drivers/rtc/max6900.c

   1 /*
   2  * (C) Copyright 2004
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 /*
   9  * Date & Time support for MAXIM MAX6900 RTC
  10  */
  11
  12 /* #define      DEBUG   */
  13
  14 #include <common.h>
  15 #include <command.h>
  16 #include <rtc.h>
  17 #include <i2c.h>
  18
  19 #if defined(CONFIG_CMD_DATE)
  20
  21 #ifndef CONFIG_SYS_I2C_RTC_ADDR
  22 #define CONFIG_SYS_I2C_RTC_ADDR 0x50
  23 #endif
  24
  25 /* ------------------------------------------------------------------------- */
  26
  27 static uchar rtc_read (uchar reg)
  28 {
  29         return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
  30 }
  31
  32 static void rtc_write (uchar reg, uchar val)
  33 {
  34         i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
  35         udelay(2500);
  36 }
  37
  38 /* ------------------------------------------------------------------------- */
  39
  40 int rtc_get (struct rtc_time *tmp)
  41 {
  42         uchar sec, min, hour, mday, wday, mon, cent, year;
  43         int retry = 1;
  44
  45         do {
  46                 sec     = rtc_read (0x80);
  47                 min     = rtc_read (0x82);
  48                 hour    = rtc_read (0x84);
  49                 mday    = rtc_read (0x86);
  50                 mon     = rtc_read (0x88);
  51                 wday    = rtc_read (0x8a);
  52                 year    = rtc_read (0x8c);
  53                 cent    = rtc_read (0x92);
  54                 /*
  55                  * Check for seconds rollover
  56                  */
  57                 if ((sec != 59) || (rtc_read(0x80) == sec)){
  58                         retry = 0;
  59                 }
  60         } while (retry);
  61
  62         debug ( "Get RTC year: %02x mon: %02x cent: %02x mday: %02x wday: %02x "
  63                 "hr: %02x min: %02x sec: %02x\n",
  64                 year, mon, cent, mday, wday,
  65                 hour, min, sec );
  66
  67         tmp->tm_sec  = bcd2bin (sec  & 0x7F);
  68         tmp->tm_min  = bcd2bin (min  & 0x7F);
  69         tmp->tm_hour = bcd2bin (hour & 0x3F);
  70         tmp->tm_mday = bcd2bin (mday & 0x3F);
  71         tmp->tm_mon  = bcd2bin (mon & 0x1F);
  72         tmp->tm_year = bcd2bin (year) + bcd2bin(cent) * 100;
  73         tmp->tm_wday = bcd2bin (wday & 0x07);
  74         tmp->tm_yday = 0;
  75         tmp->tm_isdst= 0;
  76
  77         debug ( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
  78                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
  79                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
  80
  81         return 0;
  82 }
  83
  84 int rtc_set (struct rtc_time *tmp)
  85 {
  86
  87         debug ( "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         rtc_write (0x9E, 0x00);
  92         rtc_write (0x80, 0);    /* Clear seconds to ensure no rollover */
  93         rtc_write (0x92, bin2bcd(tmp->tm_year / 100));
  94         rtc_write (0x8c, bin2bcd(tmp->tm_year % 100));
  95         rtc_write (0x8a, bin2bcd(tmp->tm_wday));
  96         rtc_write (0x88, bin2bcd(tmp->tm_mon));
  97         rtc_write (0x86, bin2bcd(tmp->tm_mday));
  98         rtc_write (0x84, bin2bcd(tmp->tm_hour));
  99         rtc_write (0x82, bin2bcd(tmp->tm_min ));
 100         rtc_write (0x80, bin2bcd(tmp->tm_sec ));
 101
 102         return 0;
 103 }
 104
 105 void rtc_reset (void)
 106 {
 107 }
 108
 109 #endif