2 * drivers/base/power/wakeup.c - System wakeup events framework
4 * Copyright (c) 2010 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
6 * This file is released under the GPLv2.
9 #include <linux/device.h>
10 #include <linux/slab.h>
11 #include <linux/sched.h>
12 #include <linux/capability.h>
13 #include <linux/export.h>
14 #include <linux/suspend.h>
15 #include <linux/seq_file.h>
16 #include <linux/debugfs.h>
17 #include <trace/events/power.h>
22 * If set, the suspend/hibernate code will abort transitions to a sleep state
23 * if wakeup events are registered during or immediately before the transition.
25 bool events_check_enabled __read_mostly;
28 * Combined counters of registered wakeup events and wakeup events in progress.
29 * They need to be modified together atomically, so it's better to use one
30 * atomic variable to hold them both.
32 static atomic_t combined_event_count = ATOMIC_INIT(0);
34 #define IN_PROGRESS_BITS (sizeof(int) * 4)
35 #define MAX_IN_PROGRESS ((1 << IN_PROGRESS_BITS) - 1)
37 static void split_counters(unsigned int *cnt, unsigned int *inpr)
39 unsigned int comb = atomic_read(&combined_event_count);
41 *cnt = (comb >> IN_PROGRESS_BITS);
42 *inpr = comb & MAX_IN_PROGRESS;
45 /* A preserved old value of the events counter. */
46 static unsigned int saved_count;
48 static DEFINE_SPINLOCK(events_lock);
50 static void pm_wakeup_timer_fn(unsigned long data);
52 static LIST_HEAD(wakeup_sources);
54 static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue);
57 * wakeup_source_prepare - Prepare a new wakeup source for initialization.
58 * @ws: Wakeup source to prepare.
59 * @name: Pointer to the name of the new wakeup source.
61 * Callers must ensure that the @name string won't be freed when @ws is still in
64 void wakeup_source_prepare(struct wakeup_source *ws, const char *name)
67 memset(ws, 0, sizeof(*ws));
71 EXPORT_SYMBOL_GPL(wakeup_source_prepare);
74 * wakeup_source_create - Create a struct wakeup_source object.
75 * @name: Name of the new wakeup source.
77 struct wakeup_source *wakeup_source_create(const char *name)
79 struct wakeup_source *ws;
81 ws = kmalloc(sizeof(*ws), GFP_KERNEL);
85 wakeup_source_prepare(ws, name ? kstrdup(name, GFP_KERNEL) : NULL);
88 EXPORT_SYMBOL_GPL(wakeup_source_create);
91 * wakeup_source_drop - Prepare a struct wakeup_source object for destruction.
92 * @ws: Wakeup source to prepare for destruction.
94 * Callers must ensure that __pm_stay_awake() or __pm_wakeup_event() will never
95 * be run in parallel with this function for the same wakeup source object.
97 void wakeup_source_drop(struct wakeup_source *ws)
102 del_timer_sync(&ws->timer);
105 EXPORT_SYMBOL_GPL(wakeup_source_drop);
108 * wakeup_source_destroy - Destroy a struct wakeup_source object.
109 * @ws: Wakeup source to destroy.
111 * Use only for wakeup source objects created with wakeup_source_create().
113 void wakeup_source_destroy(struct wakeup_source *ws)
118 wakeup_source_drop(ws);
122 EXPORT_SYMBOL_GPL(wakeup_source_destroy);
125 * wakeup_source_add - Add given object to the list of wakeup sources.
126 * @ws: Wakeup source object to add to the list.
128 void wakeup_source_add(struct wakeup_source *ws)
135 spin_lock_init(&ws->lock);
136 setup_timer(&ws->timer, pm_wakeup_timer_fn, (unsigned long)ws);
138 ws->last_time = ktime_get();
140 spin_lock_irqsave(&events_lock, flags);
141 list_add_rcu(&ws->entry, &wakeup_sources);
142 spin_unlock_irqrestore(&events_lock, flags);
144 EXPORT_SYMBOL_GPL(wakeup_source_add);
147 * wakeup_source_remove - Remove given object from the wakeup sources list.
148 * @ws: Wakeup source object to remove from the list.
150 void wakeup_source_remove(struct wakeup_source *ws)
157 spin_lock_irqsave(&events_lock, flags);
158 list_del_rcu(&ws->entry);
159 spin_unlock_irqrestore(&events_lock, flags);
162 EXPORT_SYMBOL_GPL(wakeup_source_remove);
165 * wakeup_source_register - Create wakeup source and add it to the list.
166 * @name: Name of the wakeup source to register.
168 struct wakeup_source *wakeup_source_register(const char *name)
170 struct wakeup_source *ws;
172 ws = wakeup_source_create(name);
174 wakeup_source_add(ws);
178 EXPORT_SYMBOL_GPL(wakeup_source_register);
181 * wakeup_source_unregister - Remove wakeup source from the list and remove it.
182 * @ws: Wakeup source object to unregister.
184 void wakeup_source_unregister(struct wakeup_source *ws)
187 wakeup_source_remove(ws);
188 wakeup_source_destroy(ws);
191 EXPORT_SYMBOL_GPL(wakeup_source_unregister);
194 * device_wakeup_attach - Attach a wakeup source object to a device object.
195 * @dev: Device to handle.
196 * @ws: Wakeup source object to attach to @dev.
198 * This causes @dev to be treated as a wakeup device.
200 static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
202 spin_lock_irq(&dev->power.lock);
203 if (dev->power.wakeup) {
204 spin_unlock_irq(&dev->power.lock);
207 dev->power.wakeup = ws;
208 spin_unlock_irq(&dev->power.lock);
213 * device_wakeup_enable - Enable given device to be a wakeup source.
214 * @dev: Device to handle.
216 * Create a wakeup source object, register it and attach it to @dev.
218 int device_wakeup_enable(struct device *dev)
220 struct wakeup_source *ws;
223 if (!dev || !dev->power.can_wakeup)
226 ws = wakeup_source_register(dev_name(dev));
230 ret = device_wakeup_attach(dev, ws);
232 wakeup_source_unregister(ws);
236 EXPORT_SYMBOL_GPL(device_wakeup_enable);
239 * device_wakeup_detach - Detach a device's wakeup source object from it.
240 * @dev: Device to detach the wakeup source object from.
242 * After it returns, @dev will not be treated as a wakeup device any more.
244 static struct wakeup_source *device_wakeup_detach(struct device *dev)
246 struct wakeup_source *ws;
248 spin_lock_irq(&dev->power.lock);
249 ws = dev->power.wakeup;
250 dev->power.wakeup = NULL;
251 spin_unlock_irq(&dev->power.lock);
256 * device_wakeup_disable - Do not regard a device as a wakeup source any more.
257 * @dev: Device to handle.
259 * Detach the @dev's wakeup source object from it, unregister this wakeup source
260 * object and destroy it.
262 int device_wakeup_disable(struct device *dev)
264 struct wakeup_source *ws;
266 if (!dev || !dev->power.can_wakeup)
269 ws = device_wakeup_detach(dev);
271 wakeup_source_unregister(ws);
275 EXPORT_SYMBOL_GPL(device_wakeup_disable);
278 * device_set_wakeup_capable - Set/reset device wakeup capability flag.
279 * @dev: Device to handle.
280 * @capable: Whether or not @dev is capable of waking up the system from sleep.
282 * If @capable is set, set the @dev's power.can_wakeup flag and add its
283 * wakeup-related attributes to sysfs. Otherwise, unset the @dev's
284 * power.can_wakeup flag and remove its wakeup-related attributes from sysfs.
286 * This function may sleep and it can't be called from any context where
287 * sleeping is not allowed.
289 void device_set_wakeup_capable(struct device *dev, bool capable)
291 if (!!dev->power.can_wakeup == !!capable)
294 if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
296 if (wakeup_sysfs_add(dev))
299 wakeup_sysfs_remove(dev);
302 dev->power.can_wakeup = capable;
304 EXPORT_SYMBOL_GPL(device_set_wakeup_capable);
307 * device_init_wakeup - Device wakeup initialization.
308 * @dev: Device to handle.
309 * @enable: Whether or not to enable @dev as a wakeup device.
311 * By default, most devices should leave wakeup disabled. The exceptions are
312 * devices that everyone expects to be wakeup sources: keyboards, power buttons,
313 * possibly network interfaces, etc. Also, devices that don't generate their
314 * own wakeup requests but merely forward requests from one bus to another
315 * (like PCI bridges) should have wakeup enabled by default.
317 int device_init_wakeup(struct device *dev, bool enable)
325 device_set_wakeup_capable(dev, true);
326 ret = device_wakeup_enable(dev);
328 if (dev->power.can_wakeup)
329 device_wakeup_disable(dev);
331 device_set_wakeup_capable(dev, false);
336 EXPORT_SYMBOL_GPL(device_init_wakeup);
339 * device_set_wakeup_enable - Enable or disable a device to wake up the system.
340 * @dev: Device to handle.
342 int device_set_wakeup_enable(struct device *dev, bool enable)
344 if (!dev || !dev->power.can_wakeup)
347 return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
349 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
352 * The functions below use the observation that each wakeup event starts a
353 * period in which the system should not be suspended. The moment this period
354 * will end depends on how the wakeup event is going to be processed after being
355 * detected and all of the possible cases can be divided into two distinct
358 * First, a wakeup event may be detected by the same functional unit that will
359 * carry out the entire processing of it and possibly will pass it to user space
360 * for further processing. In that case the functional unit that has detected
361 * the event may later "close" the "no suspend" period associated with it
362 * directly as soon as it has been dealt with. The pair of pm_stay_awake() and
363 * pm_relax(), balanced with each other, is supposed to be used in such
366 * Second, a wakeup event may be detected by one functional unit and processed
367 * by another one. In that case the unit that has detected it cannot really
368 * "close" the "no suspend" period associated with it, unless it knows in
369 * advance what's going to happen to the event during processing. This
370 * knowledge, however, may not be available to it, so it can simply specify time
371 * to wait before the system can be suspended and pass it as the second
372 * argument of pm_wakeup_event().
374 * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
375 * "no suspend" period will be ended either by the pm_relax(), or by the timer
376 * function executed when the timer expires, whichever comes first.
380 * wakup_source_activate - Mark given wakeup source as active.
381 * @ws: Wakeup source to handle.
383 * Update the @ws' statistics and, if @ws has just been activated, notify the PM
384 * core of the event by incrementing the counter of of wakeup events being
387 static void wakeup_source_activate(struct wakeup_source *ws)
392 * active wakeup source should bring the system
393 * out of PM_SUSPEND_FREEZE state
399 ws->last_time = ktime_get();
400 if (ws->autosleep_enabled)
401 ws->start_prevent_time = ws->last_time;
403 /* Increment the counter of events in progress. */
404 cec = atomic_inc_return(&combined_event_count);
406 trace_wakeup_source_activate(ws->name, cec);
410 * wakeup_source_report_event - Report wakeup event using the given source.
411 * @ws: Wakeup source to report the event for.
413 static void wakeup_source_report_event(struct wakeup_source *ws)
416 /* This is racy, but the counter is approximate anyway. */
417 if (events_check_enabled)
421 wakeup_source_activate(ws);
425 * __pm_stay_awake - Notify the PM core of a wakeup event.
426 * @ws: Wakeup source object associated with the source of the event.
428 * It is safe to call this function from interrupt context.
430 void __pm_stay_awake(struct wakeup_source *ws)
437 spin_lock_irqsave(&ws->lock, flags);
439 wakeup_source_report_event(ws);
440 del_timer(&ws->timer);
441 ws->timer_expires = 0;
443 spin_unlock_irqrestore(&ws->lock, flags);
445 EXPORT_SYMBOL_GPL(__pm_stay_awake);
448 * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
449 * @dev: Device the wakeup event is related to.
451 * Notify the PM core of a wakeup event (signaled by @dev) by calling
452 * __pm_stay_awake for the @dev's wakeup source object.
454 * Call this function after detecting of a wakeup event if pm_relax() is going
455 * to be called directly after processing the event (and possibly passing it to
456 * user space for further processing).
458 void pm_stay_awake(struct device *dev)
465 spin_lock_irqsave(&dev->power.lock, flags);
466 __pm_stay_awake(dev->power.wakeup);
467 spin_unlock_irqrestore(&dev->power.lock, flags);
469 EXPORT_SYMBOL_GPL(pm_stay_awake);
471 #ifdef CONFIG_PM_AUTOSLEEP
472 static void update_prevent_sleep_time(struct wakeup_source *ws, ktime_t now)
474 ktime_t delta = ktime_sub(now, ws->start_prevent_time);
475 ws->prevent_sleep_time = ktime_add(ws->prevent_sleep_time, delta);
478 static inline void update_prevent_sleep_time(struct wakeup_source *ws,
483 * wakup_source_deactivate - Mark given wakeup source as inactive.
484 * @ws: Wakeup source to handle.
486 * Update the @ws' statistics and notify the PM core that the wakeup source has
487 * become inactive by decrementing the counter of wakeup events being processed
488 * and incrementing the counter of registered wakeup events.
490 static void wakeup_source_deactivate(struct wakeup_source *ws)
492 unsigned int cnt, inpr, cec;
498 * __pm_relax() may be called directly or from a timer function.
499 * If it is called directly right after the timer function has been
500 * started, but before the timer function calls __pm_relax(), it is
501 * possible that __pm_stay_awake() will be called in the meantime and
502 * will set ws->active. Then, ws->active may be cleared immediately
503 * by the __pm_relax() called from the timer function, but in such a
504 * case ws->relax_count will be different from ws->active_count.
506 if (ws->relax_count != ws->active_count) {
514 duration = ktime_sub(now, ws->last_time);
515 ws->total_time = ktime_add(ws->total_time, duration);
516 if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
517 ws->max_time = duration;
520 del_timer(&ws->timer);
521 ws->timer_expires = 0;
523 if (ws->autosleep_enabled)
524 update_prevent_sleep_time(ws, now);
527 * Increment the counter of registered wakeup events and decrement the
528 * couter of wakeup events in progress simultaneously.
530 cec = atomic_add_return(MAX_IN_PROGRESS, &combined_event_count);
531 trace_wakeup_source_deactivate(ws->name, cec);
533 split_counters(&cnt, &inpr);
534 if (!inpr && waitqueue_active(&wakeup_count_wait_queue))
535 wake_up(&wakeup_count_wait_queue);
539 * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
540 * @ws: Wakeup source object associated with the source of the event.
542 * Call this function for wakeup events whose processing started with calling
545 * It is safe to call it from interrupt context.
547 void __pm_relax(struct wakeup_source *ws)
554 spin_lock_irqsave(&ws->lock, flags);
556 wakeup_source_deactivate(ws);
557 spin_unlock_irqrestore(&ws->lock, flags);
559 EXPORT_SYMBOL_GPL(__pm_relax);
562 * pm_relax - Notify the PM core that processing of a wakeup event has ended.
563 * @dev: Device that signaled the event.
565 * Execute __pm_relax() for the @dev's wakeup source object.
567 void pm_relax(struct device *dev)
574 spin_lock_irqsave(&dev->power.lock, flags);
575 __pm_relax(dev->power.wakeup);
576 spin_unlock_irqrestore(&dev->power.lock, flags);
578 EXPORT_SYMBOL_GPL(pm_relax);
581 * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
582 * @data: Address of the wakeup source object associated with the event source.
584 * Call wakeup_source_deactivate() for the wakeup source whose address is stored
585 * in @data if it is currently active and its timer has not been canceled and
586 * the expiration time of the timer is not in future.
588 static void pm_wakeup_timer_fn(unsigned long data)
590 struct wakeup_source *ws = (struct wakeup_source *)data;
593 spin_lock_irqsave(&ws->lock, flags);
595 if (ws->active && ws->timer_expires
596 && time_after_eq(jiffies, ws->timer_expires)) {
597 wakeup_source_deactivate(ws);
601 spin_unlock_irqrestore(&ws->lock, flags);
605 * __pm_wakeup_event - Notify the PM core of a wakeup event.
606 * @ws: Wakeup source object associated with the event source.
607 * @msec: Anticipated event processing time (in milliseconds).
609 * Notify the PM core of a wakeup event whose source is @ws that will take
610 * approximately @msec milliseconds to be processed by the kernel. If @ws is
611 * not active, activate it. If @msec is nonzero, set up the @ws' timer to
612 * execute pm_wakeup_timer_fn() in future.
614 * It is safe to call this function from interrupt context.
616 void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
619 unsigned long expires;
624 spin_lock_irqsave(&ws->lock, flags);
626 wakeup_source_report_event(ws);
629 wakeup_source_deactivate(ws);
633 expires = jiffies + msecs_to_jiffies(msec);
637 if (!ws->timer_expires || time_after(expires, ws->timer_expires)) {
638 mod_timer(&ws->timer, expires);
639 ws->timer_expires = expires;
643 spin_unlock_irqrestore(&ws->lock, flags);
645 EXPORT_SYMBOL_GPL(__pm_wakeup_event);
649 * pm_wakeup_event - Notify the PM core of a wakeup event.
650 * @dev: Device the wakeup event is related to.
651 * @msec: Anticipated event processing time (in milliseconds).
653 * Call __pm_wakeup_event() for the @dev's wakeup source object.
655 void pm_wakeup_event(struct device *dev, unsigned int msec)
662 spin_lock_irqsave(&dev->power.lock, flags);
663 __pm_wakeup_event(dev->power.wakeup, msec);
664 spin_unlock_irqrestore(&dev->power.lock, flags);
666 EXPORT_SYMBOL_GPL(pm_wakeup_event);
668 void pm_print_active_wakeup_sources(void)
670 struct wakeup_source *ws;
672 struct wakeup_source *last_activity_ws = NULL;
675 list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
677 pr_info("active wakeup source: %s\n", ws->name);
679 } else if (!active &&
680 (!last_activity_ws ||
681 ktime_to_ns(ws->last_time) >
682 ktime_to_ns(last_activity_ws->last_time))) {
683 last_activity_ws = ws;
687 if (!active && last_activity_ws)
688 pr_info("last active wakeup source: %s\n",
689 last_activity_ws->name);
692 EXPORT_SYMBOL_GPL(pm_print_active_wakeup_sources);
695 * pm_wakeup_pending - Check if power transition in progress should be aborted.
697 * Compare the current number of registered wakeup events with its preserved
698 * value from the past and return true if new wakeup events have been registered
699 * since the old value was stored. Also return true if the current number of
700 * wakeup events being processed is different from zero.
702 bool pm_wakeup_pending(void)
707 spin_lock_irqsave(&events_lock, flags);
708 if (events_check_enabled) {
709 unsigned int cnt, inpr;
711 split_counters(&cnt, &inpr);
712 ret = (cnt != saved_count || inpr > 0);
713 events_check_enabled = !ret;
715 spin_unlock_irqrestore(&events_lock, flags);
718 pr_info("PM: Wakeup pending, aborting suspend\n");
719 pm_print_active_wakeup_sources();
726 * pm_get_wakeup_count - Read the number of registered wakeup events.
727 * @count: Address to store the value at.
728 * @block: Whether or not to block.
730 * Store the number of registered wakeup events at the address in @count. If
731 * @block is set, block until the current number of wakeup events being
734 * Return 'false' if the current number of wakeup events being processed is
735 * nonzero. Otherwise return 'true'.
737 bool pm_get_wakeup_count(unsigned int *count, bool block)
739 unsigned int cnt, inpr;
745 prepare_to_wait(&wakeup_count_wait_queue, &wait,
747 split_counters(&cnt, &inpr);
748 if (inpr == 0 || signal_pending(current))
753 finish_wait(&wakeup_count_wait_queue, &wait);
756 split_counters(&cnt, &inpr);
762 * pm_save_wakeup_count - Save the current number of registered wakeup events.
763 * @count: Value to compare with the current number of registered wakeup events.
765 * If @count is equal to the current number of registered wakeup events and the
766 * current number of wakeup events being processed is zero, store @count as the
767 * old number of registered wakeup events for pm_check_wakeup_events(), enable
768 * wakeup events detection and return 'true'. Otherwise disable wakeup events
769 * detection and return 'false'.
771 bool pm_save_wakeup_count(unsigned int count)
773 unsigned int cnt, inpr;
776 events_check_enabled = false;
777 spin_lock_irqsave(&events_lock, flags);
778 split_counters(&cnt, &inpr);
779 if (cnt == count && inpr == 0) {
781 events_check_enabled = true;
783 spin_unlock_irqrestore(&events_lock, flags);
784 return events_check_enabled;
787 #ifdef CONFIG_PM_AUTOSLEEP
789 * pm_wakep_autosleep_enabled - Modify autosleep_enabled for all wakeup sources.
790 * @enabled: Whether to set or to clear the autosleep_enabled flags.
792 void pm_wakep_autosleep_enabled(bool set)
794 struct wakeup_source *ws;
795 ktime_t now = ktime_get();
798 list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
799 spin_lock_irq(&ws->lock);
800 if (ws->autosleep_enabled != set) {
801 ws->autosleep_enabled = set;
804 ws->start_prevent_time = now;
806 update_prevent_sleep_time(ws, now);
809 spin_unlock_irq(&ws->lock);
813 #endif /* CONFIG_PM_AUTOSLEEP */
815 static struct dentry *wakeup_sources_stats_dentry;
818 * print_wakeup_source_stats - Print wakeup source statistics information.
819 * @m: seq_file to print the statistics into.
820 * @ws: Wakeup source object to print the statistics for.
822 static int print_wakeup_source_stats(struct seq_file *m,
823 struct wakeup_source *ws)
828 unsigned long active_count;
830 ktime_t prevent_sleep_time;
833 spin_lock_irqsave(&ws->lock, flags);
835 total_time = ws->total_time;
836 max_time = ws->max_time;
837 prevent_sleep_time = ws->prevent_sleep_time;
838 active_count = ws->active_count;
840 ktime_t now = ktime_get();
842 active_time = ktime_sub(now, ws->last_time);
843 total_time = ktime_add(total_time, active_time);
844 if (active_time.tv64 > max_time.tv64)
845 max_time = active_time;
847 if (ws->autosleep_enabled)
848 prevent_sleep_time = ktime_add(prevent_sleep_time,
849 ktime_sub(now, ws->start_prevent_time));
851 active_time = ktime_set(0, 0);
854 ret = seq_printf(m, "%-12s\t%lu\t\t%lu\t\t%lu\t\t%lu\t\t"
855 "%lld\t\t%lld\t\t%lld\t\t%lld\t\t%lld\n",
856 ws->name, active_count, ws->event_count,
857 ws->wakeup_count, ws->expire_count,
858 ktime_to_ms(active_time), ktime_to_ms(total_time),
859 ktime_to_ms(max_time), ktime_to_ms(ws->last_time),
860 ktime_to_ms(prevent_sleep_time));
862 spin_unlock_irqrestore(&ws->lock, flags);
868 * wakeup_sources_stats_show - Print wakeup sources statistics information.
869 * @m: seq_file to print the statistics into.
871 static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
873 struct wakeup_source *ws;
875 seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
876 "expire_count\tactive_since\ttotal_time\tmax_time\t"
877 "last_change\tprevent_suspend_time\n");
880 list_for_each_entry_rcu(ws, &wakeup_sources, entry)
881 print_wakeup_source_stats(m, ws);
887 static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
889 return single_open(file, wakeup_sources_stats_show, NULL);
892 static const struct file_operations wakeup_sources_stats_fops = {
893 .owner = THIS_MODULE,
894 .open = wakeup_sources_stats_open,
897 .release = single_release,
900 static int __init wakeup_sources_debugfs_init(void)
902 wakeup_sources_stats_dentry = debugfs_create_file("wakeup_sources",
903 S_IRUGO, NULL, NULL, &wakeup_sources_stats_fops);
907 postcore_initcall(wakeup_sources_debugfs_init);