drivers/rtc/ds1337.c

   1 /*
   2  * (C) Copyright 2001-2008
   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_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 #define RTC_TC_REG_ADDR         0x10
  60
  61 /*
  62  * RTC control register bits
  63  */
  64 #define RTC_CTL_BIT_A1IE        0x1     /* Alarm 1 interrupt enable     */
  65 #define RTC_CTL_BIT_A2IE        0x2     /* Alarm 2 interrupt enable     */
  66 #define RTC_CTL_BIT_INTCN       0x4     /* Interrupt control            */
  67 #define RTC_CTL_BIT_RS1         0x8     /* Rate select 1                */
  68 #define RTC_CTL_BIT_RS2         0x10    /* Rate select 2                */
  69 #define RTC_CTL_BIT_DOSC        0x80    /* Disable Oscillator           */
  70
  71 /*
  72  * RTC status register bits
  73  */
  74 #define RTC_STAT_BIT_A1F        0x1     /* Alarm 1 flag                 */
  75 #define RTC_STAT_BIT_A2F        0x2     /* Alarm 2 flag                 */
  76 #define RTC_STAT_BIT_OSF        0x80    /* Oscillator stop flag         */
  77
  78
  79 static uchar rtc_read (uchar reg);
  80 static void rtc_write (uchar reg, uchar val);
  81
  82 /*
  83  * Get the current time from the RTC
  84  */
  85 int rtc_get (struct rtc_time *tmp)
  86 {
  87         int rel = 0;
  88         uchar sec, min, hour, mday, wday, mon_cent, year, control, status;
  89
  90         control = rtc_read (RTC_CTL_REG_ADDR);
  91         status = rtc_read (RTC_STAT_REG_ADDR);
  92         sec = rtc_read (RTC_SEC_REG_ADDR);
  93         min = rtc_read (RTC_MIN_REG_ADDR);
  94         hour = rtc_read (RTC_HR_REG_ADDR);
  95         wday = rtc_read (RTC_DAY_REG_ADDR);
  96         mday = rtc_read (RTC_DATE_REG_ADDR);
  97         mon_cent = rtc_read (RTC_MON_REG_ADDR);
  98         year = rtc_read (RTC_YR_REG_ADDR);
  99
 100         DEBUGR ("Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x "
 101                 "hr: %02x min: %02x sec: %02x control: %02x status: %02x\n",
 102                 year, mon_cent, mday, wday, hour, min, sec, control, status);
 103
 104         if (status & RTC_STAT_BIT_OSF) {
 105                 printf ("### Warning: RTC oscillator has stopped\n");
 106                 /* clear the OSF flag */
 107                 rtc_write (RTC_STAT_REG_ADDR,
 108                            rtc_read (RTC_STAT_REG_ADDR) & ~RTC_STAT_BIT_OSF);
 109                 rel = -1;
 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         return rel;
 127 }
 128
 129
 130 /*
 131  * Set the RTC
 132  */
 133 int rtc_set (struct rtc_time *tmp)
 134 {
 135         uchar century;
 136
 137         DEBUGR ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 138                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 139                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 140
 141         rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));
 142
 143         century = (tmp->tm_year >= 2000) ? 0x80 : 0;
 144         rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon) | century);
 145
 146         rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1));
 147         rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday));
 148         rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour));
 149         rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min));
 150         rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));
 151
 152         return 0;
 153 }
 154
 155
 156 /*
 157  * Reset the RTC.  We also enable the oscillator output on the
 158  * SQW/INTB* pin and program it for 32,768 Hz output. Note that
 159  * according to the datasheet, turning on the square wave output
 160  * increases the current drain on the backup battery from about
 161  * 600 nA to 2uA. Define CONFIG_SYS_RTC_DS1337_NOOSC if you wish to turn
 162  * off the OSC output.
 163  */
 164 #ifdef CONFIG_SYS_RTC_DS1337_NOOSC
 165  #define RTC_DS1337_RESET_VAL \
 166         (RTC_CTL_BIT_INTCN | RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2)
 167 #else
 168  #define RTC_DS1337_RESET_VAL (RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2)
 169 #endif
 170 void rtc_reset (void)
 171 {
 172         rtc_write (RTC_CTL_REG_ADDR, RTC_DS1337_RESET_VAL);
 173 #ifdef CONFIG_SYS_DS1339_TCR_VAL
 174         rtc_write (RTC_TC_REG_ADDR, CONFIG_SYS_DS1339_TCR_VAL);
 175 #endif
 176 }
 177
 178
 179 /*
 180  * Helper functions
 181  */
 182
 183 static
 184 uchar rtc_read (uchar reg)
 185 {
 186         return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
 187 }
 188
 189
 190 static void rtc_write (uchar reg, uchar val)
 191 {
 192         i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
 193 }
 194
 195 #endif