/* * 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/export.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}; static const unsigned short rtc_ydays[2][13] = {	/* Normal years */	{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },	/* Leap years */	{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }}; #define LEAPS_THRU_END_OF(y) ((y)/4 - (y)/100 + (y)/400) /* * The number of days in the month. */int rtc_month_days(unsigned int month, unsigned int year){	return rtc_days_in_month[month] + (is_leap_year(year) && month == 1);}EXPORT_SYMBOL(rtc_month_days); /* * The number of days since January 1. (0 to 365) */int rtc_year_days(unsigned int day, unsigned int month, unsigned int year){	return rtc_ydays[is_leap_year(year)][month] + day-1;}EXPORT_SYMBOL(rtc_year_days);  /* * rtc_time_to_tm64 - Converts time64_t to rtc_time. * Convert seconds since 01-01-1970 00:00:00 to Gregorian date. */void rtc_time64_to_tm(time64_t time, struct rtc_time *tm){	unsigned int month, year;	unsigned long secs;	int days; 	/* time must be positive */	days = div_s64(time, 86400);	secs = time - (unsigned int) 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 + is_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 = secs / 3600;	secs -= tm->tm_hour * 3600;	tm->tm_min = secs / 60;	tm->tm_sec = secs - tm->tm_min * 60; 	tm->tm_isdst = 0;}EXPORT_SYMBOL(rtc_time64_to_tm); /* * Does the rtc_time represent a valid date/time? */int rtc_valid_tm(struct rtc_time *tm){	if (tm->tm_year < 70		|| ((unsigned)tm->tm_mon) >= 12		|| tm->tm_mday < 1		|| tm->tm_mday > rtc_month_days(tm->tm_mon, tm->tm_year + 1900)		|| ((unsigned)tm->tm_hour) >= 24		|| ((unsigned)tm->tm_min) >= 60		|| ((unsigned)tm->tm_sec) >= 60)		return -EINVAL; 	return 0;}EXPORT_SYMBOL(rtc_valid_tm); /* * rtc_tm_to_time64 - Converts rtc_time to time64_t. * Convert Gregorian date to seconds since 01-01-1970 00:00:00. */time64_t rtc_tm_to_time64(struct rtc_time *tm){	return mktime64(tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,			tm->tm_hour, tm->tm_min, tm->tm_sec);}EXPORT_SYMBOL(rtc_tm_to_time64); /* * Convert rtc_time to ktime */ktime_t rtc_tm_to_ktime(struct rtc_time tm){	return ktime_set(rtc_tm_to_time64(&tm), 0);}EXPORT_SYMBOL_GPL(rtc_tm_to_ktime); /* * Convert ktime to rtc_time */struct rtc_time rtc_ktime_to_tm(ktime_t kt){	struct timespec64 ts;	struct rtc_time ret; 	ts = ktime_to_timespec64(kt);	/* Round up any ns */	if (ts.tv_nsec)		ts.tv_sec++;	rtc_time64_to_tm(ts.tv_sec, &ret);	return ret;}EXPORT_SYMBOL_GPL(rtc_ktime_to_tm);