drivers/platform/x86/wmi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  ACPI-WMI mapping driver
   4  *
   5  *  Copyright (C) 2007-2008 Carlos Corbacho <[email protected]>
   6  *
   7  *  GUID parsing code from ldm.c is:
   8  *   Copyright (C) 2001,2002 Richard Russon <[email protected]>
   9  *   Copyright (c) 2001-2007 Anton Altaparmakov
  10  *   Copyright (C) 2001,2002 Jakob Kemi <[email protected]>
  11  *
  12  *  WMI bus infrastructure by Andrew Lutomirski and Darren Hart:
  13  *    Copyright (C) 2015 Andrew Lutomirski
  14  *    Copyright (C) 2017 VMware, Inc. All Rights Reserved.
  15  */
  16
  17 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  18
  19 #include <linux/acpi.h>
  20 #include <linux/bits.h>
  21 #include <linux/build_bug.h>
  22 #include <linux/device.h>
  23 #include <linux/init.h>
  24 #include <linux/kernel.h>
  25 #include <linux/list.h>
  26 #include <linux/module.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/rwsem.h>
  29 #include <linux/slab.h>
  30 #include <linux/sysfs.h>
  31 #include <linux/types.h>
  32 #include <linux/uuid.h>
  33 #include <linux/wmi.h>
  34 #include <linux/fs.h>
  35
  36 MODULE_AUTHOR("Carlos Corbacho");
  37 MODULE_DESCRIPTION("ACPI-WMI Mapping Driver");
  38 MODULE_LICENSE("GPL");
  39
  40 static LIST_HEAD(wmi_block_list);
  41
  42 struct guid_block {
  43         guid_t guid;
  44         union {
  45                 char object_id[2];
  46                 struct {
  47                         unsigned char notify_id;
  48                         unsigned char reserved;
  49                 };
  50         };
  51         u8 instance_count;
  52         u8 flags;
  53 } __packed;
  54 static_assert(sizeof(typeof_member(struct guid_block, guid)) == 16);
  55 static_assert(sizeof(struct guid_block) == 20);
  56 static_assert(__alignof__(struct guid_block) == 1);
  57
  58 enum {  /* wmi_block flags */
  59         WMI_READ_TAKES_NO_ARGS,
  60         WMI_GUID_DUPLICATED,
  61         WMI_NO_EVENT_DATA,
  62 };
  63
  64 struct wmi_block {
  65         struct wmi_device dev;
  66         struct list_head list;
  67         struct guid_block gblock;
  68         struct acpi_device *acpi_device;
  69         struct rw_semaphore notify_lock;        /* Protects notify callback add/remove */
  70         wmi_notify_handler handler;
  71         void *handler_data;
  72         bool driver_ready;
  73         unsigned long flags;
  74 };
  75
  76
  77 /*
  78  * If the GUID data block is marked as expensive, we must enable and
  79  * explicitily disable data collection.
  80  */
  81 #define ACPI_WMI_EXPENSIVE   BIT(0)
  82 #define ACPI_WMI_METHOD      BIT(1)     /* GUID is a method */
  83 #define ACPI_WMI_STRING      BIT(2)     /* GUID takes & returns a string */
  84 #define ACPI_WMI_EVENT       BIT(3)     /* GUID is an event */
  85
  86 static const struct acpi_device_id wmi_device_ids[] = {
  87         {"PNP0C14", 0},
  88         {"pnp0c14", 0},
  89         { }
  90 };
  91 MODULE_DEVICE_TABLE(acpi, wmi_device_ids);
  92
  93 #define dev_to_wblock(__dev)    container_of_const(__dev, struct wmi_block, dev.dev)
  94 #define dev_to_wdev(__dev)      container_of_const(__dev, struct wmi_device, dev)
  95
  96 /*
  97  * GUID parsing functions
  98  */
  99
 100 static bool guid_parse_and_compare(const char *string, const guid_t *guid)
 101 {
 102         guid_t guid_input;
 103
 104         if (guid_parse(string, &guid_input))
 105                 return false;
 106
 107         return guid_equal(&guid_input, guid);
 108 }
 109
 110 static const void *find_guid_context(struct wmi_block *wblock,
 111                                      struct wmi_driver *wdriver)
 112 {
 113         const struct wmi_device_id *id;
 114
 115         id = wdriver->id_table;
 116         if (!id)
 117                 return NULL;
 118
 119         while (*id->guid_string) {
 120                 if (guid_parse_and_compare(id->guid_string, &wblock->gblock.guid))
 121                         return id->context;
 122                 id++;
 123         }
 124         return NULL;
 125 }
 126
 127 static acpi_status wmi_method_enable(struct wmi_block *wblock, bool enable)
 128 {
 129         struct guid_block *block;
 130         char method[5];
 131         acpi_status status;
 132         acpi_handle handle;
 133
 134         block = &wblock->gblock;
 135         handle = wblock->acpi_device->handle;
 136
 137         snprintf(method, 5, "WE%02X", block->notify_id);
 138         status = acpi_execute_simple_method(handle, method, enable);
 139         if (status == AE_NOT_FOUND)
 140                 return AE_OK;
 141
 142         return status;
 143 }
 144
 145 #define WMI_ACPI_METHOD_NAME_SIZE 5
 146
 147 static inline void get_acpi_method_name(const struct wmi_block *wblock,
 148                                         const char method,
 149                                         char buffer[static WMI_ACPI_METHOD_NAME_SIZE])
 150 {
 151         static_assert(ARRAY_SIZE(wblock->gblock.object_id) == 2);
 152         static_assert(WMI_ACPI_METHOD_NAME_SIZE >= 5);
 153
 154         buffer[0] = 'W';
 155         buffer[1] = method;
 156         buffer[2] = wblock->gblock.object_id[0];
 157         buffer[3] = wblock->gblock.object_id[1];
 158         buffer[4] = '\0';
 159 }
 160
 161 static inline acpi_object_type get_param_acpi_type(const struct wmi_block *wblock)
 162 {
 163         if (wblock->gblock.flags & ACPI_WMI_STRING)
 164                 return ACPI_TYPE_STRING;
 165         else
 166                 return ACPI_TYPE_BUFFER;
 167 }
 168
 169 static acpi_status get_event_data(const struct wmi_block *wblock, struct acpi_buffer *out)
 170 {
 171         union acpi_object param = {
 172                 .integer = {
 173                         .type = ACPI_TYPE_INTEGER,
 174                         .value = wblock->gblock.notify_id,
 175                 }
 176         };
 177         struct acpi_object_list input = {
 178                 .count = 1,
 179                 .pointer = &param,
 180         };
 181
 182         return acpi_evaluate_object(wblock->acpi_device->handle, "_WED", &input, out);
 183 }
 184
 185 static int wmidev_match_guid(struct device *dev, const void *data)
 186 {
 187         struct wmi_block *wblock = dev_to_wblock(dev);
 188         const guid_t *guid = data;
 189
 190         /* Legacy GUID-based functions are restricted to only see
 191          * a single WMI device for each GUID.
 192          */
 193         if (test_bit(WMI_GUID_DUPLICATED, &wblock->flags))
 194                 return 0;
 195
 196         if (guid_equal(guid, &wblock->gblock.guid))
 197                 return 1;
 198
 199         return 0;
 200 }
 201
 202 static int wmidev_match_notify_id(struct device *dev, const void *data)
 203 {
 204         struct wmi_block *wblock = dev_to_wblock(dev);
 205         const u32 *notify_id = data;
 206
 207         /* Legacy GUID-based functions are restricted to only see
 208          * a single WMI device for each GUID.
 209          */
 210         if (test_bit(WMI_GUID_DUPLICATED, &wblock->flags))
 211                 return 0;
 212
 213         if (wblock->gblock.flags & ACPI_WMI_EVENT && wblock->gblock.notify_id == *notify_id)
 214                 return 1;
 215
 216         return 0;
 217 }
 218
 219 static const struct bus_type wmi_bus_type;
 220
 221 static struct wmi_device *wmi_find_device_by_guid(const char *guid_string)
 222 {
 223         struct device *dev;
 224         guid_t guid;
 225         int ret;
 226
 227         ret = guid_parse(guid_string, &guid);
 228         if (ret < 0)
 229                 return ERR_PTR(ret);
 230
 231         dev = bus_find_device(&wmi_bus_type, NULL, &guid, wmidev_match_guid);
 232         if (!dev)
 233                 return ERR_PTR(-ENODEV);
 234
 235         return dev_to_wdev(dev);
 236 }
 237
 238 static struct wmi_device *wmi_find_event_by_notify_id(const u32 notify_id)
 239 {
 240         struct device *dev;
 241
 242         dev = bus_find_device(&wmi_bus_type, NULL, &notify_id, wmidev_match_notify_id);
 243         if (!dev)
 244                 return ERR_PTR(-ENODEV);
 245
 246         return to_wmi_device(dev);
 247 }
 248
 249 static void wmi_device_put(struct wmi_device *wdev)
 250 {
 251         put_device(&wdev->dev);
 252 }
 253
 254 /*
 255  * Exported WMI functions
 256  */
 257
 258 /**
 259  * wmi_instance_count - Get number of WMI object instances
 260  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 261  *
 262  * Get the number of WMI object instances.
 263  *
 264  * Returns: Number of WMI object instances or negative error code.
 265  */
 266 int wmi_instance_count(const char *guid_string)
 267 {
 268         struct wmi_device *wdev;
 269         int ret;
 270
 271         wdev = wmi_find_device_by_guid(guid_string);
 272         if (IS_ERR(wdev))
 273                 return PTR_ERR(wdev);
 274
 275         ret = wmidev_instance_count(wdev);
 276         wmi_device_put(wdev);
 277
 278         return ret;
 279 }
 280 EXPORT_SYMBOL_GPL(wmi_instance_count);
 281
 282 /**
 283  * wmidev_instance_count - Get number of WMI object instances
 284  * @wdev: A wmi bus device from a driver
 285  *
 286  * Get the number of WMI object instances.
 287  *
 288  * Returns: Number of WMI object instances.
 289  */
 290 u8 wmidev_instance_count(struct wmi_device *wdev)
 291 {
 292         struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
 293
 294         return wblock->gblock.instance_count;
 295 }
 296 EXPORT_SYMBOL_GPL(wmidev_instance_count);
 297
 298 /**
 299  * wmi_evaluate_method - Evaluate a WMI method (deprecated)
 300  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 301  * @instance: Instance index
 302  * @method_id: Method ID to call
 303  * @in: Mandatory buffer containing input for the method call
 304  * @out: Empty buffer to return the method results
 305  *
 306  * Call an ACPI-WMI method, the caller must free @out.
 307  *
 308  * Return: acpi_status signaling success or error.
 309  */
 310 acpi_status wmi_evaluate_method(const char *guid_string, u8 instance, u32 method_id,
 311                                 const struct acpi_buffer *in, struct acpi_buffer *out)
 312 {
 313         struct wmi_device *wdev;
 314         acpi_status status;
 315
 316         wdev = wmi_find_device_by_guid(guid_string);
 317         if (IS_ERR(wdev))
 318                 return AE_ERROR;
 319
 320         status = wmidev_evaluate_method(wdev, instance, method_id, in, out);
 321
 322         wmi_device_put(wdev);
 323
 324         return status;
 325 }
 326 EXPORT_SYMBOL_GPL(wmi_evaluate_method);
 327
 328 /**
 329  * wmidev_evaluate_method - Evaluate a WMI method
 330  * @wdev: A wmi bus device from a driver
 331  * @instance: Instance index
 332  * @method_id: Method ID to call
 333  * @in: Mandatory buffer containing input for the method call
 334  * @out: Empty buffer to return the method results
 335  *
 336  * Call an ACPI-WMI method, the caller must free @out.
 337  *
 338  * Return: acpi_status signaling success or error.
 339  */
 340 acpi_status wmidev_evaluate_method(struct wmi_device *wdev, u8 instance, u32 method_id,
 341                                    const struct acpi_buffer *in, struct acpi_buffer *out)
 342 {
 343         struct guid_block *block;
 344         struct wmi_block *wblock;
 345         acpi_handle handle;
 346         struct acpi_object_list input;
 347         union acpi_object params[3];
 348         char method[WMI_ACPI_METHOD_NAME_SIZE];
 349
 350         wblock = container_of(wdev, struct wmi_block, dev);
 351         block = &wblock->gblock;
 352         handle = wblock->acpi_device->handle;
 353
 354         if (!in)
 355                 return AE_BAD_DATA;
 356
 357         if (!(block->flags & ACPI_WMI_METHOD))
 358                 return AE_BAD_DATA;
 359
 360         if (block->instance_count <= instance)
 361                 return AE_BAD_PARAMETER;
 362
 363         input.count = 3;
 364         input.pointer = params;
 365
 366         params[0].type = ACPI_TYPE_INTEGER;
 367         params[0].integer.value = instance;
 368         params[1].type = ACPI_TYPE_INTEGER;
 369         params[1].integer.value = method_id;
 370         params[2].type = get_param_acpi_type(wblock);
 371         params[2].buffer.length = in->length;
 372         params[2].buffer.pointer = in->pointer;
 373
 374         get_acpi_method_name(wblock, 'M', method);
 375
 376         return acpi_evaluate_object(handle, method, &input, out);
 377 }
 378 EXPORT_SYMBOL_GPL(wmidev_evaluate_method);
 379
 380 static acpi_status __query_block(struct wmi_block *wblock, u8 instance,
 381                                  struct acpi_buffer *out)
 382 {
 383         struct guid_block *block;
 384         acpi_handle handle;
 385         acpi_status status, wc_status = AE_ERROR;
 386         struct acpi_object_list input;
 387         union acpi_object wq_params[1];
 388         char wc_method[WMI_ACPI_METHOD_NAME_SIZE];
 389         char method[WMI_ACPI_METHOD_NAME_SIZE];
 390
 391         if (!out)
 392                 return AE_BAD_PARAMETER;
 393
 394         block = &wblock->gblock;
 395         handle = wblock->acpi_device->handle;
 396
 397         if (block->instance_count <= instance)
 398                 return AE_BAD_PARAMETER;
 399
 400         /* Check GUID is a data block */
 401         if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
 402                 return AE_ERROR;
 403
 404         input.count = 1;
 405         input.pointer = wq_params;
 406         wq_params[0].type = ACPI_TYPE_INTEGER;
 407         wq_params[0].integer.value = instance;
 408
 409         if (instance == 0 && test_bit(WMI_READ_TAKES_NO_ARGS, &wblock->flags))
 410                 input.count = 0;
 411
 412         /*
 413          * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method first to
 414          * enable collection.
 415          */
 416         if (block->flags & ACPI_WMI_EXPENSIVE) {
 417                 get_acpi_method_name(wblock, 'C', wc_method);
 418
 419                 /*
 420                  * Some GUIDs break the specification by declaring themselves
 421                  * expensive, but have no corresponding WCxx method. So we
 422                  * should not fail if this happens.
 423                  */
 424                 wc_status = acpi_execute_simple_method(handle, wc_method, 1);
 425         }
 426
 427         get_acpi_method_name(wblock, 'Q', method);
 428         status = acpi_evaluate_object(handle, method, &input, out);
 429
 430         /*
 431          * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method, even if
 432          * the WQxx method failed - we should disable collection anyway.
 433          */
 434         if ((block->flags & ACPI_WMI_EXPENSIVE) && ACPI_SUCCESS(wc_status)) {
 435                 /*
 436                  * Ignore whether this WCxx call succeeds or not since
 437                  * the previously executed WQxx method call might have
 438                  * succeeded, and returning the failing status code
 439                  * of this call would throw away the result of the WQxx
 440                  * call, potentially leaking memory.
 441                  */
 442                 acpi_execute_simple_method(handle, wc_method, 0);
 443         }
 444
 445         return status;
 446 }
 447
 448 /**
 449  * wmi_query_block - Return contents of a WMI block (deprecated)
 450  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 451  * @instance: Instance index
 452  * @out: Empty buffer to return the contents of the data block to
 453  *
 454  * Query a ACPI-WMI block, the caller must free @out.
 455  *
 456  * Return: ACPI object containing the content of the WMI block.
 457  */
 458 acpi_status wmi_query_block(const char *guid_string, u8 instance,
 459                             struct acpi_buffer *out)
 460 {
 461         struct wmi_block *wblock;
 462         struct wmi_device *wdev;
 463         acpi_status status;
 464
 465         wdev = wmi_find_device_by_guid(guid_string);
 466         if (IS_ERR(wdev))
 467                 return AE_ERROR;
 468
 469         wblock = container_of(wdev, struct wmi_block, dev);
 470         status = __query_block(wblock, instance, out);
 471
 472         wmi_device_put(wdev);
 473
 474         return status;
 475 }
 476 EXPORT_SYMBOL_GPL(wmi_query_block);
 477
 478 /**
 479  * wmidev_block_query - Return contents of a WMI block
 480  * @wdev: A wmi bus device from a driver
 481  * @instance: Instance index
 482  *
 483  * Query an ACPI-WMI block, the caller must free the result.
 484  *
 485  * Return: ACPI object containing the content of the WMI block.
 486  */
 487 union acpi_object *wmidev_block_query(struct wmi_device *wdev, u8 instance)
 488 {
 489         struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
 490         struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
 491
 492         if (ACPI_FAILURE(__query_block(wblock, instance, &out)))
 493                 return NULL;
 494
 495         return out.pointer;
 496 }
 497 EXPORT_SYMBOL_GPL(wmidev_block_query);
 498
 499 /**
 500  * wmi_set_block - Write to a WMI block (deprecated)
 501  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 502  * @instance: Instance index
 503  * @in: Buffer containing new values for the data block
 504  *
 505  * Write the contents of the input buffer to an ACPI-WMI data block.
 506  *
 507  * Return: acpi_status signaling success or error.
 508  */
 509 acpi_status wmi_set_block(const char *guid_string, u8 instance, const struct acpi_buffer *in)
 510 {
 511         struct wmi_device *wdev;
 512         acpi_status status;
 513
 514         wdev = wmi_find_device_by_guid(guid_string);
 515         if (IS_ERR(wdev))
 516                 return AE_ERROR;
 517
 518         status =  wmidev_block_set(wdev, instance, in);
 519         wmi_device_put(wdev);
 520
 521         return status;
 522 }
 523 EXPORT_SYMBOL_GPL(wmi_set_block);
 524
 525 /**
 526  * wmidev_block_set - Write to a WMI block
 527  * @wdev: A wmi bus device from a driver
 528  * @instance: Instance index
 529  * @in: Buffer containing new values for the data block
 530  *
 531  * Write contents of the input buffer to an ACPI-WMI data block.
 532  *
 533  * Return: acpi_status signaling success or error.
 534  */
 535 acpi_status wmidev_block_set(struct wmi_device *wdev, u8 instance, const struct acpi_buffer *in)
 536 {
 537         struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
 538         acpi_handle handle = wblock->acpi_device->handle;
 539         struct guid_block *block = &wblock->gblock;
 540         char method[WMI_ACPI_METHOD_NAME_SIZE];
 541         struct acpi_object_list input;
 542         union acpi_object params[2];
 543
 544         if (!in)
 545                 return AE_BAD_DATA;
 546
 547         if (block->instance_count <= instance)
 548                 return AE_BAD_PARAMETER;
 549
 550         /* Check GUID is a data block */
 551         if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
 552                 return AE_ERROR;
 553
 554         input.count = 2;
 555         input.pointer = params;
 556         params[0].type = ACPI_TYPE_INTEGER;
 557         params[0].integer.value = instance;
 558         params[1].type = get_param_acpi_type(wblock);
 559         params[1].buffer.length = in->length;
 560         params[1].buffer.pointer = in->pointer;
 561
 562         get_acpi_method_name(wblock, 'S', method);
 563
 564         return acpi_evaluate_object(handle, method, &input, NULL);
 565 }
 566 EXPORT_SYMBOL_GPL(wmidev_block_set);
 567
 568 /**
 569  * wmi_install_notify_handler - Register handler for WMI events (deprecated)
 570  * @guid: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 571  * @handler: Function to handle notifications
 572  * @data: Data to be returned to handler when event is fired
 573  *
 574  * Register a handler for events sent to the ACPI-WMI mapper device.
 575  *
 576  * Return: acpi_status signaling success or error.
 577  */
 578 acpi_status wmi_install_notify_handler(const char *guid,
 579                                        wmi_notify_handler handler,
 580                                        void *data)
 581 {
 582         struct wmi_block *wblock;
 583         struct wmi_device *wdev;
 584         acpi_status status;
 585
 586         wdev = wmi_find_device_by_guid(guid);
 587         if (IS_ERR(wdev))
 588                 return AE_ERROR;
 589
 590         wblock = container_of(wdev, struct wmi_block, dev);
 591
 592         down_write(&wblock->notify_lock);
 593         if (wblock->handler) {
 594                 status = AE_ALREADY_ACQUIRED;
 595         } else {
 596                 wblock->handler = handler;
 597                 wblock->handler_data = data;
 598
 599                 if (ACPI_FAILURE(wmi_method_enable(wblock, true)))
 600                         dev_warn(&wblock->dev.dev, "Failed to enable device\n");
 601
 602                 status = AE_OK;
 603         }
 604         up_write(&wblock->notify_lock);
 605
 606         wmi_device_put(wdev);
 607
 608         return status;
 609 }
 610 EXPORT_SYMBOL_GPL(wmi_install_notify_handler);
 611
 612 /**
 613  * wmi_remove_notify_handler - Unregister handler for WMI events (deprecated)
 614  * @guid: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 615  *
 616  * Unregister handler for events sent to the ACPI-WMI mapper device.
 617  *
 618  * Return: acpi_status signaling success or error.
 619  */
 620 acpi_status wmi_remove_notify_handler(const char *guid)
 621 {
 622         struct wmi_block *wblock;
 623         struct wmi_device *wdev;
 624         acpi_status status;
 625
 626         wdev = wmi_find_device_by_guid(guid);
 627         if (IS_ERR(wdev))
 628                 return AE_ERROR;
 629
 630         wblock = container_of(wdev, struct wmi_block, dev);
 631
 632         down_write(&wblock->notify_lock);
 633         if (!wblock->handler) {
 634                 status = AE_NULL_ENTRY;
 635         } else {
 636                 if (ACPI_FAILURE(wmi_method_enable(wblock, false)))
 637                         dev_warn(&wblock->dev.dev, "Failed to disable device\n");
 638
 639                 wblock->handler = NULL;
 640                 wblock->handler_data = NULL;
 641
 642                 status = AE_OK;
 643         }
 644         up_write(&wblock->notify_lock);
 645
 646         wmi_device_put(wdev);
 647
 648         return status;
 649 }
 650 EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);
 651
 652 /**
 653  * wmi_get_event_data - Get WMI data associated with an event (deprecated)
 654  *
 655  * @event: Event to find
 656  * @out: Buffer to hold event data
 657  *
 658  * Get extra data associated with an WMI event, the caller needs to free @out.
 659  *
 660  * Return: acpi_status signaling success or error.
 661  */
 662 acpi_status wmi_get_event_data(u32 event, struct acpi_buffer *out)
 663 {
 664         struct wmi_block *wblock;
 665         struct wmi_device *wdev;
 666         acpi_status status;
 667
 668         wdev = wmi_find_event_by_notify_id(event);
 669         if (IS_ERR(wdev))
 670                 return AE_NOT_FOUND;
 671
 672         wblock = container_of(wdev, struct wmi_block, dev);
 673         status = get_event_data(wblock, out);
 674
 675         wmi_device_put(wdev);
 676
 677         return status;
 678 }
 679 EXPORT_SYMBOL_GPL(wmi_get_event_data);
 680
 681 /**
 682  * wmi_has_guid - Check if a GUID is available
 683  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 684  *
 685  * Check if a given GUID is defined by _WDG.
 686  *
 687  * Return: True if GUID is available, false otherwise.
 688  */
 689 bool wmi_has_guid(const char *guid_string)
 690 {
 691         struct wmi_device *wdev;
 692
 693         wdev = wmi_find_device_by_guid(guid_string);
 694         if (IS_ERR(wdev))
 695                 return false;
 696
 697         wmi_device_put(wdev);
 698
 699         return true;
 700 }
 701 EXPORT_SYMBOL_GPL(wmi_has_guid);
 702
 703 /**
 704  * wmi_get_acpi_device_uid() - Get _UID name of ACPI device that defines GUID (deprecated)
 705  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 706  *
 707  * Find the _UID of ACPI device associated with this WMI GUID.
 708  *
 709  * Return: The ACPI _UID field value or NULL if the WMI GUID was not found.
 710  */
 711 char *wmi_get_acpi_device_uid(const char *guid_string)
 712 {
 713         struct wmi_block *wblock;
 714         struct wmi_device *wdev;
 715         char *uid;
 716
 717         wdev = wmi_find_device_by_guid(guid_string);
 718         if (IS_ERR(wdev))
 719                 return NULL;
 720
 721         wblock = container_of(wdev, struct wmi_block, dev);
 722         uid = acpi_device_uid(wblock->acpi_device);
 723
 724         wmi_device_put(wdev);
 725
 726         return uid;
 727 }
 728 EXPORT_SYMBOL_GPL(wmi_get_acpi_device_uid);
 729
 730 #define drv_to_wdrv(__drv)      container_of_const(__drv, struct wmi_driver, driver)
 731
 732 /*
 733  * sysfs interface
 734  */
 735 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 736                              char *buf)
 737 {
 738         struct wmi_block *wblock = dev_to_wblock(dev);
 739
 740         return sysfs_emit(buf, "wmi:%pUL\n", &wblock->gblock.guid);
 741 }
 742 static DEVICE_ATTR_RO(modalias);
 743
 744 static ssize_t guid_show(struct device *dev, struct device_attribute *attr,
 745                          char *buf)
 746 {
 747         struct wmi_block *wblock = dev_to_wblock(dev);
 748
 749         return sysfs_emit(buf, "%pUL\n", &wblock->gblock.guid);
 750 }
 751 static DEVICE_ATTR_RO(guid);
 752
 753 static ssize_t instance_count_show(struct device *dev,
 754                                    struct device_attribute *attr, char *buf)
 755 {
 756         struct wmi_block *wblock = dev_to_wblock(dev);
 757
 758         return sysfs_emit(buf, "%d\n", (int)wblock->gblock.instance_count);
 759 }
 760 static DEVICE_ATTR_RO(instance_count);
 761
 762 static ssize_t expensive_show(struct device *dev,
 763                               struct device_attribute *attr, char *buf)
 764 {
 765         struct wmi_block *wblock = dev_to_wblock(dev);
 766
 767         return sysfs_emit(buf, "%d\n",
 768                           (wblock->gblock.flags & ACPI_WMI_EXPENSIVE) != 0);
 769 }
 770 static DEVICE_ATTR_RO(expensive);
 771
 772 static ssize_t driver_override_show(struct device *dev, struct device_attribute *attr,
 773                                     char *buf)
 774 {
 775         struct wmi_device *wdev = to_wmi_device(dev);
 776         ssize_t ret;
 777
 778         device_lock(dev);
 779         ret = sysfs_emit(buf, "%s\n", wdev->driver_override);
 780         device_unlock(dev);
 781
 782         return ret;
 783 }
 784
 785 static ssize_t driver_override_store(struct device *dev, struct device_attribute *attr,
 786                                      const char *buf, size_t count)
 787 {
 788         struct wmi_device *wdev = to_wmi_device(dev);
 789         int ret;
 790
 791         ret = driver_set_override(dev, &wdev->driver_override, buf, count);
 792         if (ret < 0)
 793                 return ret;
 794
 795         return count;
 796 }
 797 static DEVICE_ATTR_RW(driver_override);
 798
 799 static struct attribute *wmi_attrs[] = {
 800         &dev_attr_modalias.attr,
 801         &dev_attr_guid.attr,
 802         &dev_attr_instance_count.attr,
 803         &dev_attr_expensive.attr,
 804         &dev_attr_driver_override.attr,
 805         NULL
 806 };
 807 ATTRIBUTE_GROUPS(wmi);
 808
 809 static ssize_t notify_id_show(struct device *dev, struct device_attribute *attr,
 810                               char *buf)
 811 {
 812         struct wmi_block *wblock = dev_to_wblock(dev);
 813
 814         return sysfs_emit(buf, "%02X\n", (unsigned int)wblock->gblock.notify_id);
 815 }
 816 static DEVICE_ATTR_RO(notify_id);
 817
 818 static struct attribute *wmi_event_attrs[] = {
 819         &dev_attr_notify_id.attr,
 820         NULL
 821 };
 822 ATTRIBUTE_GROUPS(wmi_event);
 823
 824 static ssize_t object_id_show(struct device *dev, struct device_attribute *attr,
 825                               char *buf)
 826 {
 827         struct wmi_block *wblock = dev_to_wblock(dev);
 828
 829         return sysfs_emit(buf, "%c%c\n", wblock->gblock.object_id[0],
 830                           wblock->gblock.object_id[1]);
 831 }
 832 static DEVICE_ATTR_RO(object_id);
 833
 834 static ssize_t setable_show(struct device *dev, struct device_attribute *attr,
 835                             char *buf)
 836 {
 837         struct wmi_device *wdev = dev_to_wdev(dev);
 838
 839         return sysfs_emit(buf, "%d\n", (int)wdev->setable);
 840 }
 841 static DEVICE_ATTR_RO(setable);
 842
 843 static struct attribute *wmi_data_attrs[] = {
 844         &dev_attr_object_id.attr,
 845         &dev_attr_setable.attr,
 846         NULL
 847 };
 848 ATTRIBUTE_GROUPS(wmi_data);
 849
 850 static struct attribute *wmi_method_attrs[] = {
 851         &dev_attr_object_id.attr,
 852         NULL
 853 };
 854 ATTRIBUTE_GROUPS(wmi_method);
 855
 856 static int wmi_dev_uevent(const struct device *dev, struct kobj_uevent_env *env)
 857 {
 858         const struct wmi_block *wblock = dev_to_wblock(dev);
 859
 860         if (add_uevent_var(env, "MODALIAS=wmi:%pUL", &wblock->gblock.guid))
 861                 return -ENOMEM;
 862
 863         if (add_uevent_var(env, "WMI_GUID=%pUL", &wblock->gblock.guid))
 864                 return -ENOMEM;
 865
 866         return 0;
 867 }
 868
 869 static void wmi_dev_release(struct device *dev)
 870 {
 871         struct wmi_block *wblock = dev_to_wblock(dev);
 872
 873         kfree(wblock->dev.driver_override);
 874         kfree(wblock);
 875 }
 876
 877 static int wmi_dev_match(struct device *dev, const struct device_driver *driver)
 878 {
 879         const struct wmi_driver *wmi_driver = drv_to_wdrv(driver);
 880         struct wmi_block *wblock = dev_to_wblock(dev);
 881         const struct wmi_device_id *id = wmi_driver->id_table;
 882
 883         /* When driver_override is set, only bind to the matching driver */
 884         if (wblock->dev.driver_override)
 885                 return !strcmp(wblock->dev.driver_override, driver->name);
 886
 887         if (id == NULL)
 888                 return 0;
 889
 890         while (*id->guid_string) {
 891                 if (guid_parse_and_compare(id->guid_string, &wblock->gblock.guid))
 892                         return 1;
 893
 894                 id++;
 895         }
 896
 897         return 0;
 898 }
 899
 900 static int wmi_dev_probe(struct device *dev)
 901 {
 902         struct wmi_block *wblock = dev_to_wblock(dev);
 903         struct wmi_driver *wdriver = drv_to_wdrv(dev->driver);
 904         int ret = 0;
 905
 906         /* Some older WMI drivers will break if instantiated multiple times,
 907          * so they are blocked from probing WMI devices with a duplicated GUID.
 908          *
 909          * New WMI drivers should support being instantiated multiple times.
 910          */
 911         if (test_bit(WMI_GUID_DUPLICATED, &wblock->flags) && !wdriver->no_singleton) {
 912                 dev_warn(dev, "Legacy driver %s cannot be instantiated multiple times\n",
 913                          dev->driver->name);
 914
 915                 return -ENODEV;
 916         }
 917
 918         if (wdriver->notify) {
 919                 if (test_bit(WMI_NO_EVENT_DATA, &wblock->flags) && !wdriver->no_notify_data)
 920                         return -ENODEV;
 921         }
 922
 923         if (ACPI_FAILURE(wmi_method_enable(wblock, true)))
 924                 dev_warn(dev, "failed to enable device -- probing anyway\n");
 925
 926         if (wdriver->probe) {
 927                 ret = wdriver->probe(dev_to_wdev(dev),
 928                                 find_guid_context(wblock, wdriver));
 929                 if (ret) {
 930                         if (ACPI_FAILURE(wmi_method_enable(wblock, false)))
 931                                 dev_warn(dev, "Failed to disable device\n");
 932
 933                         return ret;
 934                 }
 935         }
 936
 937         down_write(&wblock->notify_lock);
 938         wblock->driver_ready = true;
 939         up_write(&wblock->notify_lock);
 940
 941         return 0;
 942 }
 943
 944 static void wmi_dev_remove(struct device *dev)
 945 {
 946         struct wmi_block *wblock = dev_to_wblock(dev);
 947         struct wmi_driver *wdriver = drv_to_wdrv(dev->driver);
 948
 949         down_write(&wblock->notify_lock);
 950         wblock->driver_ready = false;
 951         up_write(&wblock->notify_lock);
 952
 953         if (wdriver->remove)
 954                 wdriver->remove(dev_to_wdev(dev));
 955
 956         if (ACPI_FAILURE(wmi_method_enable(wblock, false)))
 957                 dev_warn(dev, "failed to disable device\n");
 958 }
 959
 960 static struct class wmi_bus_class = {
 961         .name = "wmi_bus",
 962 };
 963
 964 static const struct bus_type wmi_bus_type = {
 965         .name = "wmi",
 966         .dev_groups = wmi_groups,
 967         .match = wmi_dev_match,
 968         .uevent = wmi_dev_uevent,
 969         .probe = wmi_dev_probe,
 970         .remove = wmi_dev_remove,
 971 };
 972
 973 static const struct device_type wmi_type_event = {
 974         .name = "event",
 975         .groups = wmi_event_groups,
 976         .release = wmi_dev_release,
 977 };
 978
 979 static const struct device_type wmi_type_method = {
 980         .name = "method",
 981         .groups = wmi_method_groups,
 982         .release = wmi_dev_release,
 983 };
 984
 985 static const struct device_type wmi_type_data = {
 986         .name = "data",
 987         .groups = wmi_data_groups,
 988         .release = wmi_dev_release,
 989 };
 990
 991 /*
 992  * _WDG is a static list that is only parsed at startup,
 993  * so it's safe to count entries without extra protection.
 994  */
 995 static int guid_count(const guid_t *guid)
 996 {
 997         struct wmi_block *wblock;
 998         int count = 0;
 999
1000         list_for_each_entry(wblock, &wmi_block_list, list) {
1001                 if (guid_equal(&wblock->gblock.guid, guid))
1002                         count++;
1003         }
1004
1005         return count;
1006 }
1007
1008 static int wmi_create_device(struct device *wmi_bus_dev,
1009                              struct wmi_block *wblock,
1010                              struct acpi_device *device)
1011 {
1012         char method[WMI_ACPI_METHOD_NAME_SIZE];
1013         struct acpi_device_info *info;
1014         acpi_handle method_handle;
1015         acpi_status status;
1016         uint count;
1017
1018         if (wblock->gblock.flags & ACPI_WMI_EVENT) {
1019                 wblock->dev.dev.type = &wmi_type_event;
1020                 goto out_init;
1021         }
1022
1023         if (wblock->gblock.flags & ACPI_WMI_METHOD) {
1024                 get_acpi_method_name(wblock, 'M', method);
1025                 if (!acpi_has_method(device->handle, method)) {
1026                         dev_warn(wmi_bus_dev,
1027                                  FW_BUG "%s method block execution control method not found\n",
1028                                  method);
1029
1030                         return -ENXIO;
1031                 }
1032
1033                 wblock->dev.dev.type = &wmi_type_method;
1034                 goto out_init;
1035         }
1036
1037         /*
1038          * Data Block Query Control Method (WQxx by convention) is
1039          * required per the WMI documentation. If it is not present,
1040          * we ignore this data block.
1041          */
1042         get_acpi_method_name(wblock, 'Q', method);
1043         status = acpi_get_handle(device->handle, method, &method_handle);
1044         if (ACPI_FAILURE(status)) {
1045                 dev_warn(wmi_bus_dev,
1046                          FW_BUG "%s data block query control method not found\n",
1047                          method);
1048
1049                 return -ENXIO;
1050         }
1051
1052         status = acpi_get_object_info(method_handle, &info);
1053         if (ACPI_FAILURE(status))
1054                 return -EIO;
1055
1056         wblock->dev.dev.type = &wmi_type_data;
1057
1058         /*
1059          * The Microsoft documentation specifically states:
1060          *
1061          *   Data blocks registered with only a single instance
1062          *   can ignore the parameter.
1063          *
1064          * ACPICA will get mad at us if we call the method with the wrong number
1065          * of arguments, so check what our method expects.  (On some Dell
1066          * laptops, WQxx may not be a method at all.)
1067          */
1068         if (info->type != ACPI_TYPE_METHOD || info->param_count == 0)
1069                 set_bit(WMI_READ_TAKES_NO_ARGS, &wblock->flags);
1070
1071         kfree(info);
1072
1073         get_acpi_method_name(wblock, 'S', method);
1074         if (acpi_has_method(device->handle, method))
1075                 wblock->dev.setable = true;
1076
1077  out_init:
1078         init_rwsem(&wblock->notify_lock);
1079         wblock->driver_ready = false;
1080         wblock->dev.dev.bus = &wmi_bus_type;
1081         wblock->dev.dev.parent = wmi_bus_dev;
1082
1083         count = guid_count(&wblock->gblock.guid);
1084         if (count) {
1085                 dev_set_name(&wblock->dev.dev, "%pUL-%d", &wblock->gblock.guid, count);
1086                 set_bit(WMI_GUID_DUPLICATED, &wblock->flags);
1087         } else {
1088                 dev_set_name(&wblock->dev.dev, "%pUL", &wblock->gblock.guid);
1089         }
1090
1091         device_initialize(&wblock->dev.dev);
1092
1093         return 0;
1094 }
1095
1096 static int wmi_add_device(struct platform_device *pdev, struct wmi_device *wdev)
1097 {
1098         struct device_link *link;
1099
1100         /*
1101          * Many aggregate WMI drivers do not use -EPROBE_DEFER when they
1102          * are unable to find a WMI device during probe, instead they require
1103          * all WMI devices associated with an platform device to become available
1104          * at once. This device link thus prevents WMI drivers from probing until
1105          * the associated platform device has finished probing (and has registered
1106          * all discovered WMI devices).
1107          */
1108
1109         link = device_link_add(&wdev->dev, &pdev->dev, DL_FLAG_AUTOREMOVE_SUPPLIER);
1110         if (!link)
1111                 return -EINVAL;
1112
1113         return device_add(&wdev->dev);
1114 }
1115
1116 /*
1117  * Parse the _WDG method for the GUID data blocks
1118  */
1119 static int parse_wdg(struct device *wmi_bus_dev, struct platform_device *pdev)
1120 {
1121         struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
1122         struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
1123         const struct guid_block *gblock;
1124         bool event_data_available;
1125         struct wmi_block *wblock;
1126         union acpi_object *obj;
1127         acpi_status status;
1128         u32 i, total;
1129         int retval;
1130
1131         status = acpi_evaluate_object(device->handle, "_WDG", NULL, &out);
1132         if (ACPI_FAILURE(status))
1133                 return -ENXIO;
1134
1135         obj = out.pointer;
1136         if (!obj)
1137                 return -ENXIO;
1138
1139         if (obj->type != ACPI_TYPE_BUFFER) {
1140                 kfree(obj);
1141                 return -ENXIO;
1142         }
1143
1144         event_data_available = acpi_has_method(device->handle, "_WED");
1145         gblock = (const struct guid_block *)obj->buffer.pointer;
1146         total = obj->buffer.length / sizeof(struct guid_block);
1147
1148         for (i = 0; i < total; i++) {
1149                 if (!gblock[i].instance_count) {
1150                         dev_info(wmi_bus_dev, FW_INFO "%pUL has zero instances\n", &gblock[i].guid);
1151                         continue;
1152                 }
1153
1154                 wblock = kzalloc(sizeof(*wblock), GFP_KERNEL);
1155                 if (!wblock)
1156                         continue;
1157
1158                 wblock->acpi_device = device;
1159                 wblock->gblock = gblock[i];
1160                 if (gblock[i].flags & ACPI_WMI_EVENT && !event_data_available)
1161                         set_bit(WMI_NO_EVENT_DATA, &wblock->flags);
1162
1163                 retval = wmi_create_device(wmi_bus_dev, wblock, device);
1164                 if (retval) {
1165                         kfree(wblock);
1166                         continue;
1167                 }
1168
1169                 list_add_tail(&wblock->list, &wmi_block_list);
1170
1171                 retval = wmi_add_device(pdev, &wblock->dev);
1172                 if (retval) {
1173                         dev_err(wmi_bus_dev, "failed to register %pUL\n",
1174                                 &wblock->gblock.guid);
1175
1176                         list_del(&wblock->list);
1177                         put_device(&wblock->dev.dev);
1178                 }
1179         }
1180
1181         kfree(obj);
1182
1183         return 0;
1184 }
1185
1186 static int wmi_get_notify_data(struct wmi_block *wblock, union acpi_object **obj)
1187 {
1188         struct acpi_buffer data = { ACPI_ALLOCATE_BUFFER, NULL };
1189         acpi_status status;
1190
1191         if (test_bit(WMI_NO_EVENT_DATA, &wblock->flags)) {
1192                 *obj = NULL;
1193                 return 0;
1194         }
1195
1196         status = get_event_data(wblock, &data);
1197         if (ACPI_FAILURE(status)) {
1198                 dev_warn(&wblock->dev.dev, "Failed to get event data\n");
1199                 return -EIO;
1200         }
1201
1202         *obj = data.pointer;
1203
1204         return 0;
1205 }
1206
1207 static void wmi_notify_driver(struct wmi_block *wblock, union acpi_object *obj)
1208 {
1209         struct wmi_driver *driver = drv_to_wdrv(wblock->dev.dev.driver);
1210
1211         if (!obj && !driver->no_notify_data) {
1212                 dev_warn(&wblock->dev.dev, "Event contains no event data\n");
1213                 return;
1214         }
1215
1216         if (driver->notify)
1217                 driver->notify(&wblock->dev, obj);
1218 }
1219
1220 static int wmi_notify_device(struct device *dev, void *data)
1221 {
1222         struct wmi_block *wblock = dev_to_wblock(dev);
1223         union acpi_object *obj;
1224         u32 *event = data;
1225         int ret;
1226
1227         if (!(wblock->gblock.flags & ACPI_WMI_EVENT && wblock->gblock.notify_id == *event))
1228                 return 0;
1229
1230         down_read(&wblock->notify_lock);
1231         /* The WMI driver notify handler conflicts with the legacy WMI handler.
1232          * Because of this the WMI driver notify handler takes precedence.
1233          */
1234         if (wblock->dev.dev.driver && wblock->driver_ready) {
1235                 ret = wmi_get_notify_data(wblock, &obj);
1236                 if (ret >= 0) {
1237                         wmi_notify_driver(wblock, obj);
1238                         kfree(obj);
1239                 }
1240         } else {
1241                 if (wblock->handler) {
1242                         wblock->handler(*event, wblock->handler_data);
1243                 } else {
1244                         /* The ACPI WMI specification says that _WED should be
1245                          * evaluated every time an notification is received, even
1246                          * if no consumers are present.
1247                          *
1248                          * Some firmware implementations actually depend on this
1249                          * by using a queue for events which will fill up if the
1250                          * WMI driver core stops evaluating _WED due to missing
1251                          * WMI event consumers.
1252                          *
1253                          * Because of this we need this seemingly useless call to
1254                          * wmi_get_notify_data() which in turn evaluates _WED.
1255                          */
1256                         ret = wmi_get_notify_data(wblock, &obj);
1257                         if (ret >= 0)
1258                                 kfree(obj);
1259                 }
1260
1261         }
1262         up_read(&wblock->notify_lock);
1263
1264         acpi_bus_generate_netlink_event("wmi", acpi_dev_name(wblock->acpi_device), *event, 0);
1265
1266         return -EBUSY;
1267 }
1268
1269 static void acpi_wmi_notify_handler(acpi_handle handle, u32 event, void *context)
1270 {
1271         struct device *wmi_bus_dev = context;
1272
1273         device_for_each_child(wmi_bus_dev, &event, wmi_notify_device);
1274 }
1275
1276 static int wmi_remove_device(struct device *dev, void *data)
1277 {
1278         struct wmi_block *wblock = dev_to_wblock(dev);
1279
1280         list_del(&wblock->list);
1281         device_unregister(dev);
1282
1283         return 0;
1284 }
1285
1286 static void acpi_wmi_remove(struct platform_device *device)
1287 {
1288         struct device *wmi_bus_device = dev_get_drvdata(&device->dev);
1289
1290         device_for_each_child_reverse(wmi_bus_device, NULL, wmi_remove_device);
1291 }
1292
1293 static void acpi_wmi_remove_notify_handler(void *data)
1294 {
1295         struct acpi_device *acpi_device = data;
1296
1297         acpi_remove_notify_handler(acpi_device->handle, ACPI_ALL_NOTIFY, acpi_wmi_notify_handler);
1298 }
1299
1300 static void acpi_wmi_remove_bus_device(void *data)
1301 {
1302         struct device *wmi_bus_dev = data;
1303
1304         device_unregister(wmi_bus_dev);
1305 }
1306
1307 static int acpi_wmi_probe(struct platform_device *device)
1308 {
1309         struct acpi_device *acpi_device;
1310         struct device *wmi_bus_dev;
1311         acpi_status status;
1312         int error;
1313
1314         acpi_device = ACPI_COMPANION(&device->dev);
1315         if (!acpi_device) {
1316                 dev_err(&device->dev, "ACPI companion is missing\n");
1317                 return -ENODEV;
1318         }
1319
1320         wmi_bus_dev = device_create(&wmi_bus_class, &device->dev, MKDEV(0, 0), NULL, "wmi_bus-%s",
1321                                     dev_name(&device->dev));
1322         if (IS_ERR(wmi_bus_dev))
1323                 return PTR_ERR(wmi_bus_dev);
1324
1325         error = devm_add_action_or_reset(&device->dev, acpi_wmi_remove_bus_device, wmi_bus_dev);
1326         if (error < 0)
1327                 return error;
1328
1329         dev_set_drvdata(&device->dev, wmi_bus_dev);
1330
1331         status = acpi_install_notify_handler(acpi_device->handle, ACPI_ALL_NOTIFY,
1332                                              acpi_wmi_notify_handler, wmi_bus_dev);
1333         if (ACPI_FAILURE(status)) {
1334                 dev_err(&device->dev, "Error installing notify handler\n");
1335                 return -ENODEV;
1336         }
1337         error = devm_add_action_or_reset(&device->dev, acpi_wmi_remove_notify_handler,
1338                                          acpi_device);
1339         if (error < 0)
1340                 return error;
1341
1342         error = parse_wdg(wmi_bus_dev, device);
1343         if (error) {
1344                 dev_err(&device->dev, "Failed to parse _WDG method\n");
1345                 return error;
1346         }
1347
1348         return 0;
1349 }
1350
1351 int __must_check __wmi_driver_register(struct wmi_driver *driver,
1352                                        struct module *owner)
1353 {
1354         driver->driver.owner = owner;
1355         driver->driver.bus = &wmi_bus_type;
1356
1357         return driver_register(&driver->driver);
1358 }
1359 EXPORT_SYMBOL(__wmi_driver_register);
1360
1361 /**
1362  * wmi_driver_unregister() - Unregister a WMI driver
1363  * @driver: WMI driver to unregister
1364  *
1365  * Unregisters a WMI driver from the WMI bus.
1366  */
1367 void wmi_driver_unregister(struct wmi_driver *driver)
1368 {
1369         driver_unregister(&driver->driver);
1370 }
1371 EXPORT_SYMBOL(wmi_driver_unregister);
1372
1373 static struct platform_driver acpi_wmi_driver = {
1374         .driver = {
1375                 .name = "acpi-wmi",
1376                 .acpi_match_table = wmi_device_ids,
1377         },
1378         .probe = acpi_wmi_probe,
1379         .remove_new = acpi_wmi_remove,
1380 };
1381
1382 static int __init acpi_wmi_init(void)
1383 {
1384         int error;
1385
1386         if (acpi_disabled)
1387                 return -ENODEV;
1388
1389         error = class_register(&wmi_bus_class);
1390         if (error)
1391                 return error;
1392
1393         error = bus_register(&wmi_bus_type);
1394         if (error)
1395                 goto err_unreg_class;
1396
1397         error = platform_driver_register(&acpi_wmi_driver);
1398         if (error) {
1399                 pr_err("Error loading mapper\n");
1400                 goto err_unreg_bus;
1401         }
1402
1403         return 0;
1404
1405 err_unreg_bus:
1406         bus_unregister(&wmi_bus_type);
1407
1408 err_unreg_class:
1409         class_unregister(&wmi_bus_class);
1410
1411         return error;
1412 }
1413
1414 static void __exit acpi_wmi_exit(void)
1415 {
1416         platform_driver_unregister(&acpi_wmi_driver);
1417         bus_unregister(&wmi_bus_type);
1418         class_unregister(&wmi_bus_class);
1419 }
1420
1421 subsys_initcall_sync(acpi_wmi_init);
1422 module_exit(acpi_wmi_exit);