firmware/drivers/rtc/rtc_as3514.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id: rtc_as3514.c 12131 2007-01-27 20:48:48Z dan_a $
   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 "rtc.h"
  23 #include "i2c-pp.h"
  24 #include "as3514.h"
  25 #include "ascodec.h"
  26
  27 #define MINUTE_SECONDS      60
  28 #define HOUR_SECONDS        3600
  29 #define DAY_SECONDS         86400
  30 #define WEEK_SECONDS        604800
  31 #define YEAR_SECONDS        31536000
  32 #define LEAP_YEAR_SECONDS   31622400
  33
  34 #define BCD2DEC(X)          (((((X)>>4) & 0x0f) * 10) + ((X) & 0xf))
  35 #define DEC2BCD(X)          ((((X)/10)<<4) | ((X)%10))
  36
  37 /* Days in each month */
  38 static unsigned int days_in_month[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  39
  40 static inline bool is_leapyear(int year)
  41 {
  42     if( ((year%4)==0) && (((year%100)!=0) || ((year%400)==0)) )
  43         return true;
  44     else
  45         return false;
  46 }
  47
  48 void rtc_init(void)
  49 {
  50 }
  51
  52 int rtc_read_datetime(unsigned char* buf)
  53 {
  54     char tmp[4];
  55     int year;
  56     int i;
  57     unsigned int seconds;
  58
  59     /* RTC_AS3514's slave address is 0x46*/
  60     for (i=0;i<4;i++){
  61         tmp[i] = ascodec_read(AS3514_RTC_0 + i);
  62     }
  63     seconds = tmp[0] + (tmp[1]<<8) + (tmp[2]<<16) + (tmp[3]<<24);
  64
  65     /* Convert seconds since Jan-1-1980 to format compatible with
  66      * get_time() from firmware/common/timefuncs.c */
  67
  68     /* weekday */
  69     buf[3] = ((seconds % WEEK_SECONDS) / DAY_SECONDS + 2) % 7;
  70
  71     /* Year */
  72     year = 1980;
  73     while(seconds>=LEAP_YEAR_SECONDS)
  74     {
  75         if(is_leapyear(year)){
  76             seconds -= LEAP_YEAR_SECONDS;
  77         } else {
  78             seconds -= YEAR_SECONDS;
  79         }
  80
  81         year++;
  82     }
  83
  84     if(is_leapyear(year)) {
  85         days_in_month[1] = 29;
  86     } else {
  87         days_in_month[1] = 28;
  88         if(seconds>YEAR_SECONDS){
  89             year++;
  90             seconds -= YEAR_SECONDS;
  91         }
  92     }
  93     buf[6] = year%100;
  94
  95     /* Month */
  96     for(i=0; i<12; i++)
  97     {
  98         if(seconds < days_in_month[i]*DAY_SECONDS){
  99             buf[5] = i+1;
 100             break;
 101         }
 102
 103         seconds -= days_in_month[i]*DAY_SECONDS;
 104     }
 105
 106     /* Month Day */
 107     buf[4] = seconds/DAY_SECONDS;
 108     seconds -= buf[4]*DAY_SECONDS;
 109     buf[4]++; /* 1 ... 31 */
 110
 111     /* Hour */
 112     buf[2] = seconds/HOUR_SECONDS;
 113     seconds -= buf[2]*HOUR_SECONDS;
 114
 115     /* Minute */
 116     buf[1] = seconds/MINUTE_SECONDS;
 117     seconds -= buf[1]*MINUTE_SECONDS;
 118
 119     /* Second */
 120     buf[0] = seconds;
 121
 122     /* Convert to Binary Coded Decimal format */
 123     for(i=0; i<7; i++)
 124         buf[i] = DEC2BCD(buf[i]);
 125
 126     return 7;
 127 }
 128
 129 int rtc_write_datetime(unsigned char* buf)
 130 {
 131     int i, year;
 132     unsigned int year_days = 0;
 133     unsigned int month_days = 0;
 134     unsigned int seconds = 0;
 135
 136     /* Convert from Binary Coded Decimal format */
 137     for(i=0; i<7; i++)
 138         buf[i] = BCD2DEC(buf[i]);
 139
 140     year = 2000 + buf[6];
 141
 142     if(is_leapyear(year)) {
 143         days_in_month[1] = 29;
 144     } else {
 145         days_in_month[1] = 28;
 146     }
 147
 148     /* Number of days in months gone by this year*/
 149     for(i=0; i<(buf[5]-1); i++){
 150         month_days += days_in_month[i];
 151     }
 152
 153     /* Number of days in years gone by since 1-Jan-1980 */
 154     year_days = 365*(buf[6]+20) + (buf[6]-1)/4 + 6;
 155
 156     /* Convert to seconds since 1-Jan-1980 */
 157     seconds = buf[0]
 158             + buf[1]*MINUTE_SECONDS
 159             + buf[2]*HOUR_SECONDS
 160             + (buf[4]-1)*DAY_SECONDS
 161             + month_days*DAY_SECONDS
 162             + year_days*DAY_SECONDS;
 163
 164     /* Send data to RTC */
 165     for (i=0;i<4;i++){
 166         ascodec_write(AS3514_RTC_0 + i, ((seconds >> (8 * i)) & 0xff));
 167     }
 168     return 1;
 169 }
 170