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  * 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 <stdbool.h>
  20 #include "rtc.h"
  21 #include "i2c-pp.h"
  22 #include "as3514.h"
  23
  24 #define MINUTE_SECONDS      60
  25 #define HOUR_SECONDS        3600
  26 #define DAY_SECONDS         86400
  27 #define WEEK_SECONDS        604800
  28 #define YEAR_SECONDS        31536000
  29 #define LEAP_YEAR_SECONDS   31622400
  30
  31 #define BCD2DEC(X)          (((((X)>>4) & 0x0f) * 10) + ((X) & 0xf))
  32 #define DEC2BCD(X)          ((((X)/10)<<4) | ((X)%10))
  33
  34 /* Days in each month */
  35 static unsigned int days_in_month[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  36
  37 static inline bool is_leapyear(int year)
  38 {
  39     if( ((year%4)==0) && (((year%100)!=0) || ((year%400)==0)) )
  40         return true;
  41     else
  42         return false;
  43 }
  44
  45 void rtc_init(void)
  46 {
  47 }
  48
  49 int rtc_read_datetime(unsigned char* buf)
  50 {
  51     char tmp[4];
  52     int year;
  53     int i;
  54     unsigned int seconds;
  55
  56     /* RTC_AS3514's slave address is 0x46*/
  57     for (i=0;i<4;i++){
  58         tmp[i] = i2c_readbyte(AS3514_I2C_ADDR, RTC_0 + i);
  59     }
  60     seconds = tmp[0] + (tmp[1]<<8) + (tmp[2]<<16) + (tmp[3]<<24);
  61
  62     /* Convert seconds since Jan-1-1980 to format compatible with
  63      * get_time() from firmware/common/timefuncs.c */
  64
  65     /* weekday */
  66     buf[3] = ((seconds % WEEK_SECONDS) / DAY_SECONDS + 2) % 7;
  67
  68     /* Year */
  69     year = 1980;
  70     while(seconds>=LEAP_YEAR_SECONDS)
  71     {
  72         if(is_leapyear(year)){
  73             seconds -= LEAP_YEAR_SECONDS;
  74         } else {
  75             seconds -= YEAR_SECONDS;
  76         }
  77
  78         year++;
  79     }
  80
  81     if(is_leapyear(year)) {
  82         days_in_month[1] = 29;
  83     } else {
  84         days_in_month[1] = 28;
  85         if(seconds>YEAR_SECONDS){
  86             year++;
  87             seconds -= YEAR_SECONDS;
  88         }
  89     }
  90     buf[6] = year%100;
  91
  92     /* Month */
  93     for(i=0; i<12; i++)
  94     {
  95         if(seconds < days_in_month[i]*DAY_SECONDS){
  96             buf[5] = i+1;
  97             break;
  98         }
  99
 100         seconds -= days_in_month[i]*DAY_SECONDS;
 101     }
 102
 103     /* Month Day */
 104     buf[4] = seconds/DAY_SECONDS;
 105     seconds -= buf[4]*DAY_SECONDS;
 106     buf[4]++; /* 1 ... 31 */
 107
 108     /* Hour */
 109     buf[2] = seconds/HOUR_SECONDS;
 110     seconds -= buf[2]*HOUR_SECONDS;
 111
 112     /* Minute */
 113     buf[1] = seconds/MINUTE_SECONDS;
 114     seconds -= buf[1]*MINUTE_SECONDS;
 115
 116     /* Second */
 117     buf[0] = seconds;
 118
 119     /* Convert to Binary Coded Decimal format */
 120     for(i=0; i<7; i++)
 121         buf[i] = DEC2BCD(buf[i]);
 122
 123     return 7;
 124 }
 125
 126 int rtc_write_datetime(unsigned char* buf)
 127 {
 128     int i, year;
 129     unsigned int year_days = 0;
 130     unsigned int month_days = 0;
 131     unsigned int seconds = 0;
 132
 133     /* Convert from Binary Coded Decimal format */
 134     for(i=0; i<7; i++)
 135         buf[i] = BCD2DEC(buf[i]);
 136
 137     year = 2000 + buf[6];
 138
 139     if(is_leapyear(year)) {
 140         days_in_month[1] = 29;
 141     } else {
 142         days_in_month[1] = 28;
 143     }
 144
 145     /* Number of days in months gone by this year*/
 146     for(i=0; i<(buf[5]-1); i++){
 147         month_days += days_in_month[i];
 148     }
 149
 150     /* Number of days in years gone by since 1-Jan-1980 */
 151     year_days = 365*(buf[6]+20) + (buf[6]-1)/4 + 6;
 152
 153     /* Convert to seconds since 1-Jan-1980 */
 154     seconds = buf[0]
 155             + buf[1]*MINUTE_SECONDS
 156             + buf[2]*HOUR_SECONDS
 157             + (buf[4]-1)*DAY_SECONDS
 158             + month_days*DAY_SECONDS
 159             + year_days*DAY_SECONDS;
 160
 161     /* Send data to RTC */
 162     for (i=0;i<4;i++){
 163         pp_i2c_send(AS3514_I2C_ADDR, RTC_0 + i, ((seconds >> (8 * i)) & 0xff));
 164     }
 165     return 1;
 166 }
 167