drivers/rtc/isl1208.c

   1 /*
   2  * (C) Copyright 2008
   3  * Tor Krill, Excito Elektronik i Skåne , tor@excito.com
   4  *
   5  * Modelled after the ds1337 driver
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as
   9  * published by the Free Software Foundation; either version 2 of
  10  * the License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  20  * MA 02111-1307 USA
  21  */
  22
  23 /*
  24  * Date & Time support (no alarms) for Intersil
  25  * ISL1208 Real Time Clock (RTC).
  26  */
  27
  28 #include <common.h>
  29 #include <command.h>
  30 #include <rtc.h>
  31 #include <i2c.h>
  32
  33 /*---------------------------------------------------------------------*/
  34 #ifdef DEBUG_RTC
  35 #define DEBUGR(fmt,args...) printf(fmt ,##args)
  36 #else
  37 #define DEBUGR(fmt,args...)
  38 #endif
  39 /*---------------------------------------------------------------------*/
  40
  41 /*
  42  * RTC register addresses
  43  */
  44
  45 #define RTC_SEC_REG_ADDR        0x0
  46 #define RTC_MIN_REG_ADDR        0x1
  47 #define RTC_HR_REG_ADDR         0x2
  48 #define RTC_DATE_REG_ADDR       0x3
  49 #define RTC_MON_REG_ADDR        0x4
  50 #define RTC_YR_REG_ADDR         0x5
  51 #define RTC_DAY_REG_ADDR        0x6
  52 #define RTC_STAT_REG_ADDR       0x7
  53 /*
  54  * RTC control register bits
  55  */
  56
  57 /*
  58  * RTC status register bits
  59  */
  60 #define RTC_STAT_BIT_ARST       0x80    /* AUTO RESET ENABLE BIT */
  61 #define RTC_STAT_BIT_XTOSCB     0x40    /* CRYSTAL OSCILLATOR ENABLE BIT */
  62 #define RTC_STAT_BIT_WRTC       0x10    /* WRITE RTC ENABLE BIT */
  63 #define RTC_STAT_BIT_ALM        0x04    /* ALARM BIT */
  64 #define RTC_STAT_BIT_BAT        0x02    /* BATTERY BIT */
  65 #define RTC_STAT_BIT_RTCF       0x01    /* REAL TIME CLOCK FAIL BIT */
  66
  67 static uchar rtc_read (uchar reg);
  68 static void rtc_write (uchar reg, uchar val);
  69 static uchar bin2bcd (unsigned int n);
  70 static unsigned bcd2bin (uchar c);
  71
  72 /*
  73  * Get the current time from the RTC
  74  */
  75
  76 int rtc_get (struct rtc_time *tmp)
  77 {
  78         int rel = 0;
  79         uchar sec, min, hour, mday, wday, mon, year, status;
  80
  81         status = rtc_read (RTC_STAT_REG_ADDR);
  82         sec = rtc_read (RTC_SEC_REG_ADDR);
  83         min = rtc_read (RTC_MIN_REG_ADDR);
  84         hour = rtc_read (RTC_HR_REG_ADDR);
  85         wday = rtc_read (RTC_DAY_REG_ADDR);
  86         mday = rtc_read (RTC_DATE_REG_ADDR);
  87         mon = rtc_read (RTC_MON_REG_ADDR);
  88         year = rtc_read (RTC_YR_REG_ADDR);
  89
  90         DEBUGR ("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
  91                 "hr: %02x min: %02x sec: %02x status: %02x\n",
  92                 year, mon, mday, wday, hour, min, sec, status);
  93
  94         if (status & RTC_STAT_BIT_RTCF) {
  95                 printf ("### Warning: RTC oscillator has stopped\n");
  96                 rtc_write(RTC_STAT_REG_ADDR,
  97                         rtc_read(RTC_STAT_REG_ADDR) &~ (RTC_STAT_BIT_BAT|RTC_STAT_BIT_RTCF));
  98                 rel = -1;
  99         }
 100
 101         tmp->tm_sec  = bcd2bin (sec & 0x7F);
 102         tmp->tm_min  = bcd2bin (min & 0x7F);
 103         tmp->tm_hour = bcd2bin (hour & 0x3F);
 104         tmp->tm_mday = bcd2bin (mday & 0x3F);
 105         tmp->tm_mon  = bcd2bin (mon & 0x1F);
 106         tmp->tm_year = bcd2bin (year)+2000;
 107         tmp->tm_wday = bcd2bin (wday & 0x07);
 108         tmp->tm_yday = 0;
 109         tmp->tm_isdst= 0;
 110
 111         DEBUGR ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 112                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 113                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 114
 115         return rel;
 116 }
 117
 118 /*
 119  * Set the RTC
 120  */
 121 int rtc_set (struct rtc_time *tmp)
 122 {
 123         DEBUGR ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 124                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 125                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 126
 127         /* enable write */
 128         rtc_write(RTC_STAT_REG_ADDR,
 129                 rtc_read(RTC_STAT_REG_ADDR) | RTC_STAT_BIT_WRTC);
 130
 131         rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));
 132         rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon));
 133         rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday));
 134         rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday));
 135         rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour) | 0x80 ); /* 24h clock */
 136         rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min));
 137         rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));
 138
 139         /* disable write */
 140         rtc_write(RTC_STAT_REG_ADDR,
 141                 rtc_read(RTC_STAT_REG_ADDR) & ~RTC_STAT_BIT_WRTC);
 142
 143         return 0;
 144 }
 145
 146 void rtc_reset (void)
 147 {
 148 }
 149
 150 /*
 151  * Helper functions
 152  */
 153
 154 static uchar rtc_read (uchar reg)
 155 {
 156         return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
 157 }
 158
 159 static void rtc_write (uchar reg, uchar val)
 160 {
 161         i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
 162 }
 163
 164 static unsigned bcd2bin (uchar n)
 165 {
 166         return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F));
 167 }
 168
 169 static unsigned char bin2bcd (unsigned int n)
 170 {
 171         return (((n / 10) << 4) | (n % 10));
 172 }