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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) |
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. |
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 | |
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 |
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. |
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; |
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); |