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  * RTC register addresses
  39  */
  40 #define RTC_SEC_REG_ADDR        0x0
  41 #define RTC_MIN_REG_ADDR        0x1
  42 #define RTC_HR_REG_ADDR         0x2
  43 #define RTC_DAY_REG_ADDR        0x3
  44 #define RTC_DATE_REG_ADDR       0x4
  45 #define RTC_MON_REG_ADDR        0x5
  46 #define RTC_YR_REG_ADDR         0x6
  47 #define RTC_CTL_REG_ADDR        0x0e
  48 #define RTC_STAT_REG_ADDR       0x0f
  49 #define RTC_TC_REG_ADDR         0x10
  50
  51 /*
  52  * RTC control register bits
  53  */
  54 #define RTC_CTL_BIT_A1IE        0x1     /* Alarm 1 interrupt enable     */
  55 #define RTC_CTL_BIT_A2IE        0x2     /* Alarm 2 interrupt enable     */
  56 #define RTC_CTL_BIT_INTCN       0x4     /* Interrupt control            */
  57 #define RTC_CTL_BIT_RS1         0x8     /* Rate select 1                */
  58 #define RTC_CTL_BIT_RS2         0x10    /* Rate select 2                */
  59 #define RTC_CTL_BIT_DOSC        0x80    /* Disable Oscillator           */
  60
  61 /*
  62  * RTC status register bits
  63  */
  64 #define RTC_STAT_BIT_A1F        0x1     /* Alarm 1 flag                 */
  65 #define RTC_STAT_BIT_A2F        0x2     /* Alarm 2 flag                 */
  66 #define RTC_STAT_BIT_OSF        0x80    /* Oscillator stop flag         */
  67
  68
  69 static uchar rtc_read (uchar reg);
  70 static void rtc_write (uchar reg, uchar val);
  71
  72 /*
  73  * Get the current time from the RTC
  74  */
  75 int rtc_get (struct rtc_time *tmp)
  76 {
  77         int rel = 0;
  78         uchar sec, min, hour, mday, wday, mon_cent, year, control, status;
  79
  80         control = rtc_read (RTC_CTL_REG_ADDR);
  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_cent = rtc_read (RTC_MON_REG_ADDR);
  88         year = rtc_read (RTC_YR_REG_ADDR);
  89
  90         debug("Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x "
  91                 "hr: %02x min: %02x sec: %02x control: %02x status: %02x\n",
  92                 year, mon_cent, mday, wday, hour, min, sec, control, status);
  93
  94         if (status & RTC_STAT_BIT_OSF) {
  95                 printf ("### Warning: RTC oscillator has stopped\n");
  96                 /* clear the OSF flag */
  97                 rtc_write (RTC_STAT_REG_ADDR,
  98                            rtc_read (RTC_STAT_REG_ADDR) & ~RTC_STAT_BIT_OSF);
  99                 rel = -1;
 100         }
 101
 102         tmp->tm_sec  = bcd2bin (sec & 0x7F);
 103         tmp->tm_min  = bcd2bin (min & 0x7F);
 104         tmp->tm_hour = bcd2bin (hour & 0x3F);
 105         tmp->tm_mday = bcd2bin (mday & 0x3F);
 106         tmp->tm_mon  = bcd2bin (mon_cent & 0x1F);
 107         tmp->tm_year = bcd2bin (year) + ((mon_cent & 0x80) ? 2000 : 1900);
 108         tmp->tm_wday = bcd2bin ((wday - 1) & 0x07);
 109         tmp->tm_yday = 0;
 110         tmp->tm_isdst= 0;
 111
 112         debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 113                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 114                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 115
 116         return rel;
 117 }
 118
 119
 120 /*
 121  * Set the RTC
 122  */
 123 int rtc_set (struct rtc_time *tmp)
 124 {
 125         uchar century;
 126
 127         debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 128                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 129                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 130
 131         rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));
 132
 133         century = (tmp->tm_year >= 2000) ? 0x80 : 0;
 134         rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon) | century);
 135
 136         rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1));
 137         rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday));
 138         rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour));
 139         rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min));
 140         rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));
 141
 142         return 0;
 143 }
 144
 145
 146 /*
 147  * Reset the RTC.  We also enable the oscillator output on the
 148  * SQW/INTB* pin and program it for 32,768 Hz output. Note that
 149  * according to the datasheet, turning on the square wave output
 150  * increases the current drain on the backup battery from about
 151  * 600 nA to 2uA. Define CONFIG_SYS_RTC_DS1337_NOOSC if you wish to turn
 152  * off the OSC output.
 153  */
 154 #ifdef CONFIG_SYS_RTC_DS1337_NOOSC
 155  #define RTC_DS1337_RESET_VAL \
 156         (RTC_CTL_BIT_INTCN | RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2)
 157 #else
 158  #define RTC_DS1337_RESET_VAL (RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2)
 159 #endif
 160 void rtc_reset (void)
 161 {
 162         rtc_write (RTC_CTL_REG_ADDR, RTC_DS1337_RESET_VAL);
 163 #ifdef CONFIG_SYS_DS1339_TCR_VAL
 164         rtc_write (RTC_TC_REG_ADDR, CONFIG_SYS_DS1339_TCR_VAL);
 165 #endif
 166 }
 167
 168
 169 /*
 170  * Helper functions
 171  */
 172
 173 static
 174 uchar rtc_read (uchar reg)
 175 {
 176         return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
 177 }
 178
 179
 180 static void rtc_write (uchar reg, uchar val)
 181 {
 182         i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
 183 }
 184
 185 #endif