2 * rtc and date/time utility functions
4 * Copyright (C) 2005-06 Tower Technologies
5 * Author: Alessandro Zummo <a.zummo@towertech.it>
7 * based on arch/arm/common/rtctime.c and other bits
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.
14 #include <linux/module.h>
15 #include <linux/rtc.h>
17 static const unsigned char rtc_days_in_month
[] = {
18 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
21 static const unsigned short rtc_ydays
[2][13] = {
23 { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
25 { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
28 #define LEAPS_THRU_END_OF(y) ((y)/4 - (y)/100 + (y)/400)
31 * The number of days in the month.
33 int rtc_month_days(unsigned int month
, unsigned int year
)
35 return rtc_days_in_month
[month
] + (is_leap_year(year
) && month
== 1);
37 EXPORT_SYMBOL(rtc_month_days
);
40 * The number of days since January 1. (0 to 365)
42 int rtc_year_days(unsigned int day
, unsigned int month
, unsigned int year
)
44 return rtc_ydays
[is_leap_year(year
)][month
] + day
-1;
46 EXPORT_SYMBOL(rtc_year_days
);
49 * Convert seconds since 01-01-1970 00:00:00 to Gregorian date.
51 void rtc_time_to_tm(unsigned long time
, struct rtc_time
*tm
)
53 unsigned int month
, year
;
57 time
-= (unsigned int) days
* 86400;
59 /* day of the week, 1970-01-01 was a Thursday */
60 tm
->tm_wday
= (days
+ 4) % 7;
62 year
= 1970 + days
/ 365;
63 days
-= (year
- 1970) * 365
64 + LEAPS_THRU_END_OF(year
- 1)
65 - LEAPS_THRU_END_OF(1970 - 1);
68 days
+= 365 + is_leap_year(year
);
70 tm
->tm_year
= year
- 1900;
71 tm
->tm_yday
= days
+ 1;
73 for (month
= 0; month
< 11; month
++) {
76 newdays
= days
- rtc_month_days(month
, year
);
82 tm
->tm_mday
= days
+ 1;
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;
89 EXPORT_SYMBOL(rtc_time_to_tm
);
92 * Does the rtc_time represent a valid date/time?
94 int rtc_valid_tm(struct rtc_time
*tm
)
97 || ((unsigned)tm
->tm_mon
) >= 12
99 || tm
->tm_mday
> rtc_month_days(tm
->tm_mon
, tm
->tm_year
+ 1900)
100 || ((unsigned)tm
->tm_hour
) >= 24
101 || ((unsigned)tm
->tm_min
) >= 60
102 || ((unsigned)tm
->tm_sec
) >= 60)
107 EXPORT_SYMBOL(rtc_valid_tm
);
110 * Convert Gregorian date to seconds since 01-01-1970 00:00:00.
112 int rtc_tm_to_time(struct rtc_time
*tm
, unsigned long *time
)
114 *time
= mktime(tm
->tm_year
+ 1900, tm
->tm_mon
+ 1, tm
->tm_mday
,
115 tm
->tm_hour
, tm
->tm_min
, tm
->tm_sec
);
118 EXPORT_SYMBOL(rtc_tm_to_time
);
120 MODULE_LICENSE("GPL");
This page took 0.033643 seconds and 6 git commands to generate.