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1/*
2 Dell Airplane Mode Switch driver
3 Copyright (C) 2014-2015 Pali Rohár <pali.rohar@gmail.com>
4
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14*/
15
16#include <linux/module.h>
17#include <linux/acpi.h>
18#include <linux/rfkill.h>
19#include <linux/input.h>
20
21enum rbtn_type {
22 RBTN_UNKNOWN,
23 RBTN_TOGGLE,
24 RBTN_SLIDER,
25};
26
27struct rbtn_data {
28 enum rbtn_type type;
29 struct rfkill *rfkill;
30 struct input_dev *input_dev;
31 bool suspended;
32};
33
34
35/*
36 * acpi functions
37 */
38
39static enum rbtn_type rbtn_check(struct acpi_device *device)
40{
41 unsigned long long output;
42 acpi_status status;
43
44 status = acpi_evaluate_integer(device->handle, "CRBT", NULL, &output);
45 if (ACPI_FAILURE(status))
46 return RBTN_UNKNOWN;
47
48 switch (output) {
49 case 0:
50 case 1:
51 return RBTN_TOGGLE;
52 case 2:
53 case 3:
54 return RBTN_SLIDER;
55 default:
56 return RBTN_UNKNOWN;
57 }
58}
59
60static int rbtn_get(struct acpi_device *device)
61{
62 unsigned long long output;
63 acpi_status status;
64
65 status = acpi_evaluate_integer(device->handle, "GRBT", NULL, &output);
66 if (ACPI_FAILURE(status))
67 return -EINVAL;
68
69 return !output;
70}
71
72static int rbtn_acquire(struct acpi_device *device, bool enable)
73{
74 struct acpi_object_list input;
75 union acpi_object param;
76 acpi_status status;
77
78 param.type = ACPI_TYPE_INTEGER;
79 param.integer.value = enable;
80 input.count = 1;
81 input.pointer = ¶m;
82
83 status = acpi_evaluate_object(device->handle, "ARBT", &input, NULL);
84 if (ACPI_FAILURE(status))
85 return -EINVAL;
86
87 return 0;
88}
89
90
91/*
92 * rfkill device
93 */
94
95static void rbtn_rfkill_query(struct rfkill *rfkill, void *data)
96{
97 struct acpi_device *device = data;
98 int state;
99
100 state = rbtn_get(device);
101 if (state < 0)
102 return;
103
104 rfkill_set_states(rfkill, state, state);
105}
106
107static int rbtn_rfkill_set_block(void *data, bool blocked)
108{
109 /* NOTE: setting soft rfkill state is not supported */
110 return -EINVAL;
111}
112
113static const struct rfkill_ops rbtn_ops = {
114 .query = rbtn_rfkill_query,
115 .set_block = rbtn_rfkill_set_block,
116};
117
118static int rbtn_rfkill_init(struct acpi_device *device)
119{
120 struct rbtn_data *rbtn_data = device->driver_data;
121 int ret;
122
123 if (rbtn_data->rfkill)
124 return 0;
125
126 /*
127 * NOTE: rbtn controls all radio devices, not only WLAN
128 * but rfkill interface does not support "ANY" type
129 * so "WLAN" type is used
130 */
131 rbtn_data->rfkill = rfkill_alloc("dell-rbtn", &device->dev,
132 RFKILL_TYPE_WLAN, &rbtn_ops, device);
133 if (!rbtn_data->rfkill)
134 return -ENOMEM;
135
136 ret = rfkill_register(rbtn_data->rfkill);
137 if (ret) {
138 rfkill_destroy(rbtn_data->rfkill);
139 rbtn_data->rfkill = NULL;
140 return ret;
141 }
142
143 return 0;
144}
145
146static void rbtn_rfkill_exit(struct acpi_device *device)
147{
148 struct rbtn_data *rbtn_data = device->driver_data;
149
150 if (!rbtn_data->rfkill)
151 return;
152
153 rfkill_unregister(rbtn_data->rfkill);
154 rfkill_destroy(rbtn_data->rfkill);
155 rbtn_data->rfkill = NULL;
156}
157
158static void rbtn_rfkill_event(struct acpi_device *device)
159{
160 struct rbtn_data *rbtn_data = device->driver_data;
161
162 if (rbtn_data->rfkill)
163 rbtn_rfkill_query(rbtn_data->rfkill, device);
164}
165
166
167/*
168 * input device
169 */
170
171static int rbtn_input_init(struct rbtn_data *rbtn_data)
172{
173 int ret;
174
175 rbtn_data->input_dev = input_allocate_device();
176 if (!rbtn_data->input_dev)
177 return -ENOMEM;
178
179 rbtn_data->input_dev->name = "DELL Wireless hotkeys";
180 rbtn_data->input_dev->phys = "dellabce/input0";
181 rbtn_data->input_dev->id.bustype = BUS_HOST;
182 rbtn_data->input_dev->evbit[0] = BIT(EV_KEY);
183 set_bit(KEY_RFKILL, rbtn_data->input_dev->keybit);
184
185 ret = input_register_device(rbtn_data->input_dev);
186 if (ret) {
187 input_free_device(rbtn_data->input_dev);
188 rbtn_data->input_dev = NULL;
189 return ret;
190 }
191
192 return 0;
193}
194
195static void rbtn_input_exit(struct rbtn_data *rbtn_data)
196{
197 input_unregister_device(rbtn_data->input_dev);
198 rbtn_data->input_dev = NULL;
199}
200
201static void rbtn_input_event(struct rbtn_data *rbtn_data)
202{
203 input_report_key(rbtn_data->input_dev, KEY_RFKILL, 1);
204 input_sync(rbtn_data->input_dev);
205 input_report_key(rbtn_data->input_dev, KEY_RFKILL, 0);
206 input_sync(rbtn_data->input_dev);
207}
208
209
210/*
211 * acpi driver
212 */
213
214static int rbtn_add(struct acpi_device *device);
215static int rbtn_remove(struct acpi_device *device);
216static void rbtn_notify(struct acpi_device *device, u32 event);
217
218static const struct acpi_device_id rbtn_ids[] = {
219 { "DELRBTN", 0 },
220 { "DELLABCE", 0 },
221
222 /*
223 * This driver can also handle the "DELLABC6" device that
224 * appears on the XPS 13 9350, but that device is disabled by
225 * the DSDT unless booted with acpi_osi="!Windows 2012"
226 * acpi_osi="!Windows 2013".
227 *
228 * According to Mario at Dell:
229 *
230 * DELLABC6 is a custom interface that was created solely to
231 * have airplane mode support for Windows 7. For Windows 10
232 * the proper interface is to use that which is handled by
233 * intel-hid. A OEM airplane mode driver is not used.
234 *
235 * Since the kernel doesn't identify as Windows 7 it would be
236 * incorrect to do attempt to use that interface.
237 *
238 * Even if we override _OSI and bind to DELLABC6, we end up with
239 * inconsistent behavior in which userspace can get out of sync
240 * with the rfkill state as it conflicts with events from
241 * intel-hid.
242 *
243 * The upshot is that it is better to just ignore DELLABC6
244 * devices.
245 */
246
247 { "", 0 },
248};
249
250#ifdef CONFIG_PM_SLEEP
251static void ACPI_SYSTEM_XFACE rbtn_clear_suspended_flag(void *context)
252{
253 struct rbtn_data *rbtn_data = context;
254
255 rbtn_data->suspended = false;
256}
257
258static int rbtn_suspend(struct device *dev)
259{
260 struct acpi_device *device = to_acpi_device(dev);
261 struct rbtn_data *rbtn_data = acpi_driver_data(device);
262
263 rbtn_data->suspended = true;
264
265 return 0;
266}
267
268static int rbtn_resume(struct device *dev)
269{
270 struct acpi_device *device = to_acpi_device(dev);
271 struct rbtn_data *rbtn_data = acpi_driver_data(device);
272 acpi_status status;
273
274 /*
275 * Upon resume, some BIOSes send an ACPI notification thet triggers
276 * an unwanted input event. In order to ignore it, we use a flag
277 * that we set at suspend and clear once we have received the extra
278 * ACPI notification. Since ACPI notifications are delivered
279 * asynchronously to drivers, we clear the flag from the workqueue
280 * used to deliver the notifications. This should be enough
281 * to have the flag cleared only after we received the extra
282 * notification, if any.
283 */
284 status = acpi_os_execute(OSL_NOTIFY_HANDLER,
285 rbtn_clear_suspended_flag, rbtn_data);
286 if (ACPI_FAILURE(status))
287 rbtn_clear_suspended_flag(rbtn_data);
288
289 return 0;
290}
291#endif
292
293static SIMPLE_DEV_PM_OPS(rbtn_pm_ops, rbtn_suspend, rbtn_resume);
294
295static struct acpi_driver rbtn_driver = {
296 .name = "dell-rbtn",
297 .ids = rbtn_ids,
298 .drv.pm = &rbtn_pm_ops,
299 .ops = {
300 .add = rbtn_add,
301 .remove = rbtn_remove,
302 .notify = rbtn_notify,
303 },
304 .owner = THIS_MODULE,
305};
306
307
308/*
309 * notifier export functions
310 */
311
312static bool auto_remove_rfkill = true;
313
314static ATOMIC_NOTIFIER_HEAD(rbtn_chain_head);
315
316static int rbtn_inc_count(struct device *dev, void *data)
317{
318 struct acpi_device *device = to_acpi_device(dev);
319 struct rbtn_data *rbtn_data = device->driver_data;
320 int *count = data;
321
322 if (rbtn_data->type == RBTN_SLIDER)
323 (*count)++;
324
325 return 0;
326}
327
328static int rbtn_switch_dev(struct device *dev, void *data)
329{
330 struct acpi_device *device = to_acpi_device(dev);
331 struct rbtn_data *rbtn_data = device->driver_data;
332 bool enable = data;
333
334 if (rbtn_data->type != RBTN_SLIDER)
335 return 0;
336
337 if (enable)
338 rbtn_rfkill_init(device);
339 else
340 rbtn_rfkill_exit(device);
341
342 return 0;
343}
344
345int dell_rbtn_notifier_register(struct notifier_block *nb)
346{
347 bool first;
348 int count;
349 int ret;
350
351 count = 0;
352 ret = driver_for_each_device(&rbtn_driver.drv, NULL, &count,
353 rbtn_inc_count);
354 if (ret || count == 0)
355 return -ENODEV;
356
357 first = !rbtn_chain_head.head;
358
359 ret = atomic_notifier_chain_register(&rbtn_chain_head, nb);
360 if (ret != 0)
361 return ret;
362
363 if (auto_remove_rfkill && first)
364 ret = driver_for_each_device(&rbtn_driver.drv, NULL,
365 (void *)false, rbtn_switch_dev);
366
367 return ret;
368}
369EXPORT_SYMBOL_GPL(dell_rbtn_notifier_register);
370
371int dell_rbtn_notifier_unregister(struct notifier_block *nb)
372{
373 int ret;
374
375 ret = atomic_notifier_chain_unregister(&rbtn_chain_head, nb);
376 if (ret != 0)
377 return ret;
378
379 if (auto_remove_rfkill && !rbtn_chain_head.head)
380 ret = driver_for_each_device(&rbtn_driver.drv, NULL,
381 (void *)true, rbtn_switch_dev);
382
383 return ret;
384}
385EXPORT_SYMBOL_GPL(dell_rbtn_notifier_unregister);
386
387
388/*
389 * acpi driver functions
390 */
391
392static int rbtn_add(struct acpi_device *device)
393{
394 struct rbtn_data *rbtn_data;
395 enum rbtn_type type;
396 int ret = 0;
397
398 type = rbtn_check(device);
399 if (type == RBTN_UNKNOWN) {
400 dev_info(&device->dev, "Unknown device type\n");
401 return -EINVAL;
402 }
403
404 ret = rbtn_acquire(device, true);
405 if (ret < 0) {
406 dev_err(&device->dev, "Cannot enable device\n");
407 return ret;
408 }
409
410 rbtn_data = devm_kzalloc(&device->dev, sizeof(*rbtn_data), GFP_KERNEL);
411 if (!rbtn_data)
412 return -ENOMEM;
413
414 rbtn_data->type = type;
415 device->driver_data = rbtn_data;
416
417 switch (rbtn_data->type) {
418 case RBTN_TOGGLE:
419 ret = rbtn_input_init(rbtn_data);
420 break;
421 case RBTN_SLIDER:
422 if (auto_remove_rfkill && rbtn_chain_head.head)
423 ret = 0;
424 else
425 ret = rbtn_rfkill_init(device);
426 break;
427 default:
428 ret = -EINVAL;
429 }
430
431 return ret;
432
433}
434
435static int rbtn_remove(struct acpi_device *device)
436{
437 struct rbtn_data *rbtn_data = device->driver_data;
438
439 switch (rbtn_data->type) {
440 case RBTN_TOGGLE:
441 rbtn_input_exit(rbtn_data);
442 break;
443 case RBTN_SLIDER:
444 rbtn_rfkill_exit(device);
445 break;
446 default:
447 break;
448 }
449
450 rbtn_acquire(device, false);
451 device->driver_data = NULL;
452
453 return 0;
454}
455
456static void rbtn_notify(struct acpi_device *device, u32 event)
457{
458 struct rbtn_data *rbtn_data = device->driver_data;
459
460 /*
461 * Some BIOSes send a notification at resume.
462 * Ignore it to prevent unwanted input events.
463 */
464 if (rbtn_data->suspended) {
465 dev_dbg(&device->dev, "ACPI notification ignored\n");
466 return;
467 }
468
469 if (event != 0x80) {
470 dev_info(&device->dev, "Received unknown event (0x%x)\n",
471 event);
472 return;
473 }
474
475 switch (rbtn_data->type) {
476 case RBTN_TOGGLE:
477 rbtn_input_event(rbtn_data);
478 break;
479 case RBTN_SLIDER:
480 rbtn_rfkill_event(device);
481 atomic_notifier_call_chain(&rbtn_chain_head, event, device);
482 break;
483 default:
484 break;
485 }
486}
487
488
489/*
490 * module functions
491 */
492
493module_acpi_driver(rbtn_driver);
494
495module_param(auto_remove_rfkill, bool, 0444);
496
497MODULE_PARM_DESC(auto_remove_rfkill, "Automatically remove rfkill devices when "
498 "other modules start receiving events "
499 "from this module and re-add them when "
500 "the last module stops receiving events "
501 "(default true)");
502MODULE_DEVICE_TABLE(acpi, rbtn_ids);
503MODULE_DESCRIPTION("Dell Airplane Mode Switch driver");
504MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
505MODULE_LICENSE("GPL");