firmware/drivers/rtc/rtc_as3514.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2007 by Barry Wardell
  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 <stdbool.h>
  22 #include "config.h"
  23 #include "rtc.h"
  24 #include "as3514.h"
  25 #include "ascodec.h"
  26
  27 /* AMS Sansas start counting from Jan 1st 1970 instead of 1980 */
  28 #if (CONFIG_CPU==AS3525)
  29 #define SECS_ADJUST 315532800   /* seconds between 1970-1-1 and 1980-1-1 */
  30 #else
  31 #define SECS_ADJUST 0
  32 #endif
  33
  34 #define MINUTE_SECONDS      60
  35 #define HOUR_SECONDS        3600
  36 #define DAY_SECONDS         86400
  37 #define WEEK_SECONDS        604800
  38 #define YEAR_SECONDS        31536000
  39 #define LEAP_YEAR_SECONDS   31622400
  40
  41 #define BCD2DEC(X)          (((((X)>>4) & 0x0f) * 10) + ((X) & 0xf))
  42 #define DEC2BCD(X)          ((((X)/10)<<4) | ((X)%10))
  43
  44 /* Days in each month */
  45 static unsigned int days_in_month[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  46
  47 static inline bool is_leapyear(int year)
  48 {
  49     if( ((year%4)==0) && (((year%100)!=0) || ((year%400)==0)) )
  50         return true;
  51     else
  52         return false;
  53 }
  54
  55 void rtc_init(void)
  56 {
  57 }
  58
  59 int rtc_read_datetime(unsigned char* buf)
  60 {
  61     char tmp[4];
  62     int year;
  63     int i;
  64     unsigned int seconds;
  65
  66     /* RTC_AS3514's slave address is 0x46*/
  67     for (i=0;i<4;i++){
  68         tmp[i] = ascodec_read(AS3514_RTC_0 + i);
  69     }
  70     seconds = tmp[0] + (tmp[1]<<8) + (tmp[2]<<16) + (tmp[3]<<24);
  71     seconds -= SECS_ADJUST;
  72
  73     /* Convert seconds since Jan-1-1980 to format compatible with
  74      * get_time() from firmware/common/timefuncs.c */
  75
  76     /* weekday */
  77     buf[3] = ((seconds % WEEK_SECONDS) / DAY_SECONDS + 2) % 7;
  78
  79     /* Year */
  80     year = 1980;
  81     while(seconds>=LEAP_YEAR_SECONDS)
  82     {
  83         if(is_leapyear(year)){
  84             seconds -= LEAP_YEAR_SECONDS;
  85         } else {
  86             seconds -= YEAR_SECONDS;
  87         }
  88
  89         year++;
  90     }
  91
  92     if(is_leapyear(year)) {
  93         days_in_month[1] = 29;
  94     } else {
  95         days_in_month[1] = 28;
  96         if(seconds>YEAR_SECONDS){
  97             year++;
  98             seconds -= YEAR_SECONDS;
  99         }
 100     }
 101     buf[6] = year%100;
 102
 103     /* Month */
 104     for(i=0; i<12; i++)
 105     {
 106         if(seconds < days_in_month[i]*DAY_SECONDS){
 107             buf[5] = i+1;
 108             break;
 109         }
 110
 111         seconds -= days_in_month[i]*DAY_SECONDS;
 112     }
 113
 114     /* Month Day */
 115     buf[4] = seconds/DAY_SECONDS;
 116     seconds -= buf[4]*DAY_SECONDS;
 117     buf[4]++; /* 1 ... 31 */
 118
 119     /* Hour */
 120     buf[2] = seconds/HOUR_SECONDS;
 121     seconds -= buf[2]*HOUR_SECONDS;
 122
 123     /* Minute */
 124     buf[1] = seconds/MINUTE_SECONDS;
 125     seconds -= buf[1]*MINUTE_SECONDS;
 126
 127     /* Second */
 128     buf[0] = seconds;
 129
 130     /* Convert to Binary Coded Decimal format */
 131     for(i=0; i<7; i++)
 132         buf[i] = DEC2BCD(buf[i]);
 133
 134     return 7;
 135 }
 136
 137 int rtc_write_datetime(unsigned char* buf)
 138 {
 139     int i, year;
 140     unsigned int year_days = 0;
 141     unsigned int month_days = 0;
 142     unsigned int seconds = 0;
 143
 144     /* Convert from Binary Coded Decimal format */
 145     for(i=0; i<7; i++)
 146         buf[i] = BCD2DEC(buf[i]);
 147
 148     year = 2000 + buf[6];
 149
 150     if(is_leapyear(year)) {
 151         days_in_month[1] = 29;
 152     } else {
 153         days_in_month[1] = 28;
 154     }
 155
 156     /* Number of days in months gone by this year*/
 157     for(i=0; i<(buf[5]-1); i++){
 158         month_days += days_in_month[i];
 159     }
 160
 161     /* Number of days in years gone by since 1-Jan-1980 */
 162     year_days = 365*(buf[6]+20) + (buf[6]-1)/4 + 6;
 163
 164     /* Convert to seconds since 1-Jan-1980 */
 165     seconds = buf[0]
 166             + buf[1]*MINUTE_SECONDS
 167             + buf[2]*HOUR_SECONDS
 168             + (buf[4]-1)*DAY_SECONDS
 169             + month_days*DAY_SECONDS
 170             + year_days*DAY_SECONDS;
 171     seconds += SECS_ADJUST;
 172
 173     /* Send data to RTC */
 174     for (i=0;i<4;i++){
 175         ascodec_write(AS3514_RTC_0 + i, ((seconds >> (8 * i)) & 0xff));
 176     }
 177     return 1;
 178 }
 179