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  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 /*
  10  * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim)
  11  * DS1337 Real Time Clock (RTC).
  12  */
  13
  14 #include <common.h>
  15 #include <command.h>
  16 #include <rtc.h>
  17 #include <i2c.h>
  18
  19 #if defined(CONFIG_CMD_DATE)
  20
  21 /*
  22  * RTC register addresses
  23  */
  24 #if defined CONFIG_RTC_DS1337
  25 #define RTC_SEC_REG_ADDR        0x0
  26 #define RTC_MIN_REG_ADDR        0x1
  27 #define RTC_HR_REG_ADDR         0x2
  28 #define RTC_DAY_REG_ADDR        0x3
  29 #define RTC_DATE_REG_ADDR       0x4
  30 #define RTC_MON_REG_ADDR        0x5
  31 #define RTC_YR_REG_ADDR         0x6
  32 #define RTC_CTL_REG_ADDR        0x0e
  33 #define RTC_STAT_REG_ADDR       0x0f
  34 #define RTC_TC_REG_ADDR         0x10
  35 #elif defined CONFIG_RTC_DS1388
  36 #define RTC_SEC_REG_ADDR        0x1
  37 #define RTC_MIN_REG_ADDR        0x2
  38 #define RTC_HR_REG_ADDR         0x3
  39 #define RTC_DAY_REG_ADDR        0x4
  40 #define RTC_DATE_REG_ADDR       0x5
  41 #define RTC_MON_REG_ADDR        0x6
  42 #define RTC_YR_REG_ADDR         0x7
  43 #define RTC_CTL_REG_ADDR        0x0c
  44 #define RTC_STAT_REG_ADDR       0x0b
  45 #define RTC_TC_REG_ADDR         0x0a
  46 #endif
  47
  48 /*
  49  * RTC control register bits
  50  */
  51 #define RTC_CTL_BIT_A1IE        0x1     /* Alarm 1 interrupt enable     */
  52 #define RTC_CTL_BIT_A2IE        0x2     /* Alarm 2 interrupt enable     */
  53 #define RTC_CTL_BIT_INTCN       0x4     /* Interrupt control            */
  54 #define RTC_CTL_BIT_RS1         0x8     /* Rate select 1                */
  55 #define RTC_CTL_BIT_RS2         0x10    /* Rate select 2                */
  56 #define RTC_CTL_BIT_DOSC        0x80    /* Disable Oscillator           */
  57
  58 /*
  59  * RTC status register bits
  60  */
  61 #define RTC_STAT_BIT_A1F        0x1     /* Alarm 1 flag                 */
  62 #define RTC_STAT_BIT_A2F        0x2     /* Alarm 2 flag                 */
  63 #define RTC_STAT_BIT_OSF        0x80    /* Oscillator stop flag         */
  64
  65
  66 static uchar rtc_read (uchar reg);
  67 static void rtc_write (uchar reg, uchar val);
  68
  69 /*
  70  * Get the current time from the RTC
  71  */
  72 int rtc_get (struct rtc_time *tmp)
  73 {
  74         int rel = 0;
  75         uchar sec, min, hour, mday, wday, mon_cent, year, control, status;
  76
  77         control = rtc_read (RTC_CTL_REG_ADDR);
  78         status = rtc_read (RTC_STAT_REG_ADDR);
  79         sec = rtc_read (RTC_SEC_REG_ADDR);
  80         min = rtc_read (RTC_MIN_REG_ADDR);
  81         hour = rtc_read (RTC_HR_REG_ADDR);
  82         wday = rtc_read (RTC_DAY_REG_ADDR);
  83         mday = rtc_read (RTC_DATE_REG_ADDR);
  84         mon_cent = rtc_read (RTC_MON_REG_ADDR);
  85         year = rtc_read (RTC_YR_REG_ADDR);
  86
  87         /* No century bit, assume year 2000 */
  88 #ifdef CONFIG_RTC_DS1388
  89         mon_cent |= 0x80;
  90 #endif
  91
  92         debug("Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x "
  93                 "hr: %02x min: %02x sec: %02x control: %02x status: %02x\n",
  94                 year, mon_cent, mday, wday, hour, min, sec, control, status);
  95
  96         if (status & RTC_STAT_BIT_OSF) {
  97                 printf ("### Warning: RTC oscillator has stopped\n");
  98                 /* clear the OSF flag */
  99                 rtc_write (RTC_STAT_REG_ADDR,
 100                            rtc_read (RTC_STAT_REG_ADDR) & ~RTC_STAT_BIT_OSF);
 101                 rel = -1;
 102         }
 103
 104         tmp->tm_sec  = bcd2bin (sec & 0x7F);
 105         tmp->tm_min  = bcd2bin (min & 0x7F);
 106         tmp->tm_hour = bcd2bin (hour & 0x3F);
 107         tmp->tm_mday = bcd2bin (mday & 0x3F);
 108         tmp->tm_mon  = bcd2bin (mon_cent & 0x1F);
 109         tmp->tm_year = bcd2bin (year) + ((mon_cent & 0x80) ? 2000 : 1900);
 110         tmp->tm_wday = bcd2bin ((wday - 1) & 0x07);
 111         tmp->tm_yday = 0;
 112         tmp->tm_isdst= 0;
 113
 114         debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 115                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 116                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 117
 118         return rel;
 119 }
 120
 121
 122 /*
 123  * Set the RTC
 124  */
 125 int rtc_set (struct rtc_time *tmp)
 126 {
 127         uchar century;
 128
 129         debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 130                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 131                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 132
 133         rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));
 134
 135         century = (tmp->tm_year >= 2000) ? 0x80 : 0;
 136         rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon) | century);
 137
 138         rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1));
 139         rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday));
 140         rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour));
 141         rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min));
 142         rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));
 143
 144         return 0;
 145 }
 146
 147
 148 /*
 149  * Reset the RTC.  We also enable the oscillator output on the
 150  * SQW/INTB* pin and program it for 32,768 Hz output. Note that
 151  * according to the datasheet, turning on the square wave output
 152  * increases the current drain on the backup battery from about
 153  * 600 nA to 2uA. Define CONFIG_RTC_DS1337_NOOSC if you wish to turn
 154  * off the OSC output.
 155  */
 156
 157 #ifdef CONFIG_RTC_DS1337_NOOSC
 158  #define RTC_DS1337_RESET_VAL \
 159         (RTC_CTL_BIT_INTCN | RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2)
 160 #else
 161  #define RTC_DS1337_RESET_VAL (RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2)
 162 #endif
 163 void rtc_reset (void)
 164 {
 165 #ifdef CONFIG_RTC_DS1337
 166         rtc_write (RTC_CTL_REG_ADDR, RTC_DS1337_RESET_VAL);
 167 #elif defined CONFIG_RTC_DS1388
 168         rtc_write(RTC_CTL_REG_ADDR, 0x0); /* hw default */
 169 #endif
 170 #ifdef CONFIG_RTC_DS1339_TCR_VAL
 171         rtc_write (RTC_TC_REG_ADDR, CONFIG_RTC_DS1339_TCR_VAL);
 172 #endif
 173 #ifdef CONFIG_RTC_DS1388_TCR_VAL
 174         rtc_write(RTC_TC_REG_ADDR, CONFIG_RTC_DS1388_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