rfkill: detect bogus double-registering (v2)
[linux-2.6.git] / net / rfkill / rfkill.c
1 /*
2  * Copyright (C) 2006 - 2007 Ivo van Doorn
3  * Copyright (C) 2007 Dmitry Torokhov
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the
17  * Free Software Foundation, Inc.,
18  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19  */
20
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/init.h>
24 #include <linux/workqueue.h>
25 #include <linux/capability.h>
26 #include <linux/list.h>
27 #include <linux/mutex.h>
28 #include <linux/rfkill.h>
29
30 /* Get declaration of rfkill_switch_all() to shut up sparse. */
31 #include "rfkill-input.h"
32
33
34 MODULE_AUTHOR("Ivo van Doorn <IvDoorn@gmail.com>");
35 MODULE_VERSION("1.0");
36 MODULE_DESCRIPTION("RF switch support");
37 MODULE_LICENSE("GPL");
38
39 static LIST_HEAD(rfkill_list);  /* list of registered rf switches */
40 static DEFINE_MUTEX(rfkill_mutex);
41
42 static unsigned int rfkill_default_state = RFKILL_STATE_UNBLOCKED;
43 module_param_named(default_state, rfkill_default_state, uint, 0444);
44 MODULE_PARM_DESC(default_state,
45                  "Default initial state for all radio types, 0 = radio off");
46
47 static enum rfkill_state rfkill_states[RFKILL_TYPE_MAX];
48
49 static BLOCKING_NOTIFIER_HEAD(rfkill_notifier_list);
50
51
52 /**
53  * register_rfkill_notifier - Add notifier to rfkill notifier chain
54  * @nb: pointer to the new entry to add to the chain
55  *
56  * See blocking_notifier_chain_register() for return value and further
57  * observations.
58  *
59  * Adds a notifier to the rfkill notifier chain.  The chain will be
60  * called with a pointer to the relevant rfkill structure as a parameter,
61  * refer to include/linux/rfkill.h for the possible events.
62  *
63  * Notifiers added to this chain are to always return NOTIFY_DONE.  This
64  * chain is a blocking notifier chain: notifiers can sleep.
65  *
66  * Calls to this chain may have been done through a workqueue.  One must
67  * assume unordered asynchronous behaviour, there is no way to know if
68  * actions related to the event that generated the notification have been
69  * carried out already.
70  */
71 int register_rfkill_notifier(struct notifier_block *nb)
72 {
73         return blocking_notifier_chain_register(&rfkill_notifier_list, nb);
74 }
75 EXPORT_SYMBOL_GPL(register_rfkill_notifier);
76
77 /**
78  * unregister_rfkill_notifier - remove notifier from rfkill notifier chain
79  * @nb: pointer to the entry to remove from the chain
80  *
81  * See blocking_notifier_chain_unregister() for return value and further
82  * observations.
83  *
84  * Removes a notifier from the rfkill notifier chain.
85  */
86 int unregister_rfkill_notifier(struct notifier_block *nb)
87 {
88         return blocking_notifier_chain_unregister(&rfkill_notifier_list, nb);
89 }
90 EXPORT_SYMBOL_GPL(unregister_rfkill_notifier);
91
92
93 static void rfkill_led_trigger(struct rfkill *rfkill,
94                                enum rfkill_state state)
95 {
96 #ifdef CONFIG_RFKILL_LEDS
97         struct led_trigger *led = &rfkill->led_trigger;
98
99         if (!led->name)
100                 return;
101         if (state != RFKILL_STATE_UNBLOCKED)
102                 led_trigger_event(led, LED_OFF);
103         else
104                 led_trigger_event(led, LED_FULL);
105 #endif /* CONFIG_RFKILL_LEDS */
106 }
107
108 #ifdef CONFIG_RFKILL_LEDS
109 static void rfkill_led_trigger_activate(struct led_classdev *led)
110 {
111         struct rfkill *rfkill = container_of(led->trigger,
112                         struct rfkill, led_trigger);
113
114         rfkill_led_trigger(rfkill, rfkill->state);
115 }
116 #endif /* CONFIG_RFKILL_LEDS */
117
118 static void notify_rfkill_state_change(struct rfkill *rfkill)
119 {
120         blocking_notifier_call_chain(&rfkill_notifier_list,
121                         RFKILL_STATE_CHANGED,
122                         rfkill);
123 }
124
125 static void update_rfkill_state(struct rfkill *rfkill)
126 {
127         enum rfkill_state newstate, oldstate;
128
129         if (rfkill->get_state) {
130                 mutex_lock(&rfkill->mutex);
131                 if (!rfkill->get_state(rfkill->data, &newstate)) {
132                         oldstate = rfkill->state;
133                         rfkill->state = newstate;
134                         if (oldstate != newstate)
135                                 notify_rfkill_state_change(rfkill);
136                 }
137                 mutex_unlock(&rfkill->mutex);
138         }
139 }
140
141 /**
142  * rfkill_toggle_radio - wrapper for toggle_radio hook
143  * @rfkill: the rfkill struct to use
144  * @force: calls toggle_radio even if cache says it is not needed,
145  *      and also makes sure notifications of the state will be
146  *      sent even if it didn't change
147  * @state: the new state to call toggle_radio() with
148  *
149  * Calls rfkill->toggle_radio, enforcing the API for toggle_radio
150  * calls and handling all the red tape such as issuing notifications
151  * if the call is successful.
152  *
153  * Suspended devices are not touched at all, and -EAGAIN is returned.
154  *
155  * Note that the @force parameter cannot override a (possibly cached)
156  * state of RFKILL_STATE_HARD_BLOCKED.  Any device making use of
157  * RFKILL_STATE_HARD_BLOCKED implements either get_state() or
158  * rfkill_force_state(), so the cache either is bypassed or valid.
159  *
160  * Note that we do call toggle_radio for RFKILL_STATE_SOFT_BLOCKED
161  * even if the radio is in RFKILL_STATE_HARD_BLOCKED state, so as to
162  * give the driver a hint that it should double-BLOCK the transmitter.
163  *
164  * Caller must have acquired rfkill->mutex.
165  */
166 static int rfkill_toggle_radio(struct rfkill *rfkill,
167                                 enum rfkill_state state,
168                                 int force)
169 {
170         int retval = 0;
171         enum rfkill_state oldstate, newstate;
172
173         if (unlikely(rfkill->dev.power.power_state.event & PM_EVENT_SLEEP))
174                 return -EBUSY;
175
176         oldstate = rfkill->state;
177
178         if (rfkill->get_state && !force &&
179             !rfkill->get_state(rfkill->data, &newstate))
180                 rfkill->state = newstate;
181
182         switch (state) {
183         case RFKILL_STATE_HARD_BLOCKED:
184                 /* typically happens when refreshing hardware state,
185                  * such as on resume */
186                 state = RFKILL_STATE_SOFT_BLOCKED;
187                 break;
188         case RFKILL_STATE_UNBLOCKED:
189                 /* force can't override this, only rfkill_force_state() can */
190                 if (rfkill->state == RFKILL_STATE_HARD_BLOCKED)
191                         return -EPERM;
192                 break;
193         case RFKILL_STATE_SOFT_BLOCKED:
194                 /* nothing to do, we want to give drivers the hint to double
195                  * BLOCK even a transmitter that is already in state
196                  * RFKILL_STATE_HARD_BLOCKED */
197                 break;
198         }
199
200         if (force || state != rfkill->state) {
201                 retval = rfkill->toggle_radio(rfkill->data, state);
202                 /* never allow a HARD->SOFT downgrade! */
203                 if (!retval && rfkill->state != RFKILL_STATE_HARD_BLOCKED)
204                         rfkill->state = state;
205         }
206
207         if (force || rfkill->state != oldstate) {
208                 rfkill_led_trigger(rfkill, rfkill->state);
209                 notify_rfkill_state_change(rfkill);
210         }
211
212         return retval;
213 }
214
215 /**
216  * rfkill_switch_all - Toggle state of all switches of given type
217  * @type: type of interfaces to be affected
218  * @state: the new state
219  *
220  * This function toggles the state of all switches of given type,
221  * unless a specific switch is claimed by userspace (in which case,
222  * that switch is left alone) or suspended.
223  */
224 void rfkill_switch_all(enum rfkill_type type, enum rfkill_state state)
225 {
226         struct rfkill *rfkill;
227
228         mutex_lock(&rfkill_mutex);
229
230         rfkill_states[type] = state;
231
232         list_for_each_entry(rfkill, &rfkill_list, node) {
233                 if ((!rfkill->user_claim) && (rfkill->type == type)) {
234                         mutex_lock(&rfkill->mutex);
235                         rfkill_toggle_radio(rfkill, state, 0);
236                         mutex_unlock(&rfkill->mutex);
237                 }
238         }
239
240         mutex_unlock(&rfkill_mutex);
241 }
242 EXPORT_SYMBOL(rfkill_switch_all);
243
244 /**
245  * rfkill_epo - emergency power off all transmitters
246  *
247  * This kicks all non-suspended rfkill devices to RFKILL_STATE_SOFT_BLOCKED,
248  * ignoring everything in its path but rfkill_mutex and rfkill->mutex.
249  */
250 void rfkill_epo(void)
251 {
252         struct rfkill *rfkill;
253
254         mutex_lock(&rfkill_mutex);
255         list_for_each_entry(rfkill, &rfkill_list, node) {
256                 mutex_lock(&rfkill->mutex);
257                 rfkill_toggle_radio(rfkill, RFKILL_STATE_SOFT_BLOCKED, 1);
258                 mutex_unlock(&rfkill->mutex);
259         }
260         mutex_unlock(&rfkill_mutex);
261 }
262 EXPORT_SYMBOL_GPL(rfkill_epo);
263
264 /**
265  * rfkill_force_state - Force the internal rfkill radio state
266  * @rfkill: pointer to the rfkill class to modify.
267  * @state: the current radio state the class should be forced to.
268  *
269  * This function updates the internal state of the radio cached
270  * by the rfkill class.  It should be used when the driver gets
271  * a notification by the firmware/hardware of the current *real*
272  * state of the radio rfkill switch.
273  *
274  * Devices which are subject to external changes on their rfkill
275  * state (such as those caused by a hardware rfkill line) MUST
276  * have their driver arrange to call rfkill_force_state() as soon
277  * as possible after such a change.
278  *
279  * This function may not be called from an atomic context.
280  */
281 int rfkill_force_state(struct rfkill *rfkill, enum rfkill_state state)
282 {
283         enum rfkill_state oldstate;
284
285         if (state != RFKILL_STATE_SOFT_BLOCKED &&
286             state != RFKILL_STATE_UNBLOCKED &&
287             state != RFKILL_STATE_HARD_BLOCKED)
288                 return -EINVAL;
289
290         mutex_lock(&rfkill->mutex);
291
292         oldstate = rfkill->state;
293         rfkill->state = state;
294
295         if (state != oldstate)
296                 notify_rfkill_state_change(rfkill);
297
298         mutex_unlock(&rfkill->mutex);
299
300         return 0;
301 }
302 EXPORT_SYMBOL(rfkill_force_state);
303
304 static ssize_t rfkill_name_show(struct device *dev,
305                                 struct device_attribute *attr,
306                                 char *buf)
307 {
308         struct rfkill *rfkill = to_rfkill(dev);
309
310         return sprintf(buf, "%s\n", rfkill->name);
311 }
312
313 static const char *rfkill_get_type_str(enum rfkill_type type)
314 {
315         switch (type) {
316         case RFKILL_TYPE_WLAN:
317                 return "wlan";
318         case RFKILL_TYPE_BLUETOOTH:
319                 return "bluetooth";
320         case RFKILL_TYPE_UWB:
321                 return "ultrawideband";
322         case RFKILL_TYPE_WIMAX:
323                 return "wimax";
324         case RFKILL_TYPE_WWAN:
325                 return "wwan";
326         default:
327                 BUG();
328         }
329 }
330
331 static ssize_t rfkill_type_show(struct device *dev,
332                                 struct device_attribute *attr,
333                                 char *buf)
334 {
335         struct rfkill *rfkill = to_rfkill(dev);
336
337         return sprintf(buf, "%s\n", rfkill_get_type_str(rfkill->type));
338 }
339
340 static ssize_t rfkill_state_show(struct device *dev,
341                                  struct device_attribute *attr,
342                                  char *buf)
343 {
344         struct rfkill *rfkill = to_rfkill(dev);
345
346         update_rfkill_state(rfkill);
347         return sprintf(buf, "%d\n", rfkill->state);
348 }
349
350 static ssize_t rfkill_state_store(struct device *dev,
351                                   struct device_attribute *attr,
352                                   const char *buf, size_t count)
353 {
354         struct rfkill *rfkill = to_rfkill(dev);
355         unsigned int state = simple_strtoul(buf, NULL, 0);
356         int error;
357
358         if (!capable(CAP_NET_ADMIN))
359                 return -EPERM;
360
361         /* RFKILL_STATE_HARD_BLOCKED is illegal here... */
362         if (state != RFKILL_STATE_UNBLOCKED &&
363             state != RFKILL_STATE_SOFT_BLOCKED)
364                 return -EINVAL;
365
366         if (mutex_lock_interruptible(&rfkill->mutex))
367                 return -ERESTARTSYS;
368         error = rfkill_toggle_radio(rfkill, state, 0);
369         mutex_unlock(&rfkill->mutex);
370
371         return error ? error : count;
372 }
373
374 static ssize_t rfkill_claim_show(struct device *dev,
375                                  struct device_attribute *attr,
376                                  char *buf)
377 {
378         struct rfkill *rfkill = to_rfkill(dev);
379
380         return sprintf(buf, "%d", rfkill->user_claim);
381 }
382
383 static ssize_t rfkill_claim_store(struct device *dev,
384                                   struct device_attribute *attr,
385                                   const char *buf, size_t count)
386 {
387         struct rfkill *rfkill = to_rfkill(dev);
388         bool claim = !!simple_strtoul(buf, NULL, 0);
389         int error;
390
391         if (!capable(CAP_NET_ADMIN))
392                 return -EPERM;
393
394         if (rfkill->user_claim_unsupported)
395                 return -EOPNOTSUPP;
396
397         /*
398          * Take the global lock to make sure the kernel is not in
399          * the middle of rfkill_switch_all
400          */
401         error = mutex_lock_interruptible(&rfkill_mutex);
402         if (error)
403                 return error;
404
405         if (rfkill->user_claim != claim) {
406                 if (!claim) {
407                         mutex_lock(&rfkill->mutex);
408                         rfkill_toggle_radio(rfkill,
409                                             rfkill_states[rfkill->type],
410                                             0);
411                         mutex_unlock(&rfkill->mutex);
412                 }
413                 rfkill->user_claim = claim;
414         }
415
416         mutex_unlock(&rfkill_mutex);
417
418         return error ? error : count;
419 }
420
421 static struct device_attribute rfkill_dev_attrs[] = {
422         __ATTR(name, S_IRUGO, rfkill_name_show, NULL),
423         __ATTR(type, S_IRUGO, rfkill_type_show, NULL),
424         __ATTR(state, S_IRUGO|S_IWUSR, rfkill_state_show, rfkill_state_store),
425         __ATTR(claim, S_IRUGO|S_IWUSR, rfkill_claim_show, rfkill_claim_store),
426         __ATTR_NULL
427 };
428
429 static void rfkill_release(struct device *dev)
430 {
431         struct rfkill *rfkill = to_rfkill(dev);
432
433         kfree(rfkill);
434         module_put(THIS_MODULE);
435 }
436
437 #ifdef CONFIG_PM
438 static int rfkill_suspend(struct device *dev, pm_message_t state)
439 {
440         struct rfkill *rfkill = to_rfkill(dev);
441
442         if (dev->power.power_state.event != state.event) {
443                 if (state.event & PM_EVENT_SLEEP) {
444                         /* Stop transmitter, keep state, no notifies */
445                         update_rfkill_state(rfkill);
446
447                         mutex_lock(&rfkill->mutex);
448                         rfkill->toggle_radio(rfkill->data,
449                                                 RFKILL_STATE_SOFT_BLOCKED);
450                         mutex_unlock(&rfkill->mutex);
451                 }
452
453                 dev->power.power_state = state;
454         }
455
456         return 0;
457 }
458
459 static int rfkill_resume(struct device *dev)
460 {
461         struct rfkill *rfkill = to_rfkill(dev);
462
463         if (dev->power.power_state.event != PM_EVENT_ON) {
464                 mutex_lock(&rfkill->mutex);
465
466                 dev->power.power_state.event = PM_EVENT_ON;
467
468                 /* restore radio state AND notify everybody */
469                 rfkill_toggle_radio(rfkill, rfkill->state, 1);
470
471                 mutex_unlock(&rfkill->mutex);
472         }
473
474         return 0;
475 }
476 #else
477 #define rfkill_suspend NULL
478 #define rfkill_resume NULL
479 #endif
480
481 static int rfkill_blocking_uevent_notifier(struct notifier_block *nb,
482                                         unsigned long eventid,
483                                         void *data)
484 {
485         struct rfkill *rfkill = (struct rfkill *)data;
486
487         switch (eventid) {
488         case RFKILL_STATE_CHANGED:
489                 kobject_uevent(&rfkill->dev.kobj, KOBJ_CHANGE);
490                 break;
491         default:
492                 break;
493         }
494
495         return NOTIFY_DONE;
496 }
497
498 static struct notifier_block rfkill_blocking_uevent_nb = {
499         .notifier_call  = rfkill_blocking_uevent_notifier,
500         .priority       = 0,
501 };
502
503 static int rfkill_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
504 {
505         struct rfkill *rfkill = to_rfkill(dev);
506         int error;
507
508         error = add_uevent_var(env, "RFKILL_NAME=%s", rfkill->name);
509         if (error)
510                 return error;
511         error = add_uevent_var(env, "RFKILL_TYPE=%s",
512                                 rfkill_get_type_str(rfkill->type));
513         if (error)
514                 return error;
515         error = add_uevent_var(env, "RFKILL_STATE=%d", rfkill->state);
516         return error;
517 }
518
519 static struct class rfkill_class = {
520         .name           = "rfkill",
521         .dev_release    = rfkill_release,
522         .dev_attrs      = rfkill_dev_attrs,
523         .suspend        = rfkill_suspend,
524         .resume         = rfkill_resume,
525         .dev_uevent     = rfkill_dev_uevent,
526 };
527
528 static int rfkill_check_duplicity(const struct rfkill *rfkill)
529 {
530         struct rfkill *p;
531         unsigned long seen[BITS_TO_LONGS(RFKILL_TYPE_MAX)];
532
533         memset(seen, 0, sizeof(seen));
534
535         list_for_each_entry(p, &rfkill_list, node) {
536                 if (p == rfkill) {
537                         WARN_ON(1);
538                         return -EEXIST;
539                 }
540                 set_bit(p->type, seen);
541         }
542
543         /* 0: first switch of its kind */
544         return test_bit(rfkill->type, seen);
545 }
546
547 static int rfkill_add_switch(struct rfkill *rfkill)
548 {
549         int error;
550
551         mutex_lock(&rfkill_mutex);
552
553         error = rfkill_check_duplicity(rfkill);
554         if (error < 0)
555                 goto unlock_out;
556
557         rfkill_toggle_radio(rfkill, rfkill_states[rfkill->type], 0);
558
559         list_add_tail(&rfkill->node, &rfkill_list);
560
561         error = 0;
562 unlock_out:
563         mutex_unlock(&rfkill_mutex);
564
565         return error;
566 }
567
568 static void rfkill_remove_switch(struct rfkill *rfkill)
569 {
570         mutex_lock(&rfkill_mutex);
571         list_del_init(&rfkill->node);
572         mutex_unlock(&rfkill_mutex);
573
574         mutex_lock(&rfkill->mutex);
575         rfkill_toggle_radio(rfkill, RFKILL_STATE_SOFT_BLOCKED, 1);
576         mutex_unlock(&rfkill->mutex);
577 }
578
579 /**
580  * rfkill_allocate - allocate memory for rfkill structure.
581  * @parent: device that has rf switch on it
582  * @type: type of the switch (RFKILL_TYPE_*)
583  *
584  * This function should be called by the network driver when it needs
585  * rfkill structure.  Once the structure is allocated the driver should
586  * finish its initialization by setting the name, private data, enable_radio
587  * and disable_radio methods and then register it with rfkill_register().
588  *
589  * NOTE: If registration fails the structure shoudl be freed by calling
590  * rfkill_free() otherwise rfkill_unregister() should be used.
591  */
592 struct rfkill *rfkill_allocate(struct device *parent, enum rfkill_type type)
593 {
594         struct rfkill *rfkill;
595         struct device *dev;
596
597         rfkill = kzalloc(sizeof(struct rfkill), GFP_KERNEL);
598         if (!rfkill)
599                 return NULL;
600
601         mutex_init(&rfkill->mutex);
602         INIT_LIST_HEAD(&rfkill->node);
603         rfkill->type = type;
604
605         dev = &rfkill->dev;
606         dev->class = &rfkill_class;
607         dev->parent = parent;
608         device_initialize(dev);
609
610         __module_get(THIS_MODULE);
611
612         return rfkill;
613 }
614 EXPORT_SYMBOL(rfkill_allocate);
615
616 /**
617  * rfkill_free - Mark rfkill structure for deletion
618  * @rfkill: rfkill structure to be destroyed
619  *
620  * Decrements reference count of the rfkill structure so it is destroyed.
621  * Note that rfkill_free() should _not_ be called after rfkill_unregister().
622  */
623 void rfkill_free(struct rfkill *rfkill)
624 {
625         if (rfkill)
626                 put_device(&rfkill->dev);
627 }
628 EXPORT_SYMBOL(rfkill_free);
629
630 static void rfkill_led_trigger_register(struct rfkill *rfkill)
631 {
632 #ifdef CONFIG_RFKILL_LEDS
633         int error;
634
635         if (!rfkill->led_trigger.name)
636                 rfkill->led_trigger.name = rfkill->dev.bus_id;
637         if (!rfkill->led_trigger.activate)
638                 rfkill->led_trigger.activate = rfkill_led_trigger_activate;
639         error = led_trigger_register(&rfkill->led_trigger);
640         if (error)
641                 rfkill->led_trigger.name = NULL;
642 #endif /* CONFIG_RFKILL_LEDS */
643 }
644
645 static void rfkill_led_trigger_unregister(struct rfkill *rfkill)
646 {
647 #ifdef CONFIG_RFKILL_LEDS
648         if (rfkill->led_trigger.name) {
649                 led_trigger_unregister(&rfkill->led_trigger);
650                 rfkill->led_trigger.name = NULL;
651         }
652 #endif
653 }
654
655 /**
656  * rfkill_register - Register a rfkill structure.
657  * @rfkill: rfkill structure to be registered
658  *
659  * This function should be called by the network driver when the rfkill
660  * structure needs to be registered. Immediately from registration the
661  * switch driver should be able to service calls to toggle_radio.
662  */
663 int rfkill_register(struct rfkill *rfkill)
664 {
665         static atomic_t rfkill_no = ATOMIC_INIT(0);
666         struct device *dev = &rfkill->dev;
667         int error;
668
669         if (!rfkill->toggle_radio)
670                 return -EINVAL;
671         if (rfkill->type >= RFKILL_TYPE_MAX)
672                 return -EINVAL;
673
674         snprintf(dev->bus_id, sizeof(dev->bus_id),
675                  "rfkill%ld", (long)atomic_inc_return(&rfkill_no) - 1);
676
677         rfkill_led_trigger_register(rfkill);
678
679         error = rfkill_add_switch(rfkill);
680         if (error) {
681                 rfkill_led_trigger_unregister(rfkill);
682                 return error;
683         }
684
685         error = device_add(dev);
686         if (error) {
687                 rfkill_remove_switch(rfkill);
688                 rfkill_led_trigger_unregister(rfkill);
689                 return error;
690         }
691
692         return 0;
693 }
694 EXPORT_SYMBOL(rfkill_register);
695
696 /**
697  * rfkill_unregister - Unregister a rfkill structure.
698  * @rfkill: rfkill structure to be unregistered
699  *
700  * This function should be called by the network driver during device
701  * teardown to destroy rfkill structure. Note that rfkill_free() should
702  * _not_ be called after rfkill_unregister().
703  */
704 void rfkill_unregister(struct rfkill *rfkill)
705 {
706         device_del(&rfkill->dev);
707         rfkill_remove_switch(rfkill);
708         rfkill_led_trigger_unregister(rfkill);
709         put_device(&rfkill->dev);
710 }
711 EXPORT_SYMBOL(rfkill_unregister);
712
713 /*
714  * Rfkill module initialization/deinitialization.
715  */
716 static int __init rfkill_init(void)
717 {
718         int error;
719         int i;
720
721         /* RFKILL_STATE_HARD_BLOCKED is illegal here... */
722         if (rfkill_default_state != RFKILL_STATE_SOFT_BLOCKED &&
723             rfkill_default_state != RFKILL_STATE_UNBLOCKED)
724                 return -EINVAL;
725
726         for (i = 0; i < ARRAY_SIZE(rfkill_states); i++)
727                 rfkill_states[i] = rfkill_default_state;
728
729         error = class_register(&rfkill_class);
730         if (error) {
731                 printk(KERN_ERR "rfkill: unable to register rfkill class\n");
732                 return error;
733         }
734
735         register_rfkill_notifier(&rfkill_blocking_uevent_nb);
736
737         return 0;
738 }
739
740 static void __exit rfkill_exit(void)
741 {
742         unregister_rfkill_notifier(&rfkill_blocking_uevent_nb);
743         class_unregister(&rfkill_class);
744 }
745
746 subsys_initcall(rfkill_init);
747 module_exit(rfkill_exit);