avr/pcf8583.c

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