avr/pcf8583.c

   1 /*
   2  * (C) Copyright 2014 Leo C. <erbl259-lmu@yahoo.de>
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 /*
   8  * Date & Time support for Philips PCF8583 RTC
   9  */
  10
  11 #include "common.h"
  12 #include <stdlib.h>
  13 #include "time.h"
  14 #include "rtc.h"
  15 #include "i2c.h"
  16 #include "command.h"
  17 #include "debug.h"
  18
  19 #define  DEBUG_RTC 0
  20
  21 #define debug_rtc(fmt, args...)                 \
  22         debug_cond(DEBUG_RTC, fmt, ##args)
  23
  24 #define REG_CS          0x00    /* control/status */
  25 #define REG_CSEC        0x01    /* hundredth of a second */
  26 #define REG_SEC         0x02    /* seconds */
  27 #define REG_MIN         0x03    /* minutes */
  28 #define REG_HOUR        0x04    /* hours */
  29 #define REG_YRDATE      0x05    /* year/date */
  30 #define REG_WDMON       0x06    /* weekdays/months */
  31 #define NR_OF_REGS      7
  32
  33
  34 /* ------------------------------------------------------------------------- */
  35
  36 static uint_fast8_t bcd2bin(uint8_t val)
  37 {
  38         return (val >> 4) * 10 + (val & 0x0f);
  39 }
  40
  41 static uint8_t bin2bcd (uint_fast8_t val)
  42 {
  43         div_t d = div(val, 10);
  44
  45         return (d.quot << 4) | d.rem;
  46 }
  47
  48
  49 int rtc_get (struct tm *tmp)
  50 {
  51         uint8_t rtcbuf[NR_OF_REGS];
  52         int16_t year;
  53
  54         i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, rtcbuf, NR_OF_REGS);
  55         i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0x10, 1, (uint8_t *) &year, 2);
  56
  57         debug_rtc("Get RTC year: %u, wdays/month: %02x, year/date: %02x, "
  58                 "hour: %02x, min: %02x, sec: %02x, (stat: %02x)\n", year,
  59                 rtcbuf[6], rtcbuf[5], rtcbuf[4], rtcbuf[3], rtcbuf[2], rtcbuf[0]);
  60
  61         tmp->tm_sec  = bcd2bin (rtcbuf[REG_SEC]    & 0x7F);
  62         tmp->tm_min  = bcd2bin (rtcbuf[REG_MIN]    & 0x7F);
  63         tmp->tm_hour = bcd2bin (rtcbuf[REG_HOUR]   & 0x3F);
  64         tmp->tm_mday = bcd2bin (rtcbuf[REG_YRDATE] & 0x3F);
  65         tmp->tm_mon  = bcd2bin (rtcbuf[REG_WDMON]  & 0x1F) - 1;
  66         while (year%4 != (rtcbuf[REG_YRDATE]>>6)) {
  67                 year++;
  68                 i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0x10, 1, (uint8_t *) &year, 2);
  69         }
  70         tmp->tm_year  = year - 1900;
  71         tmp->tm_wday = rtcbuf[REG_WDMON] >> 5;
  72         tmp->tm_yday = 0;
  73         tmp->tm_isdst= 0;
  74
  75         debug_rtc( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
  76                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
  77                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
  78
  79         return rtcbuf[REG_CS] == 0x04 ? 0 : 1;
  80 }
  81
  82 int rtc_set (struct tm *tmp)
  83 {
  84         uint8_t rtcbuf[NR_OF_REGS];
  85         int16_t year = tmp->tm_year + 1900;
  86
  87         debug_rtc("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
  88                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
  89                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
  90
  91         rtcbuf[REG_CS] = 0x84;
  92         rtcbuf[REG_CSEC] = 0x00;
  93         rtcbuf[REG_WDMON ] = (bin2bcd(tmp->tm_mon) + 1) | ((tmp->tm_wday) << 5);
  94         rtcbuf[REG_YRDATE] = ((year % 4) << 6) | bin2bcd(tmp->tm_mday);
  95         rtcbuf[REG_HOUR  ] = bin2bcd(tmp->tm_hour);
  96         rtcbuf[REG_MIN   ] = bin2bcd(tmp->tm_min);
  97         rtcbuf[REG_SEC   ] = bin2bcd(tmp->tm_sec);
  98
  99         i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0,    1, rtcbuf, NR_OF_REGS);
 100         i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0x10, 1, (uint8_t *) &year, 2);
 101         rtcbuf[REG_CS] = 0x04;
 102         i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, rtcbuf, 1);
 103
 104         return 0;
 105 }