firmware/drivers/rtc/rtc_jz4740.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2008 by Maurus Cuelenaere
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21
  22 /*
  23  * Jz OnChip Real Time Clock interface for Linux
  24  *
  25  */
  26
  27 #include "config.h"
  28 #include "jz4740.h"
  29 #include "rtc.h"
  30 #include "timefuncs.h"
  31 #include "logf.h"
  32
  33 /* Stolen from dietlibc-0.29/libugly/gmtime_r.c (GPLv2) */
  34 #define SPD (24*60*60)
  35 #define ISLEAP(year) (!(year%4) && ((year%100) || !(year%400)))
  36 static void _localtime(const time_t t, struct tm *r)
  37 {
  38     time_t i;
  39     register time_t work = t % SPD;
  40     static int m_to_d[12] = /* This could be shared with mktime() */
  41         {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334};
  42
  43     r->tm_sec = work % 60;
  44     work /= 60;
  45     r->tm_min = work % 60;
  46     r->tm_hour = work / 60;
  47     work = t / SPD;
  48     r->tm_wday = (4 + work) % 7;
  49
  50     for (i=1970; ; ++i)
  51     {
  52         register time_t k = ISLEAP(i) ? 366 : 365;
  53
  54         if (work >= k)
  55             work -= k;
  56         else
  57             break;
  58     }
  59
  60     r->tm_year = i - 1900;
  61     r->tm_yday = work;
  62
  63     r->tm_mday = 1;
  64     if (ISLEAP(i) && (work>58))
  65     {
  66         if (work==59)
  67             r->tm_mday=2; /* 29.2. */
  68
  69         work-=1;
  70     }
  71
  72     for (i=11; i && (m_to_d[i] > work); --i);
  73     r->tm_mon = i;
  74     r->tm_mday += work - m_to_d[i];
  75 }
  76
  77 int rtc_read_datetime(struct tm *tm)
  78 {
  79     _localtime(REG_RTC_RSR, tm);
  80
  81     return 1;
  82 }
  83
  84 int rtc_write_datetime(const struct tm *tm)
  85 {
  86     time_t val = mktime((struct tm*)tm);
  87
  88     __cpm_start_rtc();
  89     udelay(100);
  90     REG_RTC_RSR = val;
  91     __cpm_stop_rtc();
  92
  93     return 0;
  94 }
  95
  96 void rtc_init(void)
  97 {
  98     __cpm_start_rtc();
  99     REG_RTC_RCR = RTC_RCR_RTCE;
 100     udelay(70);
 101     while( !(REG_RTC_RCR & RTC_RCR_WRDY) );
 102     REG_RTC_RGR = (0x7fff | RTC_RGR_LOCK);
 103     udelay(70);
 104     __cpm_stop_rtc();
 105 }