drivers/rtc/rtc-omap.c

   1 /*
   2  * TI OMAP1 Real Time Clock interface for Linux
   3  *
   4  * Copyright (C) 2003 MontaVista Software, Inc.
   5  * Author: George G. Davis <gdavis@mvista.com> or <source@mvista.com>
   6  *
   7  * Copyright (C) 2006 David Brownell (new RTC framework)
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version
  12  * 2 of the License, or (at your option) any later version.
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/ioport.h>
  19 #include <linux/delay.h>
  20 #include <linux/rtc.h>
  21 #include <linux/bcd.h>
  22 #include <linux/platform_device.h>
  23
  24 #include <asm/io.h>
  25 #include <asm/mach/time.h>
  26
  27
  28 /* The OMAP1 RTC is a year/month/day/hours/minutes/seconds BCD clock
  29  * with century-range alarm matching, driven by the 32kHz clock.
  30  *
  31  * The main user-visible ways it differs from PC RTCs are by omitting
  32  * "don't care" alarm fields and sub-second periodic IRQs, and having
  33  * an autoadjust mechanism to calibrate to the true oscillator rate.
  34  *
  35  * Board-specific wiring options include using split power mode with
  36  * RTC_OFF_NOFF used as the reset signal (so the RTC won't be reset),
  37  * and wiring RTC_WAKE_INT (so the RTC alarm can wake the system from
  38  * low power modes).  See the BOARD-SPECIFIC CUSTOMIZATION comment.
  39  */
  40
  41 #define OMAP_RTC_BASE                   0xfffb4800
  42
  43 /* RTC registers */
  44 #define OMAP_RTC_SECONDS_REG            0x00
  45 #define OMAP_RTC_MINUTES_REG            0x04
  46 #define OMAP_RTC_HOURS_REG              0x08
  47 #define OMAP_RTC_DAYS_REG               0x0C
  48 #define OMAP_RTC_MONTHS_REG             0x10
  49 #define OMAP_RTC_YEARS_REG              0x14
  50 #define OMAP_RTC_WEEKS_REG              0x18
  51
  52 #define OMAP_RTC_ALARM_SECONDS_REG      0x20
  53 #define OMAP_RTC_ALARM_MINUTES_REG      0x24
  54 #define OMAP_RTC_ALARM_HOURS_REG        0x28
  55 #define OMAP_RTC_ALARM_DAYS_REG         0x2c
  56 #define OMAP_RTC_ALARM_MONTHS_REG       0x30
  57 #define OMAP_RTC_ALARM_YEARS_REG        0x34
  58
  59 #define OMAP_RTC_CTRL_REG               0x40
  60 #define OMAP_RTC_STATUS_REG             0x44
  61 #define OMAP_RTC_INTERRUPTS_REG         0x48
  62
  63 #define OMAP_RTC_COMP_LSB_REG           0x4c
  64 #define OMAP_RTC_COMP_MSB_REG           0x50
  65 #define OMAP_RTC_OSC_REG                0x54
  66
  67 /* OMAP_RTC_CTRL_REG bit fields: */
  68 #define OMAP_RTC_CTRL_SPLIT             (1<<7)
  69 #define OMAP_RTC_CTRL_DISABLE           (1<<6)
  70 #define OMAP_RTC_CTRL_SET_32_COUNTER    (1<<5)
  71 #define OMAP_RTC_CTRL_TEST              (1<<4)
  72 #define OMAP_RTC_CTRL_MODE_12_24        (1<<3)
  73 #define OMAP_RTC_CTRL_AUTO_COMP         (1<<2)
  74 #define OMAP_RTC_CTRL_ROUND_30S         (1<<1)
  75 #define OMAP_RTC_CTRL_STOP              (1<<0)
  76
  77 /* OMAP_RTC_STATUS_REG bit fields: */
  78 #define OMAP_RTC_STATUS_POWER_UP        (1<<7)
  79 #define OMAP_RTC_STATUS_ALARM           (1<<6)
  80 #define OMAP_RTC_STATUS_1D_EVENT        (1<<5)
  81 #define OMAP_RTC_STATUS_1H_EVENT        (1<<4)
  82 #define OMAP_RTC_STATUS_1M_EVENT        (1<<3)
  83 #define OMAP_RTC_STATUS_1S_EVENT        (1<<2)
  84 #define OMAP_RTC_STATUS_RUN             (1<<1)
  85 #define OMAP_RTC_STATUS_BUSY            (1<<0)
  86
  87 /* OMAP_RTC_INTERRUPTS_REG bit fields: */
  88 #define OMAP_RTC_INTERRUPTS_IT_ALARM    (1<<3)
  89 #define OMAP_RTC_INTERRUPTS_IT_TIMER    (1<<2)
  90
  91
  92 #define rtc_read(addr)          omap_readb(OMAP_RTC_BASE + (addr))
  93 #define rtc_write(val, addr)    omap_writeb(val, OMAP_RTC_BASE + (addr))
  94
  95
  96 /* platform_bus isn't hotpluggable, so for static linkage it'd be safe
  97  * to get rid of probe() and remove() code ... too bad the driver struct
  98  * remembers probe(), that's about 25% of the runtime footprint!!
  99  */
 100 #ifndef MODULE
 101 #undef  __devexit
 102 #undef  __devexit_p
 103 #define __devexit       __exit
 104 #define __devexit_p     __exit_p
 105 #endif
 106
 107
 108 /* we rely on the rtc framework to handle locking (rtc->ops_lock),
 109  * so the only other requirement is that register accesses which
 110  * require BUSY to be clear are made with IRQs locally disabled
 111  */
 112 static void rtc_wait_not_busy(void)
 113 {
 114         int     count = 0;
 115         u8      status;
 116
 117         /* BUSY may stay active for 1/32768 second (~30 usec) */
 118         for (count = 0; count < 50; count++) {
 119                 status = rtc_read(OMAP_RTC_STATUS_REG);
 120                 if ((status & (u8)OMAP_RTC_STATUS_BUSY) == 0)
 121                         break;
 122                 udelay(1);
 123         }
 124         /* now we have ~15 usec to read/write various registers */
 125 }
 126
 127 static irqreturn_t rtc_irq(int irq, void *class_dev)
 128 {
 129         unsigned long           events = 0;
 130         u8                      irq_data;
 131
 132         irq_data = rtc_read(OMAP_RTC_STATUS_REG);
 133
 134         /* alarm irq? */
 135         if (irq_data & OMAP_RTC_STATUS_ALARM) {
 136                 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
 137                 events |= RTC_IRQF | RTC_AF;
 138         }
 139
 140         /* 1/sec periodic/update irq? */
 141         if (irq_data & OMAP_RTC_STATUS_1S_EVENT)
 142                 events |= RTC_IRQF | RTC_UF;
 143
 144         rtc_update_irq(class_dev, 1, events);
 145
 146         return IRQ_HANDLED;
 147 }
 148
 149 #ifdef  CONFIG_RTC_INTF_DEV
 150
 151 static int
 152 omap_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 153 {
 154         u8 reg;
 155
 156         switch (cmd) {
 157         case RTC_AIE_OFF:
 158         case RTC_AIE_ON:
 159         case RTC_UIE_OFF:
 160         case RTC_UIE_ON:
 161                 break;
 162         default:
 163                 return -ENOIOCTLCMD;
 164         }
 165
 166         local_irq_disable();
 167         rtc_wait_not_busy();
 168         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 169         switch (cmd) {
 170         /* AIE = Alarm Interrupt Enable */
 171         case RTC_AIE_OFF:
 172                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 173                 break;
 174         case RTC_AIE_ON:
 175                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 176                 break;
 177         /* UIE = Update Interrupt Enable (1/second) */
 178         case RTC_UIE_OFF:
 179                 reg &= ~OMAP_RTC_INTERRUPTS_IT_TIMER;
 180                 break;
 181         case RTC_UIE_ON:
 182                 reg |= OMAP_RTC_INTERRUPTS_IT_TIMER;
 183                 break;
 184         }
 185         rtc_wait_not_busy();
 186         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 187         local_irq_enable();
 188
 189         return 0;
 190 }
 191
 192 #else
 193 #define omap_rtc_ioctl  NULL
 194 #endif
 195
 196 /* this hardware doesn't support "don't care" alarm fields */
 197 static int tm2bcd(struct rtc_time *tm)
 198 {
 199         if (rtc_valid_tm(tm) != 0)
 200                 return -EINVAL;
 201
 202         tm->tm_sec = BIN2BCD(tm->tm_sec);
 203         tm->tm_min = BIN2BCD(tm->tm_min);
 204         tm->tm_hour = BIN2BCD(tm->tm_hour);
 205         tm->tm_mday = BIN2BCD(tm->tm_mday);
 206
 207         tm->tm_mon = BIN2BCD(tm->tm_mon + 1);
 208
 209         /* epoch == 1900 */
 210         if (tm->tm_year < 100 || tm->tm_year > 199)
 211                 return -EINVAL;
 212         tm->tm_year = BIN2BCD(tm->tm_year - 100);
 213
 214         return 0;
 215 }
 216
 217 static void bcd2tm(struct rtc_time *tm)
 218 {
 219         tm->tm_sec = BCD2BIN(tm->tm_sec);
 220         tm->tm_min = BCD2BIN(tm->tm_min);
 221         tm->tm_hour = BCD2BIN(tm->tm_hour);
 222         tm->tm_mday = BCD2BIN(tm->tm_mday);
 223         tm->tm_mon = BCD2BIN(tm->tm_mon) - 1;
 224         /* epoch == 1900 */
 225         tm->tm_year = BCD2BIN(tm->tm_year) + 100;
 226 }
 227
 228
 229 static int omap_rtc_read_time(struct device *dev, struct rtc_time *tm)
 230 {
 231         /* we don't report wday/yday/isdst ... */
 232         local_irq_disable();
 233         rtc_wait_not_busy();
 234
 235         tm->tm_sec = rtc_read(OMAP_RTC_SECONDS_REG);
 236         tm->tm_min = rtc_read(OMAP_RTC_MINUTES_REG);
 237         tm->tm_hour = rtc_read(OMAP_RTC_HOURS_REG);
 238         tm->tm_mday = rtc_read(OMAP_RTC_DAYS_REG);
 239         tm->tm_mon = rtc_read(OMAP_RTC_MONTHS_REG);
 240         tm->tm_year = rtc_read(OMAP_RTC_YEARS_REG);
 241
 242         local_irq_enable();
 243
 244         bcd2tm(tm);
 245         return 0;
 246 }
 247
 248 static int omap_rtc_set_time(struct device *dev, struct rtc_time *tm)
 249 {
 250         if (tm2bcd(tm) < 0)
 251                 return -EINVAL;
 252         local_irq_disable();
 253         rtc_wait_not_busy();
 254
 255         rtc_write(tm->tm_year, OMAP_RTC_YEARS_REG);
 256         rtc_write(tm->tm_mon, OMAP_RTC_MONTHS_REG);
 257         rtc_write(tm->tm_mday, OMAP_RTC_DAYS_REG);
 258         rtc_write(tm->tm_hour, OMAP_RTC_HOURS_REG);
 259         rtc_write(tm->tm_min, OMAP_RTC_MINUTES_REG);
 260         rtc_write(tm->tm_sec, OMAP_RTC_SECONDS_REG);
 261
 262         local_irq_enable();
 263
 264         return 0;
 265 }
 266
 267 static int omap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 268 {
 269         local_irq_disable();
 270         rtc_wait_not_busy();
 271
 272         alm->time.tm_sec = rtc_read(OMAP_RTC_ALARM_SECONDS_REG);
 273         alm->time.tm_min = rtc_read(OMAP_RTC_ALARM_MINUTES_REG);
 274         alm->time.tm_hour = rtc_read(OMAP_RTC_ALARM_HOURS_REG);
 275         alm->time.tm_mday = rtc_read(OMAP_RTC_ALARM_DAYS_REG);
 276         alm->time.tm_mon = rtc_read(OMAP_RTC_ALARM_MONTHS_REG);
 277         alm->time.tm_year = rtc_read(OMAP_RTC_ALARM_YEARS_REG);
 278
 279         local_irq_enable();
 280
 281         bcd2tm(&alm->time);
 282         alm->enabled = !!(rtc_read(OMAP_RTC_INTERRUPTS_REG)
 283                         & OMAP_RTC_INTERRUPTS_IT_ALARM);
 284
 285         return 0;
 286 }
 287
 288 static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 289 {
 290         u8 reg;
 291
 292         /* Much userspace code uses RTC_ALM_SET, thus "don't care" for
 293          * day/month/year specifies alarms up to 24 hours in the future.
 294          * So we need to handle that ... but let's ignore the "don't care"
 295          * values for hours/minutes/seconds.
 296          */
 297         if (alm->time.tm_mday <= 0
 298                         && alm->time.tm_mon < 0
 299                         && alm->time.tm_year < 0) {
 300                 struct rtc_time tm;
 301                 unsigned long now, then;
 302
 303                 omap_rtc_read_time(dev, &tm);
 304                 rtc_tm_to_time(&tm, &now);
 305
 306                 alm->time.tm_mday = tm.tm_mday;
 307                 alm->time.tm_mon = tm.tm_mon;
 308                 alm->time.tm_year = tm.tm_year;
 309                 rtc_tm_to_time(&alm->time, &then);
 310
 311                 /* sometimes the alarm wraps into tomorrow */
 312                 if (then < now) {
 313                         rtc_time_to_tm(now + 24 * 60 * 60, &tm);
 314                         alm->time.tm_mday = tm.tm_mday;
 315                         alm->time.tm_mon = tm.tm_mon;
 316                         alm->time.tm_year = tm.tm_year;
 317                 }
 318         }
 319
 320         if (tm2bcd(&alm->time) < 0)
 321                 return -EINVAL;
 322
 323         local_irq_disable();
 324         rtc_wait_not_busy();
 325
 326         rtc_write(alm->time.tm_year, OMAP_RTC_ALARM_YEARS_REG);
 327         rtc_write(alm->time.tm_mon, OMAP_RTC_ALARM_MONTHS_REG);
 328         rtc_write(alm->time.tm_mday, OMAP_RTC_ALARM_DAYS_REG);
 329         rtc_write(alm->time.tm_hour, OMAP_RTC_ALARM_HOURS_REG);
 330         rtc_write(alm->time.tm_min, OMAP_RTC_ALARM_MINUTES_REG);
 331         rtc_write(alm->time.tm_sec, OMAP_RTC_ALARM_SECONDS_REG);
 332
 333         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 334         if (alm->enabled)
 335                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 336         else
 337                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 338         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 339
 340         local_irq_enable();
 341
 342         return 0;
 343 }
 344
 345 static struct rtc_class_ops omap_rtc_ops = {
 346         .ioctl          = omap_rtc_ioctl,
 347         .read_time      = omap_rtc_read_time,
 348         .set_time       = omap_rtc_set_time,
 349         .read_alarm     = omap_rtc_read_alarm,
 350         .set_alarm      = omap_rtc_set_alarm,
 351 };
 352
 353 static int omap_rtc_alarm;
 354 static int omap_rtc_timer;
 355
 356 static int __devinit omap_rtc_probe(struct platform_device *pdev)
 357 {
 358         struct resource         *res, *mem;
 359         struct rtc_device       *rtc;
 360         u8                      reg, new_ctrl;
 361
 362         omap_rtc_timer = platform_get_irq(pdev, 0);
 363         if (omap_rtc_timer <= 0) {
 364                 pr_debug("%s: no update irq?\n", pdev->name);
 365                 return -ENOENT;
 366         }
 367
 368         omap_rtc_alarm = platform_get_irq(pdev, 1);
 369         if (omap_rtc_alarm <= 0) {
 370                 pr_debug("%s: no alarm irq?\n", pdev->name);
 371                 return -ENOENT;
 372         }
 373
 374         /* NOTE:  using static mapping for RTC registers */
 375         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 376         if (res && res->start != OMAP_RTC_BASE) {
 377                 pr_debug("%s: RTC registers at %08x, expected %08x\n",
 378                         pdev->name, (unsigned) res->start, OMAP_RTC_BASE);
 379                 return -ENOENT;
 380         }
 381
 382         if (res)
 383                 mem = request_mem_region(res->start,
 384                                 res->end - res->start + 1,
 385                                 pdev->name);
 386         else
 387                 mem = NULL;
 388         if (!mem) {
 389                 pr_debug("%s: RTC registers at %08x are not free\n",
 390                         pdev->name, OMAP_RTC_BASE);
 391                 return -EBUSY;
 392         }
 393
 394         rtc = rtc_device_register(pdev->name, &pdev->dev,
 395                         &omap_rtc_ops, THIS_MODULE);
 396         if (IS_ERR(rtc)) {
 397                 pr_debug("%s: can't register RTC device, err %ld\n",
 398                         pdev->name, PTR_ERR(rtc));
 399                 goto fail;
 400         }
 401         platform_set_drvdata(pdev, rtc);
 402         class_set_devdata(&rtc->class_dev, mem);
 403
 404         /* clear pending irqs, and set 1/second periodic,
 405          * which we'll use instead of update irqs
 406          */
 407         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 408
 409         /* clear old status */
 410         reg = rtc_read(OMAP_RTC_STATUS_REG);
 411         if (reg & (u8) OMAP_RTC_STATUS_POWER_UP) {
 412                 pr_info("%s: RTC power up reset detected\n",
 413                         pdev->name);
 414                 rtc_write(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG);
 415         }
 416         if (reg & (u8) OMAP_RTC_STATUS_ALARM)
 417                 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
 418
 419         /* handle periodic and alarm irqs */
 420         if (request_irq(omap_rtc_timer, rtc_irq, SA_INTERRUPT,
 421                         rtc->class_dev.class_id, &rtc->class_dev)) {
 422                 pr_debug("%s: RTC timer interrupt IRQ%d already claimed\n",
 423                         pdev->name, omap_rtc_timer);
 424                 goto fail0;
 425         }
 426         if (request_irq(omap_rtc_alarm, rtc_irq, SA_INTERRUPT,
 427                         rtc->class_dev.class_id, &rtc->class_dev)) {
 428                 pr_debug("%s: RTC alarm interrupt IRQ%d already claimed\n",
 429                         pdev->name, omap_rtc_alarm);
 430                 goto fail1;
 431         }
 432
 433         /* On boards with split power, RTC_ON_NOFF won't reset the RTC */
 434         reg = rtc_read(OMAP_RTC_CTRL_REG);
 435         if (reg & (u8) OMAP_RTC_CTRL_STOP)
 436                 pr_info("%s: already running\n", pdev->name);
 437
 438         /* force to 24 hour mode */
 439         new_ctrl = reg & ~(OMAP_RTC_CTRL_SPLIT|OMAP_RTC_CTRL_AUTO_COMP);
 440         new_ctrl |= OMAP_RTC_CTRL_STOP;
 441
 442         /* BOARD-SPECIFIC CUSTOMIZATION CAN GO HERE:
 443          *
 444          *  - Boards wired so that RTC_WAKE_INT does something, and muxed
 445          *    right (W13_1610_RTC_WAKE_INT is the default after chip reset),
 446          *    should initialize the device wakeup flag appropriately.
 447          *
 448          *  - Boards wired so RTC_ON_nOFF is used as the reset signal,
 449          *    rather than nPWRON_RESET, should forcibly enable split
 450          *    power mode.  (Some chip errata report that RTC_CTRL_SPLIT
 451          *    is write-only, and always reads as zero...)
 452          */
 453         device_init_wakeup(&pdev->dev, 0);
 454
 455         if (new_ctrl & (u8) OMAP_RTC_CTRL_SPLIT)
 456                 pr_info("%s: split power mode\n", pdev->name);
 457
 458         if (reg != new_ctrl)
 459                 rtc_write(new_ctrl, OMAP_RTC_CTRL_REG);
 460
 461         return 0;
 462
 463 fail1:
 464         free_irq(omap_rtc_timer, NULL);
 465 fail0:
 466         rtc_device_unregister(rtc);
 467 fail:
 468         release_resource(mem);
 469         return -EIO;
 470 }
 471
 472 static int __devexit omap_rtc_remove(struct platform_device *pdev)
 473 {
 474         struct rtc_device       *rtc = platform_get_drvdata(pdev);;
 475
 476         device_init_wakeup(&pdev->dev, 0);
 477
 478         /* leave rtc running, but disable irqs */
 479         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 480
 481         free_irq(omap_rtc_timer, rtc);
 482         free_irq(omap_rtc_alarm, rtc);
 483
 484         release_resource(class_get_devdata(&rtc->class_dev));
 485         rtc_device_unregister(rtc);
 486         return 0;
 487 }
 488
 489 #ifdef CONFIG_PM
 490
 491 static struct timespec rtc_delta;
 492 static u8 irqstat;
 493
 494 static int omap_rtc_suspend(struct platform_device *pdev, pm_message_t state)
 495 {
 496         struct rtc_time rtc_tm;
 497         struct timespec time;
 498
 499         time.tv_nsec = 0;
 500         omap_rtc_read_time(NULL, &rtc_tm);
 501         rtc_tm_to_time(&rtc_tm, &time.tv_sec);
 502
 503         save_time_delta(&rtc_delta, &time);
 504         irqstat = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 505
 506         /* FIXME the RTC alarm is not currently acting as a wakeup event
 507          * source, and in fact this enable() call is just saving a flag
 508          * that's never used...
 509          */
 510         if (device_may_wakeup(&pdev->dev))
 511                 enable_irq_wake(omap_rtc_alarm);
 512         else
 513                 rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 514
 515         return 0;
 516 }
 517
 518 static int omap_rtc_resume(struct platform_device *pdev)
 519 {
 520         struct rtc_time rtc_tm;
 521         struct timespec time;
 522
 523         time.tv_nsec = 0;
 524         omap_rtc_read_time(NULL, &rtc_tm);
 525         rtc_tm_to_time(&rtc_tm, &time.tv_sec);
 526
 527         restore_time_delta(&rtc_delta, &time);
 528         if (device_may_wakeup(&pdev->dev))
 529                 disable_irq_wake(omap_rtc_alarm);
 530         else
 531                 rtc_write(irqstat, OMAP_RTC_INTERRUPTS_REG);
 532         return 0;
 533 }
 534
 535 #else
 536 #define omap_rtc_suspend NULL
 537 #define omap_rtc_resume  NULL
 538 #endif
 539
 540 static void omap_rtc_shutdown(struct platform_device *pdev)
 541 {
 542         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 543 }
 544
 545 MODULE_ALIAS("omap_rtc");
 546 static struct platform_driver omap_rtc_driver = {
 547         .probe          = omap_rtc_probe,
 548         .remove         = __devexit_p(omap_rtc_remove),
 549         .suspend        = omap_rtc_suspend,
 550         .resume         = omap_rtc_resume,
 551         .shutdown       = omap_rtc_shutdown,
 552         .driver         = {
 553                 .name   = "omap_rtc",
 554                 .owner  = THIS_MODULE,
 555         },
 556 };
 557
 558 static int __init rtc_init(void)
 559 {
 560         return platform_driver_register(&omap_rtc_driver);
 561 }
 562 module_init(rtc_init);
 563
 564 static void __exit rtc_exit(void)
 565 {
 566         platform_driver_unregister(&omap_rtc_driver);
 567 }
 568 module_exit(rtc_exit);
 569
 570 MODULE_AUTHOR("George G. Davis (and others)");
 571 MODULE_LICENSE("GPL");