drivers/rtc/alarm.c

   1 /* drivers/rtc/alarm.c
   2  *
   3  * Copyright (C) 2007-2009 Google, Inc.
   4  *
   5  * This software is licensed under the terms of the GNU General Public
   6  * License version 2, as published by the Free Software Foundation, and
   7  * may be copied, distributed, and modified under those terms.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include <asm/mach/time.h>
  17 #include <linux/android_alarm.h>
  18 #include <linux/device.h>
  19 #include <linux/miscdevice.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/rtc.h>
  22 #include <linux/sched.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/sysdev.h>
  25 #include <linux/wakelock.h>
  26
  27 #define ANDROID_ALARM_PRINT_ERROR (1U << 0)
  28 #define ANDROID_ALARM_PRINT_INIT_STATUS (1U << 1)
  29 #define ANDROID_ALARM_PRINT_TSET (1U << 2)
  30 #define ANDROID_ALARM_PRINT_CALL (1U << 3)
  31 #define ANDROID_ALARM_PRINT_SUSPEND (1U << 4)
  32 #define ANDROID_ALARM_PRINT_INT (1U << 5)
  33 #define ANDROID_ALARM_PRINT_FLOW (1U << 6)
  34
  35 static int debug_mask = ANDROID_ALARM_PRINT_ERROR | \
  36                         ANDROID_ALARM_PRINT_INIT_STATUS;
  37 module_param_named(debug_mask, debug_mask, int, S_IRUGO | S_IWUSR | S_IWGRP);
  38
  39 #define pr_alarm(debug_level_mask, args...) \
  40         do { \
  41                 if (debug_mask & ANDROID_ALARM_PRINT_##debug_level_mask) { \
  42                         pr_info(args); \
  43                 } \
  44         } while (0)
  45
  46 #define ANDROID_ALARM_WAKEUP_MASK ( \
  47         ANDROID_ALARM_RTC_WAKEUP_MASK | \
  48         ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP_MASK)
  49
  50 /* support old usespace code */
  51 #define ANDROID_ALARM_SET_OLD               _IOW('a', 2, time_t) /* set alarm */
  52 #define ANDROID_ALARM_SET_AND_WAIT_OLD      _IOW('a', 3, time_t)
  53
  54 struct alarm_queue {
  55         struct rb_root alarms;
  56         struct rb_node *first;
  57         struct hrtimer timer;
  58         ktime_t delta;
  59         bool stopped;
  60         ktime_t stopped_time;
  61 };
  62
  63 static struct rtc_device *alarm_rtc_dev;
  64 static DEFINE_SPINLOCK(alarm_slock);
  65 static DEFINE_MUTEX(alarm_setrtc_mutex);
  66 static struct wake_lock alarm_rtc_wake_lock;
  67 static struct platform_device *alarm_platform_dev;
  68 struct alarm_queue alarms[ANDROID_ALARM_TYPE_COUNT];
  69 static bool suspended;
  70
  71 static void update_timer_locked(struct alarm_queue *base, bool head_removed)
  72 {
  73         struct alarm *alarm;
  74         bool is_wakeup = base == &alarms[ANDROID_ALARM_RTC_WAKEUP] ||
  75                         base == &alarms[ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP];
  76
  77         if (base->stopped) {
  78                 pr_alarm(FLOW, "changed alarm while setting the wall time\n");
  79                 return;
  80         }
  81
  82         if (is_wakeup && !suspended && head_removed)
  83                 wake_unlock(&alarm_rtc_wake_lock);
  84
  85         if (!base->first)
  86                 return;
  87
  88         alarm = container_of(base->first, struct alarm, node);
  89
  90         pr_alarm(FLOW, "selected alarm, type %d, func %pF at %lld\n",
  91                 alarm->type, alarm->function, ktime_to_ns(alarm->expires));
  92
  93         if (is_wakeup && suspended) {
  94                 pr_alarm(FLOW, "changed alarm while suspened\n");
  95                 wake_lock_timeout(&alarm_rtc_wake_lock, 1 * HZ);
  96                 return;
  97         }
  98
  99         hrtimer_try_to_cancel(&base->timer);
 100         base->timer.node.expires = ktime_add(base->delta, alarm->expires);
 101         base->timer._softexpires = ktime_add(base->delta, alarm->softexpires);
 102         hrtimer_start_expires(&base->timer, HRTIMER_MODE_ABS);
 103 }
 104
 105 static void alarm_enqueue_locked(struct alarm *alarm)
 106 {
 107         struct alarm_queue *base = &alarms[alarm->type];
 108         struct rb_node **link = &base->alarms.rb_node;
 109         struct rb_node *parent = NULL;
 110         struct alarm *entry;
 111         int leftmost = 1;
 112         bool was_first = false;
 113
 114         pr_alarm(FLOW, "added alarm, type %d, func %pF at %lld\n",
 115                 alarm->type, alarm->function, ktime_to_ns(alarm->expires));
 116
 117         if (base->first == &alarm->node) {
 118                 base->first = rb_next(&alarm->node);
 119                 was_first = true;
 120         }
 121         if (!RB_EMPTY_NODE(&alarm->node)) {
 122                 rb_erase(&alarm->node, &base->alarms);
 123                 RB_CLEAR_NODE(&alarm->node);
 124         }
 125
 126         while (*link) {
 127                 parent = *link;
 128                 entry = rb_entry(parent, struct alarm, node);
 129                 /*
 130                 * We dont care about collisions. Nodes with
 131                 * the same expiry time stay together.
 132                 */
 133                 if (alarm->expires.tv64 < entry->expires.tv64) {
 134                         link = &(*link)->rb_left;
 135                 } else {
 136                         link = &(*link)->rb_right;
 137                         leftmost = 0;
 138                 }
 139         }
 140         if (leftmost)
 141                 base->first = &alarm->node;
 142         if (leftmost || was_first)
 143                 update_timer_locked(base, was_first);
 144
 145         rb_link_node(&alarm->node, parent, link);
 146         rb_insert_color(&alarm->node, &base->alarms);
 147 }
 148
 149 /**
 150  * alarm_init - initialize an alarm
 151  * @alarm:      the alarm to be initialized
 152  * @type:       the alarm type to be used
 153  * @function:   alarm callback function
 154  */
 155 void alarm_init(struct alarm *alarm,
 156         enum android_alarm_type type, void (*function)(struct alarm *))
 157 {
 158         RB_CLEAR_NODE(&alarm->node);
 159         alarm->type = type;
 160         alarm->function = function;
 161
 162         pr_alarm(FLOW, "created alarm, type %d, func %pF\n", type, function);
 163 }
 164
 165
 166 /**
 167  * alarm_start_range - (re)start an alarm
 168  * @alarm:      the alarm to be added
 169  * @start:      earliest expiry time
 170  * @end:        expiry time
 171  */
 172 void alarm_start_range(struct alarm *alarm, ktime_t start, ktime_t end)
 173 {
 174         unsigned long flags;
 175
 176         spin_lock_irqsave(&alarm_slock, flags);
 177         alarm->softexpires = start;
 178         alarm->expires = end;
 179         alarm_enqueue_locked(alarm);
 180         spin_unlock_irqrestore(&alarm_slock, flags);
 181 }
 182
 183 /**
 184  * alarm_try_to_cancel - try to deactivate an alarm
 185  * @alarm:      alarm to stop
 186  *
 187  * Returns:
 188  *  0 when the alarm was not active
 189  *  1 when the alarm was active
 190  * -1 when the alarm may currently be excuting the callback function and
 191  *    cannot be stopped (it may also be inactive)
 192  */
 193 int alarm_try_to_cancel(struct alarm *alarm)
 194 {
 195         struct alarm_queue *base = &alarms[alarm->type];
 196         unsigned long flags;
 197         bool first = false;
 198         int ret = 0;
 199
 200         spin_lock_irqsave(&alarm_slock, flags);
 201         if (!RB_EMPTY_NODE(&alarm->node)) {
 202                 pr_alarm(FLOW, "canceled alarm, type %d, func %pF at %lld\n",
 203                         alarm->type, alarm->function,
 204                         ktime_to_ns(alarm->expires));
 205                 ret = 1;
 206                 if (base->first == &alarm->node) {
 207                         base->first = rb_next(&alarm->node);
 208                         first = true;
 209                 }
 210                 rb_erase(&alarm->node, &base->alarms);
 211                 RB_CLEAR_NODE(&alarm->node);
 212                 if (first)
 213                         update_timer_locked(base, true);
 214         } else
 215                 pr_alarm(FLOW, "tried to cancel alarm, type %d, func %pF\n",
 216                         alarm->type, alarm->function);
 217         spin_unlock_irqrestore(&alarm_slock, flags);
 218         if (!ret && hrtimer_callback_running(&base->timer))
 219                 ret = -1;
 220         return ret;
 221 }
 222
 223 /**
 224  * alarm_cancel - cancel an alarm and wait for the handler to finish.
 225  * @alarm:      the alarm to be cancelled
 226  *
 227  * Returns:
 228  *  0 when the alarm was not active
 229  *  1 when the alarm was active
 230  */
 231 int alarm_cancel(struct alarm *alarm)
 232 {
 233         for (;;) {
 234                 int ret = alarm_try_to_cancel(alarm);
 235                 if (ret >= 0)
 236                         return ret;
 237                 cpu_relax();
 238         }
 239 }
 240
 241 /**
 242  * alarm_set_rtc - set the kernel and rtc walltime
 243  * @new_time:   timespec value containing the new time
 244  */
 245 int alarm_set_rtc(struct timespec new_time)
 246 {
 247         int i;
 248         int ret;
 249         unsigned long flags;
 250         struct rtc_time rtc_new_rtc_time;
 251         struct timespec tmp_time;
 252
 253         rtc_time_to_tm(new_time.tv_sec, &rtc_new_rtc_time);
 254
 255         pr_alarm(TSET, "set rtc %ld %ld - rtc %02d:%02d:%02d %02d/%02d/%04d\n",
 256                 new_time.tv_sec, new_time.tv_nsec,
 257                 rtc_new_rtc_time.tm_hour, rtc_new_rtc_time.tm_min,
 258                 rtc_new_rtc_time.tm_sec, rtc_new_rtc_time.tm_mon + 1,
 259                 rtc_new_rtc_time.tm_mday,
 260                 rtc_new_rtc_time.tm_year + 1900);
 261
 262         mutex_lock(&alarm_setrtc_mutex);
 263         spin_lock_irqsave(&alarm_slock, flags);
 264         wake_lock(&alarm_rtc_wake_lock);
 265         getnstimeofday(&tmp_time);
 266         for (i = 0; i < ANDROID_ALARM_SYSTEMTIME; i++) {
 267                 hrtimer_try_to_cancel(&alarms[i].timer);
 268                 alarms[i].stopped = true;
 269                 alarms[i].stopped_time = timespec_to_ktime(tmp_time);
 270         }
 271         alarms[ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP].delta =
 272                 alarms[ANDROID_ALARM_ELAPSED_REALTIME].delta =
 273                 ktime_sub(alarms[ANDROID_ALARM_ELAPSED_REALTIME].delta,
 274                         timespec_to_ktime(timespec_sub(tmp_time, new_time)));
 275         spin_unlock_irqrestore(&alarm_slock, flags);
 276         ret = do_settimeofday(&new_time);
 277         spin_lock_irqsave(&alarm_slock, flags);
 278         for (i = 0; i < ANDROID_ALARM_SYSTEMTIME; i++) {
 279                 alarms[i].stopped = false;
 280                 update_timer_locked(&alarms[i], false);
 281         }
 282         spin_unlock_irqrestore(&alarm_slock, flags);
 283         if (ret < 0) {
 284                 pr_alarm(ERROR, "alarm_set_rtc: Failed to set time\n");
 285                 goto err;
 286         }
 287         if (!alarm_rtc_dev) {
 288                 pr_alarm(ERROR,
 289                         "alarm_set_rtc: no RTC, time will be lost on reboot\n");
 290                 goto err;
 291         }
 292         ret = rtc_set_time(alarm_rtc_dev, &rtc_new_rtc_time);
 293         if (ret < 0)
 294                 pr_alarm(ERROR, "alarm_set_rtc: "
 295                         "Failed to set RTC, time will be lost on reboot\n");
 296 err:
 297         wake_unlock(&alarm_rtc_wake_lock);
 298         mutex_unlock(&alarm_setrtc_mutex);
 299         return ret;
 300 }
 301
 302 /**
 303  * alarm_get_elapsed_realtime - get the elapsed real time in ktime_t format
 304  *
 305  * returns the time in ktime_t format
 306  */
 307 ktime_t alarm_get_elapsed_realtime(void)
 308 {
 309         ktime_t now;
 310         unsigned long flags;
 311         struct alarm_queue *base = &alarms[ANDROID_ALARM_ELAPSED_REALTIME];
 312
 313         spin_lock_irqsave(&alarm_slock, flags);
 314         now = base->stopped ? base->stopped_time : ktime_get_real();
 315         now = ktime_sub(now, base->delta);
 316         spin_unlock_irqrestore(&alarm_slock, flags);
 317         return now;
 318 }
 319
 320 static enum hrtimer_restart alarm_timer_triggered(struct hrtimer *timer)
 321 {
 322         struct alarm_queue *base;
 323         struct alarm *alarm;
 324         unsigned long flags;
 325         ktime_t now;
 326
 327         spin_lock_irqsave(&alarm_slock, flags);
 328
 329         base = container_of(timer, struct alarm_queue, timer);
 330         now = base->stopped ? base->stopped_time : hrtimer_cb_get_time(timer);
 331         now = ktime_sub(now, base->delta);
 332
 333         pr_alarm(INT, "alarm_timer_triggered type %d at %lld\n",
 334                 base - alarms, ktime_to_ns(now));
 335
 336         while (base->first) {
 337                 alarm = container_of(base->first, struct alarm, node);
 338                 if (alarm->softexpires.tv64 > now.tv64) {
 339                         pr_alarm(FLOW, "don't call alarm, %pF, %lld (s %lld)\n",
 340                                 alarm->function, ktime_to_ns(alarm->expires),
 341                                 ktime_to_ns(alarm->softexpires));
 342                         break;
 343                 }
 344                 base->first = rb_next(&alarm->node);
 345                 rb_erase(&alarm->node, &base->alarms);
 346                 RB_CLEAR_NODE(&alarm->node);
 347                 pr_alarm(CALL, "call alarm, type %d, func %pF, %lld (s %lld)\n",
 348                         alarm->type, alarm->function,
 349                         ktime_to_ns(alarm->expires),
 350                         ktime_to_ns(alarm->softexpires));
 351                 spin_unlock_irqrestore(&alarm_slock, flags);
 352                 alarm->function(alarm);
 353                 spin_lock_irqsave(&alarm_slock, flags);
 354         }
 355         if (!base->first)
 356                 pr_alarm(FLOW, "no more alarms of type %d\n", base - alarms);
 357         update_timer_locked(base, true);
 358         spin_unlock_irqrestore(&alarm_slock, flags);
 359         return HRTIMER_NORESTART;
 360 }
 361
 362 static void alarm_triggered_func(void *p)
 363 {
 364         struct rtc_device *rtc = alarm_rtc_dev;
 365         if (!(rtc->irq_data & RTC_AF))
 366                 return;
 367         pr_alarm(INT, "rtc alarm triggered\n");
 368         wake_lock_timeout(&alarm_rtc_wake_lock, 1 * HZ);
 369 }
 370
 371 static int alarm_suspend(struct platform_device *pdev, pm_message_t state)
 372 {
 373         int                 err = 0;
 374         unsigned long       flags;
 375         struct rtc_wkalrm   rtc_alarm;
 376         struct rtc_time     rtc_current_rtc_time;
 377         unsigned long       rtc_current_time;
 378         unsigned long       rtc_alarm_time;
 379         struct timespec     rtc_delta;
 380         struct timespec     wall_time;
 381         struct alarm_queue *wakeup_queue = NULL;
 382         struct alarm_queue *tmp_queue = NULL;
 383
 384         pr_alarm(SUSPEND, "alarm_suspend(%p, %d)\n", pdev, state.event);
 385
 386         spin_lock_irqsave(&alarm_slock, flags);
 387         suspended = true;
 388         spin_unlock_irqrestore(&alarm_slock, flags);
 389
 390         hrtimer_cancel(&alarms[ANDROID_ALARM_RTC_WAKEUP].timer);
 391         hrtimer_cancel(&alarms[
 392                         ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP_MASK].timer);
 393
 394         tmp_queue = &alarms[ANDROID_ALARM_RTC_WAKEUP];
 395         if (tmp_queue->first)
 396                 wakeup_queue = tmp_queue;
 397         tmp_queue = &alarms[ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP];
 398         if (tmp_queue->first && (!wakeup_queue ||
 399                                 hrtimer_get_expires(&tmp_queue->timer).tv64 <
 400                                 hrtimer_get_expires(&wakeup_queue->timer).tv64))
 401                 wakeup_queue = tmp_queue;
 402         if (wakeup_queue) {
 403                 rtc_read_time(alarm_rtc_dev, &rtc_current_rtc_time);
 404                 getnstimeofday(&wall_time);
 405                 rtc_tm_to_time(&rtc_current_rtc_time, &rtc_current_time);
 406                 set_normalized_timespec(&rtc_delta,
 407                                         wall_time.tv_sec - rtc_current_time,
 408                                         wall_time.tv_nsec);
 409
 410                 rtc_alarm_time = timespec_sub(ktime_to_timespec(
 411                         hrtimer_get_expires(&wakeup_queue->timer)),
 412                         rtc_delta).tv_sec;
 413
 414                 rtc_time_to_tm(rtc_alarm_time, &rtc_alarm.time);
 415                 rtc_alarm.enabled = 1;
 416                 rtc_set_alarm(alarm_rtc_dev, &rtc_alarm);
 417                 rtc_read_time(alarm_rtc_dev, &rtc_current_rtc_time);
 418                 rtc_tm_to_time(&rtc_current_rtc_time, &rtc_current_time);
 419                 pr_alarm(SUSPEND,
 420                         "rtc alarm set at %ld, now %ld, rtc delta %ld.%09ld\n",
 421                         rtc_alarm_time, rtc_current_time,
 422                         rtc_delta.tv_sec, rtc_delta.tv_nsec);
 423                 if (rtc_current_time + 1 >= rtc_alarm_time) {
 424                         pr_alarm(SUSPEND, "alarm about to go off\n");
 425                         memset(&rtc_alarm, 0, sizeof(rtc_alarm));
 426                         rtc_alarm.enabled = 0;
 427                         rtc_set_alarm(alarm_rtc_dev, &rtc_alarm);
 428
 429                         spin_lock_irqsave(&alarm_slock, flags);
 430                         suspended = false;
 431                         wake_lock_timeout(&alarm_rtc_wake_lock, 2 * HZ);
 432                         update_timer_locked(&alarms[ANDROID_ALARM_RTC_WAKEUP],
 433                                                                         false);
 434                         update_timer_locked(&alarms[
 435                                 ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP], false);
 436                         err = -EBUSY;
 437                         spin_unlock_irqrestore(&alarm_slock, flags);
 438                 }
 439         }
 440         return err;
 441 }
 442
 443 static int alarm_resume(struct platform_device *pdev)
 444 {
 445         struct rtc_wkalrm alarm;
 446         unsigned long       flags;
 447
 448         pr_alarm(SUSPEND, "alarm_resume(%p)\n", pdev);
 449
 450         memset(&alarm, 0, sizeof(alarm));
 451         alarm.enabled = 0;
 452         rtc_set_alarm(alarm_rtc_dev, &alarm);
 453
 454         spin_lock_irqsave(&alarm_slock, flags);
 455         suspended = false;
 456         update_timer_locked(&alarms[ANDROID_ALARM_RTC_WAKEUP], false);
 457         update_timer_locked(&alarms[ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP],
 458                                                                         false);
 459         spin_unlock_irqrestore(&alarm_slock, flags);
 460
 461         return 0;
 462 }
 463
 464 static struct rtc_task alarm_rtc_task = {
 465         .func = alarm_triggered_func
 466 };
 467
 468 static int rtc_alarm_add_device(struct device *dev,
 469                                 struct class_interface *class_intf)
 470 {
 471         int err;
 472         struct rtc_device *rtc = to_rtc_device(dev);
 473
 474         mutex_lock(&alarm_setrtc_mutex);
 475
 476         if (alarm_rtc_dev) {
 477                 err = -EBUSY;
 478                 goto err1;
 479         }
 480
 481         alarm_platform_dev =
 482                 platform_device_register_simple("alarm", -1, NULL, 0);
 483         if (IS_ERR(alarm_platform_dev)) {
 484                 err = PTR_ERR(alarm_platform_dev);
 485                 goto err2;
 486         }
 487         err = rtc_irq_register(rtc, &alarm_rtc_task);
 488         if (err)
 489                 goto err3;
 490         alarm_rtc_dev = rtc;
 491         pr_alarm(INIT_STATUS, "using rtc device, %s, for alarms", rtc->name);
 492         mutex_unlock(&alarm_setrtc_mutex);
 493
 494         return 0;
 495
 496 err3:
 497         platform_device_unregister(alarm_platform_dev);
 498 err2:
 499 err1:
 500         mutex_unlock(&alarm_setrtc_mutex);
 501         return err;
 502 }
 503
 504 static void rtc_alarm_remove_device(struct device *dev,
 505                                     struct class_interface *class_intf)
 506 {
 507         if (dev == &alarm_rtc_dev->dev) {
 508                 pr_alarm(INIT_STATUS, "lost rtc device for alarms");
 509                 rtc_irq_unregister(alarm_rtc_dev, &alarm_rtc_task);
 510                 platform_device_unregister(alarm_platform_dev);
 511                 alarm_rtc_dev = NULL;
 512         }
 513 }
 514
 515 static struct class_interface rtc_alarm_interface = {
 516         .add_dev = &rtc_alarm_add_device,
 517         .remove_dev = &rtc_alarm_remove_device,
 518 };
 519
 520 static struct platform_driver alarm_driver = {
 521         .suspend = alarm_suspend,
 522         .resume = alarm_resume,
 523         .driver = {
 524                 .name = "alarm"
 525         }
 526 };
 527
 528 static int __init alarm_late_init(void)
 529 {
 530         unsigned long   flags;
 531         struct timespec tmp_time, system_time;
 532
 533         /* this needs to run after the rtc is read at boot */
 534         spin_lock_irqsave(&alarm_slock, flags);
 535         /* We read the current rtc and system time so we can later calulate
 536          * elasped realtime to be (boot_systemtime + rtc - boot_rtc) ==
 537          * (rtc - (boot_rtc - boot_systemtime))
 538          */
 539         getnstimeofday(&tmp_time);
 540         ktime_get_ts(&system_time);
 541         alarms[ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP].delta =
 542                 alarms[ANDROID_ALARM_ELAPSED_REALTIME].delta =
 543                         timespec_to_ktime(timespec_sub(tmp_time, system_time));
 544
 545         spin_unlock_irqrestore(&alarm_slock, flags);
 546         return 0;
 547 }
 548
 549 static int __init alarm_driver_init(void)
 550 {
 551         int err;
 552         int i;
 553
 554         for (i = 0; i < ANDROID_ALARM_SYSTEMTIME; i++) {
 555                 hrtimer_init(&alarms[i].timer,
 556                                 CLOCK_REALTIME, HRTIMER_MODE_ABS);
 557                 alarms[i].timer.function = alarm_timer_triggered;
 558         }
 559         hrtimer_init(&alarms[ANDROID_ALARM_SYSTEMTIME].timer,
 560                      CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 561         alarms[ANDROID_ALARM_SYSTEMTIME].timer.function = alarm_timer_triggered;
 562         err = platform_driver_register(&alarm_driver);
 563         if (err < 0)
 564                 goto err1;
 565         wake_lock_init(&alarm_rtc_wake_lock, WAKE_LOCK_SUSPEND, "alarm_rtc");
 566         rtc_alarm_interface.class = rtc_class;
 567         err = class_interface_register(&rtc_alarm_interface);
 568         if (err < 0)
 569                 goto err2;
 570
 571         return 0;
 572
 573 err2:
 574         wake_lock_destroy(&alarm_rtc_wake_lock);
 575         platform_driver_unregister(&alarm_driver);
 576 err1:
 577         return err;
 578 }
 579
 580 static void  __exit alarm_exit(void)
 581 {
 582         class_interface_unregister(&rtc_alarm_interface);
 583         wake_lock_destroy(&alarm_rtc_wake_lock);
 584         platform_driver_unregister(&alarm_driver);
 585 }
 586
 587 late_initcall(alarm_late_init);
 588 module_init(alarm_driver_init);
 589 module_exit(alarm_exit);
 590