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  * 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)) && defined(CONFIG_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 int rtc_get (struct rtc_time *tm){
 111         int rel = 0;
 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                 rel = -1;
 142         }
 143
 144         DEBUGR ("Get RTC s since 1.1.1970: %d\n", time1);
 145
 146         to_tm(time1, tm); /* To Gregorian Date */
 147
 148         if (rtc_read(RTC_SR_ADDR) & RTC_SR_BIT_OSF) {
 149                 printf ("### Warning: RTC oscillator has stopped\n");
 150                 rel = -1;
 151         }
 152
 153         DEBUGR ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 154                 tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
 155                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 156
 157         return rel;
 158 }
 159
 160 /*
 161  * Set the RTC
 162  */
 163 void rtc_set (struct rtc_time *tmp){
 164
 165         unsigned long time;
 166         unsigned i;
 167
 168         DEBUGR ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 169                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 170                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 171
 172         if (tmp->tm_year < 1970 || tmp->tm_year > 2069)
 173                 printf("WARNING: year should be between 1970 and 2069!\n");
 174
 175         time = mktime(tmp->tm_year, tmp->tm_mon,
 176                         tmp->tm_mday, tmp->tm_hour,
 177                         tmp->tm_min, tmp->tm_sec);
 178
 179         DEBUGR ("Set RTC s since 1.1.1970: %d (0x%02x)\n", time, time);
 180
 181         /* write to RTC_TOD_CNT_BYTEn_ADDR */
 182         for (i = 0; i <= 3; i++) {
 183                 rtc_write_raw(RtcTodAddr[i], (unsigned char)(time & 0xff));
 184                 time = time >> 8;
 185         }
 186
 187         /* Start clock */
 188         rtc_write(RTC_CTL_ADDR, RTC_CTL_BIT_EN_OSC, FALSE);
 189 }
 190
 191 /*
 192  * Reset the RTC. We setting the date back to 1970-01-01.
 193  * We also enable the oscillator output on the SQW/OUT pin and program
 194  * it for 32,768 Hz output. Note that according to the datasheet, turning
 195  * on the square wave output increases the current drain on the backup
 196  * battery to something between 480nA and 800nA.
 197  */
 198 void rtc_reset (void){
 199
 200         struct rtc_time tmp;
 201
 202         /* clear status flags */
 203         rtc_write (RTC_SR_ADDR, (RTC_SR_BIT_AF|RTC_SR_BIT_OSF), FALSE); /* clearing OSF and AF */
 204
 205         /* Initialise DS1374 oriented to MPC8349E-ADS */
 206         rtc_write (RTC_CTL_ADDR, (RTC_CTL_BIT_EN_OSC
 207                                  |RTC_CTL_BIT_WACE
 208                                  |RTC_CTL_BIT_AIE), FALSE);/* start osc, disable WACE, clear AIE
 209                                                               - set to 0 */
 210         rtc_write (RTC_CTL_ADDR, (RTC_CTL_BIT_WD_ALM
 211                                 |RTC_CTL_BIT_WDSTR
 212                                 |RTC_CTL_BIT_RS1
 213                                 |RTC_CTL_BIT_RS2
 214                                 |RTC_CTL_BIT_BBSQW), TRUE);/* disable WD/ALM, WDSTR set to INT-pin,
 215                                                               set BBSQW and SQW to 32k
 216                                                               - set to 1 */
 217         tmp.tm_year = 1970;
 218         tmp.tm_mon = 1;
 219         tmp.tm_mday= 1;
 220         tmp.tm_hour = 0;
 221         tmp.tm_min = 0;
 222         tmp.tm_sec = 0;
 223
 224         rtc_set(&tmp);
 225
 226         printf("RTC:   %4d-%02d-%02d %2d:%02d:%02d UTC\n",
 227                 tmp.tm_year, tmp.tm_mon, tmp.tm_mday,
 228                 tmp.tm_hour, tmp.tm_min, tmp.tm_sec);
 229
 230         rtc_write(RTC_WD_ALM_CNT_BYTE2_ADDR,0xAC, TRUE);
 231         rtc_write(RTC_WD_ALM_CNT_BYTE1_ADDR,0xDE, TRUE);
 232         rtc_write(RTC_WD_ALM_CNT_BYTE2_ADDR,0xAD, TRUE);
 233 }
 234
 235 /*
 236  * Helper functions
 237  */
 238 static uchar rtc_read (uchar reg)
 239 {
 240         return (i2c_reg_read (CFG_I2C_RTC_ADDR, reg));
 241 }
 242
 243 static void rtc_write (uchar reg, uchar val, boolean_t set)
 244 {
 245         if (set == TRUE) {
 246                 val |= i2c_reg_read (CFG_I2C_RTC_ADDR, reg);
 247                 i2c_reg_write (CFG_I2C_RTC_ADDR, reg, val);
 248         } else {
 249                 val = i2c_reg_read (CFG_I2C_RTC_ADDR, reg) & ~val;
 250                 i2c_reg_write (CFG_I2C_RTC_ADDR, reg, val);
 251         }
 252 }
 253
 254 static void rtc_write_raw (uchar reg, uchar val)
 255 {
 256                 i2c_reg_write (CFG_I2C_RTC_ADDR, reg, val);
 257 }
 258 #endif