firmware/drivers/rtc/rtc_m41st84w.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 <stdbool.h>
  27
  28 #define RTC_ADR 0xd0
  29 #define RTC_DEV_WRITE   (RTC_ADR | 0x00)
  30 #define RTC_DEV_READ    (RTC_ADR | 0x01)
  31
  32 void rtc_init(void)
  33 {
  34     unsigned char data;
  35
  36 #ifdef HAVE_RTC_ALARM
  37     /* Check + save alarm bit first, before the power thread starts watching */
  38     rtc_check_alarm_started(false);
  39 #endif
  40
  41     /* Clear the Stop bit if it is set */
  42     data = rtc_read(0x01);
  43     if(data & 0x80)
  44         rtc_write(0x01, 0x00);
  45
  46     /* Clear the HT bit if it is set */
  47     data = rtc_read(0x0c);
  48
  49     if(data & 0x40)
  50     {
  51         data &= ~0x40;
  52         rtc_write(0x0c,data);
  53     }
  54
  55 #ifdef HAVE_RTC_ALARM
  56
  57     /* Clear Trec bit, write-protecting the RTC for 200ms when shutting off */
  58     /* without this, the alarm won't work! */
  59
  60     data = rtc_read(0x04);
  61     if (data & 0x80)
  62     {
  63         data &= ~0x80;
  64         rtc_write(0x04, data);
  65     }
  66
  67     /* Also, make sure that the OUT bit in register 8 is 1,
  68        otherwise the player can't be turned off. */
  69     rtc_write(8, rtc_read(8) | 0x80);
  70
  71 #endif
  72 }
  73
  74 #ifdef HAVE_RTC_ALARM
  75
  76 /* check whether the unit has been started by the RTC alarm function */
  77 /* (check for AF, which => started using wakeup alarm) */
  78 bool rtc_check_alarm_started(bool release_alarm)
  79 {
  80     static bool alarm_state, run_before;
  81     bool rc;
  82
  83     if (run_before) {
  84         rc = alarm_state;
  85         alarm_state &= ~release_alarm;
  86     } else {
  87         /* This call resets AF, so we store the state for later recall */
  88         rc = alarm_state = rtc_check_alarm_flag();
  89         run_before = true;
  90     }
  91
  92     return rc;
  93 }
  94 /*
  95  * Checks the AL register.  This call resets AL once read.
  96  *
  97  * We're only interested if ABE is set.  AL is still raised regardless
  98  * even if the unit is off when the alarm occurs.
  99  */
 100 bool rtc_check_alarm_flag(void)
 101 {
 102     return ( ( (rtc_read(0x0f) & 0x40) != 0) &&
 103                (rtc_read(0x0a) & 0x20)  );
 104 }
 105
 106 /* set alarm time registers to the given time (repeat once per day) */
 107 void rtc_set_alarm(int h, int m)
 108 {
 109     unsigned char data;
 110
 111     /* for daily alarm, RPT5=RPT4=on, RPT1=RPT2=RPT3=off */
 112
 113     rtc_write(0x0e, 0x00);      /* seconds 0 and RTP1 */
 114     rtc_write(0x0d, DEC2BCD(m)); /* minutes and RPT2 */
 115     rtc_write(0x0c, DEC2BCD(h)); /* hour and RPT3 */
 116     rtc_write(0x0b, 0xc1);      /* set date 01 and RPT4 and RTP5 */
 117
 118     /* set month to 1, if it's invalid, the rtc does an alarm every second instead */
 119     data = rtc_read(0x0a);
 120     data &= 0xe0;
 121     data |= 0x01;
 122     rtc_write(0x0a, data);
 123 }
 124
 125 /* read out the current alarm time */
 126 void rtc_get_alarm(int *h, int *m)
 127 {
 128     unsigned char data;
 129
 130     data = rtc_read(0x0c);
 131     *h = BCD2DEC(data & 0x3f);
 132
 133     data = rtc_read(0x0d);
 134     *m = BCD2DEC(data & 0x7f);
 135 }
 136
 137 /* turn alarm on or off by setting the alarm flag enable */
 138 /* the alarm is automatically disabled when the RTC gets Vcc power at startup */
 139 /* avoid that an alarm occurs when the device is on because this locks the ON key forever */
 140 /* returns false if alarm was set and alarm flag (output) is off */
 141 /* returns true if alarm flag went on, which would lock the device, so the alarm was disabled again */
 142 bool rtc_enable_alarm(bool enable)
 143 {
 144     unsigned char data = rtc_read(0x0a);
 145     if (enable)
 146     {
 147         data |= 0xa0; /* turn bit d7=AFE and d5=ABE on */
 148     }
 149     else
 150         data &= 0x5f; /* turn bit d7=AFE and d5=ABE off */
 151     rtc_write(0x0a, data);
 152
 153     /* check if alarm flag AF is off (as it should be) */
 154     /* in some cases enabling the alarm results in an activated AF flag */
 155     /* this should not happen, but it does */
 156     /* if you know why, tell me! */
 157     /* for now, we try again forever in this case */
 158     while (rtc_check_alarm_flag()) /* on */
 159     {
 160         data &= 0x5f; /* turn bit d7=AFE and d5=ABE off */
 161         rtc_write(0x0a, data);
 162         sleep(HZ / 10);
 163         rtc_check_alarm_flag();
 164         data |= 0xa0; /* turn bit d7=AFE and d5=ABE on */
 165         rtc_write(0x0a, data);
 166     }
 167
 168     return false; /* all ok */
 169 }
 170
 171 #endif /* HAVE_RTC_ALARM */
 172
 173 int rtc_write(unsigned char address, unsigned char value)
 174 {
 175     int ret = 0;
 176     unsigned char buf[2];
 177
 178     i2c_begin();
 179
 180     buf[0] = address;
 181     buf[1] = value;
 182
 183     /* send run command */
 184     if (i2c_write(RTC_DEV_WRITE,buf,2))
 185     {
 186         ret = -1;
 187     }
 188
 189     i2c_end();
 190     return ret;
 191 }
 192
 193 int rtc_read(unsigned char address)
 194 {
 195     int value = -1;
 196     unsigned char buf[1];
 197
 198     i2c_begin();
 199
 200     buf[0] = address;
 201
 202     /* send read command */
 203     if (i2c_write(RTC_DEV_READ,buf,1) >= 0)
 204     {
 205         i2c_start();
 206         i2c_outb(RTC_DEV_READ);
 207         if (i2c_getack())
 208         {
 209             value = i2c_inb(1);
 210         }
 211     }
 212
 213     i2c_stop();
 214
 215     i2c_end();
 216     return value;
 217 }
 218
 219 int rtc_read_multiple(unsigned char address, unsigned char *buf, int numbytes)
 220 {
 221     int ret = 0;
 222     unsigned char obuf[1];
 223     int i;
 224
 225     i2c_begin();
 226
 227     obuf[0] = address;
 228
 229     /* send read command */
 230     if (i2c_write(RTC_DEV_READ, obuf, 1) >= 0)
 231     {
 232         i2c_start();
 233         i2c_outb(RTC_DEV_READ);
 234         if (i2c_getack())
 235         {
 236             for(i = 0;i < numbytes-1;i++)
 237                 buf[i] = i2c_inb(0);
 238
 239             buf[i] = i2c_inb(1);
 240         }
 241         else
 242         {
 243             ret = -1;
 244         }
 245     }
 246
 247     i2c_stop();
 248
 249     i2c_end();
 250     return ret;
 251 }
 252
 253 int rtc_read_datetime(struct tm *tm)
 254 {
 255     int rc;
 256     unsigned char buf[7];
 257
 258     rc = rtc_read_multiple(1, buf, sizeof(buf));
 259
 260     /* convert from bcd, avoid getting extra bits */
 261     tm->tm_sec  = BCD2DEC(buf[0] & 0x7f);
 262     tm->tm_min  = BCD2DEC(buf[1] & 0x7f);
 263     tm->tm_hour = BCD2DEC(buf[2] & 0x3f);
 264     tm->tm_wday = BCD2DEC(buf[3] & 0x3);
 265     tm->tm_mday = BCD2DEC(buf[4] & 0x3f);
 266     tm->tm_mon  = BCD2DEC(buf[5] & 0x1f) - 1;
 267     tm->tm_year = BCD2DEC(buf[6]) + 100;
 268
 269     /* Adjust weekday */
 270     if (tm->tm_wday == 7)
 271         tm->tm_wday = 0;
 272
 273     return rc;
 274 }
 275
 276 int rtc_write_datetime(const struct tm *tm)
 277 {
 278     unsigned int i;
 279     int rc = 0;
 280     unsigned char buf[7];
 281
 282     buf[0] = tm->tm_sec;
 283     buf[1] = tm->tm_min;
 284     buf[2] = tm->tm_hour;
 285     buf[3] = tm->tm_wday;
 286     buf[4] = tm->tm_mday;
 287     buf[5] = tm->tm_mon + 1;
 288     buf[6] = tm->tm_year - 100;
 289
 290     /* Adjust weekday */
 291     if (buf[3] == 0)
 292         buf[3] = 7;
 293
 294     for (i = 0; i < sizeof(buf) ;i++)
 295     {
 296         rc |= rtc_write(i + 1, DEC2BCD(buf[i]));
 297     }
 298     rc |= rtc_write(8, 0x80); /* Out=1, calibration = 0 */
 299
 300     return rc;
 301 }
 302