drivers/rtc/ds174x.c

   1 /*
   2  * (C) Copyright 2001
   3  * ARIO Data Networks, Inc. dchiu@ariodata.com
   4  *
   5  * Based on MontaVista DS1743 code and U-Boot mc146818 code
   6  *
   7  * See file CREDITS for list of people who contributed to this
   8  * project.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of
  13  * the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  23  * MA 02111-1307 USA
  24  */
  25
  26 /*
  27  * Date & Time support for the DS174x RTC
  28  */
  29
  30 /*#define       DEBUG*/
  31
  32 #include <common.h>
  33 #include <command.h>
  34 #include <rtc.h>
  35
  36 #if defined(CONFIG_CMD_DATE)
  37
  38 static uchar rtc_read( unsigned int addr );
  39 static void  rtc_write( unsigned int addr, uchar val);
  40
  41 #define RTC_BASE                ( CONFIG_SYS_NVRAM_SIZE + CONFIG_SYS_NVRAM_BASE_ADDR )
  42
  43 #define RTC_YEAR                ( RTC_BASE + 7 )
  44 #define RTC_MONTH               ( RTC_BASE + 6 )
  45 #define RTC_DAY_OF_MONTH        ( RTC_BASE + 5 )
  46 #define RTC_DAY_OF_WEEK         ( RTC_BASE + 4 )
  47 #define RTC_HOURS               ( RTC_BASE + 3 )
  48 #define RTC_MINUTES             ( RTC_BASE + 2 )
  49 #define RTC_SECONDS             ( RTC_BASE + 1 )
  50 #define RTC_CENTURY             ( RTC_BASE + 0 )
  51
  52 #define RTC_CONTROLA            RTC_CENTURY
  53 #define RTC_CONTROLB            RTC_SECONDS
  54 #define RTC_CONTROLC            RTC_DAY_OF_WEEK
  55
  56 #define RTC_CA_WRITE            0x80
  57 #define RTC_CA_READ             0x40
  58
  59 #define RTC_CB_OSC_DISABLE      0x80
  60
  61 #define RTC_CC_BATTERY_FLAG     0x80
  62 #define RTC_CC_FREQ_TEST        0x40
  63
  64 /* ------------------------------------------------------------------------- */
  65
  66 int rtc_get( struct rtc_time *tmp )
  67 {
  68         uchar sec, min, hour;
  69         uchar mday, wday, mon, year;
  70
  71         int century;
  72
  73         uchar reg_a;
  74
  75         reg_a = rtc_read( RTC_CONTROLA );
  76         /* lock clock registers for read */
  77         rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_READ ));
  78
  79         sec     = rtc_read( RTC_SECONDS );
  80         min     = rtc_read( RTC_MINUTES );
  81         hour    = rtc_read( RTC_HOURS );
  82         mday    = rtc_read( RTC_DAY_OF_MONTH );
  83         wday    = rtc_read( RTC_DAY_OF_WEEK );
  84         mon     = rtc_read( RTC_MONTH );
  85         year    = rtc_read( RTC_YEAR );
  86         century = rtc_read( RTC_CENTURY );
  87
  88         /* unlock clock registers after read */
  89         rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_READ ));
  90
  91 #ifdef RTC_DEBUG
  92         printf( "Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x "
  93                 "hr: %02x min: %02x sec: %02x\n",
  94                 year, mon_cent, mday, wday,
  95                 hour, min, sec );
  96 #endif
  97         tmp->tm_sec  = bcd2bin( sec  & 0x7F );
  98         tmp->tm_min  = bcd2bin( min  & 0x7F );
  99         tmp->tm_hour = bcd2bin( hour & 0x3F );
 100         tmp->tm_mday = bcd2bin( mday & 0x3F );
 101         tmp->tm_mon  = bcd2bin( mon & 0x1F );
 102         tmp->tm_wday = bcd2bin( wday & 0x07 );
 103
 104         /* glue year from century and year in century */
 105         tmp->tm_year = bcd2bin( year ) +
 106                 ( bcd2bin( century & 0x3F ) * 100 );
 107
 108         tmp->tm_yday = 0;
 109         tmp->tm_isdst= 0;
 110 #ifdef RTC_DEBUG
 111         printf( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 112                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 113                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec );
 114 #endif
 115         return 0;
 116 }
 117
 118 int rtc_set( struct rtc_time *tmp )
 119 {
 120         uchar reg_a;
 121 #ifdef RTC_DEBUG
 122         printf( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 123                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 124                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 125 #endif
 126         /* lock clock registers for write */
 127         reg_a = rtc_read( RTC_CONTROLA );
 128         rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_WRITE ));
 129
 130         rtc_write( RTC_MONTH, bin2bcd( tmp->tm_mon ));
 131
 132         rtc_write( RTC_DAY_OF_WEEK, bin2bcd( tmp->tm_wday ));
 133         rtc_write( RTC_DAY_OF_MONTH, bin2bcd( tmp->tm_mday ));
 134         rtc_write( RTC_HOURS, bin2bcd( tmp->tm_hour ));
 135         rtc_write( RTC_MINUTES, bin2bcd( tmp->tm_min ));
 136         rtc_write( RTC_SECONDS, bin2bcd( tmp->tm_sec ));
 137
 138         /* break year up into century and year in century */
 139         rtc_write( RTC_YEAR, bin2bcd( tmp->tm_year % 100 ));
 140         rtc_write( RTC_CENTURY, bin2bcd( tmp->tm_year / 100 ));
 141
 142         /* unlock clock registers after read */
 143         rtc_write( RTC_CONTROLA, ( reg_a  & ~RTC_CA_WRITE ));
 144
 145         return 0;
 146 }
 147
 148 void rtc_reset (void)
 149 {
 150         uchar reg_a, reg_b, reg_c;
 151
 152         reg_a = rtc_read( RTC_CONTROLA );
 153         reg_b = rtc_read( RTC_CONTROLB );
 154
 155         if ( reg_b & RTC_CB_OSC_DISABLE )
 156         {
 157                 printf( "real-time-clock was stopped. Now starting...\n" );
 158                 reg_a |= RTC_CA_WRITE;
 159                 reg_b &= ~RTC_CB_OSC_DISABLE;
 160
 161                 rtc_write( RTC_CONTROLA, reg_a );
 162                 rtc_write( RTC_CONTROLB, reg_b );
 163         }
 164
 165         /* make sure read/write clock register bits are cleared */
 166         reg_a &= ~( RTC_CA_WRITE | RTC_CA_READ );
 167         rtc_write( RTC_CONTROLA, reg_a );
 168
 169         reg_c = rtc_read( RTC_CONTROLC );
 170         if (( reg_c & RTC_CC_BATTERY_FLAG ) == 0 )
 171                 printf( "RTC battery low. Clock setting may not be reliable.\n" );
 172 }
 173
 174 /* ------------------------------------------------------------------------- */
 175
 176 static uchar rtc_read( unsigned int addr )
 177 {
 178         uchar val = in8( addr );
 179 #ifdef RTC_DEBUG
 180         printf( "rtc_read: %x:%x\n", addr, val );
 181 #endif
 182         return( val );
 183 }
 184
 185 static void rtc_write( unsigned int addr, uchar val )
 186 {
 187 #ifdef RTC_DEBUG
 188         printf( "rtc_write: %x:%x\n", addr, val );
 189 #endif
 190         out8( addr, val );
 191 }
 192
 193 #endif