drivers/rtc/ds1306.c

   1 /*
   2  * (C) Copyright 2002 SIXNET, dge@sixnetio.com.
   3  *
   4  * (C) Copyright 2004, Li-Pro.Net <www.li-pro.net>
   5  * Stephan Linz <linz@li-pro.net>
   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 for DS1306 RTC using SPI:
  28  *
  29  *    - SXNI855T:    it uses its own soft SPI here in this file
  30  *    - all other:   use the external spi_xfer() function
  31  *                   (see include/spi.h)
  32  */
  33
  34 #include <common.h>
  35 #include <command.h>
  36 #include <rtc.h>
  37 #include <spi.h>
  38
  39 #if defined(CONFIG_CMD_DATE)
  40
  41 #define RTC_SECONDS             0x00
  42 #define RTC_MINUTES             0x01
  43 #define RTC_HOURS               0x02
  44 #define RTC_DAY_OF_WEEK         0x03
  45 #define RTC_DATE_OF_MONTH       0x04
  46 #define RTC_MONTH               0x05
  47 #define RTC_YEAR                0x06
  48
  49 #define RTC_SECONDS_ALARM0      0x07
  50 #define RTC_MINUTES_ALARM0      0x08
  51 #define RTC_HOURS_ALARM0        0x09
  52 #define RTC_DAY_OF_WEEK_ALARM0  0x0a
  53
  54 #define RTC_SECONDS_ALARM1      0x0b
  55 #define RTC_MINUTES_ALARM1      0x0c
  56 #define RTC_HOURS_ALARM1        0x0d
  57 #define RTC_DAY_OF_WEEK_ALARM1  0x0e
  58
  59 #define RTC_CONTROL             0x0f
  60 #define RTC_STATUS              0x10
  61 #define RTC_TRICKLE_CHARGER     0x11
  62
  63 #define RTC_USER_RAM_BASE       0x20
  64
  65 static unsigned int bin2bcd (unsigned int n);
  66 static unsigned char bcd2bin (unsigned char c);
  67
  68 /* ************************************************************************* */
  69 #ifdef CONFIG_SXNI855T          /* !!! SHOULD BE CHANGED TO NEW CODE !!! */
  70
  71 static void soft_spi_send (unsigned char n);
  72 static unsigned char soft_spi_read (void);
  73 static void init_spi (void);
  74
  75 /*-----------------------------------------------------------------------
  76  * Definitions
  77  */
  78
  79 #define PB_SPISCK       0x00000002      /* PB 30 */
  80 #define PB_SPIMOSI      0x00000004      /* PB 29 */
  81 #define PB_SPIMISO      0x00000008      /* PB 28 */
  82 #define PB_SPI_CE       0x00010000      /* PB 15 */
  83
  84 /* ------------------------------------------------------------------------- */
  85
  86 /* read clock time from DS1306 and return it in *tmp */
  87 int rtc_get (struct rtc_time *tmp)
  88 {
  89         volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
  90         unsigned char spi_byte; /* Data Byte */
  91
  92         init_spi ();            /* set port B for software SPI */
  93
  94         /* Now we can enable the DS1306 RTC */
  95         immap->im_cpm.cp_pbdat |= PB_SPI_CE;
  96         udelay (10);
  97
  98         /* Shift out the address (0) of the time in the Clock Chip */
  99         soft_spi_send (0);
 100
 101         /* Put the clock readings into the rtc_time structure */
 102         tmp->tm_sec = bcd2bin (soft_spi_read ());       /* Read seconds */
 103         tmp->tm_min = bcd2bin (soft_spi_read ());       /* Read minutes */
 104
 105         /* Hours are trickier */
 106         spi_byte = soft_spi_read ();    /* Read Hours into temporary value */
 107         if (spi_byte & 0x40) {
 108                 /* 12 hour mode bit is set (time is in 1-12 format) */
 109                 if (spi_byte & 0x20) {
 110                         /* since PM we add 11 to get 0-23 for hours */
 111                         tmp->tm_hour = (bcd2bin (spi_byte & 0x1F)) + 11;
 112                 } else {
 113                         /* since AM we subtract 1 to get 0-23 for hours */
 114                         tmp->tm_hour = (bcd2bin (spi_byte & 0x1F)) - 1;
 115                 }
 116         } else {
 117                 /* Otherwise, 0-23 hour format */
 118                 tmp->tm_hour = (bcd2bin (spi_byte & 0x3F));
 119         }
 120
 121         soft_spi_read ();       /* Read and discard Day of week */
 122         tmp->tm_mday = bcd2bin (soft_spi_read ());      /* Read Day of the Month */
 123         tmp->tm_mon = bcd2bin (soft_spi_read ());       /* Read Month */
 124
 125         /* Read Year and convert to this century */
 126         tmp->tm_year = bcd2bin (soft_spi_read ()) + 2000;
 127
 128         /* Now we can disable the DS1306 RTC */
 129         immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;   /* Disable DS1306 Chip */
 130         udelay (10);
 131
 132         GregorianDay (tmp);     /* Determine the day of week */
 133
 134         debug ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 135                tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 136                tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 137
 138         return 0;
 139 }
 140
 141 /* ------------------------------------------------------------------------- */
 142
 143 /* set clock time in DS1306 RTC and in MPC8xx RTC */
 144 int rtc_set (struct rtc_time *tmp)
 145 {
 146         volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
 147
 148         init_spi ();            /* set port B for software SPI */
 149
 150         /* Now we can enable the DS1306 RTC */
 151         immap->im_cpm.cp_pbdat |= PB_SPI_CE;    /* Enable DS1306 Chip */
 152         udelay (10);
 153
 154         /* First disable write protect in the clock chip control register */
 155         soft_spi_send (0x8F);   /* send address of the control register */
 156         soft_spi_send (0x00);   /* send control register contents */
 157
 158         /* Now disable the DS1306 to terminate the write */
 159         immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;
 160         udelay (10);
 161
 162         /* Now enable the DS1306 to initiate a new write */
 163         immap->im_cpm.cp_pbdat |= PB_SPI_CE;
 164         udelay (10);
 165
 166         /* Next, send the address of the clock time write registers */
 167         soft_spi_send (0x80);   /* send address of the first time register */
 168
 169         /* Use Burst Mode to send all of the time data to the clock */
 170         bin2bcd (tmp->tm_sec);
 171         soft_spi_send (bin2bcd (tmp->tm_sec));  /* Send Seconds */
 172         soft_spi_send (bin2bcd (tmp->tm_min));  /* Send Minutes */
 173         soft_spi_send (bin2bcd (tmp->tm_hour)); /* Send Hour */
 174         soft_spi_send (bin2bcd (tmp->tm_wday)); /* Send Day of the Week */
 175         soft_spi_send (bin2bcd (tmp->tm_mday)); /* Send Day of Month */
 176         soft_spi_send (bin2bcd (tmp->tm_mon));  /* Send Month */
 177         soft_spi_send (bin2bcd (tmp->tm_year - 2000));  /* Send Year */
 178
 179         /* Now we can disable the Clock chip to terminate the burst write */
 180         immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;   /* Disable DS1306 Chip */
 181         udelay (10);
 182
 183         /* Now we can enable the Clock chip to initiate a new write */
 184         immap->im_cpm.cp_pbdat |= PB_SPI_CE;    /* Enable DS1306 Chip */
 185         udelay (10);
 186
 187         /* First we Enable write protect in the clock chip control register */
 188         soft_spi_send (0x8F);   /* send address of the control register */
 189         soft_spi_send (0x40);   /* send out Control Register contents */
 190
 191         /* Now disable the DS1306 */
 192         immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;   /*  Disable DS1306 Chip */
 193         udelay (10);
 194
 195         /* Set standard MPC8xx clock to the same time so Linux will
 196          * see the time even if it doesn't have a DS1306 clock driver.
 197          * This helps with experimenting with standard kernels.
 198          */
 199         {
 200                 ulong tim;
 201
 202                 tim = mktime (tmp->tm_year, tmp->tm_mon, tmp->tm_mday,
 203                               tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 204
 205                 immap->im_sitk.sitk_rtck = KAPWR_KEY;
 206                 immap->im_sit.sit_rtc = tim;
 207         }
 208
 209         debug ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 210                tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 211                tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 212
 213         return 0;
 214 }
 215
 216 /* ------------------------------------------------------------------------- */
 217
 218 /* Initialize Port B for software SPI */
 219 static void init_spi (void)
 220 {
 221         volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
 222
 223         /* Force output pins to begin at logic 0 */
 224         immap->im_cpm.cp_pbdat &= ~(PB_SPI_CE | PB_SPIMOSI | PB_SPISCK);
 225
 226         /* Set these 3 signals as outputs */
 227         immap->im_cpm.cp_pbdir |= (PB_SPIMOSI | PB_SPI_CE | PB_SPISCK);
 228
 229         immap->im_cpm.cp_pbdir &= ~PB_SPIMISO;  /* Make MISO pin an input */
 230         udelay (10);
 231 }
 232
 233 /* ------------------------------------------------------------------------- */
 234
 235 /* NOTE: soft_spi_send() assumes that the I/O lines are configured already */
 236 static void soft_spi_send (unsigned char n)
 237 {
 238         volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
 239         unsigned char bitpos;   /* bit position to receive */
 240         unsigned char i;        /* Loop Control */
 241
 242         /* bit position to send, start with most significant bit */
 243         bitpos = 0x80;
 244
 245         /* Send 8 bits to software SPI */
 246         for (i = 0; i < 8; i++) {       /* Loop for 8 bits */
 247                 immap->im_cpm.cp_pbdat |= PB_SPISCK;    /* Raise SCK */
 248
 249                 if (n & bitpos)
 250                         immap->im_cpm.cp_pbdat |= PB_SPIMOSI;   /* Set MOSI to 1 */
 251                 else
 252                         immap->im_cpm.cp_pbdat &= ~PB_SPIMOSI;  /* Set MOSI to 0 */
 253                 udelay (10);
 254
 255                 immap->im_cpm.cp_pbdat &= ~PB_SPISCK;   /* Lower SCK */
 256                 udelay (10);
 257
 258                 bitpos >>= 1;   /* Shift for next bit position */
 259         }
 260 }
 261
 262 /* ------------------------------------------------------------------------- */
 263
 264 /* NOTE: soft_spi_read() assumes that the I/O lines are configured already */
 265 static unsigned char soft_spi_read (void)
 266 {
 267         volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
 268
 269         unsigned char spi_byte = 0;     /* Return value, assume success */
 270         unsigned char bitpos;   /* bit position to receive */
 271         unsigned char i;        /* Loop Control */
 272
 273         /* bit position to receive, start with most significant bit */
 274         bitpos = 0x80;
 275
 276         /* Read 8 bits here */
 277         for (i = 0; i < 8; i++) {       /* Do 8 bits in loop */
 278                 immap->im_cpm.cp_pbdat |= PB_SPISCK;    /* Raise SCK */
 279                 udelay (10);
 280                 if (immap->im_cpm.cp_pbdat & PB_SPIMISO)        /* Get a bit of data */
 281                         spi_byte |= bitpos;     /* Set data accordingly */
 282                 immap->im_cpm.cp_pbdat &= ~PB_SPISCK;   /* Lower SCK */
 283                 udelay (10);
 284                 bitpos >>= 1;   /* Shift for next bit position */
 285         }
 286
 287         return spi_byte;        /* Return the byte read */
 288 }
 289
 290 /* ------------------------------------------------------------------------- */
 291
 292 void rtc_reset (void)
 293 {
 294         return;                 /* nothing to do */
 295 }
 296
 297 #else  /* not CONFIG_SXNI855T */
 298 /* ************************************************************************* */
 299
 300 static unsigned char rtc_read (unsigned char reg);
 301 static void rtc_write (unsigned char reg, unsigned char val);
 302
 303 static struct spi_slave *slave;
 304
 305 /* read clock time from DS1306 and return it in *tmp */
 306 int rtc_get (struct rtc_time *tmp)
 307 {
 308         unsigned char sec, min, hour, mday, wday, mon, year;
 309
 310         /*
 311          * Assuming Vcc = 2.0V (lowest speed)
 312          *
 313          * REVISIT: If we add an rtc_init() function we can do this
 314          * step just once.
 315          */
 316         if (!slave) {
 317                 slave = spi_setup_slave(0, CONFIG_SYS_SPI_RTC_DEVID, 600000,
 318                                 SPI_MODE_3 | SPI_CS_HIGH);
 319                 if (!slave)
 320                         return;
 321         }
 322
 323         if (spi_claim_bus(slave))
 324                 return;
 325
 326         sec = rtc_read (RTC_SECONDS);
 327         min = rtc_read (RTC_MINUTES);
 328         hour = rtc_read (RTC_HOURS);
 329         mday = rtc_read (RTC_DATE_OF_MONTH);
 330         wday = rtc_read (RTC_DAY_OF_WEEK);
 331         mon = rtc_read (RTC_MONTH);
 332         year = rtc_read (RTC_YEAR);
 333
 334         spi_release_bus(slave);
 335
 336         debug ("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
 337                "hr: %02x min: %02x sec: %02x\n",
 338                year, mon, mday, wday, hour, min, sec);
 339         debug ("Alarms[0]: wday: %02x hour: %02x min: %02x sec: %02x\n",
 340                rtc_read (RTC_DAY_OF_WEEK_ALARM0),
 341                rtc_read (RTC_HOURS_ALARM0),
 342                rtc_read (RTC_MINUTES_ALARM0), rtc_read (RTC_SECONDS_ALARM0));
 343         debug ("Alarms[1]: wday: %02x hour: %02x min: %02x sec: %02x\n",
 344                rtc_read (RTC_DAY_OF_WEEK_ALARM1),
 345                rtc_read (RTC_HOURS_ALARM1),
 346                rtc_read (RTC_MINUTES_ALARM1), rtc_read (RTC_SECONDS_ALARM1));
 347
 348         tmp->tm_sec = bcd2bin (sec & 0x7F);     /* convert Seconds */
 349         tmp->tm_min = bcd2bin (min & 0x7F);     /* convert Minutes */
 350
 351         /* convert Hours */
 352         tmp->tm_hour = (hour & 0x40)
 353                 ? ((hour & 0x20)        /* 12 hour mode */
 354                    ? bcd2bin (hour & 0x1F) + 11 /* PM */
 355                    : bcd2bin (hour & 0x1F) - 1  /* AM */
 356                 )
 357                 : bcd2bin (hour & 0x3F);        /* 24 hour mode */
 358
 359         tmp->tm_mday = bcd2bin (mday & 0x3F);   /* convert Day of the Month */
 360         tmp->tm_mon = bcd2bin (mon & 0x1F);     /* convert Month */
 361         tmp->tm_year = bcd2bin (year) + 2000;   /* convert Year */
 362         tmp->tm_wday = bcd2bin (wday & 0x07) - 1;       /* convert Day of the Week */
 363         tmp->tm_yday = 0;
 364         tmp->tm_isdst = 0;
 365
 366         debug ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 367                tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 368                tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 369
 370         return 0;
 371 }
 372
 373 /* ------------------------------------------------------------------------- */
 374
 375 /* set clock time from *tmp in DS1306 RTC */
 376 int rtc_set (struct rtc_time *tmp)
 377 {
 378         /* Assuming Vcc = 2.0V (lowest speed) */
 379         if (!slave) {
 380                 slave = spi_setup_slave(0, CONFIG_SYS_SPI_RTC_DEVID, 600000,
 381                                 SPI_MODE_3 | SPI_CS_HIGH);
 382                 if (!slave)
 383                         return;
 384         }
 385
 386         if (spi_claim_bus(slave))
 387                 return;
 388
 389         debug ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 390                tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 391                tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 392
 393         rtc_write (RTC_SECONDS, bin2bcd (tmp->tm_sec));
 394         rtc_write (RTC_MINUTES, bin2bcd (tmp->tm_min));
 395         rtc_write (RTC_HOURS, bin2bcd (tmp->tm_hour));
 396         rtc_write (RTC_DAY_OF_WEEK, bin2bcd (tmp->tm_wday + 1));
 397         rtc_write (RTC_DATE_OF_MONTH, bin2bcd (tmp->tm_mday));
 398         rtc_write (RTC_MONTH, bin2bcd (tmp->tm_mon));
 399         rtc_write (RTC_YEAR, bin2bcd (tmp->tm_year - 2000));
 400
 401         spi_release_bus(slave);
 402 }
 403
 404 /* ------------------------------------------------------------------------- */
 405
 406 /* reset the DS1306 */
 407 void rtc_reset (void)
 408 {
 409         /* Assuming Vcc = 2.0V (lowest speed) */
 410         if (!slave) {
 411                 slave = spi_setup_slave(0, CONFIG_SYS_SPI_RTC_DEVID, 600000,
 412                                 SPI_MODE_3 | SPI_CS_HIGH);
 413                 if (!slave)
 414                         return;
 415         }
 416
 417         if (spi_claim_bus(slave))
 418                 return;
 419
 420         /* clear the control register */
 421         rtc_write (RTC_CONTROL, 0x00);  /* 1st step: reset WP */
 422         rtc_write (RTC_CONTROL, 0x00);  /* 2nd step: reset 1Hz, AIE1, AIE0 */
 423
 424         /* reset all alarms */
 425         rtc_write (RTC_SECONDS_ALARM0, 0x00);
 426         rtc_write (RTC_SECONDS_ALARM1, 0x00);
 427         rtc_write (RTC_MINUTES_ALARM0, 0x00);
 428         rtc_write (RTC_MINUTES_ALARM1, 0x00);
 429         rtc_write (RTC_HOURS_ALARM0, 0x00);
 430         rtc_write (RTC_HOURS_ALARM1, 0x00);
 431         rtc_write (RTC_DAY_OF_WEEK_ALARM0, 0x00);
 432         rtc_write (RTC_DAY_OF_WEEK_ALARM1, 0x00);
 433
 434         spi_release_bus(slave);
 435 }
 436
 437 /* ------------------------------------------------------------------------- */
 438
 439 static unsigned char rtc_read (unsigned char reg)
 440 {
 441         int ret;
 442
 443         ret = spi_w8r8(slave, reg);
 444         return ret < 0 ? 0 : ret;
 445 }
 446
 447 /* ------------------------------------------------------------------------- */
 448
 449 static void rtc_write (unsigned char reg, unsigned char val)
 450 {
 451         unsigned char dout[2];  /* SPI Output Data Bytes */
 452         unsigned char din[2];   /* SPI Input Data Bytes */
 453
 454         dout[0] = 0x80 | reg;
 455         dout[1] = val;
 456
 457         spi_xfer (slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
 458 }
 459
 460 #endif /* end of code exclusion (see #ifdef CONFIG_SXNI855T above) */
 461
 462 /* ------------------------------------------------------------------------- */
 463
 464 static unsigned char bcd2bin (unsigned char n)
 465 {
 466         return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F));
 467 }
 468
 469 /* ------------------------------------------------------------------------- */
 470
 471 static unsigned int bin2bcd (unsigned int n)
 472 {
 473         return (((n / 10) << 4) | (n % 10));
 474 }
 475 /* ------------------------------------------------------------------------- */
 476
 477 #endif