drivers/rtc/m41t62.c

   1 /*
   2  * (C) Copyright 2008
   3  * Stefan Roese, DENX Software Engineering, sr@denx.de.
   4  *
   5  * based on a the Linux rtc-m41t80.c driver which is:
   6  *   Alexander Bigga <ab@mycable.de>, 2006 (c) mycable GmbH
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  */
  23
  24 /*
  25  * Date & Time support for STMicroelectronics M41T62
  26  */
  27
  28 /* #define      DEBUG   */
  29
  30 #include <common.h>
  31 #include <command.h>
  32 #include <rtc.h>
  33 #include <i2c.h>
  34 #include <bcd.h>
  35
  36 #if defined(CONFIG_CMD_DATE)
  37
  38 #define M41T62_REG_SSEC 0
  39 #define M41T62_REG_SEC  1
  40 #define M41T62_REG_MIN  2
  41 #define M41T62_REG_HOUR 3
  42 #define M41T62_REG_WDAY 4
  43 #define M41T62_REG_DAY  5
  44 #define M41T62_REG_MON  6
  45 #define M41T62_REG_YEAR 7
  46 #define M41T62_REG_ALARM_MON    0xa
  47 #define M41T62_REG_ALARM_DAY    0xb
  48 #define M41T62_REG_ALARM_HOUR   0xc
  49 #define M41T62_REG_ALARM_MIN    0xd
  50 #define M41T62_REG_ALARM_SEC    0xe
  51 #define M41T62_REG_FLAGS        0xf
  52
  53 #define M41T62_DATETIME_REG_SIZE        (M41T62_REG_YEAR + 1)
  54 #define M41T62_ALARM_REG_SIZE   \
  55         (M41T62_REG_ALARM_SEC + 1 - M41T62_REG_ALARM_MON)
  56
  57 #define M41T62_SEC_ST           (1 << 7)        /* ST: Stop Bit */
  58 #define M41T62_ALMON_AFE        (1 << 7)        /* AFE: AF Enable Bit */
  59 #define M41T62_ALMON_SQWE       (1 << 6)        /* SQWE: SQW Enable Bit */
  60 #define M41T62_ALHOUR_HT        (1 << 6)        /* HT: Halt Update Bit */
  61 #define M41T62_FLAGS_AF         (1 << 6)        /* AF: Alarm Flag Bit */
  62 #define M41T62_FLAGS_BATT_LOW   (1 << 4)        /* BL: Battery Low Bit */
  63
  64 #define M41T62_FEATURE_HT       (1 << 0)
  65 #define M41T62_FEATURE_BL       (1 << 1)
  66
  67 void rtc_get(struct rtc_time *tm)
  68 {
  69         u8 buf[M41T62_DATETIME_REG_SIZE];
  70
  71         i2c_read(CFG_I2C_RTC_ADDR, 0, 1, buf, M41T62_DATETIME_REG_SIZE);
  72
  73         debug("%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
  74               "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
  75               __FUNCTION__,
  76               buf[0], buf[1], buf[2], buf[3],
  77               buf[4], buf[5], buf[6], buf[7]);
  78
  79         tm->tm_sec = BCD2BIN(buf[M41T62_REG_SEC] & 0x7f);
  80         tm->tm_min = BCD2BIN(buf[M41T62_REG_MIN] & 0x7f);
  81         tm->tm_hour = BCD2BIN(buf[M41T62_REG_HOUR] & 0x3f);
  82         tm->tm_mday = BCD2BIN(buf[M41T62_REG_DAY] & 0x3f);
  83         tm->tm_wday = buf[M41T62_REG_WDAY] & 0x07;
  84         tm->tm_mon = BCD2BIN(buf[M41T62_REG_MON] & 0x1f) - 1;
  85
  86         /* assume 20YY not 19YY, and ignore the Century Bit */
  87         /* U-Boot needs to add 1900 here */
  88         tm->tm_year = BCD2BIN(buf[M41T62_REG_YEAR]) + 100 + 1900;
  89
  90         debug("%s: tm is secs=%d, mins=%d, hours=%d, "
  91               "mday=%d, mon=%d, year=%d, wday=%d\n",
  92               __FUNCTION__,
  93               tm->tm_sec, tm->tm_min, tm->tm_hour,
  94               tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
  95 }
  96
  97 void rtc_set(struct rtc_time *tm)
  98 {
  99         u8 buf[M41T62_DATETIME_REG_SIZE];
 100
 101         debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 102               tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
 103               tm->tm_hour, tm->tm_min, tm->tm_sec);
 104
 105         i2c_read(CFG_I2C_RTC_ADDR, 0, 1, buf, M41T62_DATETIME_REG_SIZE);
 106
 107         /* Merge time-data and register flags into buf[0..7] */
 108         buf[M41T62_REG_SSEC] = 0;
 109         buf[M41T62_REG_SEC] =
 110                 BIN2BCD(tm->tm_sec) | (buf[M41T62_REG_SEC] & ~0x7f);
 111         buf[M41T62_REG_MIN] =
 112                 BIN2BCD(tm->tm_min) | (buf[M41T62_REG_MIN] & ~0x7f);
 113         buf[M41T62_REG_HOUR] =
 114                 BIN2BCD(tm->tm_hour) | (buf[M41T62_REG_HOUR] & ~0x3f) ;
 115         buf[M41T62_REG_WDAY] =
 116                 (tm->tm_wday & 0x07) | (buf[M41T62_REG_WDAY] & ~0x07);
 117         buf[M41T62_REG_DAY] =
 118                 BIN2BCD(tm->tm_mday) | (buf[M41T62_REG_DAY] & ~0x3f);
 119         buf[M41T62_REG_MON] =
 120                 BIN2BCD(tm->tm_mon + 1) | (buf[M41T62_REG_MON] & ~0x1f);
 121         /* assume 20YY not 19YY */
 122         buf[M41T62_REG_YEAR] = BIN2BCD(tm->tm_year % 100);
 123
 124         if (i2c_write(CFG_I2C_RTC_ADDR, 0, 1, buf, M41T62_DATETIME_REG_SIZE))
 125                 printf("I2C write failed in %s()\n", __func__);
 126 }
 127
 128 void rtc_reset(void)
 129 {
 130         /*
 131          * Nothing to do
 132          */
 133 }
 134
 135 #endif