xref: /openbmc/linux/drivers/acpi/button.c (revision e149ca29)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  button.c - ACPI Button Driver
4  *
5  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
6  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
7  */
8 
9 #define pr_fmt(fmt) "ACPI: button: " fmt
10 
11 #include <linux/compiler.h>
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/types.h>
16 #include <linux/proc_fs.h>
17 #include <linux/seq_file.h>
18 #include <linux/input.h>
19 #include <linux/slab.h>
20 #include <linux/acpi.h>
21 #include <linux/dmi.h>
22 #include <acpi/button.h>
23 
24 #define PREFIX "ACPI: "
25 
26 #define ACPI_BUTTON_CLASS		"button"
27 #define ACPI_BUTTON_FILE_INFO		"info"
28 #define ACPI_BUTTON_FILE_STATE		"state"
29 #define ACPI_BUTTON_TYPE_UNKNOWN	0x00
30 #define ACPI_BUTTON_NOTIFY_STATUS	0x80
31 
32 #define ACPI_BUTTON_SUBCLASS_POWER	"power"
33 #define ACPI_BUTTON_DEVICE_NAME_POWER	"Power Button"
34 #define ACPI_BUTTON_TYPE_POWER		0x01
35 
36 #define ACPI_BUTTON_SUBCLASS_SLEEP	"sleep"
37 #define ACPI_BUTTON_DEVICE_NAME_SLEEP	"Sleep Button"
38 #define ACPI_BUTTON_TYPE_SLEEP		0x03
39 
40 #define ACPI_BUTTON_SUBCLASS_LID	"lid"
41 #define ACPI_BUTTON_DEVICE_NAME_LID	"Lid Switch"
42 #define ACPI_BUTTON_TYPE_LID		0x05
43 
44 enum {
45 	ACPI_BUTTON_LID_INIT_IGNORE,
46 	ACPI_BUTTON_LID_INIT_OPEN,
47 	ACPI_BUTTON_LID_INIT_METHOD,
48 	ACPI_BUTTON_LID_INIT_DISABLED,
49 };
50 
51 static const char * const lid_init_state_str[] = {
52 	[ACPI_BUTTON_LID_INIT_IGNORE]		= "ignore",
53 	[ACPI_BUTTON_LID_INIT_OPEN]		= "open",
54 	[ACPI_BUTTON_LID_INIT_METHOD]		= "method",
55 	[ACPI_BUTTON_LID_INIT_DISABLED]		= "disabled",
56 };
57 
58 #define _COMPONENT		ACPI_BUTTON_COMPONENT
59 ACPI_MODULE_NAME("button");
60 
61 MODULE_AUTHOR("Paul Diefenbaugh");
62 MODULE_DESCRIPTION("ACPI Button Driver");
63 MODULE_LICENSE("GPL");
64 
65 static const struct acpi_device_id button_device_ids[] = {
66 	{ACPI_BUTTON_HID_LID,    0},
67 	{ACPI_BUTTON_HID_SLEEP,  0},
68 	{ACPI_BUTTON_HID_SLEEPF, 0},
69 	{ACPI_BUTTON_HID_POWER,  0},
70 	{ACPI_BUTTON_HID_POWERF, 0},
71 	{"", 0},
72 };
73 MODULE_DEVICE_TABLE(acpi, button_device_ids);
74 
75 /* Please keep this list sorted alphabetically by vendor and model */
76 static const struct dmi_system_id dmi_lid_quirks[] = {
77 	{
78 		/*
79 		 * Acer Switch 10 SW5-012. _LID method messes with home and
80 		 * power button GPIO IRQ settings causing an interrupt storm on
81 		 * both GPIOs. This is unfixable without a DSDT override, so we
82 		 * have to disable the lid-switch functionality altogether :|
83 		 */
84 		.matches = {
85 			DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
86 			DMI_MATCH(DMI_PRODUCT_NAME, "Aspire SW5-012"),
87 		},
88 		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
89 	},
90 	{
91 		/*
92 		 * Asus T200TA, _LID keeps reporting closed after every second
93 		 * openening of the lid. Causing immediate re-suspend after
94 		 * opening every other open. Using LID_INIT_OPEN fixes this.
95 		 */
96 		.matches = {
97 			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
98 			DMI_MATCH(DMI_PRODUCT_NAME, "T200TA"),
99 		},
100 		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
101 	},
102 	{
103 		/* GP-electronic T701, _LID method points to a floating GPIO */
104 		.matches = {
105 			DMI_MATCH(DMI_SYS_VENDOR, "Insyde"),
106 			DMI_MATCH(DMI_PRODUCT_NAME, "T701"),
107 			DMI_MATCH(DMI_BIOS_VERSION, "BYT70A.YNCHENG.WIN.007"),
108 		},
109 		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
110 	},
111 	{
112 		/*
113 		 * Medion Akoya E2215T, notification of the LID device only
114 		 * happens on close, not on open and _LID always returns closed.
115 		 */
116 		.matches = {
117 			DMI_MATCH(DMI_SYS_VENDOR, "MEDION"),
118 			DMI_MATCH(DMI_PRODUCT_NAME, "E2215T MD60198"),
119 		},
120 		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
121 	},
122 	{
123 		/*
124 		 * Razer Blade Stealth 13 late 2019, notification of the LID device
125 		 * only happens on close, not on open and _LID always returns closed.
126 		 */
127 		.matches = {
128 			DMI_MATCH(DMI_SYS_VENDOR, "Razer"),
129 			DMI_MATCH(DMI_PRODUCT_NAME, "Razer Blade Stealth 13 Late 2019"),
130 		},
131 		.driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
132 	},
133 	{}
134 };
135 
136 static int acpi_button_add(struct acpi_device *device);
137 static int acpi_button_remove(struct acpi_device *device);
138 static void acpi_button_notify(struct acpi_device *device, u32 event);
139 
140 #ifdef CONFIG_PM_SLEEP
141 static int acpi_button_suspend(struct device *dev);
142 static int acpi_button_resume(struct device *dev);
143 #else
144 #define acpi_button_suspend NULL
145 #define acpi_button_resume NULL
146 #endif
147 static SIMPLE_DEV_PM_OPS(acpi_button_pm, acpi_button_suspend, acpi_button_resume);
148 
149 static struct acpi_driver acpi_button_driver = {
150 	.name = "button",
151 	.class = ACPI_BUTTON_CLASS,
152 	.ids = button_device_ids,
153 	.ops = {
154 		.add = acpi_button_add,
155 		.remove = acpi_button_remove,
156 		.notify = acpi_button_notify,
157 	},
158 	.drv.pm = &acpi_button_pm,
159 };
160 
161 struct acpi_button {
162 	unsigned int type;
163 	struct input_dev *input;
164 	char phys[32];			/* for input device */
165 	unsigned long pushed;
166 	int last_state;
167 	ktime_t last_time;
168 	bool suspended;
169 };
170 
171 static struct acpi_device *lid_device;
172 static long lid_init_state = -1;
173 
174 static unsigned long lid_report_interval __read_mostly = 500;
175 module_param(lid_report_interval, ulong, 0644);
176 MODULE_PARM_DESC(lid_report_interval, "Interval (ms) between lid key events");
177 
178 /* --------------------------------------------------------------------------
179                               FS Interface (/proc)
180    -------------------------------------------------------------------------- */
181 
182 static struct proc_dir_entry *acpi_button_dir;
183 static struct proc_dir_entry *acpi_lid_dir;
184 
185 static int acpi_lid_evaluate_state(struct acpi_device *device)
186 {
187 	unsigned long long lid_state;
188 	acpi_status status;
189 
190 	status = acpi_evaluate_integer(device->handle, "_LID", NULL, &lid_state);
191 	if (ACPI_FAILURE(status))
192 		return -ENODEV;
193 
194 	return lid_state ? 1 : 0;
195 }
196 
197 static int acpi_lid_notify_state(struct acpi_device *device, int state)
198 {
199 	struct acpi_button *button = acpi_driver_data(device);
200 	ktime_t next_report;
201 	bool do_update;
202 
203 	/*
204 	 * In lid_init_state=ignore mode, if user opens/closes lid
205 	 * frequently with "open" missing, and "last_time" is also updated
206 	 * frequently, "close" cannot be delivered to the userspace.
207 	 * So "last_time" is only updated after a timeout or an actual
208 	 * switch.
209 	 */
210 	if (lid_init_state != ACPI_BUTTON_LID_INIT_IGNORE ||
211 	    button->last_state != !!state)
212 		do_update = true;
213 	else
214 		do_update = false;
215 
216 	next_report = ktime_add(button->last_time,
217 				ms_to_ktime(lid_report_interval));
218 	if (button->last_state == !!state &&
219 	    ktime_after(ktime_get(), next_report)) {
220 		/* Complain the buggy firmware */
221 		pr_warn_once("The lid device is not compliant to SW_LID.\n");
222 
223 		/*
224 		 * Send the unreliable complement switch event:
225 		 *
226 		 * On most platforms, the lid device is reliable. However
227 		 * there are exceptions:
228 		 * 1. Platforms returning initial lid state as "close" by
229 		 *    default after booting/resuming:
230 		 *     https://bugzilla.kernel.org/show_bug.cgi?id=89211
231 		 *     https://bugzilla.kernel.org/show_bug.cgi?id=106151
232 		 * 2. Platforms never reporting "open" events:
233 		 *     https://bugzilla.kernel.org/show_bug.cgi?id=106941
234 		 * On these buggy platforms, the usage model of the ACPI
235 		 * lid device actually is:
236 		 * 1. The initial returning value of _LID may not be
237 		 *    reliable.
238 		 * 2. The open event may not be reliable.
239 		 * 3. The close event is reliable.
240 		 *
241 		 * But SW_LID is typed as input switch event, the input
242 		 * layer checks if the event is redundant. Hence if the
243 		 * state is not switched, the userspace cannot see this
244 		 * platform triggered reliable event. By inserting a
245 		 * complement switch event, it then is guaranteed that the
246 		 * platform triggered reliable one can always be seen by
247 		 * the userspace.
248 		 */
249 		if (lid_init_state == ACPI_BUTTON_LID_INIT_IGNORE) {
250 			do_update = true;
251 			/*
252 			 * Do generate complement switch event for "close"
253 			 * as "close" is reliable and wrong "open" won't
254 			 * trigger unexpected behaviors.
255 			 * Do not generate complement switch event for
256 			 * "open" as "open" is not reliable and wrong
257 			 * "close" will trigger unexpected behaviors.
258 			 */
259 			if (!state) {
260 				input_report_switch(button->input,
261 						    SW_LID, state);
262 				input_sync(button->input);
263 			}
264 		}
265 	}
266 	/* Send the platform triggered reliable event */
267 	if (do_update) {
268 		acpi_handle_debug(device->handle, "ACPI LID %s\n",
269 				  state ? "open" : "closed");
270 		input_report_switch(button->input, SW_LID, !state);
271 		input_sync(button->input);
272 		button->last_state = !!state;
273 		button->last_time = ktime_get();
274 	}
275 
276 	return 0;
277 }
278 
279 static int __maybe_unused acpi_button_state_seq_show(struct seq_file *seq,
280 						     void *offset)
281 {
282 	struct acpi_device *device = seq->private;
283 	int state;
284 
285 	state = acpi_lid_evaluate_state(device);
286 	seq_printf(seq, "state:      %s\n",
287 		   state < 0 ? "unsupported" : (state ? "open" : "closed"));
288 	return 0;
289 }
290 
291 static int acpi_button_add_fs(struct acpi_device *device)
292 {
293 	struct acpi_button *button = acpi_driver_data(device);
294 	struct proc_dir_entry *entry = NULL;
295 	int ret = 0;
296 
297 	/* procfs I/F for ACPI lid device only */
298 	if (button->type != ACPI_BUTTON_TYPE_LID)
299 		return 0;
300 
301 	if (acpi_button_dir || acpi_lid_dir) {
302 		printk(KERN_ERR PREFIX "More than one Lid device found!\n");
303 		return -EEXIST;
304 	}
305 
306 	/* create /proc/acpi/button */
307 	acpi_button_dir = proc_mkdir(ACPI_BUTTON_CLASS, acpi_root_dir);
308 	if (!acpi_button_dir)
309 		return -ENODEV;
310 
311 	/* create /proc/acpi/button/lid */
312 	acpi_lid_dir = proc_mkdir(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
313 	if (!acpi_lid_dir) {
314 		ret = -ENODEV;
315 		goto remove_button_dir;
316 	}
317 
318 	/* create /proc/acpi/button/lid/LID/ */
319 	acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device), acpi_lid_dir);
320 	if (!acpi_device_dir(device)) {
321 		ret = -ENODEV;
322 		goto remove_lid_dir;
323 	}
324 
325 	/* create /proc/acpi/button/lid/LID/state */
326 	entry = proc_create_single_data(ACPI_BUTTON_FILE_STATE, S_IRUGO,
327 			acpi_device_dir(device), acpi_button_state_seq_show,
328 			device);
329 	if (!entry) {
330 		ret = -ENODEV;
331 		goto remove_dev_dir;
332 	}
333 
334 done:
335 	return ret;
336 
337 remove_dev_dir:
338 	remove_proc_entry(acpi_device_bid(device),
339 			  acpi_lid_dir);
340 	acpi_device_dir(device) = NULL;
341 remove_lid_dir:
342 	remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
343 	acpi_lid_dir = NULL;
344 remove_button_dir:
345 	remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
346 	acpi_button_dir = NULL;
347 	goto done;
348 }
349 
350 static int acpi_button_remove_fs(struct acpi_device *device)
351 {
352 	struct acpi_button *button = acpi_driver_data(device);
353 
354 	if (button->type != ACPI_BUTTON_TYPE_LID)
355 		return 0;
356 
357 	remove_proc_entry(ACPI_BUTTON_FILE_STATE,
358 			  acpi_device_dir(device));
359 	remove_proc_entry(acpi_device_bid(device),
360 			  acpi_lid_dir);
361 	acpi_device_dir(device) = NULL;
362 	remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
363 	acpi_lid_dir = NULL;
364 	remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
365 	acpi_button_dir = NULL;
366 
367 	return 0;
368 }
369 
370 /* --------------------------------------------------------------------------
371                                 Driver Interface
372    -------------------------------------------------------------------------- */
373 int acpi_lid_open(void)
374 {
375 	if (!lid_device)
376 		return -ENODEV;
377 
378 	return acpi_lid_evaluate_state(lid_device);
379 }
380 EXPORT_SYMBOL(acpi_lid_open);
381 
382 static int acpi_lid_update_state(struct acpi_device *device,
383 				 bool signal_wakeup)
384 {
385 	int state;
386 
387 	state = acpi_lid_evaluate_state(device);
388 	if (state < 0)
389 		return state;
390 
391 	if (state && signal_wakeup)
392 		acpi_pm_wakeup_event(&device->dev);
393 
394 	return acpi_lid_notify_state(device, state);
395 }
396 
397 static void acpi_lid_initialize_state(struct acpi_device *device)
398 {
399 	switch (lid_init_state) {
400 	case ACPI_BUTTON_LID_INIT_OPEN:
401 		(void)acpi_lid_notify_state(device, 1);
402 		break;
403 	case ACPI_BUTTON_LID_INIT_METHOD:
404 		(void)acpi_lid_update_state(device, false);
405 		break;
406 	case ACPI_BUTTON_LID_INIT_IGNORE:
407 	default:
408 		break;
409 	}
410 }
411 
412 static void acpi_button_notify(struct acpi_device *device, u32 event)
413 {
414 	struct acpi_button *button = acpi_driver_data(device);
415 	struct input_dev *input;
416 	int users;
417 
418 	switch (event) {
419 	case ACPI_FIXED_HARDWARE_EVENT:
420 		event = ACPI_BUTTON_NOTIFY_STATUS;
421 		/* fall through */
422 	case ACPI_BUTTON_NOTIFY_STATUS:
423 		input = button->input;
424 		if (button->type == ACPI_BUTTON_TYPE_LID) {
425 			mutex_lock(&button->input->mutex);
426 			users = button->input->users;
427 			mutex_unlock(&button->input->mutex);
428 			if (users)
429 				acpi_lid_update_state(device, true);
430 		} else {
431 			int keycode;
432 
433 			acpi_pm_wakeup_event(&device->dev);
434 			if (button->suspended)
435 				break;
436 
437 			keycode = test_bit(KEY_SLEEP, input->keybit) ?
438 						KEY_SLEEP : KEY_POWER;
439 			input_report_key(input, keycode, 1);
440 			input_sync(input);
441 			input_report_key(input, keycode, 0);
442 			input_sync(input);
443 
444 			acpi_bus_generate_netlink_event(
445 					device->pnp.device_class,
446 					dev_name(&device->dev),
447 					event, ++button->pushed);
448 		}
449 		break;
450 	default:
451 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
452 				  "Unsupported event [0x%x]\n", event));
453 		break;
454 	}
455 }
456 
457 #ifdef CONFIG_PM_SLEEP
458 static int acpi_button_suspend(struct device *dev)
459 {
460 	struct acpi_device *device = to_acpi_device(dev);
461 	struct acpi_button *button = acpi_driver_data(device);
462 
463 	button->suspended = true;
464 	return 0;
465 }
466 
467 static int acpi_button_resume(struct device *dev)
468 {
469 	struct acpi_device *device = to_acpi_device(dev);
470 	struct acpi_button *button = acpi_driver_data(device);
471 
472 	button->suspended = false;
473 	if (button->type == ACPI_BUTTON_TYPE_LID && button->input->users) {
474 		button->last_state = !!acpi_lid_evaluate_state(device);
475 		button->last_time = ktime_get();
476 		acpi_lid_initialize_state(device);
477 	}
478 	return 0;
479 }
480 #endif
481 
482 static int acpi_lid_input_open(struct input_dev *input)
483 {
484 	struct acpi_device *device = input_get_drvdata(input);
485 	struct acpi_button *button = acpi_driver_data(device);
486 
487 	button->last_state = !!acpi_lid_evaluate_state(device);
488 	button->last_time = ktime_get();
489 	acpi_lid_initialize_state(device);
490 
491 	return 0;
492 }
493 
494 static int acpi_button_add(struct acpi_device *device)
495 {
496 	struct acpi_button *button;
497 	struct input_dev *input;
498 	const char *hid = acpi_device_hid(device);
499 	char *name, *class;
500 	int error;
501 
502 	if (!strcmp(hid, ACPI_BUTTON_HID_LID) &&
503 	     lid_init_state == ACPI_BUTTON_LID_INIT_DISABLED)
504 		return -ENODEV;
505 
506 	button = kzalloc(sizeof(struct acpi_button), GFP_KERNEL);
507 	if (!button)
508 		return -ENOMEM;
509 
510 	device->driver_data = button;
511 
512 	button->input = input = input_allocate_device();
513 	if (!input) {
514 		error = -ENOMEM;
515 		goto err_free_button;
516 	}
517 
518 	name = acpi_device_name(device);
519 	class = acpi_device_class(device);
520 
521 	if (!strcmp(hid, ACPI_BUTTON_HID_POWER) ||
522 	    !strcmp(hid, ACPI_BUTTON_HID_POWERF)) {
523 		button->type = ACPI_BUTTON_TYPE_POWER;
524 		strcpy(name, ACPI_BUTTON_DEVICE_NAME_POWER);
525 		sprintf(class, "%s/%s",
526 			ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_POWER);
527 	} else if (!strcmp(hid, ACPI_BUTTON_HID_SLEEP) ||
528 		   !strcmp(hid, ACPI_BUTTON_HID_SLEEPF)) {
529 		button->type = ACPI_BUTTON_TYPE_SLEEP;
530 		strcpy(name, ACPI_BUTTON_DEVICE_NAME_SLEEP);
531 		sprintf(class, "%s/%s",
532 			ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_SLEEP);
533 	} else if (!strcmp(hid, ACPI_BUTTON_HID_LID)) {
534 		button->type = ACPI_BUTTON_TYPE_LID;
535 		strcpy(name, ACPI_BUTTON_DEVICE_NAME_LID);
536 		sprintf(class, "%s/%s",
537 			ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_LID);
538 		input->open = acpi_lid_input_open;
539 	} else {
540 		printk(KERN_ERR PREFIX "Unsupported hid [%s]\n", hid);
541 		error = -ENODEV;
542 		goto err_free_input;
543 	}
544 
545 	error = acpi_button_add_fs(device);
546 	if (error)
547 		goto err_free_input;
548 
549 	snprintf(button->phys, sizeof(button->phys), "%s/button/input0", hid);
550 
551 	input->name = name;
552 	input->phys = button->phys;
553 	input->id.bustype = BUS_HOST;
554 	input->id.product = button->type;
555 	input->dev.parent = &device->dev;
556 
557 	switch (button->type) {
558 	case ACPI_BUTTON_TYPE_POWER:
559 		input_set_capability(input, EV_KEY, KEY_POWER);
560 		break;
561 
562 	case ACPI_BUTTON_TYPE_SLEEP:
563 		input_set_capability(input, EV_KEY, KEY_SLEEP);
564 		break;
565 
566 	case ACPI_BUTTON_TYPE_LID:
567 		input_set_capability(input, EV_SW, SW_LID);
568 		break;
569 	}
570 
571 	input_set_drvdata(input, device);
572 	error = input_register_device(input);
573 	if (error)
574 		goto err_remove_fs;
575 	if (button->type == ACPI_BUTTON_TYPE_LID) {
576 		/*
577 		 * This assumes there's only one lid device, or if there are
578 		 * more we only care about the last one...
579 		 */
580 		lid_device = device;
581 	}
582 
583 	device_init_wakeup(&device->dev, true);
584 	printk(KERN_INFO PREFIX "%s [%s]\n", name, acpi_device_bid(device));
585 	return 0;
586 
587  err_remove_fs:
588 	acpi_button_remove_fs(device);
589  err_free_input:
590 	input_free_device(input);
591  err_free_button:
592 	kfree(button);
593 	return error;
594 }
595 
596 static int acpi_button_remove(struct acpi_device *device)
597 {
598 	struct acpi_button *button = acpi_driver_data(device);
599 
600 	acpi_button_remove_fs(device);
601 	input_unregister_device(button->input);
602 	kfree(button);
603 	return 0;
604 }
605 
606 static int param_set_lid_init_state(const char *val,
607 				    const struct kernel_param *kp)
608 {
609 	int i;
610 
611 	i = sysfs_match_string(lid_init_state_str, val);
612 	if (i < 0)
613 		return i;
614 
615 	lid_init_state = i;
616 	pr_info("Initial lid state set to '%s'\n", lid_init_state_str[i]);
617 	return 0;
618 }
619 
620 static int param_get_lid_init_state(char *buf, const struct kernel_param *kp)
621 {
622 	int i, c = 0;
623 
624 	for (i = 0; i < ARRAY_SIZE(lid_init_state_str); i++)
625 		if (i == lid_init_state)
626 			c += sprintf(buf + c, "[%s] ", lid_init_state_str[i]);
627 		else
628 			c += sprintf(buf + c, "%s ", lid_init_state_str[i]);
629 
630 	buf[c - 1] = '\n'; /* Replace the final space with a newline */
631 
632 	return c;
633 }
634 
635 module_param_call(lid_init_state,
636 		  param_set_lid_init_state, param_get_lid_init_state,
637 		  NULL, 0644);
638 MODULE_PARM_DESC(lid_init_state, "Behavior for reporting LID initial state");
639 
640 static int acpi_button_register_driver(struct acpi_driver *driver)
641 {
642 	const struct dmi_system_id *dmi_id;
643 
644 	if (lid_init_state == -1) {
645 		dmi_id = dmi_first_match(dmi_lid_quirks);
646 		if (dmi_id)
647 			lid_init_state = (long)dmi_id->driver_data;
648 		else
649 			lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
650 	}
651 
652 	/*
653 	 * Modules such as nouveau.ko and i915.ko have a link time dependency
654 	 * on acpi_lid_open(), and would therefore not be loadable on ACPI
655 	 * capable kernels booted in non-ACPI mode if the return value of
656 	 * acpi_bus_register_driver() is returned from here with ACPI disabled
657 	 * when this driver is built as a module.
658 	 */
659 	if (acpi_disabled)
660 		return 0;
661 
662 	return acpi_bus_register_driver(driver);
663 }
664 
665 static void acpi_button_unregister_driver(struct acpi_driver *driver)
666 {
667 	if (!acpi_disabled)
668 		acpi_bus_unregister_driver(driver);
669 }
670 
671 module_driver(acpi_button_driver, acpi_button_register_driver,
672 	       acpi_button_unregister_driver);
673