drivers/rtc/ds1374.c

   1 /*
   2  * (C) Copyright 2001, 2002, 2003
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  * Keith Outwater, keith_outwater@mvis.com`
   5  * Steven Scholz, steven.scholz@imc-berlin.de
   6  *
   7  * SPDX-License-Identifier:     GPL-2.0+
   8  */
   9
  10 /*
  11  * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim)
  12  * DS1374 Real Time Clock (RTC).
  13  *
  14  * based on ds1337.c
  15  */
  16
  17 #include <common.h>
  18 #include <command.h>
  19 #include <rtc.h>
  20 #include <i2c.h>
  21
  22 #if defined(CONFIG_CMD_DATE)
  23
  24 /*---------------------------------------------------------------------*/
  25 #undef DEBUG_RTC
  26 #define DEBUG_RTC
  27
  28 #ifdef DEBUG_RTC
  29 #define DEBUGR(fmt,args...) printf(fmt ,##args)
  30 #else
  31 #define DEBUGR(fmt,args...)
  32 #endif
  33 /*---------------------------------------------------------------------*/
  34
  35 #ifndef CONFIG_SYS_I2C_RTC_ADDR
  36 # define CONFIG_SYS_I2C_RTC_ADDR        0x68
  37 #endif
  38
  39 #if defined(CONFIG_RTC_DS1374) && (CONFIG_SYS_I2C_SPEED > 400000)
  40 # error The DS1374 is specified up to 400kHz in fast mode!
  41 #endif
  42
  43 /*
  44  * RTC register addresses
  45  */
  46 #define RTC_TOD_CNT_BYTE0_ADDR          0x00 /* TimeOfDay */
  47 #define RTC_TOD_CNT_BYTE1_ADDR          0x01
  48 #define RTC_TOD_CNT_BYTE2_ADDR          0x02
  49 #define RTC_TOD_CNT_BYTE3_ADDR          0x03
  50
  51 #define RTC_WD_ALM_CNT_BYTE0_ADDR       0x04
  52 #define RTC_WD_ALM_CNT_BYTE1_ADDR       0x05
  53 #define RTC_WD_ALM_CNT_BYTE2_ADDR       0x06
  54
  55 #define RTC_CTL_ADDR                    0x07 /* RTC-CoNTrol-register */
  56 #define RTC_SR_ADDR                     0x08 /* RTC-StatusRegister */
  57 #define RTC_TCS_DS_ADDR                 0x09 /* RTC-TrickleChargeSelect DiodeSelect-register */
  58
  59 #define RTC_CTL_BIT_AIE                 (1<<0) /* Bit 0 - Alarm Interrupt enable */
  60 #define RTC_CTL_BIT_RS1                 (1<<1) /* Bit 1/2 - Rate Select square wave output */
  61 #define RTC_CTL_BIT_RS2                 (1<<2) /* Bit 2/2 - Rate Select square wave output */
  62 #define RTC_CTL_BIT_WDSTR               (1<<3) /* Bit 3 - Watchdog Reset Steering */
  63 #define RTC_CTL_BIT_BBSQW               (1<<4) /* Bit 4 - Battery-Backed Square-Wave */
  64 #define RTC_CTL_BIT_WD_ALM              (1<<5) /* Bit 5 - Watchdoc/Alarm Counter Select */
  65 #define RTC_CTL_BIT_WACE                (1<<6) /* Bit 6 - Watchdog/Alarm Counter Enable WACE*/
  66 #define RTC_CTL_BIT_EN_OSC              (1<<7) /* Bit 7 - Enable Oscilator */
  67
  68 #define RTC_SR_BIT_AF                   0x01 /* Bit 0 = Alarm Flag */
  69 #define RTC_SR_BIT_OSF                  0x80 /* Bit 7 - Osc Stop Flag */
  70
  71 const char RtcTodAddr[] = {
  72         RTC_TOD_CNT_BYTE0_ADDR,
  73         RTC_TOD_CNT_BYTE1_ADDR,
  74         RTC_TOD_CNT_BYTE2_ADDR,
  75         RTC_TOD_CNT_BYTE3_ADDR
  76 };
  77
  78 static uchar rtc_read (uchar reg);
  79 static void rtc_write(uchar reg, uchar val, bool set);
  80 static void rtc_write_raw (uchar reg, uchar val);
  81
  82 /*
  83  * Get the current time from the RTC
  84  */
  85 int rtc_get (struct rtc_time *tm){
  86         int rel = 0;
  87         unsigned long time1, time2;
  88         unsigned int limit;
  89         unsigned char tmp;
  90         unsigned int i;
  91
  92         /*
  93          * Since the reads are being performed one byte at a time,
  94          * there is a chance that a carry will occur during the read.
  95          * To detect this, 2 reads are performed and compared.
  96          */
  97         limit = 10;
  98         do {
  99                 i = 4;
 100                 time1 = 0;
 101                 while (i--) {
 102                         tmp = rtc_read(RtcTodAddr[i]);
 103                         time1 = (time1 << 8) | (tmp & 0xff);
 104                 }
 105
 106                 i = 4;
 107                 time2 = 0;
 108                 while (i--) {
 109                         tmp = rtc_read(RtcTodAddr[i]);
 110                         time2 = (time2 << 8) | (tmp & 0xff);
 111                 }
 112         } while ((time1 != time2) && limit--);
 113
 114         if (time1 != time2) {
 115                 printf("can't get consistent time from rtc chip\n");
 116                 rel = -1;
 117         }
 118
 119         DEBUGR ("Get RTC s since 1.1.1970: %ld\n", time1);
 120
 121         to_tm(time1, tm); /* To Gregorian Date */
 122
 123         if (rtc_read(RTC_SR_ADDR) & RTC_SR_BIT_OSF) {
 124                 printf ("### Warning: RTC oscillator has stopped\n");
 125                 rel = -1;
 126         }
 127
 128         DEBUGR ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 129                 tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
 130                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 131
 132         return rel;
 133 }
 134
 135 /*
 136  * Set the RTC
 137  */
 138 int rtc_set (struct rtc_time *tmp){
 139
 140         unsigned long time;
 141         unsigned i;
 142
 143         DEBUGR ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 144                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 145                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 146
 147         if (tmp->tm_year < 1970 || tmp->tm_year > 2069)
 148                 printf("WARNING: year should be between 1970 and 2069!\n");
 149
 150         time = mktime(tmp->tm_year, tmp->tm_mon,
 151                         tmp->tm_mday, tmp->tm_hour,
 152                         tmp->tm_min, tmp->tm_sec);
 153
 154         DEBUGR ("Set RTC s since 1.1.1970: %ld (0x%02lx)\n", time, time);
 155
 156         /* write to RTC_TOD_CNT_BYTEn_ADDR */
 157         for (i = 0; i <= 3; i++) {
 158                 rtc_write_raw(RtcTodAddr[i], (unsigned char)(time & 0xff));
 159                 time = time >> 8;
 160         }
 161
 162         /* Start clock */
 163         rtc_write(RTC_CTL_ADDR, RTC_CTL_BIT_EN_OSC, false);
 164
 165         return 0;
 166 }
 167
 168 /*
 169  * Reset the RTC. We setting the date back to 1970-01-01.
 170  * We also enable the oscillator output on the SQW/OUT pin and program
 171  * it for 32,768 Hz output. Note that according to the datasheet, turning
 172  * on the square wave output increases the current drain on the backup
 173  * battery to something between 480nA and 800nA.
 174  */
 175 void rtc_reset (void){
 176
 177         struct rtc_time tmp;
 178
 179         /* clear status flags */
 180         rtc_write(RTC_SR_ADDR, (RTC_SR_BIT_AF|RTC_SR_BIT_OSF), false); /* clearing OSF and AF */
 181
 182         /* Initialise DS1374 oriented to MPC8349E-ADS */
 183         rtc_write (RTC_CTL_ADDR, (RTC_CTL_BIT_EN_OSC
 184                                  |RTC_CTL_BIT_WACE
 185                                  |RTC_CTL_BIT_AIE), false);/* start osc, disable WACE, clear AIE
 186                                                               - set to 0 */
 187         rtc_write (RTC_CTL_ADDR, (RTC_CTL_BIT_WD_ALM
 188                                 |RTC_CTL_BIT_WDSTR
 189                                 |RTC_CTL_BIT_RS1
 190                                 |RTC_CTL_BIT_RS2
 191                                 |RTC_CTL_BIT_BBSQW), true);/* disable WD/ALM, WDSTR set to INT-pin,
 192                                                               set BBSQW and SQW to 32k
 193                                                               - set to 1 */
 194         tmp.tm_year = 1970;
 195         tmp.tm_mon = 1;
 196         tmp.tm_mday= 1;
 197         tmp.tm_hour = 0;
 198         tmp.tm_min = 0;
 199         tmp.tm_sec = 0;
 200
 201         rtc_set(&tmp);
 202
 203         printf("RTC:   %4d-%02d-%02d %2d:%02d:%02d UTC\n",
 204                 tmp.tm_year, tmp.tm_mon, tmp.tm_mday,
 205                 tmp.tm_hour, tmp.tm_min, tmp.tm_sec);
 206
 207         rtc_write(RTC_WD_ALM_CNT_BYTE2_ADDR, 0xAC, true);
 208         rtc_write(RTC_WD_ALM_CNT_BYTE1_ADDR, 0xDE, true);
 209         rtc_write(RTC_WD_ALM_CNT_BYTE2_ADDR, 0xAD, true);
 210 }
 211
 212 /*
 213  * Helper functions
 214  */
 215 static uchar rtc_read (uchar reg)
 216 {
 217         return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
 218 }
 219
 220 static void rtc_write(uchar reg, uchar val, bool set)
 221 {
 222         if (set == true) {
 223                 val |= i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg);
 224                 i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
 225         } else {
 226                 val = i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg) & ~val;
 227                 i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
 228         }
 229 }
 230
 231 static void rtc_write_raw (uchar reg, uchar val)
 232 {
 233                 i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
 234 }
 235 #endif