m48t35ax.c
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/*
* (C) Copyright 2001
* Erik Theisen, Wave 7 Optics, etheisen@mindspring.com.
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*
* Date & Time support for ST Electronics M48T35Ax RTC
*/
/*#define DEBUG */
#include <common.h>
#include <command.h>
#include <rtc.h>
#include <config.h>
#if defined(CONFIG_CMD_DATE)
static uchar rtc_read (uchar reg);
static void rtc_write (uchar reg, uchar val);
/* ------------------------------------------------------------------------- */
int rtc_get (struct rtc_time *tmp)
{
uchar sec, min, hour, cent_day, date, month, year;
uchar ccr; /* Clock control register */
/* Lock RTC for read using clock control register */
ccr = rtc_read(0);
ccr = ccr | 0x40;
rtc_write(0, ccr);
sec = rtc_read (0x1);
min = rtc_read (0x2);
hour = rtc_read (0x3);
cent_day= rtc_read (0x4);
date = rtc_read (0x5);
month = rtc_read (0x6);
year = rtc_read (0x7);
/* UNLock RTC */
ccr = rtc_read(0);
ccr = ccr & 0xBF;
rtc_write(0, ccr);
debug ( "Get RTC year: %02x month: %02x date: %02x cent_day: %02x "
"hr: %02x min: %02x sec: %02x\n",
year, month, date, cent_day,
hour, min, sec );
tmp->tm_sec = bcd2bin (sec & 0x7F);
tmp->tm_min = bcd2bin (min & 0x7F);
tmp->tm_hour = bcd2bin (hour & 0x3F);
tmp->tm_mday = bcd2bin (date & 0x3F);
tmp->tm_mon = bcd2bin (month & 0x1F);
tmp->tm_year = bcd2bin (year) + ((cent_day & 0x10) ? 2000 : 1900);
tmp->tm_wday = bcd2bin (cent_day & 0x07);
tmp->tm_yday = 0;
tmp->tm_isdst= 0;
debug ( "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);
return 0;
}
int rtc_set (struct rtc_time *tmp)
{
uchar ccr; /* Clock control register */
uchar century;
debug ( "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);
/* Lock RTC for write using clock control register */
ccr = rtc_read(0);
ccr = ccr | 0x80;
rtc_write(0, ccr);
rtc_write (0x07, bin2bcd(tmp->tm_year % 100));
rtc_write (0x06, bin2bcd(tmp->tm_mon));
rtc_write (0x05, bin2bcd(tmp->tm_mday));
century = ((tmp->tm_year >= 2000) ? 0x10 : 0) | 0x20;
rtc_write (0x04, bin2bcd(tmp->tm_wday) | century);
rtc_write (0x03, bin2bcd(tmp->tm_hour));
rtc_write (0x02, bin2bcd(tmp->tm_min ));
rtc_write (0x01, bin2bcd(tmp->tm_sec ));
/* UNLock RTC */
ccr = rtc_read(0);
ccr = ccr & 0x7F;
rtc_write(0, ccr);
return 0;
}
void rtc_reset (void)
{
uchar val;
/* Clear all clock control registers */
rtc_write (0x0, 0x80); /* No Read Lock or calibration */
/* Clear stop bit */
val = rtc_read (0x1);
val &= 0x7f;
rtc_write(0x1, val);
/* Enable century / disable frequency test */
val = rtc_read (0x4);
val = (val & 0xBF) | 0x20;
rtc_write(0x4, val);
/* Clear write lock */
rtc_write(0x0, 0);
}
/* ------------------------------------------------------------------------- */
static uchar rtc_read (uchar reg)
{
return *(unsigned char *)
((CONFIG_SYS_NVRAM_BASE_ADDR + CONFIG_SYS_NVRAM_SIZE - 8) + reg);
}
static void rtc_write (uchar reg, uchar val)
{
*(unsigned char *)
((CONFIG_SYS_NVRAM_BASE_ADDR + CONFIG_SYS_NVRAM_SIZE - 8) + reg) = val;
}
#endif