[mirror_ubuntu-bionic-kernel.git] / drivers / rtc / rtc-lib.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/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);
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 <a.zummo@towertech.it>
	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
87ebfd64	14	#include <linux/export.h>
c58411e9 AZ	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
c2c11ae4	48
c58411e9	49	/*
c2c11ae4	50	* rtc_time_to_tm64 - Converts time64_t to rtc_time.
c58411e9 AZ	51	* Convert seconds since 01-01-1970 00:00:00 to Gregorian date.
c58411e9 AZ	52	*/
c2c11ae4	53	void rtc_time64_to_tm(time64_t time, struct rtc_time *tm)
c58411e9	54	{
73442daf	55	unsigned int month, year;
c2c11ae4	56	unsigned long secs;
73442daf	57	int days;
c58411e9	58
c2c11ae4	59	/* time must be positive */
	60	days = div_s64(time, 86400);
	61	secs = time - (unsigned int) days * 86400;
c58411e9 AZ	62
	63	/* day of the week, 1970-01-01 was a Thursday */
	64	tm->tm_wday = (days + 4) % 7;
	65
	66	year = 1970 + days / 365;
	67	days -= (year - 1970) * 365
	68	+ LEAPS_THRU_END_OF(year - 1)
	69	- LEAPS_THRU_END_OF(1970 - 1);
	70	if (days < 0) {
	71	year -= 1;
78d89ef4	72	days += 365 + is_leap_year(year);
c58411e9 AZ	73	}
	74	tm->tm_year = year - 1900;
	75	tm->tm_yday = days + 1;
	76
	77	for (month = 0; month < 11; month++) {
	78	int newdays;
	79
	80	newdays = days - rtc_month_days(month, year);
	81	if (newdays < 0)
	82	break;
	83	days = newdays;
	84	}
	85	tm->tm_mon = month;
	86	tm->tm_mday = days + 1;
	87
c2c11ae4	88	tm->tm_hour = secs / 3600;
	89	secs -= tm->tm_hour * 3600;
	90	tm->tm_min = secs / 60;
	91	tm->tm_sec = secs - tm->tm_min * 60;
a7402deb MW	92
a7402deb MW	93	tm->tm_isdst = 0;
c58411e9	94	}
c2c11ae4	95	EXPORT_SYMBOL(rtc_time64_to_tm);
c58411e9 AZ	96
	97	/*
	98	* Does the rtc_time represent a valid date/time?
	99	*/
	100	int rtc_valid_tm(struct rtc_time *tm)
	101	{
	102	if (tm->tm_year < 70
db621f17	103	\|\| ((unsigned)tm->tm_mon) >= 12
c58411e9 AZ	104	\|\| tm->tm_mday < 1
c58411e9 AZ	105	\|\| tm->tm_mday > rtc_month_days(tm->tm_mon, tm->tm_year + 1900)
db621f17 DB	106	\|\| ((unsigned)tm->tm_hour) >= 24
	107	\|\| ((unsigned)tm->tm_min) >= 60
	108	\|\| ((unsigned)tm->tm_sec) >= 60)
c58411e9 AZ	109	return -EINVAL;
	110
	111	return 0;
	112	}
	113	EXPORT_SYMBOL(rtc_valid_tm);
	114
	115	/*
c2c11ae4	116	* rtc_tm_to_time64 - Converts rtc_time to time64_t.
c58411e9 AZ	117	* Convert Gregorian date to seconds since 01-01-1970 00:00:00.
c58411e9 AZ	118	*/
c2c11ae4	119	time64_t rtc_tm_to_time64(struct rtc_time *tm)
c58411e9	120	{
c2c11ae4	121	return mktime64(tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
c58411e9	122	tm->tm_hour, tm->tm_min, tm->tm_sec);
c58411e9	123	}
c2c11ae4	124	EXPORT_SYMBOL(rtc_tm_to_time64);
c58411e9	125
6610e089 JS	126	/*
	127	* Convert rtc_time to ktime
	128	*/
	129	ktime_t rtc_tm_to_ktime(struct rtc_time tm)
	130	{
c2c11ae4	131	return ktime_set(rtc_tm_to_time64(&tm), 0);
6610e089 JS	132	}
	133	EXPORT_SYMBOL_GPL(rtc_tm_to_ktime);
	134
	135	/*
	136	* Convert ktime to rtc_time
	137	*/
	138	struct rtc_time rtc_ktime_to_tm(ktime_t kt)
	139	{
c2c11ae4	140	struct timespec64 ts;
6610e089 JS	141	struct rtc_time ret;
6610e089 JS	142
c2c11ae4	143	ts = ktime_to_timespec64(kt);
6610e089 JS	144	/* Round up any ns */
	145	if (ts.tv_nsec)
	146	ts.tv_sec++;
c2c11ae4	147	rtc_time64_to_tm(ts.tv_sec, &ret);
6610e089 JS	148	return ret;
	149	}
	150	EXPORT_SYMBOL_GPL(rtc_ktime_to_tm);