1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * ACPI-WMI mapping driver
4 *
5 * Copyright (C) 2007-2008 Carlos Corbacho <carlos@strangeworlds.co.uk>
6 *
7 * GUID parsing code from ldm.c is:
8 * Copyright (C) 2001,2002 Richard Russon <ldm@flatcap.org>
9 * Copyright (c) 2001-2007 Anton Altaparmakov
10 * Copyright (C) 2001,2002 Jakob Kemi <jakob.kemi@telia.com>
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
36MODULE_AUTHOR("Carlos Corbacho");
37MODULE_DESCRIPTION("ACPI-WMI Mapping Driver");
38MODULE_LICENSE("GPL");
39
40static LIST_HEAD(wmi_block_list);
41
42struct 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;
54static_assert(sizeof(typeof_member(struct guid_block, guid)) == 16);
55static_assert(sizeof(struct guid_block) == 20);
56static_assert(__alignof__(struct guid_block) == 1);
57
58enum { /* wmi_block flags */
59 WMI_READ_TAKES_NO_ARGS,
60 WMI_GUID_DUPLICATED,
61 WMI_NO_EVENT_DATA,
62};
63
64struct 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
86static const struct acpi_device_id wmi_device_ids[] = {
87 {"PNP0C14", 0},
88 {"pnp0c14", 0},
89 { }
90};
91MODULE_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
100static bool guid_parse_and_compare(const char *string, const guid_t *guid)
101{
102 guid_t guid_input;
103
104 if (guid_parse(uuid: string, u: &guid_input))
105 return false;
106
107 return guid_equal(u1: &guid_input, u2: guid);
108}
109
110static 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(string: id->guid_string, guid: &wblock->gblock.guid))
121 return id->context;
122 id++;
123 }
124 return NULL;
125}
126
127static 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(buf: method, size: 5, fmt: "WE%02X", block->notify_id);
138 status = acpi_execute_simple_method(handle, method, arg: 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
147static 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
161static 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
169static 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(object: wblock->acpi_device->handle, pathname: "_WED", parameter_objects: &input, return_object_buffer: out);
183}
184
185static 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(u1: guid, u2: &wblock->gblock.guid))
197 return 1;
198
199 return 0;
200}
201
202static 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
219static const struct bus_type wmi_bus_type;
220
221static 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(uuid: guid_string, u: &guid);
228 if (ret < 0)
229 return ERR_PTR(error: ret);
230
231 dev = bus_find_device(bus: &wmi_bus_type, NULL, data: &guid, match: wmidev_match_guid);
232 if (!dev)
233 return ERR_PTR(error: -ENODEV);
234
235 return dev_to_wdev(dev);
236}
237
238static struct wmi_device *wmi_find_event_by_notify_id(const u32 notify_id)
239{
240 struct device *dev;
241
242 dev = bus_find_device(bus: &wmi_bus_type, NULL, data: &notify_id, match: wmidev_match_notify_id);
243 if (!dev)
244 return ERR_PTR(error: -ENODEV);
245
246 return to_wmi_device(dev);
247}
248
249static void wmi_device_put(struct wmi_device *wdev)
250{
251 put_device(dev: &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 */
266int 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(ptr: wdev))
273 return PTR_ERR(ptr: wdev);
274
275 ret = wmidev_instance_count(wdev);
276 wmi_device_put(wdev);
277
278 return ret;
279}
280EXPORT_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 */
290u8 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}
296EXPORT_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 */
310acpi_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(ptr: 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}
326EXPORT_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 */
340acpi_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, method: 'M', buffer: method);
375
376 return acpi_evaluate_object(object: handle, pathname: method, parameter_objects: &input, return_object_buffer: out);
377}
378EXPORT_SYMBOL_GPL(wmidev_evaluate_method);
379
380static 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, method: 'C', buffer: 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, method: wc_method, arg: 1);
425 }
426
427 get_acpi_method_name(wblock, method: 'Q', buffer: method);
428 status = acpi_evaluate_object(object: handle, pathname: method, parameter_objects: &input, return_object_buffer: 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, method: wc_method, arg: 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 */
458acpi_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(ptr: 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}
476EXPORT_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 */
487union 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}
497EXPORT_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 */
509acpi_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(ptr: wdev))
516 return AE_ERROR;
517
518 status = wmidev_block_set(wdev, instance, in);
519 wmi_device_put(wdev);
520
521 return status;
522}
523EXPORT_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 */
535acpi_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, method: 'S', buffer: method);
563
564 return acpi_evaluate_object(object: handle, pathname: method, parameter_objects: &input, NULL);
565}
566EXPORT_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 */
578acpi_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_string: guid);
587 if (IS_ERR(ptr: wdev))
588 return AE_ERROR;
589
590 wblock = container_of(wdev, struct wmi_block, dev);
591
592 down_write(sem: &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(sem: &wblock->notify_lock);
605
606 wmi_device_put(wdev);
607
608 return status;
609}
610EXPORT_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 */
620acpi_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_string: guid);
627 if (IS_ERR(ptr: wdev))
628 return AE_ERROR;
629
630 wblock = container_of(wdev, struct wmi_block, dev);
631
632 down_write(sem: &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(sem: &wblock->notify_lock);
645
646 wmi_device_put(wdev);
647
648 return status;
649}
650EXPORT_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 */
662acpi_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(notify_id: event);
669 if (IS_ERR(ptr: 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}
679EXPORT_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 */
689bool 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(ptr: wdev))
695 return false;
696
697 wmi_device_put(wdev);
698
699 return true;
700}
701EXPORT_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 */
711char *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(ptr: 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}
728EXPORT_SYMBOL_GPL(wmi_get_acpi_device_uid);
729
730static inline struct wmi_driver *drv_to_wdrv(struct device_driver *drv)
731{
732 return container_of(drv, struct wmi_driver, driver);
733}
734
735/*
736 * sysfs interface
737 */
738static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
739 char *buf)
740{
741 struct wmi_block *wblock = dev_to_wblock(dev);
742
743 return sysfs_emit(buf, fmt: "wmi:%pUL\n", &wblock->gblock.guid);
744}
745static DEVICE_ATTR_RO(modalias);
746
747static ssize_t guid_show(struct device *dev, struct device_attribute *attr,
748 char *buf)
749{
750 struct wmi_block *wblock = dev_to_wblock(dev);
751
752 return sysfs_emit(buf, fmt: "%pUL\n", &wblock->gblock.guid);
753}
754static DEVICE_ATTR_RO(guid);
755
756static ssize_t instance_count_show(struct device *dev,
757 struct device_attribute *attr, char *buf)
758{
759 struct wmi_block *wblock = dev_to_wblock(dev);
760
761 return sysfs_emit(buf, fmt: "%d\n", (int)wblock->gblock.instance_count);
762}
763static DEVICE_ATTR_RO(instance_count);
764
765static ssize_t expensive_show(struct device *dev,
766 struct device_attribute *attr, char *buf)
767{
768 struct wmi_block *wblock = dev_to_wblock(dev);
769
770 return sysfs_emit(buf, fmt: "%d\n",
771 (wblock->gblock.flags & ACPI_WMI_EXPENSIVE) != 0);
772}
773static DEVICE_ATTR_RO(expensive);
774
775static struct attribute *wmi_attrs[] = {
776 &dev_attr_modalias.attr,
777 &dev_attr_guid.attr,
778 &dev_attr_instance_count.attr,
779 &dev_attr_expensive.attr,
780 NULL
781};
782ATTRIBUTE_GROUPS(wmi);
783
784static ssize_t notify_id_show(struct device *dev, struct device_attribute *attr,
785 char *buf)
786{
787 struct wmi_block *wblock = dev_to_wblock(dev);
788
789 return sysfs_emit(buf, fmt: "%02X\n", (unsigned int)wblock->gblock.notify_id);
790}
791static DEVICE_ATTR_RO(notify_id);
792
793static struct attribute *wmi_event_attrs[] = {
794 &dev_attr_notify_id.attr,
795 NULL
796};
797ATTRIBUTE_GROUPS(wmi_event);
798
799static ssize_t object_id_show(struct device *dev, struct device_attribute *attr,
800 char *buf)
801{
802 struct wmi_block *wblock = dev_to_wblock(dev);
803
804 return sysfs_emit(buf, fmt: "%c%c\n", wblock->gblock.object_id[0],
805 wblock->gblock.object_id[1]);
806}
807static DEVICE_ATTR_RO(object_id);
808
809static ssize_t setable_show(struct device *dev, struct device_attribute *attr,
810 char *buf)
811{
812 struct wmi_device *wdev = dev_to_wdev(dev);
813
814 return sysfs_emit(buf, fmt: "%d\n", (int)wdev->setable);
815}
816static DEVICE_ATTR_RO(setable);
817
818static struct attribute *wmi_data_attrs[] = {
819 &dev_attr_object_id.attr,
820 &dev_attr_setable.attr,
821 NULL
822};
823ATTRIBUTE_GROUPS(wmi_data);
824
825static struct attribute *wmi_method_attrs[] = {
826 &dev_attr_object_id.attr,
827 NULL
828};
829ATTRIBUTE_GROUPS(wmi_method);
830
831static int wmi_dev_uevent(const struct device *dev, struct kobj_uevent_env *env)
832{
833 const struct wmi_block *wblock = dev_to_wblock(dev);
834
835 if (add_uevent_var(env, format: "MODALIAS=wmi:%pUL", &wblock->gblock.guid))
836 return -ENOMEM;
837
838 if (add_uevent_var(env, format: "WMI_GUID=%pUL", &wblock->gblock.guid))
839 return -ENOMEM;
840
841 return 0;
842}
843
844static void wmi_dev_release(struct device *dev)
845{
846 struct wmi_block *wblock = dev_to_wblock(dev);
847
848 kfree(objp: wblock);
849}
850
851static int wmi_dev_match(struct device *dev, struct device_driver *driver)
852{
853 struct wmi_driver *wmi_driver = drv_to_wdrv(drv: driver);
854 struct wmi_block *wblock = dev_to_wblock(dev);
855 const struct wmi_device_id *id = wmi_driver->id_table;
856
857 if (id == NULL)
858 return 0;
859
860 while (*id->guid_string) {
861 if (guid_parse_and_compare(string: id->guid_string, guid: &wblock->gblock.guid))
862 return 1;
863
864 id++;
865 }
866
867 return 0;
868}
869
870static int wmi_dev_probe(struct device *dev)
871{
872 struct wmi_block *wblock = dev_to_wblock(dev);
873 struct wmi_driver *wdriver = drv_to_wdrv(drv: dev->driver);
874 int ret = 0;
875
876 /* Some older WMI drivers will break if instantiated multiple times,
877 * so they are blocked from probing WMI devices with a duplicated GUID.
878 *
879 * New WMI drivers should support being instantiated multiple times.
880 */
881 if (test_bit(WMI_GUID_DUPLICATED, &wblock->flags) && !wdriver->no_singleton) {
882 dev_warn(dev, "Legacy driver %s cannot be instantiated multiple times\n",
883 dev->driver->name);
884
885 return -ENODEV;
886 }
887
888 if (wdriver->notify) {
889 if (test_bit(WMI_NO_EVENT_DATA, &wblock->flags) && !wdriver->no_notify_data)
890 return -ENODEV;
891 }
892
893 if (ACPI_FAILURE(wmi_method_enable(wblock, true)))
894 dev_warn(dev, "failed to enable device -- probing anyway\n");
895
896 if (wdriver->probe) {
897 ret = wdriver->probe(dev_to_wdev(dev),
898 find_guid_context(wblock, wdriver));
899 if (ret) {
900 if (ACPI_FAILURE(wmi_method_enable(wblock, false)))
901 dev_warn(dev, "Failed to disable device\n");
902
903 return ret;
904 }
905 }
906
907 down_write(sem: &wblock->notify_lock);
908 wblock->driver_ready = true;
909 up_write(sem: &wblock->notify_lock);
910
911 return 0;
912}
913
914static void wmi_dev_remove(struct device *dev)
915{
916 struct wmi_block *wblock = dev_to_wblock(dev);
917 struct wmi_driver *wdriver = drv_to_wdrv(drv: dev->driver);
918
919 down_write(sem: &wblock->notify_lock);
920 wblock->driver_ready = false;
921 up_write(sem: &wblock->notify_lock);
922
923 if (wdriver->remove)
924 wdriver->remove(dev_to_wdev(dev));
925
926 if (ACPI_FAILURE(wmi_method_enable(wblock, false)))
927 dev_warn(dev, "failed to disable device\n");
928}
929
930static struct class wmi_bus_class = {
931 .name = "wmi_bus",
932};
933
934static const struct bus_type wmi_bus_type = {
935 .name = "wmi",
936 .dev_groups = wmi_groups,
937 .match = wmi_dev_match,
938 .uevent = wmi_dev_uevent,
939 .probe = wmi_dev_probe,
940 .remove = wmi_dev_remove,
941};
942
943static const struct device_type wmi_type_event = {
944 .name = "event",
945 .groups = wmi_event_groups,
946 .release = wmi_dev_release,
947};
948
949static const struct device_type wmi_type_method = {
950 .name = "method",
951 .groups = wmi_method_groups,
952 .release = wmi_dev_release,
953};
954
955static const struct device_type wmi_type_data = {
956 .name = "data",
957 .groups = wmi_data_groups,
958 .release = wmi_dev_release,
959};
960
961/*
962 * _WDG is a static list that is only parsed at startup,
963 * so it's safe to count entries without extra protection.
964 */
965static int guid_count(const guid_t *guid)
966{
967 struct wmi_block *wblock;
968 int count = 0;
969
970 list_for_each_entry(wblock, &wmi_block_list, list) {
971 if (guid_equal(u1: &wblock->gblock.guid, u2: guid))
972 count++;
973 }
974
975 return count;
976}
977
978static int wmi_create_device(struct device *wmi_bus_dev,
979 struct wmi_block *wblock,
980 struct acpi_device *device)
981{
982 char method[WMI_ACPI_METHOD_NAME_SIZE];
983 struct acpi_device_info *info;
984 acpi_handle method_handle;
985 acpi_status status;
986 uint count;
987
988 if (wblock->gblock.flags & ACPI_WMI_EVENT) {
989 wblock->dev.dev.type = &wmi_type_event;
990 goto out_init;
991 }
992
993 if (wblock->gblock.flags & ACPI_WMI_METHOD) {
994 get_acpi_method_name(wblock, method: 'M', buffer: method);
995 if (!acpi_has_method(handle: device->handle, name: method)) {
996 dev_warn(wmi_bus_dev,
997 FW_BUG "%s method block execution control method not found\n",
998 method);
999
1000 return -ENXIO;
1001 }
1002
1003 wblock->dev.dev.type = &wmi_type_method;
1004 goto out_init;
1005 }
1006
1007 /*
1008 * Data Block Query Control Method (WQxx by convention) is
1009 * required per the WMI documentation. If it is not present,
1010 * we ignore this data block.
1011 */
1012 get_acpi_method_name(wblock, method: 'Q', buffer: method);
1013 status = acpi_get_handle(parent: device->handle, pathname: method, ret_handle: &method_handle);
1014 if (ACPI_FAILURE(status)) {
1015 dev_warn(wmi_bus_dev,
1016 FW_BUG "%s data block query control method not found\n",
1017 method);
1018
1019 return -ENXIO;
1020 }
1021
1022 status = acpi_get_object_info(object: method_handle, return_buffer: &info);
1023 if (ACPI_FAILURE(status))
1024 return -EIO;
1025
1026 wblock->dev.dev.type = &wmi_type_data;
1027
1028 /*
1029 * The Microsoft documentation specifically states:
1030 *
1031 * Data blocks registered with only a single instance
1032 * can ignore the parameter.
1033 *
1034 * ACPICA will get mad at us if we call the method with the wrong number
1035 * of arguments, so check what our method expects. (On some Dell
1036 * laptops, WQxx may not be a method at all.)
1037 */
1038 if (info->type != ACPI_TYPE_METHOD || info->param_count == 0)
1039 set_bit(nr: WMI_READ_TAKES_NO_ARGS, addr: &wblock->flags);
1040
1041 kfree(objp: info);
1042
1043 get_acpi_method_name(wblock, method: 'S', buffer: method);
1044 if (acpi_has_method(handle: device->handle, name: method))
1045 wblock->dev.setable = true;
1046
1047 out_init:
1048 init_rwsem(&wblock->notify_lock);
1049 wblock->driver_ready = false;
1050 wblock->dev.dev.bus = &wmi_bus_type;
1051 wblock->dev.dev.parent = wmi_bus_dev;
1052
1053 count = guid_count(guid: &wblock->gblock.guid);
1054 if (count) {
1055 dev_set_name(dev: &wblock->dev.dev, name: "%pUL-%d", &wblock->gblock.guid, count);
1056 set_bit(nr: WMI_GUID_DUPLICATED, addr: &wblock->flags);
1057 } else {
1058 dev_set_name(dev: &wblock->dev.dev, name: "%pUL", &wblock->gblock.guid);
1059 }
1060
1061 device_initialize(dev: &wblock->dev.dev);
1062
1063 return 0;
1064}
1065
1066static int wmi_add_device(struct platform_device *pdev, struct wmi_device *wdev)
1067{
1068 struct device_link *link;
1069
1070 /*
1071 * Many aggregate WMI drivers do not use -EPROBE_DEFER when they
1072 * are unable to find a WMI device during probe, instead they require
1073 * all WMI devices associated with an platform device to become available
1074 * at once. This device link thus prevents WMI drivers from probing until
1075 * the associated platform device has finished probing (and has registered
1076 * all discovered WMI devices).
1077 */
1078
1079 link = device_link_add(consumer: &wdev->dev, supplier: &pdev->dev, DL_FLAG_AUTOREMOVE_SUPPLIER);
1080 if (!link)
1081 return -EINVAL;
1082
1083 return device_add(dev: &wdev->dev);
1084}
1085
1086/*
1087 * Parse the _WDG method for the GUID data blocks
1088 */
1089static int parse_wdg(struct device *wmi_bus_dev, struct platform_device *pdev)
1090{
1091 struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
1092 struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
1093 const struct guid_block *gblock;
1094 bool event_data_available;
1095 struct wmi_block *wblock;
1096 union acpi_object *obj;
1097 acpi_status status;
1098 u32 i, total;
1099 int retval;
1100
1101 status = acpi_evaluate_object(object: device->handle, pathname: "_WDG", NULL, return_object_buffer: &out);
1102 if (ACPI_FAILURE(status))
1103 return -ENXIO;
1104
1105 obj = out.pointer;
1106 if (!obj)
1107 return -ENXIO;
1108
1109 if (obj->type != ACPI_TYPE_BUFFER) {
1110 kfree(objp: obj);
1111 return -ENXIO;
1112 }
1113
1114 event_data_available = acpi_has_method(handle: device->handle, name: "_WED");
1115 gblock = (const struct guid_block *)obj->buffer.pointer;
1116 total = obj->buffer.length / sizeof(struct guid_block);
1117
1118 for (i = 0; i < total; i++) {
1119 if (!gblock[i].instance_count) {
1120 dev_info(wmi_bus_dev, FW_INFO "%pUL has zero instances\n", &gblock[i].guid);
1121 continue;
1122 }
1123
1124 wblock = kzalloc(size: sizeof(*wblock), GFP_KERNEL);
1125 if (!wblock)
1126 continue;
1127
1128 wblock->acpi_device = device;
1129 wblock->gblock = gblock[i];
1130 if (gblock[i].flags & ACPI_WMI_EVENT && !event_data_available)
1131 set_bit(nr: WMI_NO_EVENT_DATA, addr: &wblock->flags);
1132
1133 retval = wmi_create_device(wmi_bus_dev, wblock, device);
1134 if (retval) {
1135 kfree(objp: wblock);
1136 continue;
1137 }
1138
1139 list_add_tail(new: &wblock->list, head: &wmi_block_list);
1140
1141 retval = wmi_add_device(pdev, wdev: &wblock->dev);
1142 if (retval) {
1143 dev_err(wmi_bus_dev, "failed to register %pUL\n",
1144 &wblock->gblock.guid);
1145
1146 list_del(entry: &wblock->list);
1147 put_device(dev: &wblock->dev.dev);
1148 }
1149 }
1150
1151 kfree(objp: obj);
1152
1153 return 0;
1154}
1155
1156/*
1157 * WMI can have EmbeddedControl access regions. In which case, we just want to
1158 * hand these off to the EC driver.
1159 */
1160static acpi_status
1161acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
1162 u32 bits, u64 *value,
1163 void *handler_context, void *region_context)
1164{
1165 int result = 0;
1166 u8 temp = 0;
1167
1168 if ((address > 0xFF) || !value)
1169 return AE_BAD_PARAMETER;
1170
1171 if (function != ACPI_READ && function != ACPI_WRITE)
1172 return AE_BAD_PARAMETER;
1173
1174 if (bits != 8)
1175 return AE_BAD_PARAMETER;
1176
1177 if (function == ACPI_READ) {
1178 result = ec_read(addr: address, val: &temp);
1179 *value = temp;
1180 } else {
1181 temp = 0xff & *value;
1182 result = ec_write(addr: address, val: temp);
1183 }
1184
1185 switch (result) {
1186 case -EINVAL:
1187 return AE_BAD_PARAMETER;
1188 case -ENODEV:
1189 return AE_NOT_FOUND;
1190 case -ETIME:
1191 return AE_TIME;
1192 default:
1193 return AE_OK;
1194 }
1195}
1196
1197static int wmi_get_notify_data(struct wmi_block *wblock, union acpi_object **obj)
1198{
1199 struct acpi_buffer data = { ACPI_ALLOCATE_BUFFER, NULL };
1200 acpi_status status;
1201
1202 if (test_bit(WMI_NO_EVENT_DATA, &wblock->flags)) {
1203 *obj = NULL;
1204 return 0;
1205 }
1206
1207 status = get_event_data(wblock, out: &data);
1208 if (ACPI_FAILURE(status)) {
1209 dev_warn(&wblock->dev.dev, "Failed to get event data\n");
1210 return -EIO;
1211 }
1212
1213 *obj = data.pointer;
1214
1215 return 0;
1216}
1217
1218static void wmi_notify_driver(struct wmi_block *wblock, union acpi_object *obj)
1219{
1220 struct wmi_driver *driver = drv_to_wdrv(drv: wblock->dev.dev.driver);
1221
1222 if (!obj && !driver->no_notify_data) {
1223 dev_warn(&wblock->dev.dev, "Event contains no event data\n");
1224 return;
1225 }
1226
1227 if (driver->notify)
1228 driver->notify(&wblock->dev, obj);
1229}
1230
1231static int wmi_notify_device(struct device *dev, void *data)
1232{
1233 struct wmi_block *wblock = dev_to_wblock(dev);
1234 union acpi_object *obj;
1235 u32 *event = data;
1236 int ret;
1237
1238 if (!(wblock->gblock.flags & ACPI_WMI_EVENT && wblock->gblock.notify_id == *event))
1239 return 0;
1240
1241 down_read(sem: &wblock->notify_lock);
1242 /* The WMI driver notify handler conflicts with the legacy WMI handler.
1243 * Because of this the WMI driver notify handler takes precedence.
1244 */
1245 if (wblock->dev.dev.driver && wblock->driver_ready) {
1246 ret = wmi_get_notify_data(wblock, obj: &obj);
1247 if (ret >= 0) {
1248 wmi_notify_driver(wblock, obj);
1249 kfree(objp: obj);
1250 }
1251 } else {
1252 if (wblock->handler) {
1253 wblock->handler(*event, wblock->handler_data);
1254 } else {
1255 /* The ACPI WMI specification says that _WED should be
1256 * evaluated every time an notification is received, even
1257 * if no consumers are present.
1258 *
1259 * Some firmware implementations actually depend on this
1260 * by using a queue for events which will fill up if the
1261 * WMI driver core stops evaluating _WED due to missing
1262 * WMI event consumers.
1263 *
1264 * Because of this we need this seemingly useless call to
1265 * wmi_get_notify_data() which in turn evaluates _WED.
1266 */
1267 ret = wmi_get_notify_data(wblock, obj: &obj);
1268 if (ret >= 0)
1269 kfree(objp: obj);
1270 }
1271
1272 }
1273 up_read(sem: &wblock->notify_lock);
1274
1275 acpi_bus_generate_netlink_event("wmi", acpi_dev_name(adev: wblock->acpi_device), *event, 0);
1276
1277 return -EBUSY;
1278}
1279
1280static void acpi_wmi_notify_handler(acpi_handle handle, u32 event, void *context)
1281{
1282 struct device *wmi_bus_dev = context;
1283
1284 device_for_each_child(dev: wmi_bus_dev, data: &event, fn: wmi_notify_device);
1285}
1286
1287static int wmi_remove_device(struct device *dev, void *data)
1288{
1289 struct wmi_block *wblock = dev_to_wblock(dev);
1290
1291 list_del(entry: &wblock->list);
1292 device_unregister(dev);
1293
1294 return 0;
1295}
1296
1297static void acpi_wmi_remove(struct platform_device *device)
1298{
1299 struct device *wmi_bus_device = dev_get_drvdata(dev: &device->dev);
1300
1301 device_for_each_child_reverse(dev: wmi_bus_device, NULL, fn: wmi_remove_device);
1302}
1303
1304static void acpi_wmi_remove_notify_handler(void *data)
1305{
1306 struct acpi_device *acpi_device = data;
1307
1308 acpi_remove_notify_handler(device: acpi_device->handle, ACPI_ALL_NOTIFY, handler: acpi_wmi_notify_handler);
1309}
1310
1311static void acpi_wmi_remove_address_space_handler(void *data)
1312{
1313 struct acpi_device *acpi_device = data;
1314
1315 acpi_remove_address_space_handler(device: acpi_device->handle, ACPI_ADR_SPACE_EC,
1316 handler: &acpi_wmi_ec_space_handler);
1317}
1318
1319static void acpi_wmi_remove_bus_device(void *data)
1320{
1321 struct device *wmi_bus_dev = data;
1322
1323 device_unregister(dev: wmi_bus_dev);
1324}
1325
1326static int acpi_wmi_probe(struct platform_device *device)
1327{
1328 struct acpi_device *acpi_device;
1329 struct device *wmi_bus_dev;
1330 acpi_status status;
1331 int error;
1332
1333 acpi_device = ACPI_COMPANION(&device->dev);
1334 if (!acpi_device) {
1335 dev_err(&device->dev, "ACPI companion is missing\n");
1336 return -ENODEV;
1337 }
1338
1339 wmi_bus_dev = device_create(cls: &wmi_bus_class, parent: &device->dev, MKDEV(0, 0), NULL, fmt: "wmi_bus-%s",
1340 dev_name(dev: &device->dev));
1341 if (IS_ERR(ptr: wmi_bus_dev))
1342 return PTR_ERR(ptr: wmi_bus_dev);
1343
1344 error = devm_add_action_or_reset(&device->dev, acpi_wmi_remove_bus_device, wmi_bus_dev);
1345 if (error < 0)
1346 return error;
1347
1348 dev_set_drvdata(dev: &device->dev, data: wmi_bus_dev);
1349
1350 status = acpi_install_address_space_handler(device: acpi_device->handle,
1351 ACPI_ADR_SPACE_EC,
1352 handler: &acpi_wmi_ec_space_handler,
1353 NULL, NULL);
1354 if (ACPI_FAILURE(status)) {
1355 dev_err(&device->dev, "Error installing EC region handler\n");
1356 return -ENODEV;
1357 }
1358 error = devm_add_action_or_reset(&device->dev, acpi_wmi_remove_address_space_handler,
1359 acpi_device);
1360 if (error < 0)
1361 return error;
1362
1363 status = acpi_install_notify_handler(device: acpi_device->handle, ACPI_ALL_NOTIFY,
1364 handler: acpi_wmi_notify_handler, context: wmi_bus_dev);
1365 if (ACPI_FAILURE(status)) {
1366 dev_err(&device->dev, "Error installing notify handler\n");
1367 return -ENODEV;
1368 }
1369 error = devm_add_action_or_reset(&device->dev, acpi_wmi_remove_notify_handler,
1370 acpi_device);
1371 if (error < 0)
1372 return error;
1373
1374 error = parse_wdg(wmi_bus_dev, pdev: device);
1375 if (error) {
1376 dev_err(&device->dev, "Failed to parse _WDG method\n");
1377 return error;
1378 }
1379
1380 return 0;
1381}
1382
1383int __must_check __wmi_driver_register(struct wmi_driver *driver,
1384 struct module *owner)
1385{
1386 driver->driver.owner = owner;
1387 driver->driver.bus = &wmi_bus_type;
1388
1389 return driver_register(drv: &driver->driver);
1390}
1391EXPORT_SYMBOL(__wmi_driver_register);
1392
1393/**
1394 * wmi_driver_unregister() - Unregister a WMI driver
1395 * @driver: WMI driver to unregister
1396 *
1397 * Unregisters a WMI driver from the WMI bus.
1398 */
1399void wmi_driver_unregister(struct wmi_driver *driver)
1400{
1401 driver_unregister(drv: &driver->driver);
1402}
1403EXPORT_SYMBOL(wmi_driver_unregister);
1404
1405static struct platform_driver acpi_wmi_driver = {
1406 .driver = {
1407 .name = "acpi-wmi",
1408 .acpi_match_table = wmi_device_ids,
1409 },
1410 .probe = acpi_wmi_probe,
1411 .remove_new = acpi_wmi_remove,
1412};
1413
1414static int __init acpi_wmi_init(void)
1415{
1416 int error;
1417
1418 if (acpi_disabled)
1419 return -ENODEV;
1420
1421 error = class_register(class: &wmi_bus_class);
1422 if (error)
1423 return error;
1424
1425 error = bus_register(bus: &wmi_bus_type);
1426 if (error)
1427 goto err_unreg_class;
1428
1429 error = platform_driver_register(&acpi_wmi_driver);
1430 if (error) {
1431 pr_err("Error loading mapper\n");
1432 goto err_unreg_bus;
1433 }
1434
1435 return 0;
1436
1437err_unreg_bus:
1438 bus_unregister(bus: &wmi_bus_type);
1439
1440err_unreg_class:
1441 class_unregister(class: &wmi_bus_class);
1442
1443 return error;
1444}
1445
1446static void __exit acpi_wmi_exit(void)
1447{
1448 platform_driver_unregister(&acpi_wmi_driver);
1449 bus_unregister(bus: &wmi_bus_type);
1450 class_unregister(class: &wmi_bus_class);
1451}
1452
1453subsys_initcall_sync(acpi_wmi_init);
1454module_exit(acpi_wmi_exit);
1455

source code of linux/drivers/platform/x86/wmi.c