avr/pcf8583.c

   1 /*
   2  * Date & Time support for Philips PCF8583 RTC
   3  */
   4
   5 /* #define      DEBUG   */
   6
   7 #include "common.h"
   8 #include <stdlib.h>
   9 #include "debug.h"
  10 #include "command.h"
  11 #include "rtc.h"
  12 #include "i2c.h"
  13
  14 #define REG_CS          0x00    /* control/status */
  15 #define REG_CSEC        0x01    /* hundredth of a second */
  16 #define REG_SEC         0x02    /* seconds */
  17 #define REG_MIN         0x03    /* minutes */
  18 #define REG_HOUR        0x04    /* hours */
  19 #define REG_YRDATE      0x05    /* year/date */
  20 #define REG_WDMON       0x06    /* weekdays/months */
  21 #define NR_OF_REGS      7
  22
  23
  24 /* ------------------------------------------------------------------------- */
  25
  26 static uint_fast8_t bcd2bin(uint8_t val)
  27 {
  28         return (val >> 4) * 10 + (val & 0x0f);
  29 }
  30
  31 static uint8_t bin2bcd (uint_fast8_t val)
  32 {
  33         div_t d = div(val, 10);
  34
  35         return (d.quot << 4) | d.rem;
  36 }
  37
  38
  39 int rtc_get (struct rtc_time *tmp)
  40 {
  41         int rel = 0;
  42         uint8_t rtcbuf[NR_OF_REGS];
  43         uint16_t year;
  44
  45         i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, rtcbuf, NR_OF_REGS);
  46         i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0x10, 1, (uint8_t *) &year, 2);
  47
  48         debug("Get RTC year: %u, year/date: %02x, wdays/month: %02x, "
  49                 "hour: %02x, min: %02x, sec: %02x, (stat: %02x)\n", year,
  50                 rtcbuf[6], rtcbuf[5], rtcbuf[4], rtcbuf[3], rtcbuf[2], rtcbuf[0]);
  51
  52         tmp->tm_sec  = bcd2bin (rtcbuf[REG_SEC]    & 0x7F);
  53         tmp->tm_min  = bcd2bin (rtcbuf[REG_MIN]    & 0x7F);
  54         tmp->tm_hour = bcd2bin (rtcbuf[REG_HOUR]   & 0x3F);
  55         tmp->tm_mday = bcd2bin (rtcbuf[REG_YRDATE] & 0x3F);
  56         tmp->tm_mon  = bcd2bin (rtcbuf[REG_WDMON]  & 0x1F);
  57         while (year%4 < (rtcbuf[REG_YRDATE]>>6)) {
  58                 year++;
  59                 /* TODO: update RTC ram */
  60         }
  61         tmp->tm_year  = year;
  62         tmp->tm_wday = rtcbuf[REG_WDMON] >> 5;
  63         tmp->tm_yday = 0;
  64         tmp->tm_isdst= 0;
  65
  66
  67         debug ( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
  68                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
  69                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
  70
  71         return rel;
  72 }
  73
  74 int rtc_set (struct rtc_time *tmp)
  75 {
  76         uint8_t rtcbuf[NR_OF_REGS];
  77
  78         debug ( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
  79                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
  80                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
  81
  82         rtcbuf[REG_CS] = 0x84;
  83         rtcbuf[REG_CSEC] = 0x00;
  84         rtcbuf[REG_WDMON ] = bin2bcd(tmp->tm_mon) | ((tmp->tm_wday) << 5);
  85         rtcbuf[REG_YRDATE] = ((tmp->tm_year % 4) << 6) | bin2bcd(tmp->tm_mday);
  86         rtcbuf[REG_HOUR  ] = bin2bcd(tmp->tm_hour);
  87         rtcbuf[REG_MIN   ] = bin2bcd(tmp->tm_min);
  88         rtcbuf[REG_SEC   ] = bin2bcd(tmp->tm_sec);
  89
  90         i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0,    1, rtcbuf, NR_OF_REGS);
  91         i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0x10, 1, (uint8_t *) &tmp->tm_year, 2);
  92         rtcbuf[REG_CS] = 0x04;
  93         i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, rtcbuf, 1);
  94
  95
  96         return 0;
  97 }
  98
  99 void rtc_reset (void)
 100 {
 101         uint8_t c = 0;
 102
 103         i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, &c, 1);
 104 }
 105
 106