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 /* Days in each month */
  42 static unsigned int days_in_month[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  43
  44 static inline bool is_leapyear(int year)
  45 {
  46     if( ((year%4)==0) && (((year%100)!=0) || ((year%400)==0)) )
  47         return true;
  48     else
  49         return false;
  50 }
  51
  52 void rtc_init(void)
  53 {
  54 }
  55
  56 int rtc_read_datetime(struct tm *tm)
  57 {
  58     char tmp[4];
  59     int i, year, mday, hour, min;
  60     unsigned int seconds;
  61
  62     /* RTC_AS3514's slave address is 0x46*/
  63     for (i = 0; i < 4; i++){
  64         tmp[i] = ascodec_read(AS3514_RTC_0 + i);
  65     }
  66     seconds = tmp[0] + (tmp[1]<<8) + (tmp[2]<<16) + (tmp[3]<<24);
  67     seconds -= SECS_ADJUST;
  68
  69     /* Convert seconds since Jan-1-1980 to format compatible with
  70      * get_time() from firmware/common/timefuncs.c */
  71
  72     /* weekday */
  73     tm->tm_wday = ((seconds % WEEK_SECONDS) / DAY_SECONDS + 2) % 7;
  74
  75     /* Year */
  76     year = 1980;
  77     while (seconds >= LEAP_YEAR_SECONDS)
  78     {
  79         if (is_leapyear(year)){
  80             seconds -= LEAP_YEAR_SECONDS;
  81         } else {
  82             seconds -= YEAR_SECONDS;
  83         }
  84
  85         year++;
  86     }
  87
  88     if (is_leapyear(year)) {
  89         days_in_month[1] = 29;
  90     } else {
  91         days_in_month[1] = 28;
  92         if(seconds>YEAR_SECONDS){
  93             year++;
  94             seconds -= YEAR_SECONDS;
  95         }
  96     }
  97     tm->tm_year = year%100 + 100;
  98
  99     /* Month */
 100     for (i = 0; i < 12; i++)
 101     {
 102         if (seconds < days_in_month[i]*DAY_SECONDS){
 103             tm->tm_mon = i;
 104             break;
 105         }
 106
 107         seconds -= days_in_month[i]*DAY_SECONDS;
 108     }
 109
 110     /* Month Day */
 111     mday = seconds/DAY_SECONDS;
 112     seconds -= mday*DAY_SECONDS;
 113     tm->tm_mday = mday + 1; /* 1 ... 31 */
 114
 115     /* Hour */
 116     hour = seconds/HOUR_SECONDS;
 117     seconds -= hour*HOUR_SECONDS;
 118     tm->tm_hour = hour;
 119
 120     /* Minute */
 121     min = seconds/MINUTE_SECONDS;
 122     seconds -= min*MINUTE_SECONDS;
 123     tm->tm_min = min;
 124
 125     /* Second */
 126     tm->tm_sec = seconds;
 127
 128     return 7;
 129 }
 130
 131 int rtc_write_datetime(const struct tm *tm)
 132 {
 133     int i, year;
 134     unsigned int year_days = 0;
 135     unsigned int month_days = 0;
 136     unsigned int seconds = 0;
 137
 138     year = 2000 + tm->tm_year - 100;
 139
 140     if(is_leapyear(year)) {
 141         days_in_month[1] = 29;
 142     } else {
 143         days_in_month[1] = 28;
 144     }
 145
 146     /* Number of days in months gone by this year*/
 147     for(i = 0; i < tm->tm_mon; i++){
 148         month_days += days_in_month[i];
 149     }
 150
 151     /* Number of days in years gone by since 1-Jan-1980 */
 152     year_days = 365*(tm->tm_year-100+20) + (tm->tm_year-100-1)/4 + 6;
 153
 154     /* Convert to seconds since 1-Jan-1980 */
 155     seconds = tm->tm_sec
 156             + tm->tm_min*MINUTE_SECONDS
 157             + tm->tm_hour*HOUR_SECONDS
 158             + (tm->tm_mday-1)*DAY_SECONDS
 159             + month_days*DAY_SECONDS
 160             + year_days*DAY_SECONDS;
 161     seconds += SECS_ADJUST;
 162
 163     /* Send data to RTC */
 164     for (i=0; i<4; i++){
 165         ascodec_write(AS3514_RTC_0 + i, ((seconds >> (8 * i)) & 0xff));
 166     }
 167     return 1;
 168 }
 169