102 lines
2.3 KiB
C
102 lines
2.3 KiB
C
![]() |
/*
|
||
|
* 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");
|