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Commit c58411e9 authored by Alessandro Zummo's avatar Alessandro Zummo Committed by Linus Torvalds
Browse files

[PATCH] RTC Subsystem: library functions 



RTC and date/time related functions.

Signed-off-by: default avatarAlessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent d23ee8fe

drivers/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -70,4 +70,6 @@ source "drivers/sn/Kconfig" 


source "drivers/edac/Kconfig"



source "drivers/rtc/Kconfig"



endmenu

drivers/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ obj-$(CONFIG_USB_GADGET) += usb/gadget/ 
obj-$(CONFIG_GAMEPORT)		+= input/gameport/

obj-$(CONFIG_INPUT)		+= input/

obj-$(CONFIG_I2O)		+= message/

obj-$(CONFIG_RTC_LIB)		+= rtc/

obj-$(CONFIG_I2C)		+= i2c/

obj-$(CONFIG_W1)		+= w1/

obj-$(CONFIG_HWMON)		+= hwmon/

drivers/rtc/Kconfig

0 → 100644
+6 −0
Original line number Diff line number Diff line 
#

# RTC class/drivers configuration

#



config RTC_LIB

	tristate
 
 No newline at end of file

drivers/rtc/Makefile

0 → 100644
+5 −0
Original line number Diff line number Diff line 
#

# Makefile for RTC class/drivers.

#



obj-$(CONFIG_RTC_LIB)	+= rtc-lib.o

drivers/rtc/rtc-lib.c

0 → 100644
+101 −0
Original line number Diff line number Diff line 
/*

 * 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");