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  * See file CREDITS for list of people who contributed to this
   8  * project.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of
  13  * the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  23  * MA 02111-1307 USA
  24  */
  25
  26 /*
  27  * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim)
  28  * DS1374 Real Time Clock (RTC).
  29  *
  30  * based on ds1337.c
  31  */
  32
  33 #include <common.h>
  34 #include <command.h>
  35 #include <rtc.h>
  36 #include <i2c.h>
  37
  38 #if (defined(CONFIG_RTC_DS1374)) && (CONFIG_COMMANDS & CFG_CMD_DATE)
  39
  40 /*---------------------------------------------------------------------*/
  41 #undef DEBUG_RTC
  42 #define DEBUG_RTC
  43
  44 #ifdef DEBUG_RTC
  45 #define DEBUGR(fmt,args...) printf(fmt ,##args)
  46 #else
  47 #define DEBUGR(fmt,args...)
  48 #endif
  49 /*---------------------------------------------------------------------*/
  50
  51 #ifndef CFG_I2C_RTC_ADDR
  52 # define CFG_I2C_RTC_ADDR       0x68
  53 #endif
  54
  55 #if defined(CONFIG_RTC_DS1374) && (CFG_I2C_SPEED > 400000)
  56 # error The DS1374 is specified up to 400kHz in fast mode!
  57 #endif
  58
  59 /*
  60  * RTC register addresses
  61  */
  62 #define RTC_TOD_CNT_BYTE0_ADDR          0x00 /* TimeOfDay */
  63 #define RTC_TOD_CNT_BYTE1_ADDR          0x01
  64 #define RTC_TOD_CNT_BYTE2_ADDR          0x02
  65 #define RTC_TOD_CNT_BYTE3_ADDR          0x03
  66
  67 #define RTC_WD_ALM_CNT_BYTE0_ADDR       0x04
  68 #define RTC_WD_ALM_CNT_BYTE1_ADDR       0x05
  69 #define RTC_WD_ALM_CNT_BYTE2_ADDR       0x06
  70
  71 #define RTC_CTL_ADDR                    0x07 /* RTC-CoNTrol-register */
  72 #define RTC_SR_ADDR                     0x08 /* RTC-StatusRegister */
  73 #define RTC_TCS_DS_ADDR                 0x09 /* RTC-TrickleChargeSelect DiodeSelect-register */
  74
  75 #define RTC_CTL_BIT_AIE                 (1<<0) /* Bit 0 - Alarm Interrupt enable */
  76 #define RTC_CTL_BIT_RS1                 (1<<1) /* Bit 1/2 - Rate Select square wave output */
  77 #define RTC_CTL_BIT_RS2                 (1<<2) /* Bit 2/2 - Rate Select square wave output */
  78 #define RTC_CTL_BIT_WDSTR               (1<<3) /* Bit 3 - Watchdog Reset Steering */
  79 #define RTC_CTL_BIT_BBSQW               (1<<4) /* Bit 4 - Battery-Backed Square-Wave */
  80 #define RTC_CTL_BIT_WD_ALM              (1<<5) /* Bit 5 - Watchdoc/Alarm Counter Select */
  81 #define RTC_CTL_BIT_WACE                (1<<6) /* Bit 6 - Watchdog/Alarm Counter Enable WACE*/
  82 #define RTC_CTL_BIT_EN_OSC              (1<<7) /* Bit 7 - Enable Oscilator */
  83
  84 #define RTC_SR_BIT_AF                   0x01 /* Bit 0 = Alarm Flag */
  85 #define RTC_SR_BIT_OSF                  0x80 /* Bit 7 - Osc Stop Flag */
  86
  87 typedef unsigned char boolean_t;
  88
  89 #ifndef TRUE
  90 #define TRUE ((boolean_t)(0==0))
  91 #endif
  92 #ifndef FALSE
  93 #define FALSE (!TRUE)
  94 #endif
  95
  96 const char RtcTodAddr[] = {
  97         RTC_TOD_CNT_BYTE0_ADDR,
  98         RTC_TOD_CNT_BYTE1_ADDR,
  99         RTC_TOD_CNT_BYTE2_ADDR,
 100         RTC_TOD_CNT_BYTE3_ADDR
 101 };
 102
 103 static uchar rtc_read (uchar reg);
 104 static void rtc_write (uchar reg, uchar val, boolean_t set);
 105 static void rtc_write_raw (uchar reg, uchar val);
 106
 107 /*
 108  * Get the current time from the RTC
 109  */
 110 void rtc_get (struct rtc_time *tm){
 111
 112         unsigned long time1, time2;
 113         unsigned int limit;
 114         unsigned char tmp;
 115         unsigned int i;
 116
 117         /*
 118          * Since the reads are being performed one byte at a time,
 119          * there is a chance that a carry will occur during the read.
 120          * To detect this, 2 reads are performed and compared.
 121          */
 122         limit = 10;
 123         do {
 124                 i = 4;
 125                 time1 = 0;
 126                 while (i--) {
 127                         tmp = rtc_read(RtcTodAddr[i]);
 128                         time1 = (time1 << 8) | (tmp & 0xff);
 129                 }
 130
 131                 i = 4;
 132                 time2 = 0;
 133                 while (i--) {
 134                         tmp = rtc_read(RtcTodAddr[i]);
 135                         time2 = (time2 << 8) | (tmp & 0xff);
 136                 }
 137         } while ((time1 != time2) && limit--);
 138
 139         if (time1 != time2) {
 140                 printf("can't get consistent time from rtc chip\n");
 141         }
 142
 143         DEBUGR ("Get RTC s since 1.1.1970: %d\n", time1);
 144
 145         to_tm(time1, tm); /* To Gregorian Date */
 146
 147         if (rtc_read(RTC_SR_ADDR) & RTC_SR_BIT_OSF)
 148                 printf ("### Warning: RTC oscillator has stopped\n");
 149
 150         DEBUGR ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 151                 tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
 152                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 153 }
 154
 155 /*
 156  * Set the RTC
 157  */
 158 void rtc_set (struct rtc_time *tmp){
 159
 160         unsigned long time;
 161         unsigned i;
 162
 163         DEBUGR ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 164                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 165                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 166
 167         if (tmp->tm_year < 1970 || tmp->tm_year > 2069)
 168                 printf("WARNING: year should be between 1970 and 2069!\n");
 169
 170         time = mktime(tmp->tm_year, tmp->tm_mon,
 171                         tmp->tm_mday, tmp->tm_hour,
 172                         tmp->tm_min, tmp->tm_sec);
 173
 174         DEBUGR ("Set RTC s since 1.1.1970: %d (0x%02x)\n", time, time);
 175
 176         /* write to RTC_TOD_CNT_BYTEn_ADDR */
 177         for (i = 0; i <= 3; i++) {
 178                 rtc_write_raw(RtcTodAddr[i], (unsigned char)(time & 0xff));
 179                 time = time >> 8;
 180         }
 181
 182         /* Start clock */
 183         rtc_write(RTC_CTL_ADDR, RTC_CTL_BIT_EN_OSC, FALSE);
 184 }
 185
 186 /*
 187  * Reset the RTC. We setting the date back to 1970-01-01.
 188  * We also enable the oscillator output on the SQW/OUT pin and program
 189  * it for 32,768 Hz output. Note that according to the datasheet, turning
 190  * on the square wave output increases the current drain on the backup
 191  * battery to something between 480nA and 800nA.
 192  */
 193 void rtc_reset (void){
 194
 195         struct rtc_time tmp;
 196
 197         /* clear status flags */
 198         rtc_write (RTC_SR_ADDR, (RTC_SR_BIT_AF|RTC_SR_BIT_OSF), FALSE); /* clearing OSF and AF */
 199
 200         /* Initialise DS1374 oriented to MPC8349E-ADS */
 201         rtc_write (RTC_CTL_ADDR, (RTC_CTL_BIT_EN_OSC
 202                                  |RTC_CTL_BIT_WACE
 203                                  |RTC_CTL_BIT_AIE), FALSE);/* start osc, disable WACE, clear AIE
 204                                                               - set to 0 */
 205         rtc_write (RTC_CTL_ADDR, (RTC_CTL_BIT_WD_ALM
 206                                 |RTC_CTL_BIT_WDSTR
 207                                 |RTC_CTL_BIT_RS1
 208                                 |RTC_CTL_BIT_RS2
 209                                 |RTC_CTL_BIT_BBSQW), TRUE);/* disable WD/ALM, WDSTR set to INT-pin,
 210                                                               set BBSQW and SQW to 32k
 211                                                               - set to 1 */
 212         tmp.tm_year = 1970;
 213         tmp.tm_mon = 1;
 214         tmp.tm_mday= 1;
 215         tmp.tm_hour = 0;
 216         tmp.tm_min = 0;
 217         tmp.tm_sec = 0;
 218
 219         rtc_set(&tmp);
 220
 221         printf("RTC:   %4d-%02d-%02d %2d:%02d:%02d UTC\n",
 222                 tmp.tm_year, tmp.tm_mon, tmp.tm_mday,
 223                 tmp.tm_hour, tmp.tm_min, tmp.tm_sec);
 224
 225         rtc_write(RTC_WD_ALM_CNT_BYTE2_ADDR,0xAC, TRUE);
 226         rtc_write(RTC_WD_ALM_CNT_BYTE1_ADDR,0xDE, TRUE);
 227         rtc_write(RTC_WD_ALM_CNT_BYTE2_ADDR,0xAD, TRUE);
 228 }
 229
 230 /*
 231  * Helper functions
 232  */
 233 static uchar rtc_read (uchar reg)
 234 {
 235         return (i2c_reg_read (CFG_I2C_RTC_ADDR, reg));
 236 }
 237
 238 static void rtc_write (uchar reg, uchar val, boolean_t set)
 239 {
 240         if (set == TRUE) {
 241                 val |= i2c_reg_read (CFG_I2C_RTC_ADDR, reg);
 242                 i2c_reg_write (CFG_I2C_RTC_ADDR, reg, val);
 243         } else {
 244                 val = i2c_reg_read (CFG_I2C_RTC_ADDR, reg) & ~val;
 245                 i2c_reg_write (CFG_I2C_RTC_ADDR, reg, val);
 246         }
 247 }
 248
 249 static void rtc_write_raw (uchar reg, uchar val)
 250 {
 251                 i2c_reg_write (CFG_I2C_RTC_ADDR, reg, val);
 252 }
 253 #endif /* (CONFIG_RTC_DS1374) && (CFG_COMMANDS & CFG_CMD_DATE) */