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bootloader/u-boot_2015_04/drivers/rtc/rtc4543.c 2.4 KB
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  /*
   * (C) Copyright 2008, 2009
   * Andreas Pfefferle, DENX Software Engineering, ap@denx.de.
   *
   * SPDX-License-Identifier:	GPL-2.0+
   */
  
  #include <asm/io.h>
  #include <common.h>
  #include <command.h>
  #include <config.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
  ");
  		rel = -1;
  	}
  
  	debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d
  ",
  		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
  ",
  		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