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_global_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 struct rfkill_gsw_state {
  48         enum rfkill_state current_state;
  49         enum rfkill_state default_state;
  50 };
  51
  52 static struct rfkill_gsw_state rfkill_global_states[RFKILL_TYPE_MAX];
  53 static unsigned long rfkill_states_lockdflt[BITS_TO_LONGS(RFKILL_TYPE_MAX)];
  54
  55 static BLOCKING_NOTIFIER_HEAD(rfkill_notifier_list);
  56
  57
  58 /**
  59  * register_rfkill_notifier - Add notifier to rfkill notifier chain
  60  * @nb: pointer to the new entry to add to the chain
  61  *
  62  * See blocking_notifier_chain_register() for return value and further
  63  * observations.
  64  *
  65  * Adds a notifier to the rfkill notifier chain.  The chain will be
  66  * called with a pointer to the relevant rfkill structure as a parameter,
  67  * refer to include/linux/rfkill.h for the possible events.
  68  *
  69  * Notifiers added to this chain are to always return NOTIFY_DONE.  This
  70  * chain is a blocking notifier chain: notifiers can sleep.
  71  *
  72  * Calls to this chain may have been done through a workqueue.  One must
  73  * assume unordered asynchronous behaviour, there is no way to know if
  74  * actions related to the event that generated the notification have been
  75  * carried out already.
  76  */
  77 int register_rfkill_notifier(struct notifier_block *nb)
  78 {
  79         BUG_ON(!nb);
  80         return blocking_notifier_chain_register(&rfkill_notifier_list, nb);
  81 }
  82 EXPORT_SYMBOL_GPL(register_rfkill_notifier);
  83
  84 /**
  85  * unregister_rfkill_notifier - remove notifier from rfkill notifier chain
  86  * @nb: pointer to the entry to remove from the chain
  87  *
  88  * See blocking_notifier_chain_unregister() for return value and further
  89  * observations.
  90  *
  91  * Removes a notifier from the rfkill notifier chain.
  92  */
  93 int unregister_rfkill_notifier(struct notifier_block *nb)
  94 {
  95         BUG_ON(!nb);
  96         return blocking_notifier_chain_unregister(&rfkill_notifier_list, nb);
  97 }
  98 EXPORT_SYMBOL_GPL(unregister_rfkill_notifier);
  99
 100
 101 static void rfkill_led_trigger(struct rfkill *rfkill,
 102                                enum rfkill_state state)
 103 {
 104 #ifdef CONFIG_RFKILL_LEDS
 105         struct led_trigger *led = &rfkill->led_trigger;
 106
 107         if (!led->name)
 108                 return;
 109         if (state != RFKILL_STATE_UNBLOCKED)
 110                 led_trigger_event(led, LED_OFF);
 111         else
 112                 led_trigger_event(led, LED_FULL);
 113 #endif /* CONFIG_RFKILL_LEDS */
 114 }
 115
 116 #ifdef CONFIG_RFKILL_LEDS
 117 static void rfkill_led_trigger_activate(struct led_classdev *led)
 118 {
 119         struct rfkill *rfkill = container_of(led->trigger,
 120                         struct rfkill, led_trigger);
 121
 122         rfkill_led_trigger(rfkill, rfkill->state);
 123 }
 124 #endif /* CONFIG_RFKILL_LEDS */
 125
 126 static void notify_rfkill_state_change(struct rfkill *rfkill)
 127 {
 128         rfkill_led_trigger(rfkill, rfkill->state);
 129         blocking_notifier_call_chain(&rfkill_notifier_list,
 130                         RFKILL_STATE_CHANGED,
 131                         rfkill);
 132 }
 133
 134 static void update_rfkill_state(struct rfkill *rfkill)
 135 {
 136         enum rfkill_state newstate, oldstate;
 137
 138         if (rfkill->get_state) {
 139                 mutex_lock(&rfkill->mutex);
 140                 if (!rfkill->get_state(rfkill->data, &newstate)) {
 141                         oldstate = rfkill->state;
 142                         rfkill->state = newstate;
 143                         if (oldstate != newstate)
 144                                 notify_rfkill_state_change(rfkill);
 145                 }
 146                 mutex_unlock(&rfkill->mutex);
 147         }
 148 }
 149
 150 /**
 151  * rfkill_toggle_radio - wrapper for toggle_radio hook
 152  * @rfkill: the rfkill struct to use
 153  * @force: calls toggle_radio even if cache says it is not needed,
 154  *      and also makes sure notifications of the state will be
 155  *      sent even if it didn't change
 156  * @state: the new state to call toggle_radio() with
 157  *
 158  * Calls rfkill->toggle_radio, enforcing the API for toggle_radio
 159  * calls and handling all the red tape such as issuing notifications
 160  * if the call is successful.
 161  *
 162  * Suspended devices are not touched at all, and -EAGAIN is returned.
 163  *
 164  * Note that the @force parameter cannot override a (possibly cached)
 165  * state of RFKILL_STATE_HARD_BLOCKED.  Any device making use of
 166  * RFKILL_STATE_HARD_BLOCKED implements either get_state() or
 167  * rfkill_force_state(), so the cache either is bypassed or valid.
 168  *
 169  * Note that we do call toggle_radio for RFKILL_STATE_SOFT_BLOCKED
 170  * even if the radio is in RFKILL_STATE_HARD_BLOCKED state, so as to
 171  * give the driver a hint that it should double-BLOCK the transmitter.
 172  *
 173  * Caller must have acquired rfkill->mutex.
 174  */
 175 static int rfkill_toggle_radio(struct rfkill *rfkill,
 176                                 enum rfkill_state state,
 177                                 int force)
 178 {
 179         int retval = 0;
 180         enum rfkill_state oldstate, newstate;
 181
 182         if (unlikely(rfkill->dev.power.power_state.event & PM_EVENT_SLEEP))
 183                 return -EBUSY;
 184
 185         oldstate = rfkill->state;
 186
 187         if (rfkill->get_state && !force &&
 188             !rfkill->get_state(rfkill->data, &newstate))
 189                 rfkill->state = newstate;
 190
 191         switch (state) {
 192         case RFKILL_STATE_HARD_BLOCKED:
 193                 /* typically happens when refreshing hardware state,
 194                  * such as on resume */
 195                 state = RFKILL_STATE_SOFT_BLOCKED;
 196                 break;
 197         case RFKILL_STATE_UNBLOCKED:
 198                 /* force can't override this, only rfkill_force_state() can */
 199                 if (rfkill->state == RFKILL_STATE_HARD_BLOCKED)
 200                         return -EPERM;
 201                 break;
 202         case RFKILL_STATE_SOFT_BLOCKED:
 203                 /* nothing to do, we want to give drivers the hint to double
 204                  * BLOCK even a transmitter that is already in state
 205                  * RFKILL_STATE_HARD_BLOCKED */
 206                 break;
 207         default:
 208                 WARN(1, KERN_WARNING
 209                         "rfkill: illegal state %d passed as parameter "
 210                         "to rfkill_toggle_radio\n", state);
 211                 return -EINVAL;
 212         }
 213
 214         if (force || state != rfkill->state) {
 215                 retval = rfkill->toggle_radio(rfkill->data, state);
 216                 /* never allow a HARD->SOFT downgrade! */
 217                 if (!retval && rfkill->state != RFKILL_STATE_HARD_BLOCKED)
 218                         rfkill->state = state;
 219         }
 220
 221         if (force || rfkill->state != oldstate)
 222                 notify_rfkill_state_change(rfkill);
 223
 224         return retval;
 225 }
 226
 227 /**
 228  * __rfkill_switch_all - Toggle state of all switches of given type
 229  * @type: type of interfaces to be affected
 230  * @state: the new state
 231  *
 232  * This function toggles the state of all switches of given type,
 233  * unless a specific switch is claimed by userspace (in which case,
 234  * that switch is left alone) or suspended.
 235  *
 236  * Caller must have acquired rfkill_global_mutex.
 237  */
 238 static void __rfkill_switch_all(const enum rfkill_type type,
 239                                 const enum rfkill_state state)
 240 {
 241         struct rfkill *rfkill;
 242
 243         if (WARN((state >= RFKILL_STATE_MAX || type >= RFKILL_TYPE_MAX),
 244                         KERN_WARNING
 245                         "rfkill: illegal state %d or type %d "
 246                         "passed as parameter to __rfkill_switch_all\n",
 247                         state, type))
 248                 return;
 249
 250         rfkill_global_states[type].current_state = state;
 251         list_for_each_entry(rfkill, &rfkill_list, node) {
 252                 if ((!rfkill->user_claim) && (rfkill->type == type)) {
 253                         mutex_lock(&rfkill->mutex);
 254                         rfkill_toggle_radio(rfkill, state, 0);
 255                         mutex_unlock(&rfkill->mutex);
 256                 }
 257         }
 258 }
 259
 260 /**
 261  * rfkill_switch_all - Toggle state of all switches of given type
 262  * @type: type of interfaces to be affected
 263  * @state: the new state
 264  *
 265  * Acquires rfkill_global_mutex and calls __rfkill_switch_all(@type, @state).
 266  * Please refer to __rfkill_switch_all() for details.
 267  */
 268 void rfkill_switch_all(enum rfkill_type type, enum rfkill_state state)
 269 {
 270         mutex_lock(&rfkill_global_mutex);
 271         __rfkill_switch_all(type, state);
 272         mutex_unlock(&rfkill_global_mutex);
 273 }
 274 EXPORT_SYMBOL(rfkill_switch_all);
 275
 276 /**
 277  * rfkill_epo - emergency power off all transmitters
 278  *
 279  * This kicks all non-suspended rfkill devices to RFKILL_STATE_SOFT_BLOCKED,
 280  * ignoring everything in its path but rfkill_global_mutex and rfkill->mutex.
 281  *
 282  * The global state before the EPO is saved and can be restored later
 283  * using rfkill_restore_states().
 284  */
 285 void rfkill_epo(void)
 286 {
 287         struct rfkill *rfkill;
 288         int i;
 289
 290         mutex_lock(&rfkill_global_mutex);
 291
 292         list_for_each_entry(rfkill, &rfkill_list, node) {
 293                 mutex_lock(&rfkill->mutex);
 294                 rfkill_toggle_radio(rfkill, RFKILL_STATE_SOFT_BLOCKED, 1);
 295                 mutex_unlock(&rfkill->mutex);
 296         }
 297         for (i = 0; i < RFKILL_TYPE_MAX; i++) {
 298                 rfkill_global_states[i].default_state =
 299                                 rfkill_global_states[i].current_state;
 300                 rfkill_global_states[i].current_state =
 301                                 RFKILL_STATE_SOFT_BLOCKED;
 302         }
 303         mutex_unlock(&rfkill_global_mutex);
 304 }
 305 EXPORT_SYMBOL_GPL(rfkill_epo);
 306
 307 /**
 308  * rfkill_restore_states - restore global states
 309  *
 310  * Restore (and sync switches to) the global state from the
 311  * states in rfkill_default_states.  This can undo the effects of
 312  * a call to rfkill_epo().
 313  */
 314 void rfkill_restore_states(void)
 315 {
 316         int i;
 317
 318         mutex_lock(&rfkill_global_mutex);
 319
 320         for (i = 0; i < RFKILL_TYPE_MAX; i++)
 321                 __rfkill_switch_all(i, rfkill_global_states[i].default_state);
 322         mutex_unlock(&rfkill_global_mutex);
 323 }
 324 EXPORT_SYMBOL_GPL(rfkill_restore_states);
 325
 326 /**
 327  * rfkill_force_state - Force the internal rfkill radio state
 328  * @rfkill: pointer to the rfkill class to modify.
 329  * @state: the current radio state the class should be forced to.
 330  *
 331  * This function updates the internal state of the radio cached
 332  * by the rfkill class.  It should be used when the driver gets
 333  * a notification by the firmware/hardware of the current *real*
 334  * state of the radio rfkill switch.
 335  *
 336  * Devices which are subject to external changes on their rfkill
 337  * state (such as those caused by a hardware rfkill line) MUST
 338  * have their driver arrange to call rfkill_force_state() as soon
 339  * as possible after such a change.
 340  *
 341  * This function may not be called from an atomic context.
 342  */
 343 int rfkill_force_state(struct rfkill *rfkill, enum rfkill_state state)
 344 {
 345         enum rfkill_state oldstate;
 346
 347         BUG_ON(!rfkill);
 348         if (WARN((state >= RFKILL_STATE_MAX),
 349                         KERN_WARNING
 350                         "rfkill: illegal state %d passed as parameter "
 351                         "to rfkill_force_state\n", state))
 352                 return -EINVAL;
 353
 354         mutex_lock(&rfkill->mutex);
 355
 356         oldstate = rfkill->state;
 357         rfkill->state = state;
 358
 359         if (state != oldstate)
 360                 notify_rfkill_state_change(rfkill);
 361
 362         mutex_unlock(&rfkill->mutex);
 363
 364         return 0;
 365 }
 366 EXPORT_SYMBOL(rfkill_force_state);
 367
 368 static ssize_t rfkill_name_show(struct device *dev,
 369                                 struct device_attribute *attr,
 370                                 char *buf)
 371 {
 372         struct rfkill *rfkill = to_rfkill(dev);
 373
 374         return sprintf(buf, "%s\n", rfkill->name);
 375 }
 376
 377 static const char *rfkill_get_type_str(enum rfkill_type type)
 378 {
 379         switch (type) {
 380         case RFKILL_TYPE_WLAN:
 381                 return "wlan";
 382         case RFKILL_TYPE_BLUETOOTH:
 383                 return "bluetooth";
 384         case RFKILL_TYPE_UWB:
 385                 return "ultrawideband";
 386         case RFKILL_TYPE_WIMAX:
 387                 return "wimax";
 388         case RFKILL_TYPE_WWAN:
 389                 return "wwan";
 390         default:
 391                 BUG();
 392         }
 393 }
 394
 395 static ssize_t rfkill_type_show(struct device *dev,
 396                                 struct device_attribute *attr,
 397                                 char *buf)
 398 {
 399         struct rfkill *rfkill = to_rfkill(dev);
 400
 401         return sprintf(buf, "%s\n", rfkill_get_type_str(rfkill->type));
 402 }
 403
 404 static ssize_t rfkill_state_show(struct device *dev,
 405                                  struct device_attribute *attr,
 406                                  char *buf)
 407 {
 408         struct rfkill *rfkill = to_rfkill(dev);
 409
 410         update_rfkill_state(rfkill);
 411         return sprintf(buf, "%d\n", rfkill->state);
 412 }
 413
 414 static ssize_t rfkill_state_store(struct device *dev,
 415                                   struct device_attribute *attr,
 416                                   const char *buf, size_t count)
 417 {
 418         struct rfkill *rfkill = to_rfkill(dev);
 419         unsigned long state;
 420         int error;
 421
 422         if (!capable(CAP_NET_ADMIN))
 423                 return -EPERM;
 424
 425         error = strict_strtoul(buf, 0, &state);
 426         if (error)
 427                 return error;
 428
 429         /* RFKILL_STATE_HARD_BLOCKED is illegal here... */
 430         if (state != RFKILL_STATE_UNBLOCKED &&
 431             state != RFKILL_STATE_SOFT_BLOCKED)
 432                 return -EINVAL;
 433
 434         if (mutex_lock_interruptible(&rfkill->mutex))
 435                 return -ERESTARTSYS;
 436         error = rfkill_toggle_radio(rfkill, state, 0);
 437         mutex_unlock(&rfkill->mutex);
 438
 439         return error ? error : count;
 440 }
 441
 442 static ssize_t rfkill_claim_show(struct device *dev,
 443                                  struct device_attribute *attr,
 444                                  char *buf)
 445 {
 446         struct rfkill *rfkill = to_rfkill(dev);
 447
 448         return sprintf(buf, "%d\n", rfkill->user_claim);
 449 }
 450
 451 static ssize_t rfkill_claim_store(struct device *dev,
 452                                   struct device_attribute *attr,
 453                                   const char *buf, size_t count)
 454 {
 455         struct rfkill *rfkill = to_rfkill(dev);
 456         unsigned long claim_tmp;
 457         bool claim;
 458         int error;
 459
 460         if (!capable(CAP_NET_ADMIN))
 461                 return -EPERM;
 462
 463         if (rfkill->user_claim_unsupported)
 464                 return -EOPNOTSUPP;
 465
 466         error = strict_strtoul(buf, 0, &claim_tmp);
 467         if (error)
 468                 return error;
 469         claim = !!claim_tmp;
 470
 471         /*
 472          * Take the global lock to make sure the kernel is not in
 473          * the middle of rfkill_switch_all
 474          */
 475         error = mutex_lock_interruptible(&rfkill_global_mutex);
 476         if (error)
 477                 return error;
 478
 479         if (rfkill->user_claim != claim) {
 480                 if (!claim) {
 481                         mutex_lock(&rfkill->mutex);
 482                         rfkill_toggle_radio(rfkill,
 483                                         rfkill_global_states[rfkill->type].current_state,
 484                                         0);
 485                         mutex_unlock(&rfkill->mutex);
 486                 }
 487                 rfkill->user_claim = claim;
 488         }
 489
 490         mutex_unlock(&rfkill_global_mutex);
 491
 492         return error ? error : count;
 493 }
 494
 495 static struct device_attribute rfkill_dev_attrs[] = {
 496         __ATTR(name, S_IRUGO, rfkill_name_show, NULL),
 497         __ATTR(type, S_IRUGO, rfkill_type_show, NULL),
 498         __ATTR(state, S_IRUGO|S_IWUSR, rfkill_state_show, rfkill_state_store),
 499         __ATTR(claim, S_IRUGO|S_IWUSR, rfkill_claim_show, rfkill_claim_store),
 500         __ATTR_NULL
 501 };
 502
 503 static void rfkill_release(struct device *dev)
 504 {
 505         struct rfkill *rfkill = to_rfkill(dev);
 506
 507         kfree(rfkill);
 508         module_put(THIS_MODULE);
 509 }
 510
 511 #ifdef CONFIG_PM
 512 static int rfkill_suspend(struct device *dev, pm_message_t state)
 513 {
 514         /* mark class device as suspended */
 515         if (dev->power.power_state.event != state.event)
 516                 dev->power.power_state = state;
 517
 518         return 0;
 519 }
 520
 521 static int rfkill_resume(struct device *dev)
 522 {
 523         struct rfkill *rfkill = to_rfkill(dev);
 524
 525         if (dev->power.power_state.event != PM_EVENT_ON) {
 526                 mutex_lock(&rfkill->mutex);
 527
 528                 dev->power.power_state.event = PM_EVENT_ON;
 529
 530                 /* restore radio state AND notify everybody */
 531                 rfkill_toggle_radio(rfkill, rfkill->state, 1);
 532
 533                 mutex_unlock(&rfkill->mutex);
 534         }
 535
 536         return 0;
 537 }
 538 #else
 539 #define rfkill_suspend NULL
 540 #define rfkill_resume NULL
 541 #endif
 542
 543 static int rfkill_blocking_uevent_notifier(struct notifier_block *nb,
 544                                         unsigned long eventid,
 545                                         void *data)
 546 {
 547         struct rfkill *rfkill = (struct rfkill *)data;
 548
 549         switch (eventid) {
 550         case RFKILL_STATE_CHANGED:
 551                 kobject_uevent(&rfkill->dev.kobj, KOBJ_CHANGE);
 552                 break;
 553         default:
 554                 break;
 555         }
 556
 557         return NOTIFY_DONE;
 558 }
 559
 560 static struct notifier_block rfkill_blocking_uevent_nb = {
 561         .notifier_call  = rfkill_blocking_uevent_notifier,
 562         .priority       = 0,
 563 };
 564
 565 static int rfkill_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
 566 {
 567         struct rfkill *rfkill = to_rfkill(dev);
 568         int error;
 569
 570         error = add_uevent_var(env, "RFKILL_NAME=%s", rfkill->name);
 571         if (error)
 572                 return error;
 573         error = add_uevent_var(env, "RFKILL_TYPE=%s",
 574                                 rfkill_get_type_str(rfkill->type));
 575         if (error)
 576                 return error;
 577         error = add_uevent_var(env, "RFKILL_STATE=%d", rfkill->state);
 578         return error;
 579 }
 580
 581 static struct class rfkill_class = {
 582         .name           = "rfkill",
 583         .dev_release    = rfkill_release,
 584         .dev_attrs      = rfkill_dev_attrs,
 585         .suspend        = rfkill_suspend,
 586         .resume         = rfkill_resume,
 587         .dev_uevent     = rfkill_dev_uevent,
 588 };
 589
 590 static int rfkill_check_duplicity(const struct rfkill *rfkill)
 591 {
 592         struct rfkill *p;
 593         unsigned long seen[BITS_TO_LONGS(RFKILL_TYPE_MAX)];
 594
 595         memset(seen, 0, sizeof(seen));
 596
 597         list_for_each_entry(p, &rfkill_list, node) {
 598                 if (WARN((p == rfkill), KERN_WARNING
 599                                 "rfkill: illegal attempt to register "
 600                                 "an already registered rfkill struct\n"))
 601                         return -EEXIST;
 602                 set_bit(p->type, seen);
 603         }
 604
 605         /* 0: first switch of its kind */
 606         return test_bit(rfkill->type, seen);
 607 }
 608
 609 static int rfkill_add_switch(struct rfkill *rfkill)
 610 {
 611         int error;
 612
 613         mutex_lock(&rfkill_global_mutex);
 614
 615         error = rfkill_check_duplicity(rfkill);
 616         if (error < 0)
 617                 goto unlock_out;
 618
 619         if (!error) {
 620                 /* lock default after first use */
 621                 set_bit(rfkill->type, rfkill_states_lockdflt);
 622                 rfkill_global_states[rfkill->type].current_state =
 623                         rfkill_global_states[rfkill->type].default_state;
 624         }
 625
 626         rfkill_toggle_radio(rfkill,
 627                             rfkill_global_states[rfkill->type].current_state,
 628                             0);
 629
 630         list_add_tail(&rfkill->node, &rfkill_list);
 631
 632         error = 0;
 633 unlock_out:
 634         mutex_unlock(&rfkill_global_mutex);
 635
 636         return error;
 637 }
 638
 639 static void rfkill_remove_switch(struct rfkill *rfkill)
 640 {
 641         mutex_lock(&rfkill_global_mutex);
 642         list_del_init(&rfkill->node);
 643         mutex_unlock(&rfkill_global_mutex);
 644
 645         mutex_lock(&rfkill->mutex);
 646         rfkill_toggle_radio(rfkill, RFKILL_STATE_SOFT_BLOCKED, 1);
 647         mutex_unlock(&rfkill->mutex);
 648 }
 649
 650 /**
 651  * rfkill_allocate - allocate memory for rfkill structure.
 652  * @parent: device that has rf switch on it
 653  * @type: type of the switch (RFKILL_TYPE_*)
 654  *
 655  * This function should be called by the network driver when it needs
 656  * rfkill structure.  Once the structure is allocated the driver should
 657  * finish its initialization by setting the name, private data, enable_radio
 658  * and disable_radio methods and then register it with rfkill_register().
 659  *
 660  * NOTE: If registration fails the structure shoudl be freed by calling
 661  * rfkill_free() otherwise rfkill_unregister() should be used.
 662  */
 663 struct rfkill * __must_check rfkill_allocate(struct device *parent,
 664                                              enum rfkill_type type)
 665 {
 666         struct rfkill *rfkill;
 667         struct device *dev;
 668
 669         if (WARN((type >= RFKILL_TYPE_MAX),
 670                         KERN_WARNING
 671                         "rfkill: illegal type %d passed as parameter "
 672                         "to rfkill_allocate\n", type))
 673                 return NULL;
 674
 675         rfkill = kzalloc(sizeof(struct rfkill), GFP_KERNEL);
 676         if (!rfkill)
 677                 return NULL;
 678
 679         mutex_init(&rfkill->mutex);
 680         INIT_LIST_HEAD(&rfkill->node);
 681         rfkill->type = type;
 682
 683         dev = &rfkill->dev;
 684         dev->class = &rfkill_class;
 685         dev->parent = parent;
 686         device_initialize(dev);
 687
 688         __module_get(THIS_MODULE);
 689
 690         return rfkill;
 691 }
 692 EXPORT_SYMBOL(rfkill_allocate);
 693
 694 /**
 695  * rfkill_free - Mark rfkill structure for deletion
 696  * @rfkill: rfkill structure to be destroyed
 697  *
 698  * Decrements reference count of the rfkill structure so it is destroyed.
 699  * Note that rfkill_free() should _not_ be called after rfkill_unregister().
 700  */
 701 void rfkill_free(struct rfkill *rfkill)
 702 {
 703         if (rfkill)
 704                 put_device(&rfkill->dev);
 705 }
 706 EXPORT_SYMBOL(rfkill_free);
 707
 708 static void rfkill_led_trigger_register(struct rfkill *rfkill)
 709 {
 710 #ifdef CONFIG_RFKILL_LEDS
 711         int error;
 712
 713         if (!rfkill->led_trigger.name)
 714                 rfkill->led_trigger.name = rfkill->dev.bus_id;
 715         if (!rfkill->led_trigger.activate)
 716                 rfkill->led_trigger.activate = rfkill_led_trigger_activate;
 717         error = led_trigger_register(&rfkill->led_trigger);
 718         if (error)
 719                 rfkill->led_trigger.name = NULL;
 720 #endif /* CONFIG_RFKILL_LEDS */
 721 }
 722
 723 static void rfkill_led_trigger_unregister(struct rfkill *rfkill)
 724 {
 725 #ifdef CONFIG_RFKILL_LEDS
 726         if (rfkill->led_trigger.name) {
 727                 led_trigger_unregister(&rfkill->led_trigger);
 728                 rfkill->led_trigger.name = NULL;
 729         }
 730 #endif
 731 }
 732
 733 /**
 734  * rfkill_register - Register a rfkill structure.
 735  * @rfkill: rfkill structure to be registered
 736  *
 737  * This function should be called by the network driver when the rfkill
 738  * structure needs to be registered. Immediately from registration the
 739  * switch driver should be able to service calls to toggle_radio.
 740  */
 741 int __must_check rfkill_register(struct rfkill *rfkill)
 742 {
 743         static atomic_t rfkill_no = ATOMIC_INIT(0);
 744         struct device *dev = &rfkill->dev;
 745         int error;
 746
 747         if (WARN((!rfkill || !rfkill->toggle_radio ||
 748                         rfkill->type >= RFKILL_TYPE_MAX ||
 749                         rfkill->state >= RFKILL_STATE_MAX),
 750                         KERN_WARNING
 751                         "rfkill: attempt to register a "
 752                         "badly initialized rfkill struct\n"))
 753                 return -EINVAL;
 754
 755         snprintf(dev->bus_id, sizeof(dev->bus_id),
 756                  "rfkill%ld", (long)atomic_inc_return(&rfkill_no) - 1);
 757
 758         rfkill_led_trigger_register(rfkill);
 759
 760         error = rfkill_add_switch(rfkill);
 761         if (error) {
 762                 rfkill_led_trigger_unregister(rfkill);
 763                 return error;
 764         }
 765
 766         error = device_add(dev);
 767         if (error) {
 768                 rfkill_remove_switch(rfkill);
 769                 rfkill_led_trigger_unregister(rfkill);
 770                 return error;
 771         }
 772
 773         return 0;
 774 }
 775 EXPORT_SYMBOL(rfkill_register);
 776
 777 /**
 778  * rfkill_unregister - Unregister a rfkill structure.
 779  * @rfkill: rfkill structure to be unregistered
 780  *
 781  * This function should be called by the network driver during device
 782  * teardown to destroy rfkill structure. Note that rfkill_free() should
 783  * _not_ be called after rfkill_unregister().
 784  */
 785 void rfkill_unregister(struct rfkill *rfkill)
 786 {
 787         BUG_ON(!rfkill);
 788         device_del(&rfkill->dev);
 789         rfkill_remove_switch(rfkill);
 790         rfkill_led_trigger_unregister(rfkill);
 791         put_device(&rfkill->dev);
 792 }
 793 EXPORT_SYMBOL(rfkill_unregister);
 794
 795 /**
 796  * rfkill_set_default - set initial value for a switch type
 797  * @type - the type of switch to set the default state of
 798  * @state - the new default state for that group of switches
 799  *
 800  * Sets the initial state rfkill should use for a given type.
 801  * The following initial states are allowed: RFKILL_STATE_SOFT_BLOCKED
 802  * and RFKILL_STATE_UNBLOCKED.
 803  *
 804  * This function is meant to be used by platform drivers for platforms
 805  * that can save switch state across power down/reboot.
 806  *
 807  * The default state for each switch type can be changed exactly once.
 808  * After a switch of that type is registered, the default state cannot
 809  * be changed anymore.  This guards against multiple drivers it the
 810  * same platform trying to set the initial switch default state, which
 811  * is not allowed.
 812  *
 813  * Returns -EPERM if the state has already been set once or is in use,
 814  * so drivers likely want to either ignore or at most printk(KERN_NOTICE)
 815  * if this function returns -EPERM.
 816  *
 817  * Returns 0 if the new default state was set, or an error if it
 818  * could not be set.
 819  */
 820 int rfkill_set_default(enum rfkill_type type, enum rfkill_state state)
 821 {
 822         int error;
 823
 824         if (WARN((type >= RFKILL_TYPE_MAX ||
 825                         (state != RFKILL_STATE_SOFT_BLOCKED &&
 826                          state != RFKILL_STATE_UNBLOCKED)),
 827                         KERN_WARNING
 828                         "rfkill: illegal state %d or type %d passed as "
 829                         "parameter to rfkill_set_default\n", state, type))
 830                 return -EINVAL;
 831
 832         mutex_lock(&rfkill_global_mutex);
 833
 834         if (!test_and_set_bit(type, rfkill_states_lockdflt)) {
 835                 rfkill_global_states[type].default_state = state;
 836                 error = 0;
 837         } else
 838                 error = -EPERM;
 839
 840         mutex_unlock(&rfkill_global_mutex);
 841         return error;
 842 }
 843 EXPORT_SYMBOL_GPL(rfkill_set_default);
 844
 845 /*
 846  * Rfkill module initialization/deinitialization.
 847  */
 848 static int __init rfkill_init(void)
 849 {
 850         int error;
 851         int i;
 852
 853         /* RFKILL_STATE_HARD_BLOCKED is illegal here... */
 854         if (rfkill_default_state != RFKILL_STATE_SOFT_BLOCKED &&
 855             rfkill_default_state != RFKILL_STATE_UNBLOCKED)
 856                 return -EINVAL;
 857
 858         for (i = 0; i < RFKILL_TYPE_MAX; i++)
 859                 rfkill_global_states[i].default_state = rfkill_default_state;
 860
 861         error = class_register(&rfkill_class);
 862         if (error) {
 863                 printk(KERN_ERR "rfkill: unable to register rfkill class\n");
 864                 return error;
 865         }
 866
 867         register_rfkill_notifier(&rfkill_blocking_uevent_nb);
 868
 869         return 0;
 870 }
 871
 872 static void __exit rfkill_exit(void)
 873 {
 874         unregister_rfkill_notifier(&rfkill_blocking_uevent_nb);
 875         class_unregister(&rfkill_class);
 876 }
 877
 878 subsys_initcall(rfkill_init);
 879 module_exit(rfkill_exit);