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  * SPDX-License-Identifier:     GPL-2.0+
   8  */
   9
  10 /*
  11  * Date & Time support for the DS174x RTC
  12  */
  13
  14 /*#define       DEBUG*/
  15
  16 #include <common.h>
  17 #include <command.h>
  18 #include <rtc.h>
  19
  20 #if defined(CONFIG_CMD_DATE)
  21
  22 static uchar rtc_read( unsigned int addr );
  23 static void  rtc_write( unsigned int addr, uchar val);
  24
  25 #define RTC_BASE                ( CONFIG_SYS_NVRAM_SIZE + CONFIG_SYS_NVRAM_BASE_ADDR )
  26
  27 #define RTC_YEAR                ( RTC_BASE + 7 )
  28 #define RTC_MONTH               ( RTC_BASE + 6 )
  29 #define RTC_DAY_OF_MONTH        ( RTC_BASE + 5 )
  30 #define RTC_DAY_OF_WEEK         ( RTC_BASE + 4 )
  31 #define RTC_HOURS               ( RTC_BASE + 3 )
  32 #define RTC_MINUTES             ( RTC_BASE + 2 )
  33 #define RTC_SECONDS             ( RTC_BASE + 1 )
  34 #define RTC_CENTURY             ( RTC_BASE + 0 )
  35
  36 #define RTC_CONTROLA            RTC_CENTURY
  37 #define RTC_CONTROLB            RTC_SECONDS
  38 #define RTC_CONTROLC            RTC_DAY_OF_WEEK
  39
  40 #define RTC_CA_WRITE            0x80
  41 #define RTC_CA_READ             0x40
  42
  43 #define RTC_CB_OSC_DISABLE      0x80
  44
  45 #define RTC_CC_BATTERY_FLAG     0x80
  46 #define RTC_CC_FREQ_TEST        0x40
  47
  48 /* ------------------------------------------------------------------------- */
  49
  50 int rtc_get( struct rtc_time *tmp )
  51 {
  52         uchar sec, min, hour;
  53         uchar mday, wday, mon, year;
  54
  55         int century;
  56
  57         uchar reg_a;
  58
  59         reg_a = rtc_read( RTC_CONTROLA );
  60         /* lock clock registers for read */
  61         rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_READ ));
  62
  63         sec     = rtc_read( RTC_SECONDS );
  64         min     = rtc_read( RTC_MINUTES );
  65         hour    = rtc_read( RTC_HOURS );
  66         mday    = rtc_read( RTC_DAY_OF_MONTH );
  67         wday    = rtc_read( RTC_DAY_OF_WEEK );
  68         mon     = rtc_read( RTC_MONTH );
  69         year    = rtc_read( RTC_YEAR );
  70         century = rtc_read( RTC_CENTURY );
  71
  72         /* unlock clock registers after read */
  73         rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_READ ));
  74
  75 #ifdef RTC_DEBUG
  76         printf( "Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x "
  77                 "hr: %02x min: %02x sec: %02x\n",
  78                 year, mon_cent, mday, wday,
  79                 hour, min, sec );
  80 #endif
  81         tmp->tm_sec  = bcd2bin( sec  & 0x7F );
  82         tmp->tm_min  = bcd2bin( min  & 0x7F );
  83         tmp->tm_hour = bcd2bin( hour & 0x3F );
  84         tmp->tm_mday = bcd2bin( mday & 0x3F );
  85         tmp->tm_mon  = bcd2bin( mon & 0x1F );
  86         tmp->tm_wday = bcd2bin( wday & 0x07 );
  87
  88         /* glue year from century and year in century */
  89         tmp->tm_year = bcd2bin( year ) +
  90                 ( bcd2bin( century & 0x3F ) * 100 );
  91
  92         tmp->tm_yday = 0;
  93         tmp->tm_isdst= 0;
  94 #ifdef RTC_DEBUG
  95         printf( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
  96                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
  97                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec );
  98 #endif
  99         return 0;
 100 }
 101
 102 int rtc_set( struct rtc_time *tmp )
 103 {
 104         uchar reg_a;
 105 #ifdef RTC_DEBUG
 106         printf( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 107                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 108                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 109 #endif
 110         /* lock clock registers for write */
 111         reg_a = rtc_read( RTC_CONTROLA );
 112         rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_WRITE ));
 113
 114         rtc_write( RTC_MONTH, bin2bcd( tmp->tm_mon ));
 115
 116         rtc_write( RTC_DAY_OF_WEEK, bin2bcd( tmp->tm_wday ));
 117         rtc_write( RTC_DAY_OF_MONTH, bin2bcd( tmp->tm_mday ));
 118         rtc_write( RTC_HOURS, bin2bcd( tmp->tm_hour ));
 119         rtc_write( RTC_MINUTES, bin2bcd( tmp->tm_min ));
 120         rtc_write( RTC_SECONDS, bin2bcd( tmp->tm_sec ));
 121
 122         /* break year up into century and year in century */
 123         rtc_write( RTC_YEAR, bin2bcd( tmp->tm_year % 100 ));
 124         rtc_write( RTC_CENTURY, bin2bcd( tmp->tm_year / 100 ));
 125
 126         /* unlock clock registers after read */
 127         rtc_write( RTC_CONTROLA, ( reg_a  & ~RTC_CA_WRITE ));
 128
 129         return 0;
 130 }
 131
 132 void rtc_reset (void)
 133 {
 134         uchar reg_a, reg_b, reg_c;
 135
 136         reg_a = rtc_read( RTC_CONTROLA );
 137         reg_b = rtc_read( RTC_CONTROLB );
 138
 139         if ( reg_b & RTC_CB_OSC_DISABLE )
 140         {
 141                 printf( "real-time-clock was stopped. Now starting...\n" );
 142                 reg_a |= RTC_CA_WRITE;
 143                 reg_b &= ~RTC_CB_OSC_DISABLE;
 144
 145                 rtc_write( RTC_CONTROLA, reg_a );
 146                 rtc_write( RTC_CONTROLB, reg_b );
 147         }
 148
 149         /* make sure read/write clock register bits are cleared */
 150         reg_a &= ~( RTC_CA_WRITE | RTC_CA_READ );
 151         rtc_write( RTC_CONTROLA, reg_a );
 152
 153         reg_c = rtc_read( RTC_CONTROLC );
 154         if (( reg_c & RTC_CC_BATTERY_FLAG ) == 0 )
 155                 printf( "RTC battery low. Clock setting may not be reliable.\n" );
 156 }
 157
 158 /* ------------------------------------------------------------------------- */
 159
 160 static uchar rtc_read( unsigned int addr )
 161 {
 162         uchar val = in8( addr );
 163 #ifdef RTC_DEBUG
 164         printf( "rtc_read: %x:%x\n", addr, val );
 165 #endif
 166         return( val );
 167 }
 168
 169 static void rtc_write( unsigned int addr, uchar val )
 170 {
 171 #ifdef RTC_DEBUG
 172         printf( "rtc_write: %x:%x\n", addr, val );
 173 #endif
 174         out8( addr, val );
 175 }
 176
 177 #endif