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)
29 #define LEAP_YEAR(year) ((!(year % 4) && (year % 100)) || !(year % 400))
32 * The number of days in the month.
34 int rtc_month_days(unsigned int month
, unsigned int year
)
36 return rtc_days_in_month
[month
] + (LEAP_YEAR(year
) && month
== 1);
38 EXPORT_SYMBOL(rtc_month_days
);
41 * The number of days since January 1. (0 to 365)
43 int rtc_year_days(unsigned int day
, unsigned int month
, unsigned int year
)
45 return rtc_ydays
[LEAP_YEAR(year
)][month
] + day
-1;
47 EXPORT_SYMBOL(rtc_year_days
);
50 * Convert seconds since 01-01-1970 00:00:00 to Gregorian date.
52 void rtc_time_to_tm(unsigned long time
, struct rtc_time
*tm
)
54 unsigned int month
, year
;
58 time
-= (unsigned int) days
* 86400;
60 /* day of the week, 1970-01-01 was a Thursday */
61 tm
->tm_wday
= (days
+ 4) % 7;
63 year
= 1970 + days
/ 365;
64 days
-= (year
- 1970) * 365
65 + LEAPS_THRU_END_OF(year
- 1)
66 - LEAPS_THRU_END_OF(1970 - 1);
69 days
+= 365 + LEAP_YEAR(year
);
71 tm
->tm_year
= year
- 1900;
72 tm
->tm_yday
= days
+ 1;
74 for (month
= 0; month
< 11; month
++) {
77 newdays
= days
- rtc_month_days(month
, year
);
83 tm
->tm_mday
= days
+ 1;
85 tm
->tm_hour
= time
/ 3600;
86 time
-= tm
->tm_hour
* 3600;
87 tm
->tm_min
= time
/ 60;
88 tm
->tm_sec
= time
- tm
->tm_min
* 60;
90 EXPORT_SYMBOL(rtc_time_to_tm
);
93 * Does the rtc_time represent a valid date/time?
95 int rtc_valid_tm(struct rtc_time
*tm
)
98 || ((unsigned)tm
->tm_mon
) >= 12
100 || tm
->tm_mday
> rtc_month_days(tm
->tm_mon
, tm
->tm_year
+ 1900)
101 || ((unsigned)tm
->tm_hour
) >= 24
102 || ((unsigned)tm
->tm_min
) >= 60
103 || ((unsigned)tm
->tm_sec
) >= 60)
108 EXPORT_SYMBOL(rtc_valid_tm
);
111 * Convert Gregorian date to seconds since 01-01-1970 00:00:00.
113 int rtc_tm_to_time(struct rtc_time
*tm
, unsigned long *time
)
115 *time
= mktime(tm
->tm_year
+ 1900, tm
->tm_mon
+ 1, tm
->tm_mday
,
116 tm
->tm_hour
, tm
->tm_min
, tm
->tm_sec
);
119 EXPORT_SYMBOL(rtc_tm_to_time
);
121 MODULE_LICENSE("GPL");
This page took 0.031584 seconds and 5 git commands to generate.