rtc/m48t35ax.c

   1 /*
   2  * (C) Copyright 2001
   3  * Erik Theisen,  Wave 7 Optics, etheisen@mindspring.com.
   4  *
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  */
  23
  24 /*
  25  * Date & Time support for ST Electronics M48T35Ax RTC
  26  */
  27
  28 /*#define       DEBUG */
  29
  30
  31 #include <common.h>
  32 #include <command.h>
  33 #include <rtc.h>
  34 #include <config.h>
  35
  36 #if defined(CONFIG_RTC_M48T35A) && (CONFIG_COMMANDS & CFG_CMD_DATE)
  37
  38 static uchar rtc_read  (uchar reg);
  39 static void  rtc_write (uchar reg, uchar val);
  40 static uchar bin2bcd   (unsigned int n);
  41 static unsigned bcd2bin(uchar c);
  42
  43 /* ------------------------------------------------------------------------- */
  44
  45 void rtc_get (struct rtc_time *tmp)
  46 {
  47         uchar sec, min, hour, cent_day, date, month, year;
  48         uchar ccr;                      /* Clock control register */
  49
  50         /* Lock RTC for read using clock control register */
  51         ccr = rtc_read(0);
  52         ccr = ccr | 0x40;
  53         rtc_write(0, ccr);
  54
  55         sec     = rtc_read (0x1);
  56         min     = rtc_read (0x2);
  57         hour    = rtc_read (0x3);
  58         cent_day= rtc_read (0x4);
  59         date    = rtc_read (0x5);
  60         month   = rtc_read (0x6);
  61         year    = rtc_read (0x7);
  62
  63         /* UNLock RTC */
  64         ccr = rtc_read(0);
  65         ccr = ccr & 0xBF;
  66         rtc_write(0, ccr);
  67
  68         debug ( "Get RTC year: %02x month: %02x date: %02x cent_day: %02x "
  69                 "hr: %02x min: %02x sec: %02x\n",
  70                 year, month, date, cent_day,
  71                 hour, min, sec );
  72
  73         tmp->tm_sec  = bcd2bin (sec  & 0x7F);
  74         tmp->tm_min  = bcd2bin (min  & 0x7F);
  75         tmp->tm_hour = bcd2bin (hour & 0x3F);
  76         tmp->tm_mday = bcd2bin (date & 0x3F);
  77         tmp->tm_mon  = bcd2bin (month & 0x1F);
  78         tmp->tm_year = bcd2bin (year) + ((cent_day & 0x10) ? 2000 : 1900);
  79         tmp->tm_wday = bcd2bin (cent_day & 0x07);
  80         tmp->tm_yday = 0;
  81         tmp->tm_isdst= 0;
  82
  83         debug ( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
  84                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
  85                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
  86 }
  87
  88 void rtc_set (struct rtc_time *tmp)
  89 {
  90         uchar ccr;                      /* Clock control register */
  91         uchar century;
  92
  93         debug ( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
  94                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
  95                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
  96
  97         /* Lock RTC for write using clock control register */
  98         ccr = rtc_read(0);
  99         ccr = ccr | 0x80;
 100         rtc_write(0, ccr);
 101
 102         rtc_write (0x07, bin2bcd(tmp->tm_year % 100));
 103         rtc_write (0x06, bin2bcd(tmp->tm_mon));
 104         rtc_write (0x05, bin2bcd(tmp->tm_mday));
 105
 106         century = ((tmp->tm_year >= 2000) ? 0x10 : 0) | 0x20;
 107         rtc_write (0x04, bin2bcd(tmp->tm_wday) | century);
 108
 109         rtc_write (0x03, bin2bcd(tmp->tm_hour));
 110         rtc_write (0x02, bin2bcd(tmp->tm_min ));
 111         rtc_write (0x01, bin2bcd(tmp->tm_sec ));
 112
 113         /* UNLock RTC */
 114         ccr = rtc_read(0);
 115         ccr = ccr & 0x7F;
 116         rtc_write(0, ccr);
 117 }
 118
 119 void rtc_reset (void)
 120 {
 121         uchar val;
 122
 123         /* Clear all clock control registers */
 124         rtc_write (0x0, 0x80);          /* No Read Lock or calibration */
 125
 126         /* Clear stop bit */
 127         val = rtc_read (0x1);
 128         val &= 0x7f;
 129         rtc_write(0x1, val);
 130
 131         /* Enable century / disable frequency test */
 132         val = rtc_read (0x4);
 133         val = (val & 0xBF) | 0x20;
 134         rtc_write(0x4, val);
 135
 136         /* Clear write lock */
 137         rtc_write(0x0, 0);
 138 }
 139
 140 /* ------------------------------------------------------------------------- */
 141
 142 static uchar rtc_read (uchar reg)
 143 {
 144         uchar val;
 145         val = *(unsigned char *)
 146                 ((CFG_NVRAM_BASE_ADDR + CFG_NVRAM_SIZE - 8) + reg);
 147         return val;
 148 }
 149
 150 static void rtc_write (uchar reg, uchar val)
 151 {
 152         *(unsigned char *)
 153                 ((CFG_NVRAM_BASE_ADDR + CFG_NVRAM_SIZE - 8) + reg) = val;
 154 }
 155
 156 static unsigned bcd2bin (uchar n)
 157 {
 158         return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F));
 159 }
 160
 161 static unsigned char bin2bcd (unsigned int n)
 162 {
 163         return (((n / 10) << 4) | (n % 10));
 164 }
 165
 166 #endif  /* CONFIG_RTC_M48T35A && CFG_CMD_DATE */