rtc/ds1337.c

   1 /*
   2  * (C) Copyright 2001, 2002
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  * Keith Outwater, keith_outwater@mvis.com`
   5  *
   6  * See file CREDITS for list of people who contributed to this
   7  * project.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation; either version 2 of
  12  * the License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  22  * MA 02111-1307 USA
  23  */
  24
  25 /*
  26  * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim)
  27  * DS1337 Real Time Clock (RTC).
  28  */
  29
  30 #include <common.h>
  31 #include <command.h>
  32 #include <rtc.h>
  33 #include <i2c.h>
  34
  35 #if defined(CONFIG_RTC_DS1337) && (CONFIG_COMMANDS & CFG_CMD_DATE)
  36
  37 /*---------------------------------------------------------------------*/
  38 #undef DEBUG_RTC
  39
  40 #ifdef DEBUG_RTC
  41 #define DEBUGR(fmt,args...) printf(fmt ,##args)
  42 #else
  43 #define DEBUGR(fmt,args...)
  44 #endif
  45 /*---------------------------------------------------------------------*/
  46
  47 /*
  48  * RTC register addresses
  49  */
  50 #define RTC_SEC_REG_ADDR        0x0
  51 #define RTC_MIN_REG_ADDR        0x1
  52 #define RTC_HR_REG_ADDR         0x2
  53 #define RTC_DAY_REG_ADDR        0x3
  54 #define RTC_DATE_REG_ADDR       0x4
  55 #define RTC_MON_REG_ADDR        0x5
  56 #define RTC_YR_REG_ADDR         0x6
  57 #define RTC_CTL_REG_ADDR        0x0e
  58 #define RTC_STAT_REG_ADDR       0x0f
  59
  60 /*
  61  * RTC control register bits
  62  */
  63 #define RTC_CTL_BIT_A1IE        0x1     /* Alarm 1 interrupt enable     */
  64 #define RTC_CTL_BIT_A2IE        0x2     /* Alarm 2 interrupt enable     */
  65 #define RTC_CTL_BIT_INTCN       0x4     /* Interrupt control            */
  66 #define RTC_CTL_BIT_RS1         0x8     /* Rate select 1                */
  67 #define RTC_CTL_BIT_RS2         0x10    /* Rate select 2                */
  68 #define RTC_CTL_BIT_DOSC        0x80    /* Disable Oscillator           */
  69
  70 /*
  71  * RTC status register bits
  72  */
  73 #define RTC_STAT_BIT_A1F        0x1     /* Alarm 1 flag                 */
  74 #define RTC_STAT_BIT_A2F        0x2     /* Alarm 2 flag                 */
  75 #define RTC_STAT_BIT_OSF        0x80    /* Oscillator stop flag         */
  76
  77
  78 static uchar rtc_read (uchar reg);
  79 static void rtc_write (uchar reg, uchar val);
  80 static uchar bin2bcd (unsigned int n);
  81 static unsigned bcd2bin (uchar c);
  82
  83
  84 /*
  85  * Get the current time from the RTC
  86  */
  87 void rtc_get (struct rtc_time *tmp)
  88 {
  89         uchar sec, min, hour, mday, wday, mon_cent, year, control, status;
  90
  91         control = rtc_read (RTC_CTL_REG_ADDR);
  92         status = rtc_read (RTC_STAT_REG_ADDR);
  93         sec = rtc_read (RTC_SEC_REG_ADDR);
  94         min = rtc_read (RTC_MIN_REG_ADDR);
  95         hour = rtc_read (RTC_HR_REG_ADDR);
  96         wday = rtc_read (RTC_DAY_REG_ADDR);
  97         mday = rtc_read (RTC_DATE_REG_ADDR);
  98         mon_cent = rtc_read (RTC_MON_REG_ADDR);
  99         year = rtc_read (RTC_YR_REG_ADDR);
 100
 101         DEBUGR ("Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x "
 102                 "hr: %02x min: %02x sec: %02x control: %02x status: %02x\n",
 103                 year, mon_cent, mday, wday, hour, min, sec, control, status);
 104
 105         if (status & RTC_STAT_BIT_OSF) {
 106                 printf ("### Warning: RTC oscillator has stopped\n");
 107                 /* clear the OSF flag */
 108                 rtc_write (RTC_STAT_REG_ADDR,
 109                            rtc_read (RTC_STAT_REG_ADDR) & ~RTC_STAT_BIT_OSF);
 110         }
 111
 112         tmp->tm_sec  = bcd2bin (sec & 0x7F);
 113         tmp->tm_min  = bcd2bin (min & 0x7F);
 114         tmp->tm_hour = bcd2bin (hour & 0x3F);
 115         tmp->tm_mday = bcd2bin (mday & 0x3F);
 116         tmp->tm_mon  = bcd2bin (mon_cent & 0x1F);
 117         tmp->tm_year = bcd2bin (year) + ((mon_cent & 0x80) ? 2000 : 1900);
 118         tmp->tm_wday = bcd2bin ((wday - 1) & 0x07);
 119         tmp->tm_yday = 0;
 120         tmp->tm_isdst= 0;
 121
 122         DEBUGR ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 123                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 124                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 125 }
 126
 127
 128 /*
 129  * Set the RTC
 130  */
 131 void rtc_set (struct rtc_time *tmp)
 132 {
 133         uchar century;
 134
 135         DEBUGR ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 136                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 137                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 138
 139         rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));
 140
 141         century = (tmp->tm_year >= 2000) ? 0x80 : 0;
 142         rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon) | century);
 143
 144         rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1));
 145         rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday));
 146         rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour));
 147         rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min));
 148         rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));
 149 }
 150
 151
 152 /*
 153  * Reset the RTC.  We also enable the oscillator output on the
 154  * SQW/INTB* pin and program it for 32,768 Hz output. Note that
 155  * according to the datasheet, turning on the square wave output
 156  * increases the current drain on the backup battery from about
 157  * 600 nA to 2uA.
 158  */
 159 void rtc_reset (void)
 160 {
 161         rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2);
 162 }
 163
 164
 165 /*
 166  * Helper functions
 167  */
 168
 169 static
 170 uchar rtc_read (uchar reg)
 171 {
 172         return (i2c_reg_read (CFG_I2C_RTC_ADDR, reg));
 173 }
 174
 175
 176 static void rtc_write (uchar reg, uchar val)
 177 {
 178         i2c_reg_write (CFG_I2C_RTC_ADDR, reg, val);
 179 }
 180
 181 static unsigned bcd2bin (uchar n)
 182 {
 183         return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F));
 184 }
 185
 186 static unsigned char bin2bcd (unsigned int n)
 187 {
 188         return (((n / 10) << 4) | (n % 10));
 189 }
 190
 191 #endif /* CONFIG_RTC_DS1337 && (CFG_COMMANDS & CFG_CMD_DATE) */