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 ACPI_BUTTON_CLASS "button"
25#define ACPI_BUTTON_FILE_STATE "state"
26#define ACPI_BUTTON_TYPE_UNKNOWN 0x00
27#define ACPI_BUTTON_NOTIFY_STATUS 0x80
28
29#define ACPI_BUTTON_SUBCLASS_POWER "power"
30#define ACPI_BUTTON_DEVICE_NAME_POWER "Power Button"
31#define ACPI_BUTTON_TYPE_POWER 0x01
32
33#define ACPI_BUTTON_SUBCLASS_SLEEP "sleep"
34#define ACPI_BUTTON_DEVICE_NAME_SLEEP "Sleep Button"
35#define ACPI_BUTTON_TYPE_SLEEP 0x03
36
37#define ACPI_BUTTON_SUBCLASS_LID "lid"
38#define ACPI_BUTTON_DEVICE_NAME_LID "Lid Switch"
39#define ACPI_BUTTON_TYPE_LID 0x05
40
41enum {
42 ACPI_BUTTON_LID_INIT_IGNORE,
43 ACPI_BUTTON_LID_INIT_OPEN,
44 ACPI_BUTTON_LID_INIT_METHOD,
45 ACPI_BUTTON_LID_INIT_DISABLED,
46};
47
48static const char * const lid_init_state_str[] = {
49 [ACPI_BUTTON_LID_INIT_IGNORE] = "ignore",
50 [ACPI_BUTTON_LID_INIT_OPEN] = "open",
51 [ACPI_BUTTON_LID_INIT_METHOD] = "method",
52 [ACPI_BUTTON_LID_INIT_DISABLED] = "disabled",
53};
54
55MODULE_AUTHOR("Paul Diefenbaugh");
56MODULE_DESCRIPTION("ACPI Button Driver");
57MODULE_LICENSE("GPL");
58
59static const struct acpi_device_id button_device_ids[] = {
60 {ACPI_BUTTON_HID_LID, 0},
61 {ACPI_BUTTON_HID_SLEEP, 0},
62 {ACPI_BUTTON_HID_SLEEPF, 0},
63 {ACPI_BUTTON_HID_POWER, 0},
64 {ACPI_BUTTON_HID_POWERF, 0},
65 {"", 0},
66};
67MODULE_DEVICE_TABLE(acpi, button_device_ids);
68
69/* Please keep this list sorted alphabetically by vendor and model */
70static const struct dmi_system_id dmi_lid_quirks[] = {
71 {
72 /* GP-electronic T701, _LID method points to a floating GPIO */
73 .matches = {
74 DMI_MATCH(DMI_SYS_VENDOR, "Insyde"),
75 DMI_MATCH(DMI_PRODUCT_NAME, "T701"),
76 DMI_MATCH(DMI_BIOS_VERSION, "BYT70A.YNCHENG.WIN.007"),
77 },
78 .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
79 },
80 {
81 /* Nextbook Ares 8A tablet, _LID device always reports lid closed */
82 .matches = {
83 DMI_MATCH(DMI_SYS_VENDOR, "Insyde"),
84 DMI_MATCH(DMI_PRODUCT_NAME, "CherryTrail"),
85 DMI_MATCH(DMI_BIOS_VERSION, "M882"),
86 },
87 .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
88 },
89 {
90 /*
91 * Lenovo Yoga 9 14ITL5, initial notification of the LID device
92 * never happens.
93 */
94 .matches = {
95 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
96 DMI_MATCH(DMI_PRODUCT_NAME, "82BG"),
97 },
98 .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
99 },
100 {
101 /*
102 * Medion Akoya E2215T, notification of the LID device only
103 * happens on close, not on open and _LID always returns closed.
104 */
105 .matches = {
106 DMI_MATCH(DMI_SYS_VENDOR, "MEDION"),
107 DMI_MATCH(DMI_PRODUCT_NAME, "E2215T"),
108 },
109 .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
110 },
111 {
112 /*
113 * Medion Akoya E2228T, 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, "E2228T"),
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
136static int acpi_button_add(struct acpi_device *device);
137static void acpi_button_remove(struct acpi_device *device);
138
139#ifdef CONFIG_PM_SLEEP
140static int acpi_button_suspend(struct device *dev);
141static int acpi_button_resume(struct device *dev);
142#else
143#define acpi_button_suspend NULL
144#define acpi_button_resume NULL
145#endif
146static SIMPLE_DEV_PM_OPS(acpi_button_pm, acpi_button_suspend, acpi_button_resume);
147
148static struct acpi_driver acpi_button_driver = {
149 .name = "button",
150 .class = ACPI_BUTTON_CLASS,
151 .ids = button_device_ids,
152 .ops = {
153 .add = acpi_button_add,
154 .remove = acpi_button_remove,
155 },
156 .drv.pm = &acpi_button_pm,
157};
158
159struct acpi_button {
160 unsigned int type;
161 struct input_dev *input;
162 char phys[32]; /* for input device */
163 unsigned long pushed;
164 int last_state;
165 ktime_t last_time;
166 bool suspended;
167 bool lid_state_initialized;
168};
169
170static struct acpi_device *lid_device;
171static long lid_init_state = -1;
172
173static unsigned long lid_report_interval __read_mostly = 500;
174module_param(lid_report_interval, ulong, 0644);
175MODULE_PARM_DESC(lid_report_interval, "Interval (ms) between lid key events");
176
177/* FS Interface (/proc) */
178static struct proc_dir_entry *acpi_button_dir;
179static struct proc_dir_entry *acpi_lid_dir;
180
181static int acpi_lid_evaluate_state(struct acpi_device *device)
182{
183 unsigned long long lid_state;
184 acpi_status status;
185
186 status = acpi_evaluate_integer(handle: device->handle, pathname: "_LID", NULL, data: &lid_state);
187 if (ACPI_FAILURE(status))
188 return -ENODEV;
189
190 return lid_state ? 1 : 0;
191}
192
193static int acpi_lid_notify_state(struct acpi_device *device, int state)
194{
195 struct acpi_button *button = acpi_driver_data(d: device);
196 ktime_t next_report;
197 bool do_update;
198
199 /*
200 * In lid_init_state=ignore mode, if user opens/closes lid
201 * frequently with "open" missing, and "last_time" is also updated
202 * frequently, "close" cannot be delivered to the userspace.
203 * So "last_time" is only updated after a timeout or an actual
204 * switch.
205 */
206 if (lid_init_state != ACPI_BUTTON_LID_INIT_IGNORE ||
207 button->last_state != !!state)
208 do_update = true;
209 else
210 do_update = false;
211
212 next_report = ktime_add(button->last_time,
213 ms_to_ktime(lid_report_interval));
214 if (button->last_state == !!state &&
215 ktime_after(cmp1: ktime_get(), cmp2: next_report)) {
216 /* Complain the buggy firmware */
217 pr_warn_once("The lid device is not compliant to SW_LID.\n");
218
219 /*
220 * Send the unreliable complement switch event:
221 *
222 * On most platforms, the lid device is reliable. However
223 * there are exceptions:
224 * 1. Platforms returning initial lid state as "close" by
225 * default after booting/resuming:
226 * https://bugzilla.kernel.org/show_bug.cgi?id=89211
227 * https://bugzilla.kernel.org/show_bug.cgi?id=106151
228 * 2. Platforms never reporting "open" events:
229 * https://bugzilla.kernel.org/show_bug.cgi?id=106941
230 * On these buggy platforms, the usage model of the ACPI
231 * lid device actually is:
232 * 1. The initial returning value of _LID may not be
233 * reliable.
234 * 2. The open event may not be reliable.
235 * 3. The close event is reliable.
236 *
237 * But SW_LID is typed as input switch event, the input
238 * layer checks if the event is redundant. Hence if the
239 * state is not switched, the userspace cannot see this
240 * platform triggered reliable event. By inserting a
241 * complement switch event, it then is guaranteed that the
242 * platform triggered reliable one can always be seen by
243 * the userspace.
244 */
245 if (lid_init_state == ACPI_BUTTON_LID_INIT_IGNORE) {
246 do_update = true;
247 /*
248 * Do generate complement switch event for "close"
249 * as "close" is reliable and wrong "open" won't
250 * trigger unexpected behaviors.
251 * Do not generate complement switch event for
252 * "open" as "open" is not reliable and wrong
253 * "close" will trigger unexpected behaviors.
254 */
255 if (!state) {
256 input_report_switch(dev: button->input,
257 SW_LID, value: state);
258 input_sync(dev: button->input);
259 }
260 }
261 }
262 /* Send the platform triggered reliable event */
263 if (do_update) {
264 acpi_handle_debug(device->handle, "ACPI LID %s\n",
265 state ? "open" : "closed");
266 input_report_switch(dev: button->input, SW_LID, value: !state);
267 input_sync(dev: button->input);
268 button->last_state = !!state;
269 button->last_time = ktime_get();
270 }
271
272 return 0;
273}
274
275static int __maybe_unused acpi_button_state_seq_show(struct seq_file *seq,
276 void *offset)
277{
278 struct acpi_device *device = seq->private;
279 int state;
280
281 state = acpi_lid_evaluate_state(device);
282 seq_printf(m: seq, fmt: "state: %s\n",
283 state < 0 ? "unsupported" : (state ? "open" : "closed"));
284 return 0;
285}
286
287static int acpi_button_add_fs(struct acpi_device *device)
288{
289 struct acpi_button *button = acpi_driver_data(d: device);
290 struct proc_dir_entry *entry = NULL;
291 int ret = 0;
292
293 /* procfs I/F for ACPI lid device only */
294 if (button->type != ACPI_BUTTON_TYPE_LID)
295 return 0;
296
297 if (acpi_button_dir || acpi_lid_dir) {
298 pr_info("More than one Lid device found!\n");
299 return -EEXIST;
300 }
301
302 /* create /proc/acpi/button */
303 acpi_button_dir = proc_mkdir(ACPI_BUTTON_CLASS, acpi_root_dir);
304 if (!acpi_button_dir)
305 return -ENODEV;
306
307 /* create /proc/acpi/button/lid */
308 acpi_lid_dir = proc_mkdir(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
309 if (!acpi_lid_dir) {
310 ret = -ENODEV;
311 goto remove_button_dir;
312 }
313
314 /* create /proc/acpi/button/lid/LID/ */
315 acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device), acpi_lid_dir);
316 if (!acpi_device_dir(device)) {
317 ret = -ENODEV;
318 goto remove_lid_dir;
319 }
320
321 /* create /proc/acpi/button/lid/LID/state */
322 entry = proc_create_single_data(ACPI_BUTTON_FILE_STATE, S_IRUGO,
323 acpi_device_dir(device), show: acpi_button_state_seq_show,
324 data: device);
325 if (!entry) {
326 ret = -ENODEV;
327 goto remove_dev_dir;
328 }
329
330done:
331 return ret;
332
333remove_dev_dir:
334 remove_proc_entry(acpi_device_bid(device),
335 acpi_lid_dir);
336 acpi_device_dir(device) = NULL;
337remove_lid_dir:
338 remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
339 acpi_lid_dir = NULL;
340remove_button_dir:
341 remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
342 acpi_button_dir = NULL;
343 goto done;
344}
345
346static int acpi_button_remove_fs(struct acpi_device *device)
347{
348 struct acpi_button *button = acpi_driver_data(d: device);
349
350 if (button->type != ACPI_BUTTON_TYPE_LID)
351 return 0;
352
353 remove_proc_entry(ACPI_BUTTON_FILE_STATE,
354 acpi_device_dir(device));
355 remove_proc_entry(acpi_device_bid(device),
356 acpi_lid_dir);
357 acpi_device_dir(device) = NULL;
358 remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
359 acpi_lid_dir = NULL;
360 remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
361 acpi_button_dir = NULL;
362
363 return 0;
364}
365
366/* Driver Interface */
367int acpi_lid_open(void)
368{
369 if (!lid_device)
370 return -ENODEV;
371
372 return acpi_lid_evaluate_state(device: lid_device);
373}
374EXPORT_SYMBOL(acpi_lid_open);
375
376static int acpi_lid_update_state(struct acpi_device *device,
377 bool signal_wakeup)
378{
379 int state;
380
381 state = acpi_lid_evaluate_state(device);
382 if (state < 0)
383 return state;
384
385 if (state && signal_wakeup)
386 acpi_pm_wakeup_event(dev: &device->dev);
387
388 return acpi_lid_notify_state(device, state);
389}
390
391static void acpi_lid_initialize_state(struct acpi_device *device)
392{
393 struct acpi_button *button = acpi_driver_data(d: device);
394
395 switch (lid_init_state) {
396 case ACPI_BUTTON_LID_INIT_OPEN:
397 (void)acpi_lid_notify_state(device, state: 1);
398 break;
399 case ACPI_BUTTON_LID_INIT_METHOD:
400 (void)acpi_lid_update_state(device, signal_wakeup: false);
401 break;
402 case ACPI_BUTTON_LID_INIT_IGNORE:
403 default:
404 break;
405 }
406
407 button->lid_state_initialized = true;
408}
409
410static void acpi_lid_notify(acpi_handle handle, u32 event, void *data)
411{
412 struct acpi_device *device = data;
413 struct acpi_button *button;
414
415 if (event != ACPI_BUTTON_NOTIFY_STATUS) {
416 acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
417 event);
418 return;
419 }
420
421 button = acpi_driver_data(d: device);
422 if (!button->lid_state_initialized)
423 return;
424
425 acpi_lid_update_state(device, signal_wakeup: true);
426}
427
428static void acpi_button_notify(acpi_handle handle, u32 event, void *data)
429{
430 struct acpi_device *device = data;
431 struct acpi_button *button;
432 struct input_dev *input;
433 int keycode;
434
435 if (event != ACPI_BUTTON_NOTIFY_STATUS) {
436 acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
437 event);
438 return;
439 }
440
441 acpi_pm_wakeup_event(dev: &device->dev);
442
443 button = acpi_driver_data(d: device);
444 if (button->suspended)
445 return;
446
447 input = button->input;
448 keycode = test_bit(KEY_SLEEP, input->keybit) ? KEY_SLEEP : KEY_POWER;
449
450 input_report_key(dev: input, code: keycode, value: 1);
451 input_sync(dev: input);
452 input_report_key(dev: input, code: keycode, value: 0);
453 input_sync(dev: input);
454
455 acpi_bus_generate_netlink_event(device->pnp.device_class,
456 dev_name(dev: &device->dev),
457 event, ++button->pushed);
458}
459
460static void acpi_button_notify_run(void *data)
461{
462 acpi_button_notify(NULL, ACPI_BUTTON_NOTIFY_STATUS, data);
463}
464
465static u32 acpi_button_event(void *data)
466{
467 acpi_os_execute(type: OSL_NOTIFY_HANDLER, function: acpi_button_notify_run, context: data);
468 return ACPI_INTERRUPT_HANDLED;
469}
470
471#ifdef CONFIG_PM_SLEEP
472static int acpi_button_suspend(struct device *dev)
473{
474 struct acpi_device *device = to_acpi_device(dev);
475 struct acpi_button *button = acpi_driver_data(d: device);
476
477 button->suspended = true;
478 return 0;
479}
480
481static int acpi_button_resume(struct device *dev)
482{
483 struct acpi_device *device = to_acpi_device(dev);
484 struct acpi_button *button = acpi_driver_data(d: device);
485
486 button->suspended = false;
487 if (button->type == ACPI_BUTTON_TYPE_LID) {
488 button->last_state = !!acpi_lid_evaluate_state(device);
489 button->last_time = ktime_get();
490 acpi_lid_initialize_state(device);
491 }
492 return 0;
493}
494#endif
495
496static int acpi_lid_input_open(struct input_dev *input)
497{
498 struct acpi_device *device = input_get_drvdata(dev: input);
499 struct acpi_button *button = acpi_driver_data(d: device);
500
501 button->last_state = !!acpi_lid_evaluate_state(device);
502 button->last_time = ktime_get();
503 acpi_lid_initialize_state(device);
504
505 return 0;
506}
507
508static int acpi_button_add(struct acpi_device *device)
509{
510 acpi_notify_handler handler;
511 struct acpi_button *button;
512 struct input_dev *input;
513 const char *hid = acpi_device_hid(device);
514 acpi_status status;
515 char *name, *class;
516 int error = 0;
517
518 if (!strcmp(hid, ACPI_BUTTON_HID_LID) &&
519 lid_init_state == ACPI_BUTTON_LID_INIT_DISABLED)
520 return -ENODEV;
521
522 button = kzalloc(size: sizeof(struct acpi_button), GFP_KERNEL);
523 if (!button)
524 return -ENOMEM;
525
526 device->driver_data = button;
527
528 button->input = input = input_allocate_device();
529 if (!input) {
530 error = -ENOMEM;
531 goto err_free_button;
532 }
533
534 name = acpi_device_name(device);
535 class = acpi_device_class(device);
536
537 if (!strcmp(hid, ACPI_BUTTON_HID_POWER) ||
538 !strcmp(hid, ACPI_BUTTON_HID_POWERF)) {
539 button->type = ACPI_BUTTON_TYPE_POWER;
540 handler = acpi_button_notify;
541 strcpy(p: name, ACPI_BUTTON_DEVICE_NAME_POWER);
542 sprintf(buf: class, fmt: "%s/%s",
543 ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_POWER);
544 } else if (!strcmp(hid, ACPI_BUTTON_HID_SLEEP) ||
545 !strcmp(hid, ACPI_BUTTON_HID_SLEEPF)) {
546 button->type = ACPI_BUTTON_TYPE_SLEEP;
547 handler = acpi_button_notify;
548 strcpy(p: name, ACPI_BUTTON_DEVICE_NAME_SLEEP);
549 sprintf(buf: class, fmt: "%s/%s",
550 ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_SLEEP);
551 } else if (!strcmp(hid, ACPI_BUTTON_HID_LID)) {
552 button->type = ACPI_BUTTON_TYPE_LID;
553 handler = acpi_lid_notify;
554 strcpy(p: name, ACPI_BUTTON_DEVICE_NAME_LID);
555 sprintf(buf: class, fmt: "%s/%s",
556 ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_LID);
557 input->open = acpi_lid_input_open;
558 } else {
559 pr_info("Unsupported hid [%s]\n", hid);
560 error = -ENODEV;
561 }
562
563 if (!error)
564 error = acpi_button_add_fs(device);
565
566 if (error) {
567 input_free_device(dev: input);
568 goto err_free_button;
569 }
570
571 snprintf(buf: button->phys, size: sizeof(button->phys), fmt: "%s/button/input0", hid);
572
573 input->name = name;
574 input->phys = button->phys;
575 input->id.bustype = BUS_HOST;
576 input->id.product = button->type;
577 input->dev.parent = &device->dev;
578
579 switch (button->type) {
580 case ACPI_BUTTON_TYPE_POWER:
581 input_set_capability(dev: input, EV_KEY, KEY_POWER);
582 break;
583
584 case ACPI_BUTTON_TYPE_SLEEP:
585 input_set_capability(dev: input, EV_KEY, KEY_SLEEP);
586 break;
587
588 case ACPI_BUTTON_TYPE_LID:
589 input_set_capability(dev: input, EV_SW, SW_LID);
590 break;
591 }
592
593 input_set_drvdata(dev: input, data: device);
594 error = input_register_device(input);
595 if (error)
596 goto err_remove_fs;
597
598 switch (device->device_type) {
599 case ACPI_BUS_TYPE_POWER_BUTTON:
600 status = acpi_install_fixed_event_handler(ACPI_EVENT_POWER_BUTTON,
601 handler: acpi_button_event,
602 context: device);
603 break;
604 case ACPI_BUS_TYPE_SLEEP_BUTTON:
605 status = acpi_install_fixed_event_handler(ACPI_EVENT_SLEEP_BUTTON,
606 handler: acpi_button_event,
607 context: device);
608 break;
609 default:
610 status = acpi_install_notify_handler(device: device->handle,
611 ACPI_DEVICE_NOTIFY, handler,
612 context: device);
613 break;
614 }
615 if (ACPI_FAILURE(status)) {
616 error = -ENODEV;
617 goto err_input_unregister;
618 }
619
620 if (button->type == ACPI_BUTTON_TYPE_LID) {
621 /*
622 * This assumes there's only one lid device, or if there are
623 * more we only care about the last one...
624 */
625 lid_device = device;
626 }
627
628 device_init_wakeup(dev: &device->dev, enable: true);
629 pr_info("%s [%s]\n", name, acpi_device_bid(device));
630 return 0;
631
632err_input_unregister:
633 input_unregister_device(input);
634err_remove_fs:
635 acpi_button_remove_fs(device);
636err_free_button:
637 kfree(objp: button);
638 return error;
639}
640
641static void acpi_button_remove(struct acpi_device *device)
642{
643 struct acpi_button *button = acpi_driver_data(d: device);
644
645 switch (device->device_type) {
646 case ACPI_BUS_TYPE_POWER_BUTTON:
647 acpi_remove_fixed_event_handler(ACPI_EVENT_POWER_BUTTON,
648 handler: acpi_button_event);
649 break;
650 case ACPI_BUS_TYPE_SLEEP_BUTTON:
651 acpi_remove_fixed_event_handler(ACPI_EVENT_SLEEP_BUTTON,
652 handler: acpi_button_event);
653 break;
654 default:
655 acpi_remove_notify_handler(device: device->handle, ACPI_DEVICE_NOTIFY,
656 handler: button->type == ACPI_BUTTON_TYPE_LID ?
657 acpi_lid_notify :
658 acpi_button_notify);
659 break;
660 }
661 acpi_os_wait_events_complete();
662
663 acpi_button_remove_fs(device);
664 input_unregister_device(button->input);
665 kfree(objp: button);
666}
667
668static int param_set_lid_init_state(const char *val,
669 const struct kernel_param *kp)
670{
671 int i;
672
673 i = sysfs_match_string(lid_init_state_str, val);
674 if (i < 0)
675 return i;
676
677 lid_init_state = i;
678 pr_info("Initial lid state set to '%s'\n", lid_init_state_str[i]);
679 return 0;
680}
681
682static int param_get_lid_init_state(char *buf, const struct kernel_param *kp)
683{
684 int i, c = 0;
685
686 for (i = 0; i < ARRAY_SIZE(lid_init_state_str); i++)
687 if (i == lid_init_state)
688 c += sprintf(buf: buf + c, fmt: "[%s] ", lid_init_state_str[i]);
689 else
690 c += sprintf(buf: buf + c, fmt: "%s ", lid_init_state_str[i]);
691
692 buf[c - 1] = '\n'; /* Replace the final space with a newline */
693
694 return c;
695}
696
697module_param_call(lid_init_state,
698 param_set_lid_init_state, param_get_lid_init_state,
699 NULL, 0644);
700MODULE_PARM_DESC(lid_init_state, "Behavior for reporting LID initial state");
701
702static int acpi_button_register_driver(struct acpi_driver *driver)
703{
704 const struct dmi_system_id *dmi_id;
705
706 if (lid_init_state == -1) {
707 dmi_id = dmi_first_match(list: dmi_lid_quirks);
708 if (dmi_id)
709 lid_init_state = (long)dmi_id->driver_data;
710 else
711 lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
712 }
713
714 /*
715 * Modules such as nouveau.ko and i915.ko have a link time dependency
716 * on acpi_lid_open(), and would therefore not be loadable on ACPI
717 * capable kernels booted in non-ACPI mode if the return value of
718 * acpi_bus_register_driver() is returned from here with ACPI disabled
719 * when this driver is built as a module.
720 */
721 if (acpi_disabled)
722 return 0;
723
724 return acpi_bus_register_driver(driver);
725}
726
727static void acpi_button_unregister_driver(struct acpi_driver *driver)
728{
729 if (!acpi_disabled)
730 acpi_bus_unregister_driver(driver);
731}
732
733module_driver(acpi_button_driver, acpi_button_register_driver,
734 acpi_button_unregister_driver);
735

source code of linux/drivers/acpi/button.c