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  * All files in this archive are subject to the GNU General Public License.
  13  * See the file COPYING in the source tree root for full license agreement.
  14  *
  15  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  16  * KIND, either express or implied.
  17  *
  18  ****************************************************************************/
  19 #include "config.h"
  20 #include "i2c.h"
  21 #include "rtc.h"
  22 #include "kernel.h"
  23 #include "system.h"
  24 #include "pcf50605.h"
  25 #include <stdbool.h>
  26
  27 /* Values which each disable one alarm time register */
  28 static const char alarm_disable[] = {
  29     0x7f, 0x7f, 0x3f, 0x07, 0x3f, 0x1f, 0xff
  30 };
  31
  32 void rtc_init(void)
  33 {
  34     rtc_check_alarm_started(false);
  35 }
  36
  37 int rtc_read_datetime(unsigned char* buf)
  38 {
  39     return pcf50605_read_multiple(0x0a, buf, 7);
  40 }
  41
  42 int rtc_write_datetime(unsigned char* buf)
  43 {
  44     pcf50605_write_multiple(0x0a, buf, 7);
  45     return 1;
  46 }
  47
  48 /**
  49  * Checks the PCF interrupt 1 register bit 7 to see if an alarm interrupt has
  50  * triggered since last we checked.
  51  */
  52 bool rtc_check_alarm_flag(void)
  53 {
  54     return pcf50605_read(0x02) & 0x80;
  55 }
  56
  57 /**
  58  * Enables or disables the alarm.
  59  * The Ipod bootloader clears all PCF interrupt registers and always enables
  60  * the "wake on RTC" bit on OOCC1, so we have to rely on other means to find
  61  * out if we just woke from an alarm.
  62  * Return value is always false for us.
  63  */
  64 bool rtc_enable_alarm(bool enable)
  65 {
  66     if (enable) {
  67         /* Tell the PCF to ignore everything but second, minute and hour, so
  68          * that an alarm will trigger the next time the alarm time occurs.
  69          */
  70         pcf50605_write_multiple(0x14, alarm_disable + 3, 4);
  71         /* Unmask the alarm interrupt (might be unneeded) */
  72         pcf50605_write(0x5, pcf50605_read(0x5) & ~0x80);
  73         /* Make sure wake on RTC is set when shutting down */
  74         pcf50605_wakeup_flags |= 0x10;
  75     } else {
  76         /* We use this year to indicate a disabled alarm. If you happen to live
  77          * around this time and are annoyed by this, feel free to seek out my
  78          * grave and do something nasty to it.
  79          */
  80         pcf50605_write(0x17, 0x99);
  81         /* Make sure we don't wake on RTC after shutting down */
  82         pcf50605_wakeup_flags &= ~0x10;
  83     }
  84     return false;
  85 }
  86
  87 /**
  88  * Check if alarm caused unit to start.
  89  */
  90 bool rtc_check_alarm_started(bool release_alarm)
  91 {
  92     static bool run_before = false, alarm_state;
  93     bool rc;
  94
  95     if (run_before) {
  96         rc = alarm_state;
  97         alarm_state &= ~release_alarm;
  98     } else {
  99         char rt[3], at[3];
 100         /* The Ipod bootloader seems to read (and thus clear) the PCF interrupt
 101          * registers, so we need to find some other way to detect if an alarm
 102          * just happened
 103          */
 104         pcf50605_read_multiple(0x0a, rt, 3);
 105         pcf50605_read_multiple(0x11, at, 3);
 106
 107         /* If alarm time and real time match within 10 seconds of each other, we
 108          * assume an alarm just triggered
 109          */
 110         rc = alarm_state = rt[1] == at[1] && rt[2] == at[2]
 111                            && (rt[0] - at[0]) <= 10;
 112         run_before = true;
 113     }
 114     return rc;
 115 }
 116
 117 void rtc_set_alarm(int h, int m)
 118 {
 119     /* Set us to wake at the first second of the specified time */
 120     pcf50605_write(0x11, 0);
 121     /* Convert to BCD */
 122     pcf50605_write(0x12, ((m/10) << 4) | m%10);
 123     pcf50605_write(0x13, ((h/10) << 4) | h%10);
 124 }
 125
 126 void rtc_get_alarm(int *h, int *m)
 127 {
 128     char buf[2];
 129
 130     pcf50605_read_multiple(0x12, buf, 2);
 131     /* Convert from BCD */
 132     *m = ((buf[0] >> 4) & 0x7)*10 + (buf[0] & 0x0f);
 133     *h = ((buf[1] >> 4) & 0x3)*10 + (buf[1] & 0x0f);
 134 }
 135