[linux.git] / drivers / rtc / rtc-lib.c

/*
 * rtc and date/time utility functions
 *
 * Copyright (C) 2005-06 Tower Technologies
 * Author: Alessandro Zummo <[email protected]>
 *
 * 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
};

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);

/*
 * Convert seconds since 01-01-1970 00:00:00 to Gregorian date.
 */
void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
{
	unsigned int month, year;
	int days;

	days = time / 86400;
	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 = time / 3600;
	time -= tm->tm_hour * 3600;
	tm->tm_min = time / 60;
	tm->tm_sec = time - tm->tm_min * 60;

	tm->tm_isdst = 0;
}
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
		|| ((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);

/*
 * 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);

/*
 * Convert rtc_time to ktime
 */
ktime_t rtc_tm_to_ktime(struct rtc_time tm)
{
	time_t time;
	rtc_tm_to_time(&tm, &time);
	return ktime_set(time, 0);
}
EXPORT_SYMBOL_GPL(rtc_tm_to_ktime);

/*
 * Convert ktime to rtc_time
 */
struct rtc_time rtc_ktime_to_tm(ktime_t kt)
{
	struct timespec ts;
	struct rtc_time ret;

	ts = ktime_to_timespec(kt);
	/* Round up any ns */
	if (ts.tv_nsec)
		ts.tv_sec++;
	rtc_time_to_tm(ts.tv_sec, &ret);
	return ret;
}
EXPORT_SYMBOL_GPL(rtc_ktime_to_tm);

MODULE_LICENSE("GPL");
Commit	Line	Data
c58411e9 AZ	1	/*
	2	* rtc and date/time utility functions
	3	*
	4	* Copyright (C) 2005-06 Tower Technologies
	5	* Author: Alessandro Zummo <[email protected]>
	6	*
	7	* based on arch/arm/common/rtctime.c and other bits
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License version 2 as
	11	* published by the Free Software Foundation.
	12	*/
	13
	14	#include <linux/module.h>
	15	#include <linux/rtc.h>
	16
	17	static const unsigned char rtc_days_in_month[] = {
	18	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
	19	};
	20
8232212e AV	21	static const unsigned short rtc_ydays[2][13] = {
	22	/* Normal years */
	23	{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
	24	/* Leap years */
	25	{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
	26	};
	27
c58411e9	28	#define LEAPS_THRU_END_OF(y) ((y)/4 - (y)/100 + (y)/400)
c58411e9	29
8232212e AV	30	/*
	31	* The number of days in the month.
	32	*/
c58411e9 AZ	33	int rtc_month_days(unsigned int month, unsigned int year)
c58411e9 AZ	34	{
78d89ef4	35	return rtc_days_in_month[month] + (is_leap_year(year) && month == 1);
c58411e9 AZ	36	}
	37	EXPORT_SYMBOL(rtc_month_days);
	38
8232212e AV	39	/*
	40	* The number of days since January 1. (0 to 365)
	41	*/
	42	int rtc_year_days(unsigned int day, unsigned int month, unsigned int year)
	43	{
78d89ef4	44	return rtc_ydays[is_leap_year(year)][month] + day-1;
8232212e AV	45	}
	46	EXPORT_SYMBOL(rtc_year_days);
	47
c58411e9 AZ	48	/*
	49	* Convert seconds since 01-01-1970 00:00:00 to Gregorian date.
	50	*/
	51	void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
	52	{
73442daf JA	53	unsigned int month, year;
73442daf JA	54	int days;
c58411e9 AZ	55
c58411e9 AZ	56	days = time / 86400;
73442daf	57	time -= (unsigned int) days * 86400;
c58411e9 AZ	58
	59	/* day of the week, 1970-01-01 was a Thursday */
	60	tm->tm_wday = (days + 4) % 7;
	61
	62	year = 1970 + days / 365;
	63	days -= (year - 1970) * 365
	64	+ LEAPS_THRU_END_OF(year - 1)
	65	- LEAPS_THRU_END_OF(1970 - 1);
	66	if (days < 0) {
	67	year -= 1;
78d89ef4	68	days += 365 + is_leap_year(year);
c58411e9 AZ	69	}
	70	tm->tm_year = year - 1900;
	71	tm->tm_yday = days + 1;
	72
	73	for (month = 0; month < 11; month++) {
	74	int newdays;
	75
	76	newdays = days - rtc_month_days(month, year);
	77	if (newdays < 0)
	78	break;
	79	days = newdays;
	80	}
	81	tm->tm_mon = month;
	82	tm->tm_mday = days + 1;
	83
	84	tm->tm_hour = time / 3600;
	85	time -= tm->tm_hour * 3600;
	86	tm->tm_min = time / 60;
	87	tm->tm_sec = time - tm->tm_min * 60;
a7402deb MW	88
a7402deb MW	89	tm->tm_isdst = 0;
c58411e9 AZ	90	}
	91	EXPORT_SYMBOL(rtc_time_to_tm);
	92
	93	/*
	94	* Does the rtc_time represent a valid date/time?
	95	*/
	96	int rtc_valid_tm(struct rtc_time *tm)
	97	{
	98	if (tm->tm_year < 70
db621f17	99	\|\| ((unsigned)tm->tm_mon) >= 12
c58411e9 AZ	100	\|\| tm->tm_mday < 1
c58411e9 AZ	101	\|\| tm->tm_mday > rtc_month_days(tm->tm_mon, tm->tm_year + 1900)
db621f17 DB	102	\|\| ((unsigned)tm->tm_hour) >= 24
	103	\|\| ((unsigned)tm->tm_min) >= 60
	104	\|\| ((unsigned)tm->tm_sec) >= 60)
c58411e9 AZ	105	return -EINVAL;
	106
	107	return 0;
	108	}
	109	EXPORT_SYMBOL(rtc_valid_tm);
	110
	111	/*
	112	* Convert Gregorian date to seconds since 01-01-1970 00:00:00.
	113	*/
	114	int rtc_tm_to_time(struct rtc_time tm, unsigned long time)
	115	{
	116	*time = mktime(tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
	117	tm->tm_hour, tm->tm_min, tm->tm_sec);
	118	return 0;
	119	}
	120	EXPORT_SYMBOL(rtc_tm_to_time);
	121
6610e089 JS	122	/*
	123	* Convert rtc_time to ktime
	124	*/
	125	ktime_t rtc_tm_to_ktime(struct rtc_time tm)
	126	{
	127	time_t time;
	128	rtc_tm_to_time(&tm, &time);
	129	return ktime_set(time, 0);
	130	}
	131	EXPORT_SYMBOL_GPL(rtc_tm_to_ktime);
	132
	133	/*
	134	* Convert ktime to rtc_time
	135	*/
	136	struct rtc_time rtc_ktime_to_tm(ktime_t kt)
	137	{
	138	struct timespec ts;
	139	struct rtc_time ret;
	140
	141	ts = ktime_to_timespec(kt);
	142	/* Round up any ns */
	143	if (ts.tv_nsec)
	144	ts.tv_sec++;
	145	rtc_time_to_tm(ts.tv_sec, &ret);
	146	return ret;
	147	}
	148	EXPORT_SYMBOL_GPL(rtc_ktime_to_tm);
	149
c58411e9	150	MODULE_LICENSE("GPL");