3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 * See file CREDITS for list of people who contributed to this
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of
11 * the License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
25 * Date & Time support for Philips PCF8563 RTC
32 #if (CONFIG_COMMANDS & CFG_CMD_DATE) || defined(CONFIG_TIMESTAMP)
34 #define STARTOFTIME 1970
36 #define SECYR (SECDAY * 365)
37 #define leapyear(year) ((year) % 4 == 0)
38 #define days_in_year(a) (leapyear(a) ? 366 : 365)
39 #define days_in_month(a) (month_days[(a) - 1])
41 static int month_days[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
44 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
46 void GregorianDay(struct rtc_time * tm) {
50 int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
52 lastYear = tm->tm_year - 1;
55 * Number of leap corrections to apply up to end of last year
57 leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400;
60 * This year is a leap year if it is divisible by 4 except when it is
61 * divisible by 100 unless it is divisible by 400
63 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 will be
65 if ((tm->tm_year % 4 == 0) && ((tm->tm_year % 100 != 0) || (tm->tm_year % 400 == 0)) && (tm->tm_mon > 2)) {
67 * We are past Feb. 29 in a leap year
74 day += lastYear * 365 + leapsToDate + MonthOffset[tm->tm_mon - 1] + tm->tm_mday;
75 tm->tm_wday = day % 7;
78 void to_tm(int tim, struct rtc_time * tm) {
80 register long hms, day;
85 /* Hours, minutes, seconds are easy */
86 tm->tm_hour = hms / 3600;
87 tm->tm_min = (hms % 3600) / 60;
88 tm->tm_sec = (hms % 3600) % 60;
90 /* Number of years in days */
91 for (i = STARTOFTIME; day >= days_in_year(i); i++) {
92 day -= days_in_year(i);
96 /* Number of months in days left */
97 if (leapyear(tm->tm_year)) {
98 days_in_month(FEBRUARY) = 29;
101 for (i = 1; day >= days_in_month(i); i++) {
102 day -= days_in_month(i);
104 days_in_month(FEBRUARY) = 28;
107 /* Days are what is left over (+1) from all that. */
108 tm->tm_mday = day + 1;
111 * Determine the day of week
116 /* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
117 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
118 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
120 * [For the Julian calendar (which was used in Russia before 1917,
121 * Britain & colonies before 1752, anywhere else before 1582,
122 * and is still in use by some communities) leave out the
123 * -year/100+year/400 terms, and add 10.]
125 * This algorithm was first published by Gauss (I think).
127 * WARNING: this function will overflow on 2106-02-07 06:28:16 on
128 * machines were long is 32-bit! (However, as time_t is signed, we
129 * will already get problems at other places on 2038-01-19 03:14:08)
131 unsigned long mktime(unsigned int year, unsigned int mon, unsigned int day, unsigned int hour, unsigned int min, unsigned int sec) {
132 if (0 >= (int) (mon -= 2)) { /* 1..12 -> 11,12,1..10 */
133 mon += 12; /* Puts Feb last since it has leap day */
137 return ((((unsigned long) (year / 4 - year / 100 + year / 400 + 367 * mon / 12 + day) + year * 365 - 719499) * 24 + hour /* now have hours */
138 ) * 60 + min /* now have minutes */
139 ) * 60 + sec; /* finally seconds */
142 #endif /* CFG_CMD_DATE */