u-boot/drivers/rtc/rtc4543.c
Detlev Zundel 04e11cf383 rtc: add support for 4543 RTC (manufactured by e.g. EPSON)
Signed-off-by: Detlev Zundel <dzu@denx.de>
Signed-off-by: Andreas Pfefferle <ap@denx.de>
2009-03-30 09:39:46 +02:00

118 lines
3.2 KiB
C

/*
* (C) Copyright 2008, 2009
* Andreas Pfefferle, DENX Software Engineering, ap@denx.de.
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <asm/io.h>
#include <common.h>
#include <command.h>
#include <config.h>
#include <bcd.h>
#include <rtc.h>
#include <tws.h>
#if defined(CONFIG_CMD_DATE)
/*
* Note: The acrobatics below is due to the hideously ingenius idea of
* the chip designers. As the chip does not allow register
* addressing, all values need to be read and written in one go. Sure
* enough, the 'wday' field (0-6) is transferred using the economic
* number of 4 bits right in the middle of the packet.....
*/
int rtc_get(struct rtc_time *tm)
{
int rel = 0;
uchar buffer[7];
memset(buffer, 0, 7);
/* Read 52 bits into our buffer */
tws_read(buffer, 52);
tm->tm_sec = BCD2BIN( buffer[0] & 0x7F);
tm->tm_min = BCD2BIN( buffer[1] & 0x7F);
tm->tm_hour = BCD2BIN( buffer[2] & 0x3F);
tm->tm_wday = BCD2BIN( buffer[3] & 0x07);
tm->tm_mday = BCD2BIN((buffer[3] & 0xF0) >> 4 | (buffer[4] & 0x0F) << 4);
tm->tm_mon = BCD2BIN((buffer[4] & 0x30) >> 4 | (buffer[5] & 0x0F) << 4);
tm->tm_year = BCD2BIN((buffer[5] & 0xF0) >> 4 | (buffer[6] & 0x0F) << 4) + 2000;
tm->tm_yday = 0;
tm->tm_isdst = 0;
if (tm->tm_sec & 0x80) {
puts("### Warning: RTC Low Voltage - date/time not reliable\n");
rel = -1;
}
debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
tm->tm_hour, tm->tm_min, tm->tm_sec);
return rel;
}
int rtc_set(struct rtc_time *tm)
{
uchar buffer[7];
uchar tmp;
debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
tm->tm_hour, tm->tm_min, tm->tm_sec);
memset(buffer, 0, 7);
buffer[0] = BIN2BCD(tm->tm_sec);
buffer[1] = BIN2BCD(tm->tm_min);
buffer[2] = BIN2BCD(tm->tm_hour);
buffer[3] = BIN2BCD(tm->tm_wday);
tmp = BIN2BCD(tm->tm_mday);
buffer[3] |= (tmp & 0x0F) << 4;
buffer[4] = (tmp & 0xF0) >> 4;
tmp = BIN2BCD(tm->tm_mon);
buffer[4] |= (tmp & 0x0F) << 4;
buffer[5] = (tmp & 0xF0) >> 4;
tmp = BIN2BCD(tm->tm_year % 100);
buffer[5] |= (tmp & 0x0F) << 4;
buffer[6] = (tmp & 0xF0) >> 4;
/* Write the resulting 52 bits to device */
tws_write(buffer, 52);
return 0;
}
void rtc_reset(void)
{
struct rtc_time tmp;
tmp.tm_sec = 0;
tmp.tm_min = 0;
tmp.tm_hour = 0;
tmp.tm_wday = 4;
tmp.tm_mday = 1;
tmp.tm_mon = 1;
tmp.tm_year = 2000;
rtc_set(&tmp);
}
#endif