firmware/drivers/rtc/rtc_ds1339_ds3231.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2006 by Robert Kukla
  11  * based on Archos code by Linus Nielsen Feltzing, Uwe Freese, Laurent Baum
  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 #include "rtc.h"
  22 #include "logf.h"
  23 #include "sw_i2c.h"
  24
  25 #define RTC_ADDR   0xD0
  26
  27 void rtc_init(void)
  28 {
  29     sw_i2c_init();
  30
  31 #ifdef HAVE_RTC_ALARM
  32     /* Check + save alarm bit first, before the power thread starts watching */
  33     rtc_check_alarm_started(false);
  34 #endif
  35
  36 }
  37
  38 #ifdef HAVE_RTC_ALARM
  39
  40 /* check whether the unit has been started by the RTC alarm function */
  41 /* (check for A2F, which => started using wakeup alarm) */
  42 bool rtc_check_alarm_started(bool release_alarm)
  43 {
  44     static bool alarm_state, run_before;
  45     bool rc;
  46
  47     if (run_before) {
  48         rc = alarm_state;
  49         alarm_state &= ~release_alarm;
  50     } else {
  51         /* This call resets AF, so we store the state for later recall */
  52         rc = alarm_state = rtc_check_alarm_flag();
  53         run_before = true;
  54     }
  55
  56     return rc;
  57 }
  58 /*
  59  * Checks the A2F flag.  This call resets A2F once read.
  60  *
  61  */
  62 bool rtc_check_alarm_flag(void)
  63 {
  64     unsigned char buf[1];
  65     bool flag = false;
  66
  67     sw_i2c_read(RTC_ADDR, 0x0f, buf, 1);
  68     if (buf[0] & 0x02) flag = true;
  69
  70     buf[0] = 0x00;
  71     sw_i2c_write(RTC_ADDR, 0x0f, buf, 1);
  72
  73     return flag;
  74 }
  75
  76 /* set alarm time registers to the given time (repeat once per day) */
  77 void rtc_set_alarm(int h, int m)
  78 {
  79     unsigned char buf[3];
  80
  81     buf[0] = (((m / 10) << 4) | (m % 10)) & 0x7f; /* minutes */
  82     buf[1] = (((h / 10) << 4) | (h % 10)) & 0x3f; /* hour */
  83     buf[2] = 0x80;                                /* repeat every day */
  84
  85     sw_i2c_write(RTC_ADDR, 0x0b, buf, 3);
  86 }
  87
  88 /* read out the current alarm time */
  89 void rtc_get_alarm(int *h, int *m)
  90 {
  91     unsigned char buf[2];
  92
  93     sw_i2c_read(RTC_ADDR, 0x0b, buf, 2);
  94
  95     *m = ((buf[0] & 0x70) >> 4) * 10 + (buf[0] & 0x0f);
  96     *h = ((buf[1] & 0x30) >> 4) * 10 + (buf[1] & 0x0f);
  97 }
  98
  99 /* turn alarm on or off by setting the alarm flag enable */
 100 /* the alarm is automatically disabled when the RTC gets Vcc power at startup */
 101 /* avoid that an alarm occurs when the device is on because this locks the ON key forever */
 102 /* returns false if alarm was set and alarm flag (output) is off */
 103 /* returns true if alarm flag went on, which would lock the device, so the alarm was disabled again */
 104 bool rtc_enable_alarm(bool enable)
 105 {
 106     unsigned char buf[2];
 107
 108     buf[0] = enable ? 0x26 : 0x24; /* BBSQI INTCN A2IE vs INTCH  only */
 109     buf[1] = 0x00; /* reset alarm flags (and OSF for good measure) */
 110
 111     sw_i2c_write(RTC_ADDR, 0x0e, buf, 2);
 112
 113     return false; /* all ok */
 114 }
 115
 116 #endif /* HAVE_RTC_ALARM */
 117
 118 int rtc_read_datetime(struct tm *tm)
 119 {
 120     int rc;
 121     unsigned char buf[7];
 122
 123     rc = sw_i2c_read(RTC_ADDR, 0, buf, sizeof(buf));
 124
 125     /* convert from bcd, avoid getting extra bits */
 126     tm->tm_sec  = BCD2DEC(buf[0] & 0x7f);
 127     tm->tm_min  = BCD2DEC(buf[1] & 0x7f);
 128     tm->tm_hour = BCD2DEC(buf[2] & 0x3f);
 129     tm->tm_wday = BCD2DEC(buf[3] & 0x7) - 1; /* timefuncs wants 0..6 for wday */
 130     tm->tm_mday = BCD2DEC(buf[4] & 0x3f);
 131     tm->tm_mon  = BCD2DEC(buf[5] & 0x1f) - 1;
 132     tm->tm_year = BCD2DEC(buf[6]) + 100;
 133
 134     return rc;
 135 }
 136
 137 int rtc_write_datetime(const struct tm *tm)
 138 {
 139     unsigned int i;
 140     int rc;
 141     unsigned char buf[7];
 142
 143     buf[0] = tm->tm_sec;
 144     buf[1] = tm->tm_min;
 145     buf[2] = tm->tm_hour;
 146     buf[3] = tm->tm_wday + 1; /* chip wants 1..7 for wday */
 147     buf[4] = tm->tm_mday;
 148     buf[5] = tm->tm_mon + 1;
 149     buf[6] = tm->tm_year - 100;
 150
 151     for (i = 0; i < sizeof(buf); i++)
 152         buf[i] = DEC2BCD(buf[i]);
 153
 154     buf[5] |= 0x80; /* chip wants century (always 20xx) */
 155
 156     rc = sw_i2c_write(RTC_ADDR, 0, buf, sizeof(buf));
 157
 158     return rc;
 159 }
 160