drivers/rtc/rtc4543.c

   1 /*
   2  * (C) Copyright 2008, 2009
   3  * Andreas Pfefferle, DENX Software Engineering, ap@denx.de.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <asm/io.h>
   9 #include <common.h>
  10 #include <command.h>
  11 #include <config.h>
  12 #include <rtc.h>
  13 #include <tws.h>
  14
  15 #if defined(CONFIG_CMD_DATE)
  16
  17 /*
  18  * Note: The acrobatics below is due to the hideously ingenius idea of
  19  * the chip designers.  As the chip does not allow register
  20  * addressing, all values need to be read and written in one go.  Sure
  21  * enough, the 'wday' field (0-6) is transferred using the economic
  22  * number of 4 bits right in the middle of the packet.....
  23  */
  24
  25 int rtc_get(struct rtc_time *tm)
  26 {
  27         int rel = 0;
  28         uchar buffer[7];
  29
  30         memset(buffer, 0, 7);
  31
  32         /* Read 52 bits into our buffer */
  33         tws_read(buffer, 52);
  34
  35         tm->tm_sec  = bcd2bin( buffer[0] & 0x7F);
  36         tm->tm_min  = bcd2bin( buffer[1] & 0x7F);
  37         tm->tm_hour = bcd2bin( buffer[2] & 0x3F);
  38         tm->tm_wday = bcd2bin( buffer[3] & 0x07);
  39         tm->tm_mday = bcd2bin((buffer[3] & 0xF0) >> 4 | (buffer[4] & 0x0F) << 4);
  40         tm->tm_mon  = bcd2bin((buffer[4] & 0x30) >> 4 | (buffer[5] & 0x0F) << 4);
  41         tm->tm_year = bcd2bin((buffer[5] & 0xF0) >> 4 | (buffer[6] & 0x0F) << 4) + 2000;
  42         tm->tm_yday = 0;
  43         tm->tm_isdst = 0;
  44
  45         if (tm->tm_sec & 0x80) {
  46                 puts("### Warning: RTC Low Voltage - date/time not reliable\n");
  47                 rel = -1;
  48         }
  49
  50         debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
  51                 tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
  52                 tm->tm_hour, tm->tm_min, tm->tm_sec);
  53
  54         return rel;
  55 }
  56
  57 int rtc_set(struct rtc_time *tm)
  58 {
  59         uchar buffer[7];
  60         uchar tmp;
  61
  62         debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
  63                 tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
  64                 tm->tm_hour, tm->tm_min, tm->tm_sec);
  65
  66         memset(buffer, 0, 7);
  67         buffer[0] = bin2bcd(tm->tm_sec);
  68         buffer[1] = bin2bcd(tm->tm_min);
  69         buffer[2] = bin2bcd(tm->tm_hour);
  70         buffer[3] = bin2bcd(tm->tm_wday);
  71         tmp = bin2bcd(tm->tm_mday);
  72         buffer[3] |= (tmp & 0x0F) << 4;
  73         buffer[4] =  (tmp & 0xF0) >> 4;
  74         tmp = bin2bcd(tm->tm_mon);
  75         buffer[4] |= (tmp & 0x0F) << 4;
  76         buffer[5] =  (tmp & 0xF0) >> 4;
  77         tmp = bin2bcd(tm->tm_year  % 100);
  78         buffer[5] |= (tmp & 0x0F) << 4;
  79         buffer[6] =  (tmp & 0xF0) >> 4;
  80
  81         /* Write the resulting 52 bits to device */
  82         tws_write(buffer, 52);
  83
  84         return 0;
  85 }
  86
  87 void rtc_reset(void)
  88 {
  89         struct rtc_time tmp;
  90
  91         tmp.tm_sec = 0;
  92         tmp.tm_min = 0;
  93         tmp.tm_hour = 0;
  94         tmp.tm_wday = 4;
  95         tmp.tm_mday = 1;
  96         tmp.tm_mon = 1;
  97         tmp.tm_year = 2000;
  98         rtc_set(&tmp);
  99 }
 100
 101 #endif