to seconds since 01-01-1970 00:00:00. */int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time){	*time = mktime(tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,			tm->tm_hour, tm->tm_min, tm->tm_sec);	return 0;}EXPORT_SYMBOL(rtc_tm_to_time); MODULE_LICENSE("GPL");