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rtc4543.c 3.16 KiB
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  • /*
     * (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