drivers/rtc/m48t35ax.c

   1 /*
   2  * (C) Copyright 2001
   3  * Erik Theisen,  Wave 7 Optics, etheisen@mindspring.com.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 /*
   9  * Date & Time support for ST Electronics M48T35Ax RTC
  10  */
  11
  12 /*#define       DEBUG */
  13
  14
  15 #include <common.h>
  16 #include <command.h>
  17 #include <rtc.h>
  18 #include <config.h>
  19
  20 #if defined(CONFIG_CMD_DATE)
  21
  22 static uchar rtc_read  (uchar reg);
  23 static void  rtc_write (uchar reg, uchar val);
  24
  25 /* ------------------------------------------------------------------------- */
  26
  27 int rtc_get (struct rtc_time *tmp)
  28 {
  29         uchar sec, min, hour, cent_day, date, month, year;
  30         uchar ccr;                      /* Clock control register */
  31
  32         /* Lock RTC for read using clock control register */
  33         ccr = rtc_read(0);
  34         ccr = ccr | 0x40;
  35         rtc_write(0, ccr);
  36
  37         sec     = rtc_read (0x1);
  38         min     = rtc_read (0x2);
  39         hour    = rtc_read (0x3);
  40         cent_day= rtc_read (0x4);
  41         date    = rtc_read (0x5);
  42         month   = rtc_read (0x6);
  43         year    = rtc_read (0x7);
  44
  45         /* UNLock RTC */
  46         ccr = rtc_read(0);
  47         ccr = ccr & 0xBF;
  48         rtc_write(0, ccr);
  49
  50         debug ( "Get RTC year: %02x month: %02x date: %02x cent_day: %02x "
  51                 "hr: %02x min: %02x sec: %02x\n",
  52                 year, month, date, cent_day,
  53                 hour, min, sec );
  54
  55         tmp->tm_sec  = bcd2bin (sec  & 0x7F);
  56         tmp->tm_min  = bcd2bin (min  & 0x7F);
  57         tmp->tm_hour = bcd2bin (hour & 0x3F);
  58         tmp->tm_mday = bcd2bin (date & 0x3F);
  59         tmp->tm_mon  = bcd2bin (month & 0x1F);
  60         tmp->tm_year = bcd2bin (year) + ((cent_day & 0x10) ? 2000 : 1900);
  61         tmp->tm_wday = bcd2bin (cent_day & 0x07);
  62         tmp->tm_yday = 0;
  63         tmp->tm_isdst= 0;
  64
  65         debug ( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
  66                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
  67                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
  68
  69         return 0;
  70 }
  71
  72 int rtc_set (struct rtc_time *tmp)
  73 {
  74         uchar ccr;                      /* Clock control register */
  75         uchar century;
  76
  77         debug ( "Set 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         /* Lock RTC for write using clock control register */
  82         ccr = rtc_read(0);
  83         ccr = ccr | 0x80;
  84         rtc_write(0, ccr);
  85
  86         rtc_write (0x07, bin2bcd(tmp->tm_year % 100));
  87         rtc_write (0x06, bin2bcd(tmp->tm_mon));
  88         rtc_write (0x05, bin2bcd(tmp->tm_mday));
  89
  90         century = ((tmp->tm_year >= 2000) ? 0x10 : 0) | 0x20;
  91         rtc_write (0x04, bin2bcd(tmp->tm_wday) | century);
  92
  93         rtc_write (0x03, bin2bcd(tmp->tm_hour));
  94         rtc_write (0x02, bin2bcd(tmp->tm_min ));
  95         rtc_write (0x01, bin2bcd(tmp->tm_sec ));
  96
  97         /* UNLock RTC */
  98         ccr = rtc_read(0);
  99         ccr = ccr & 0x7F;
 100         rtc_write(0, ccr);
 101
 102         return 0;
 103 }
 104
 105 void rtc_reset (void)
 106 {
 107         uchar val;
 108
 109         /* Clear all clock control registers */
 110         rtc_write (0x0, 0x80);          /* No Read Lock or calibration */
 111
 112         /* Clear stop bit */
 113         val = rtc_read (0x1);
 114         val &= 0x7f;
 115         rtc_write(0x1, val);
 116
 117         /* Enable century / disable frequency test */
 118         val = rtc_read (0x4);
 119         val = (val & 0xBF) | 0x20;
 120         rtc_write(0x4, val);
 121
 122         /* Clear write lock */
 123         rtc_write(0x0, 0);
 124 }
 125
 126 /* ------------------------------------------------------------------------- */
 127
 128 static uchar rtc_read (uchar reg)
 129 {
 130         uchar val;
 131         val = *(unsigned char *)
 132                 ((CONFIG_SYS_NVRAM_BASE_ADDR + CONFIG_SYS_NVRAM_SIZE - 8) + reg);
 133         return val;
 134 }
 135
 136 static void rtc_write (uchar reg, uchar val)
 137 {
 138         *(unsigned char *)
 139                 ((CONFIG_SYS_NVRAM_BASE_ADDR + CONFIG_SYS_NVRAM_SIZE - 8) + reg) = val;
 140 }
 141
 142 #endif