/* * 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");