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(unsigned char* buf)
  40 {
  41     return pcf50605_read_multiple(0x0a, buf, 7);
  42 }
  43
  44 int rtc_write_datetime(unsigned char* buf)
  45 {
  46     pcf50605_write_multiple(0x0a, buf, 7);
  47     return 1;
  48 }
  49
  50 /**
  51  * Checks the PCF interrupt 1 register bit 7 to see if an alarm interrupt has
  52  * triggered since last we checked.
  53  */
  54 bool rtc_check_alarm_flag(void)
  55 {
  56     return pcf50605_read(0x02) & 0x80;
  57 }
  58
  59 /**
  60  * Enables or disables the alarm.
  61  * The Ipod bootloader clears all PCF interrupt registers and always enables
  62  * the "wake on RTC" bit on OOCC1, so we have to rely on other means to find
  63  * out if we just woke from an alarm.
  64  * Return value is always false for us.
  65  */
  66 bool rtc_enable_alarm(bool enable)
  67 {
  68     if (enable) {
  69         /* Tell the PCF to ignore everything but second, minute and hour, so
  70          * that an alarm will trigger the next time the alarm time occurs.
  71          */
  72         pcf50605_write_multiple(0x14, alarm_disable + 3, 4);
  73         /* Unmask the alarm interrupt (might be unneeded) */
  74         pcf50605_write(0x5, pcf50605_read(0x5) & ~0x80);
  75         /* Make sure wake on RTC is set when shutting down */
  76         pcf50605_wakeup_flags |= 0x10;
  77     } else {
  78         /* We use this year to indicate a disabled alarm. If you happen to live
  79          * around this time and are annoyed by this, feel free to seek out my
  80          * grave and do something nasty to it.
  81          */
  82         pcf50605_write(0x17, 0x99);
  83         /* Make sure we don't wake on RTC after shutting down */
  84         pcf50605_wakeup_flags &= ~0x10;
  85     }
  86     return false;
  87 }
  88
  89 /**
  90  * Check if alarm caused unit to start.
  91  */
  92 bool rtc_check_alarm_started(bool release_alarm)
  93 {
  94     static bool run_before = false, alarm_state;
  95     bool rc;
  96
  97     if (run_before) {
  98         rc = alarm_state;
  99         alarm_state &= ~release_alarm;
 100     } else {
 101         char rt[3], at[3];
 102         /* The Ipod bootloader seems to read (and thus clear) the PCF interrupt
 103          * registers, so we need to find some other way to detect if an alarm
 104          * just happened
 105          */
 106         pcf50605_read_multiple(0x0a, rt, 3);
 107         pcf50605_read_multiple(0x11, at, 3);
 108
 109         /* If alarm time and real time match within 10 seconds of each other, we
 110          * assume an alarm just triggered
 111          */
 112         rc = alarm_state = rt[1] == at[1] && rt[2] == at[2]
 113                            && (rt[0] - at[0]) <= 10;
 114         run_before = true;
 115     }
 116     return rc;
 117 }
 118
 119 void rtc_set_alarm(int h, int m)
 120 {
 121     /* Set us to wake at the first second of the specified time */
 122     pcf50605_write(0x11, 0);
 123     /* Convert to BCD */
 124     pcf50605_write(0x12, ((m/10) << 4) | m%10);
 125     pcf50605_write(0x13, ((h/10) << 4) | h%10);
 126 }
 127
 128 void rtc_get_alarm(int *h, int *m)
 129 {
 130     char buf[2];
 131
 132     pcf50605_read_multiple(0x12, buf, 2);
 133     /* Convert from BCD */
 134     *m = ((buf[0] >> 4) & 0x7)*10 + (buf[0] & 0x0f);
 135     *h = ((buf[1] >> 4) & 0x3)*10 + (buf[1] & 0x0f);
 136 }
 137