firmware/drivers/rtc/rtc_pcf50605.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2002 by Linus Nielsen Feltzing, Uwe Freese, Laurent Baum
  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 #include "config.h"
  22 #include "i2c.h"
  23 #include "rtc.h"
  24 #include "kernel.h"
  25 #include "system.h"
  26 #include "pcf50605.h"
  27 #include <stdbool.h>
  28
  29 /* Values which each disable one alarm time register */
  30 static const char alarm_disable[] = {
  31     0x7f, 0x7f, 0x3f, 0x07, 0x3f, 0x1f, 0xff
  32 };
  33
  34 void rtc_init(void)
  35 {
  36     rtc_check_alarm_started(false);
  37 }
  38
  39 int rtc_read_datetime(struct tm *tm)
  40 {
  41     unsigned int i;
  42     int rc;
  43     unsigned char buf[7];
  44     rc = pcf50605_read_multiple(0x0a, buf, sizeof(buf));
  45
  46     for (i = 0; i < sizeof(buf); i++)
  47         buf[i] = BCD2DEC(buf[i]);
  48
  49     tm->tm_sec  = buf[0];
  50     tm->tm_min  = buf[1];
  51     tm->tm_hour = buf[2];
  52     tm->tm_wday = buf[3];
  53     tm->tm_mday = buf[4];
  54     tm->tm_mon  = buf[5] - 1;
  55     tm->tm_year = buf[6] + 100;
  56
  57     return rc;
  58 }
  59
  60 int rtc_write_datetime(const struct tm *tm)
  61 {
  62     unsigned int i;
  63     unsigned char buf[7];
  64
  65     buf[0] = tm->tm_sec;
  66     buf[1] = tm->tm_min;
  67     buf[2] = tm->tm_hour;
  68     buf[3] = tm->tm_wday;
  69     buf[4] = tm->tm_mday;
  70     buf[5] = tm->tm_mon + 1;
  71     buf[6] = tm->tm_year - 100;
  72
  73     for (i = 0; i < sizeof(buf); i++)
  74         buf[i] = DEC2BCD(buf[i]);
  75
  76     pcf50605_write_multiple(0x0a, buf, sizeof(buf));
  77
  78     return 1;
  79 }
  80
  81 /**
  82  * Checks the PCF interrupt 1 register bit 7 to see if an alarm interrupt has
  83  * triggered since last we checked.
  84  */
  85 bool rtc_check_alarm_flag(void)
  86 {
  87     return pcf50605_read(0x02) & 0x80;
  88 }
  89
  90 /**
  91  * Enables or disables the alarm.
  92  * The Ipod bootloader clears all PCF interrupt registers and always enables
  93  * the "wake on RTC" bit on OOCC1, so we have to rely on other means to find
  94  * out if we just woke from an alarm.
  95  * Return value is always false for us.
  96  */
  97 bool rtc_enable_alarm(bool enable)
  98 {
  99     if (enable) {
 100         /* Tell the PCF to ignore everything but second, minute and hour, so
 101          * that an alarm will trigger the next time the alarm time occurs.
 102          */
 103         pcf50605_write_multiple(0x14, alarm_disable + 3, 4);
 104         /* Unmask the alarm interrupt (might be unneeded) */
 105         pcf50605_write(0x5, pcf50605_read(0x5) & ~0x80);
 106         /* Make sure wake on RTC is set when shutting down */
 107         pcf50605_wakeup_flags |= 0x10;
 108     } else {
 109         /* We use this year to indicate a disabled alarm. If you happen to live
 110          * around this time and are annoyed by this, feel free to seek out my
 111          * grave and do something nasty to it.
 112          */
 113         pcf50605_write(0x17, 0x99);
 114         /* Make sure we don't wake on RTC after shutting down */
 115         pcf50605_wakeup_flags &= ~0x10;
 116     }
 117     return false;
 118 }
 119
 120 /**
 121  * Check if alarm caused unit to start.
 122  */
 123 bool rtc_check_alarm_started(bool release_alarm)
 124 {
 125     static bool run_before = false, alarm_state;
 126     bool rc;
 127
 128     if (run_before) {
 129         rc = alarm_state;
 130         alarm_state &= ~release_alarm;
 131     } else {
 132         char rt[3], at[3];
 133         /* The Ipod bootloader seems to read (and thus clear) the PCF interrupt
 134          * registers, so we need to find some other way to detect if an alarm
 135          * just happened
 136          */
 137         pcf50605_read_multiple(0x0a, rt, 3);
 138         pcf50605_read_multiple(0x11, at, 3);
 139
 140         /* If alarm time and real time match within 10 seconds of each other, we
 141          * assume an alarm just triggered
 142          */
 143         rc = alarm_state = rt[1] == at[1] && rt[2] == at[2]
 144                            && (rt[0] - at[0]) <= 10;
 145         run_before = true;
 146     }
 147     return rc;
 148 }
 149
 150 void rtc_set_alarm(int h, int m)
 151 {
 152     /* Set us to wake at the first second of the specified time */
 153     pcf50605_write(0x11, 0);
 154     /* Convert to BCD */
 155     pcf50605_write(0x12, DEC2BCD(m));
 156     pcf50605_write(0x13, DEC2BCD(h));
 157 }
 158
 159 void rtc_get_alarm(int *h, int *m)
 160 {
 161     char buf[2];
 162
 163     pcf50605_read_multiple(0x12, buf, sizeof(buf));
 164     /* Convert from BCD */
 165     *m = BCD2DEC(buf[0]);
 166     *h = BCD2DEC(buf[1]);
 167 }
 168