summaryrefslogtreecommitdiffstats
path: root/drivers/platform/x86/dell-rbtn.c
blob: a6b856cd86bd62da248204ec5a3be67095c73244 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
// SPDX-License-Identifier: GPL-2.0-or-later
/*
    Dell Airplane Mode Switch driver
    Copyright (C) 2014-2015  Pali Rohár <pali.rohar@gmail.com>

*/

#include <linux/module.h>
#include <linux/acpi.h>
#include <linux/rfkill.h>
#include <linux/input.h>

#include "dell-rbtn.h"

enum rbtn_type {
	RBTN_UNKNOWN,
	RBTN_TOGGLE,
	RBTN_SLIDER,
};

struct rbtn_data {
	enum rbtn_type type;
	struct rfkill *rfkill;
	struct input_dev *input_dev;
	bool suspended;
};


/*
 * acpi functions
 */

static enum rbtn_type rbtn_check(struct acpi_device *device)
{
	unsigned long long output;
	acpi_status status;

	status = acpi_evaluate_integer(device->handle, "CRBT", NULL, &output);
	if (ACPI_FAILURE(status))
		return RBTN_UNKNOWN;

	switch (output) {
	case 0:
	case 1:
		return RBTN_TOGGLE;
	case 2:
	case 3:
		return RBTN_SLIDER;
	default:
		return RBTN_UNKNOWN;
	}
}

static int rbtn_get(struct acpi_device *device)
{
	unsigned long long output;
	acpi_status status;

	status = acpi_evaluate_integer(device->handle, "GRBT", NULL, &output);
	if (ACPI_FAILURE(status))
		return -EINVAL;

	return !output;
}

static int rbtn_acquire(struct acpi_device *device, bool enable)
{
	struct acpi_object_list input;
	union acpi_object param;
	acpi_status status;

	param.type = ACPI_TYPE_INTEGER;
	param.integer.value = enable;
	input.count = 1;
	input.pointer = &param;

	status = acpi_evaluate_object(device->handle, "ARBT", &input, NULL);
	if (ACPI_FAILURE(status))
		return -EINVAL;

	return 0;
}


/*
 * rfkill device
 */

static void rbtn_rfkill_query(struct rfkill *rfkill, void *data)
{
	struct acpi_device *device = data;
	int state;

	state = rbtn_get(device);
	if (state < 0)
		return;

	rfkill_set_states(rfkill, state, state);
}

static int rbtn_rfkill_set_block(void *data, bool blocked)
{
	/* NOTE: setting soft rfkill state is not supported */
	return -EINVAL;
}

static const struct rfkill_ops rbtn_ops = {
	.query = rbtn_rfkill_query,
	.set_block = rbtn_rfkill_set_block,
};

static int rbtn_rfkill_init(struct acpi_device *device)
{
	struct rbtn_data *rbtn_data = device->driver_data;
	int ret;

	if (rbtn_data->rfkill)
		return 0;

	/*
	 * NOTE: rbtn controls all radio devices, not only WLAN
	 *       but rfkill interface does not support "ANY" type
	 *       so "WLAN" type is used
	 */
	rbtn_data->rfkill = rfkill_alloc("dell-rbtn", &device->dev,
					 RFKILL_TYPE_WLAN, &rbtn_ops, device);
	if (!rbtn_data->rfkill)
		return -ENOMEM;

	ret = rfkill_register(rbtn_data->rfkill);
	if (ret) {
		rfkill_destroy(rbtn_data->rfkill);
		rbtn_data->rfkill = NULL;
		return ret;
	}

	return 0;
}

static void rbtn_rfkill_exit(struct acpi_device *device)
{
	struct rbtn_data *rbtn_data = device->driver_data;

	if (!rbtn_data->rfkill)
		return;

	rfkill_unregister(rbtn_data->rfkill);
	rfkill_destroy(rbtn_data->rfkill);
	rbtn_data->rfkill = NULL;
}

static void rbtn_rfkill_event(struct acpi_device *device)
{
	struct rbtn_data *rbtn_data = device->driver_data;

	if (rbtn_data->rfkill)
		rbtn_rfkill_query(rbtn_data->rfkill, device);
}


/*
 * input device
 */

static int rbtn_input_init(struct rbtn_data *rbtn_data)
{
	int ret;

	rbtn_data->input_dev = input_allocate_device();
	if (!rbtn_data->input_dev)
		return -ENOMEM;

	rbtn_data->input_dev->name = "DELL Wireless hotkeys";
	rbtn_data->input_dev->phys = "dellabce/input0";
	rbtn_data->input_dev->id.bustype = BUS_HOST;
	rbtn_data->input_dev->evbit[0] = BIT(EV_KEY);
	set_bit(KEY_RFKILL, rbtn_data->input_dev->keybit);

	ret = input_register_device(rbtn_data->input_dev);
	if (ret) {
		input_free_device(rbtn_data->input_dev);
		rbtn_data->input_dev = NULL;
		return ret;
	}

	return 0;
}

static void rbtn_input_exit(struct rbtn_data *rbtn_data)
{
	input_unregister_device(rbtn_data->input_dev);
	rbtn_data->input_dev = NULL;
}

static void rbtn_input_event(struct rbtn_data *rbtn_data)
{
	input_report_key(rbtn_data->input_dev, KEY_RFKILL, 1);
	input_sync(rbtn_data->input_dev);
	input_report_key(rbtn_data->input_dev, KEY_RFKILL, 0);
	input_sync(rbtn_data->input_dev);
}


/*
 * acpi driver
 */

static int rbtn_add(struct acpi_device *device);
static int rbtn_remove(struct acpi_device *device);
static void rbtn_notify(struct acpi_device *device, u32 event);

static const struct acpi_device_id rbtn_ids[] = {
	{ "DELRBTN", 0 },
	{ "DELLABCE", 0 },

	/*
	 * This driver can also handle the "DELLABC6" device that
	 * appears on the XPS 13 9350, but that device is disabled by
	 * the DSDT unless booted with acpi_osi="!Windows 2012"
	 * acpi_osi="!Windows 2013".
	 *
	 * According to Mario at Dell:
	 *
	 *  DELLABC6 is a custom interface that was created solely to
	 *  have airplane mode support for Windows 7.  For Windows 10
	 *  the proper interface is to use that which is handled by
	 *  intel-hid. A OEM airplane mode driver is not used.
	 *
	 *  Since the kernel doesn't identify as Windows 7 it would be
	 *  incorrect to do attempt to use that interface.
	 *
	 * Even if we override _OSI and bind to DELLABC6, we end up with
	 * inconsistent behavior in which userspace can get out of sync
	 * with the rfkill state as it conflicts with events from
	 * intel-hid.
	 *
	 * The upshot is that it is better to just ignore DELLABC6
	 * devices.
	 */

	{ "", 0 },
};

#ifdef CONFIG_PM_SLEEP
static void ACPI_SYSTEM_XFACE rbtn_clear_suspended_flag(void *context)
{
	struct rbtn_data *rbtn_data = context;

	rbtn_data->suspended = false;
}

static int rbtn_suspend(struct device *dev)
{
	struct acpi_device *device = to_acpi_device(dev);
	struct rbtn_data *rbtn_data = acpi_driver_data(device);

	rbtn_data->suspended = true;

	return 0;
}

static int rbtn_resume(struct device *dev)
{
	struct acpi_device *device = to_acpi_device(dev);
	struct rbtn_data *rbtn_data = acpi_driver_data(device);
	acpi_status status;

	/*
	 * Upon resume, some BIOSes send an ACPI notification thet triggers
	 * an unwanted input event. In order to ignore it, we use a flag
	 * that we set at suspend and clear once we have received the extra
	 * ACPI notification. Since ACPI notifications are delivered
	 * asynchronously to drivers, we clear the flag from the workqueue
	 * used to deliver the notifications. This should be enough
	 * to have the flag cleared only after we received the extra
	 * notification, if any.
	 */
	status = acpi_os_execute(OSL_NOTIFY_HANDLER,
			 rbtn_clear_suspended_flag, rbtn_data);
	if (ACPI_FAILURE(status))
		rbtn_clear_suspended_flag(rbtn_data);

	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(rbtn_pm_ops, rbtn_suspend, rbtn_resume);

static struct acpi_driver rbtn_driver = {
	.name = "dell-rbtn",
	.ids = rbtn_ids,
	.drv.pm = &rbtn_pm_ops,
	.ops = {
		.add = rbtn_add,
		.remove = rbtn_remove,
		.notify = rbtn_notify,
	},
	.owner = THIS_MODULE,
};


/*
 * notifier export functions
 */

static bool auto_remove_rfkill = true;

static ATOMIC_NOTIFIER_HEAD(rbtn_chain_head);

static int rbtn_inc_count(struct device *dev, void *data)
{
	struct acpi_device *device = to_acpi_device(dev);
	struct rbtn_data *rbtn_data = device->driver_data;
	int *count = data;

	if (rbtn_data->type == RBTN_SLIDER)
		(*count)++;

	return 0;
}

static int rbtn_switch_dev(struct device *dev, void *data)
{
	struct acpi_device *device = to_acpi_device(dev);
	struct rbtn_data *rbtn_data = device->driver_data;
	bool enable = data;

	if (rbtn_data->type != RBTN_SLIDER)
		return 0;

	if (enable)
		rbtn_rfkill_init(device);
	else
		rbtn_rfkill_exit(device);

	return 0;
}

int dell_rbtn_notifier_register(struct notifier_block *nb)
{
	bool first;
	int count;
	int ret;

	count = 0;
	ret = driver_for_each_device(&rbtn_driver.drv, NULL, &count,
				     rbtn_inc_count);
	if (ret || count == 0)
		return -ENODEV;

	first = !rbtn_chain_head.head;

	ret = atomic_notifier_chain_register(&rbtn_chain_head, nb);
	if (ret != 0)
		return ret;

	if (auto_remove_rfkill && first)
		ret = driver_for_each_device(&rbtn_driver.drv, NULL,
					     (void *)false, rbtn_switch_dev);

	return ret;
}
EXPORT_SYMBOL_GPL(dell_rbtn_notifier_register);

int dell_rbtn_notifier_unregister(struct notifier_block *nb)
{
	int ret;

	ret = atomic_notifier_chain_unregister(&rbtn_chain_head, nb);
	if (ret != 0)
		return ret;

	if (auto_remove_rfkill && !rbtn_chain_head.head)
		ret = driver_for_each_device(&rbtn_driver.drv, NULL,
					     (void *)true, rbtn_switch_dev);

	return ret;
}
EXPORT_SYMBOL_GPL(dell_rbtn_notifier_unregister);


/*
 * acpi driver functions
 */

static int rbtn_add(struct acpi_device *device)
{
	struct rbtn_data *rbtn_data;
	enum rbtn_type type;
	int ret = 0;

	type = rbtn_check(device);
	if (type == RBTN_UNKNOWN) {
		dev_info(&device->dev, "Unknown device type\n");
		return -EINVAL;
	}

	ret = rbtn_acquire(device, true);
	if (ret < 0) {
		dev_err(&device->dev, "Cannot enable device\n");
		return ret;
	}

	rbtn_data = devm_kzalloc(&device->dev, sizeof(*rbtn_data), GFP_KERNEL);
	if (!rbtn_data)
		return -ENOMEM;

	rbtn_data->type = type;
	device->driver_data = rbtn_data;

	switch (rbtn_data->type) {
	case RBTN_TOGGLE:
		ret = rbtn_input_init(rbtn_data);
		break;
	case RBTN_SLIDER:
		if (auto_remove_rfkill && rbtn_chain_head.head)
			ret = 0;
		else
			ret = rbtn_rfkill_init(device);
		break;
	default:
		ret = -EINVAL;
	}

	return ret;

}

static int rbtn_remove(struct acpi_device *device)
{
	struct rbtn_data *rbtn_data = device->driver_data;

	switch (rbtn_data->type) {
	case RBTN_TOGGLE:
		rbtn_input_exit(rbtn_data);
		break;
	case RBTN_SLIDER:
		rbtn_rfkill_exit(device);
		break;
	default:
		break;
	}

	rbtn_acquire(device, false);
	device->driver_data = NULL;

	return 0;
}

static void rbtn_notify(struct acpi_device *device, u32 event)
{
	struct rbtn_data *rbtn_data = device->driver_data;

	/*
	 * Some BIOSes send a notification at resume.
	 * Ignore it to prevent unwanted input events.
	 */
	if (rbtn_data->suspended) {
		dev_dbg(&device->dev, "ACPI notification ignored\n");
		return;
	}

	if (event != 0x80) {
		dev_info(&device->dev, "Received unknown event (0x%x)\n",
			 event);
		return;
	}

	switch (rbtn_data->type) {
	case RBTN_TOGGLE:
		rbtn_input_event(rbtn_data);
		break;
	case RBTN_SLIDER:
		rbtn_rfkill_event(device);
		atomic_notifier_call_chain(&rbtn_chain_head, event, device);
		break;
	default:
		break;
	}
}


/*
 * module functions
 */

module_acpi_driver(rbtn_driver);

module_param(auto_remove_rfkill, bool, 0444);

MODULE_PARM_DESC(auto_remove_rfkill, "Automatically remove rfkill devices when "
				     "other modules start receiving events "
				     "from this module and re-add them when "
				     "the last module stops receiving events "
				     "(default true)");
MODULE_DEVICE_TABLE(acpi, rbtn_ids);
MODULE_DESCRIPTION("Dell Airplane Mode Switch driver");
MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
MODULE_LICENSE("GPL");