ds174x.c
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/*
* (C) Copyright 2001
* ARIO Data Networks, Inc. dchiu@ariodata.com
*
* Based on MontaVista DS1743 code and U-Boot mc146818 code
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*
* Date & Time support for the DS174x RTC
*/
/*#define DEBUG*/
#include <common.h>
#include <command.h>
#include <rtc.h>
#if defined(CONFIG_CMD_DATE)
static uchar rtc_read( unsigned int addr );
static void rtc_write( unsigned int addr, uchar val);
#define RTC_BASE ( CONFIG_SYS_NVRAM_SIZE + CONFIG_SYS_NVRAM_BASE_ADDR )
#define RTC_YEAR ( RTC_BASE + 7 )
#define RTC_MONTH ( RTC_BASE + 6 )
#define RTC_DAY_OF_MONTH ( RTC_BASE + 5 )
#define RTC_DAY_OF_WEEK ( RTC_BASE + 4 )
#define RTC_HOURS ( RTC_BASE + 3 )
#define RTC_MINUTES ( RTC_BASE + 2 )
#define RTC_SECONDS ( RTC_BASE + 1 )
#define RTC_CENTURY ( RTC_BASE + 0 )
#define RTC_CONTROLA RTC_CENTURY
#define RTC_CONTROLB RTC_SECONDS
#define RTC_CONTROLC RTC_DAY_OF_WEEK
#define RTC_CA_WRITE 0x80
#define RTC_CA_READ 0x40
#define RTC_CB_OSC_DISABLE 0x80
#define RTC_CC_BATTERY_FLAG 0x80
#define RTC_CC_FREQ_TEST 0x40
/* ------------------------------------------------------------------------- */
int rtc_get( struct rtc_time *tmp )
{
uchar sec, min, hour;
uchar mday, wday, mon, year;
int century;
uchar reg_a;
reg_a = rtc_read( RTC_CONTROLA );
/* lock clock registers for read */
rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_READ ));
sec = rtc_read( RTC_SECONDS );
min = rtc_read( RTC_MINUTES );
hour = rtc_read( RTC_HOURS );
mday = rtc_read( RTC_DAY_OF_MONTH );
wday = rtc_read( RTC_DAY_OF_WEEK );
mon = rtc_read( RTC_MONTH );
year = rtc_read( RTC_YEAR );
century = rtc_read( RTC_CENTURY );
/* unlock clock registers after read */
rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_READ ));
#ifdef RTC_DEBUG
printf( "Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x "
"hr: %02x min: %02x sec: %02x\n",
year, mon_cent, mday, wday,
hour, min, sec );
#endif
tmp->tm_sec = bcd2bin( sec & 0x7F );
tmp->tm_min = bcd2bin( min & 0x7F );
tmp->tm_hour = bcd2bin( hour & 0x3F );
tmp->tm_mday = bcd2bin( mday & 0x3F );
tmp->tm_mon = bcd2bin( mon & 0x1F );
tmp->tm_wday = bcd2bin( wday & 0x07 );
/* glue year from century and year in century */
tmp->tm_year = bcd2bin( year ) +
( bcd2bin( century & 0x3F ) * 100 );
tmp->tm_yday = 0;
tmp->tm_isdst= 0;
#ifdef RTC_DEBUG
printf( "Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
tmp->tm_hour, tmp->tm_min, tmp->tm_sec );
#endif
return 0;
}
int rtc_set( struct rtc_time *tmp )
{
uchar reg_a;
#ifdef RTC_DEBUG
printf( "Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
#endif
/* lock clock registers for write */
reg_a = rtc_read( RTC_CONTROLA );
rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_WRITE ));
rtc_write( RTC_MONTH, bin2bcd( tmp->tm_mon ));
rtc_write( RTC_DAY_OF_WEEK, bin2bcd( tmp->tm_wday ));
rtc_write( RTC_DAY_OF_MONTH, bin2bcd( tmp->tm_mday ));
rtc_write( RTC_HOURS, bin2bcd( tmp->tm_hour ));
rtc_write( RTC_MINUTES, bin2bcd( tmp->tm_min ));
rtc_write( RTC_SECONDS, bin2bcd( tmp->tm_sec ));
/* break year up into century and year in century */
rtc_write( RTC_YEAR, bin2bcd( tmp->tm_year % 100 ));
rtc_write( RTC_CENTURY, bin2bcd( tmp->tm_year / 100 ));
/* unlock clock registers after read */
rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_WRITE ));
return 0;
}
void rtc_reset (void)
{
uchar reg_a, reg_b, reg_c;
reg_a = rtc_read( RTC_CONTROLA );
reg_b = rtc_read( RTC_CONTROLB );
if ( reg_b & RTC_CB_OSC_DISABLE )
{
printf( "real-time-clock was stopped. Now starting...\n" );
reg_a |= RTC_CA_WRITE;
reg_b &= ~RTC_CB_OSC_DISABLE;
rtc_write( RTC_CONTROLA, reg_a );
rtc_write( RTC_CONTROLB, reg_b );
}
/* make sure read/write clock register bits are cleared */
reg_a &= ~( RTC_CA_WRITE | RTC_CA_READ );
rtc_write( RTC_CONTROLA, reg_a );
reg_c = rtc_read( RTC_CONTROLC );
if (( reg_c & RTC_CC_BATTERY_FLAG ) == 0 )
printf( "RTC battery low. Clock setting may not be reliable.\n" );
}
/* ------------------------------------------------------------------------- */
static uchar rtc_read( unsigned int addr )
{
uchar val = in8( addr );
#ifdef RTC_DEBUG
printf( "rtc_read: %x:%x\n", addr, val );
#endif
return( val );
}
static void rtc_write( unsigned int addr, uchar val )
{
#ifdef RTC_DEBUG
printf( "rtc_write: %x:%x\n", addr, val );
#endif
out8( addr, val );
}
#endif