dell-rbtn.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3    Dell Airplane Mode Switch driver
  4    Copyright (C) 2014-2015  Pali Rohár <pali@kernel.org>
  5
  6*/
  7
  8#include <linux/module.h>
  9#include <linux/acpi.h>
 10#include <linux/rfkill.h>
 11#include <linux/input.h>
 12
 13#include "dell-rbtn.h"
 14
 15enum rbtn_type {
 16	RBTN_UNKNOWN,
 17	RBTN_TOGGLE,
 18	RBTN_SLIDER,
 19};
 20
 21struct rbtn_data {
 22	enum rbtn_type type;
 23	struct rfkill *rfkill;
 24	struct input_dev *input_dev;
 25	bool suspended;
 26};
 27
 28
 29/*
 30 * acpi functions
 31 */
 32
 33static enum rbtn_type rbtn_check(struct acpi_device *device)
 34{
 35	unsigned long long output;
 36	acpi_status status;
 37
 38	status = acpi_evaluate_integer(device->handle, "CRBT", NULL, &output);
 39	if (ACPI_FAILURE(status))
 40		return RBTN_UNKNOWN;
 41
 42	switch (output) {
 43	case 0:
 44	case 1:
 45		return RBTN_TOGGLE;
 46	case 2:
 47	case 3:
 48		return RBTN_SLIDER;
 49	default:
 50		return RBTN_UNKNOWN;
 51	}
 52}
 53
 54static int rbtn_get(struct acpi_device *device)
 55{
 56	unsigned long long output;
 57	acpi_status status;
 58
 59	status = acpi_evaluate_integer(device->handle, "GRBT", NULL, &output);
 60	if (ACPI_FAILURE(status))
 61		return -EINVAL;
 62
 63	return !output;
 64}
 65
 66static int rbtn_acquire(struct acpi_device *device, bool enable)
 67{
 68	struct acpi_object_list input;
 69	union acpi_object param;
 70	acpi_status status;
 71
 72	param.type = ACPI_TYPE_INTEGER;
 73	param.integer.value = enable;
 74	input.count = 1;
 75	input.pointer = &param;
 76
 77	status = acpi_evaluate_object(device->handle, "ARBT", &input, NULL);
 78	if (ACPI_FAILURE(status))
 79		return -EINVAL;
 80
 81	return 0;
 82}
 83
 84
 85/*
 86 * rfkill device
 87 */
 88
 89static void rbtn_rfkill_query(struct rfkill *rfkill, void *data)
 90{
 91	struct acpi_device *device = data;
 92	int state;
 93
 94	state = rbtn_get(device);
 95	if (state < 0)
 96		return;
 97
 98	rfkill_set_states(rfkill, state, state);
 99}
100
101static int rbtn_rfkill_set_block(void *data, bool blocked)
102{
103	/* NOTE: setting soft rfkill state is not supported */
104	return -EINVAL;
105}
106
107static const struct rfkill_ops rbtn_ops = {
108	.query = rbtn_rfkill_query,
109	.set_block = rbtn_rfkill_set_block,
110};
111
112static int rbtn_rfkill_init(struct acpi_device *device)
113{
114	struct rbtn_data *rbtn_data = device->driver_data;
115	int ret;
116
117	if (rbtn_data->rfkill)
118		return 0;
119
120	/*
121	 * NOTE: rbtn controls all radio devices, not only WLAN
122	 *       but rfkill interface does not support "ANY" type
123	 *       so "WLAN" type is used
124	 */
125	rbtn_data->rfkill = rfkill_alloc("dell-rbtn", &device->dev,
126					 RFKILL_TYPE_WLAN, &rbtn_ops, device);
127	if (!rbtn_data->rfkill)
128		return -ENOMEM;
129
130	ret = rfkill_register(rbtn_data->rfkill);
131	if (ret) {
132		rfkill_destroy(rbtn_data->rfkill);
133		rbtn_data->rfkill = NULL;
134		return ret;
135	}
136
137	return 0;
138}
139
140static void rbtn_rfkill_exit(struct acpi_device *device)
141{
142	struct rbtn_data *rbtn_data = device->driver_data;
143
144	if (!rbtn_data->rfkill)
145		return;
146
147	rfkill_unregister(rbtn_data->rfkill);
148	rfkill_destroy(rbtn_data->rfkill);
149	rbtn_data->rfkill = NULL;
150}
151
152static void rbtn_rfkill_event(struct acpi_device *device)
153{
154	struct rbtn_data *rbtn_data = device->driver_data;
155
156	if (rbtn_data->rfkill)
157		rbtn_rfkill_query(rbtn_data->rfkill, device);
158}
159
160
161/*
162 * input device
163 */
164
165static int rbtn_input_init(struct rbtn_data *rbtn_data)
166{
167	int ret;
168
169	rbtn_data->input_dev = input_allocate_device();
170	if (!rbtn_data->input_dev)
171		return -ENOMEM;
172
173	rbtn_data->input_dev->name = "DELL Wireless hotkeys";
174	rbtn_data->input_dev->phys = "dellabce/input0";
175	rbtn_data->input_dev->id.bustype = BUS_HOST;
176	rbtn_data->input_dev->evbit[0] = BIT(EV_KEY);
177	set_bit(KEY_RFKILL, rbtn_data->input_dev->keybit);
178
179	ret = input_register_device(rbtn_data->input_dev);
180	if (ret) {
181		input_free_device(rbtn_data->input_dev);
182		rbtn_data->input_dev = NULL;
183		return ret;
184	}
185
186	return 0;
187}
188
189static void rbtn_input_exit(struct rbtn_data *rbtn_data)
190{
191	input_unregister_device(rbtn_data->input_dev);
192	rbtn_data->input_dev = NULL;
193}
194
195static void rbtn_input_event(struct rbtn_data *rbtn_data)
196{
197	input_report_key(rbtn_data->input_dev, KEY_RFKILL, 1);
198	input_sync(rbtn_data->input_dev);
199	input_report_key(rbtn_data->input_dev, KEY_RFKILL, 0);
200	input_sync(rbtn_data->input_dev);
201}
202
203
204/*
205 * acpi driver
206 */
207
208static int rbtn_add(struct acpi_device *device);
209static void rbtn_remove(struct acpi_device *device);
210static void rbtn_notify(struct acpi_device *device, u32 event);
211
212static const struct acpi_device_id rbtn_ids[] = {
213	{ "DELRBTN", 0 },
214	{ "DELLABCE", 0 },
215
216	/*
217	 * This driver can also handle the "DELLABC6" device that
218	 * appears on the XPS 13 9350, but that device is disabled by
219	 * the DSDT unless booted with acpi_osi="!Windows 2012"
220	 * acpi_osi="!Windows 2013".
221	 *
222	 * According to Mario at Dell:
223	 *
224	 *  DELLABC6 is a custom interface that was created solely to
225	 *  have airplane mode support for Windows 7.  For Windows 10
226	 *  the proper interface is to use that which is handled by
227	 *  intel-hid. A OEM airplane mode driver is not used.
228	 *
229	 *  Since the kernel doesn't identify as Windows 7 it would be
230	 *  incorrect to do attempt to use that interface.
231	 *
232	 * Even if we override _OSI and bind to DELLABC6, we end up with
233	 * inconsistent behavior in which userspace can get out of sync
234	 * with the rfkill state as it conflicts with events from
235	 * intel-hid.
236	 *
237	 * The upshot is that it is better to just ignore DELLABC6
238	 * devices.
239	 */
240
241	{ "", 0 },
242};
243
244#ifdef CONFIG_PM_SLEEP
245static void ACPI_SYSTEM_XFACE rbtn_clear_suspended_flag(void *context)
246{
247	struct rbtn_data *rbtn_data = context;
248
249	rbtn_data->suspended = false;
250}
251
252static int rbtn_suspend(struct device *dev)
253{
254	struct acpi_device *device = to_acpi_device(dev);
255	struct rbtn_data *rbtn_data = acpi_driver_data(device);
256
257	rbtn_data->suspended = true;
258
259	return 0;
260}
261
262static int rbtn_resume(struct device *dev)
263{
264	struct acpi_device *device = to_acpi_device(dev);
265	struct rbtn_data *rbtn_data = acpi_driver_data(device);
266	acpi_status status;
267
268	/*
269	 * Upon resume, some BIOSes send an ACPI notification thet triggers
270	 * an unwanted input event. In order to ignore it, we use a flag
271	 * that we set at suspend and clear once we have received the extra
272	 * ACPI notification. Since ACPI notifications are delivered
273	 * asynchronously to drivers, we clear the flag from the workqueue
274	 * used to deliver the notifications. This should be enough
275	 * to have the flag cleared only after we received the extra
276	 * notification, if any.
277	 */
278	status = acpi_os_execute(OSL_NOTIFY_HANDLER,
279			 rbtn_clear_suspended_flag, rbtn_data);
280	if (ACPI_FAILURE(status))
281		rbtn_clear_suspended_flag(rbtn_data);
282
283	return 0;
284}
285#endif
286
287static SIMPLE_DEV_PM_OPS(rbtn_pm_ops, rbtn_suspend, rbtn_resume);
288
289static struct acpi_driver rbtn_driver = {
290	.name = "dell-rbtn",
291	.ids = rbtn_ids,
292	.drv.pm = &rbtn_pm_ops,
293	.ops = {
294		.add = rbtn_add,
295		.remove = rbtn_remove,
296		.notify = rbtn_notify,
297	},
298};
299
300
301/*
302 * notifier export functions
303 */
304
305static bool auto_remove_rfkill = true;
306
307static ATOMIC_NOTIFIER_HEAD(rbtn_chain_head);
308
309static int rbtn_inc_count(struct device *dev, void *data)
310{
311	struct acpi_device *device = to_acpi_device(dev);
312	struct rbtn_data *rbtn_data = device->driver_data;
313	int *count = data;
314
315	if (rbtn_data->type == RBTN_SLIDER)
316		(*count)++;
317
318	return 0;
319}
320
321static int rbtn_switch_dev(struct device *dev, void *data)
322{
323	struct acpi_device *device = to_acpi_device(dev);
324	struct rbtn_data *rbtn_data = device->driver_data;
325	bool enable = data;
326
327	if (rbtn_data->type != RBTN_SLIDER)
328		return 0;
329
330	if (enable)
331		rbtn_rfkill_init(device);
332	else
333		rbtn_rfkill_exit(device);
334
335	return 0;
336}
337
338int dell_rbtn_notifier_register(struct notifier_block *nb)
339{
340	bool first;
341	int count;
342	int ret;
343
344	count = 0;
345	ret = driver_for_each_device(&rbtn_driver.drv, NULL, &count,
346				     rbtn_inc_count);
347	if (ret || count == 0)
348		return -ENODEV;
349
350	first = !rbtn_chain_head.head;
351
352	ret = atomic_notifier_chain_register(&rbtn_chain_head, nb);
353	if (ret != 0)
354		return ret;
355
356	if (auto_remove_rfkill && first)
357		ret = driver_for_each_device(&rbtn_driver.drv, NULL,
358					     (void *)false, rbtn_switch_dev);
359
360	return ret;
361}
362EXPORT_SYMBOL_GPL(dell_rbtn_notifier_register);
363
364int dell_rbtn_notifier_unregister(struct notifier_block *nb)
365{
366	int ret;
367
368	ret = atomic_notifier_chain_unregister(&rbtn_chain_head, nb);
369	if (ret != 0)
370		return ret;
371
372	if (auto_remove_rfkill && !rbtn_chain_head.head)
373		ret = driver_for_each_device(&rbtn_driver.drv, NULL,
374					     (void *)true, rbtn_switch_dev);
375
376	return ret;
377}
378EXPORT_SYMBOL_GPL(dell_rbtn_notifier_unregister);
379
380
381/*
382 * acpi driver functions
383 */
384
385static int rbtn_add(struct acpi_device *device)
386{
387	struct rbtn_data *rbtn_data;
388	enum rbtn_type type;
389	int ret = 0;
390
391	type = rbtn_check(device);
392	if (type == RBTN_UNKNOWN) {
393		dev_info(&device->dev, "Unknown device type\n");
394		return -EINVAL;
395	}
396
397	rbtn_data = devm_kzalloc(&device->dev, sizeof(*rbtn_data), GFP_KERNEL);
398	if (!rbtn_data)
399		return -ENOMEM;
400
401	ret = rbtn_acquire(device, true);
402	if (ret < 0) {
403		dev_err(&device->dev, "Cannot enable device\n");
404		return ret;
405	}
406
407	rbtn_data->type = type;
408	device->driver_data = rbtn_data;
409
410	switch (rbtn_data->type) {
411	case RBTN_TOGGLE:
412		ret = rbtn_input_init(rbtn_data);
413		break;
414	case RBTN_SLIDER:
415		if (auto_remove_rfkill && rbtn_chain_head.head)
416			ret = 0;
417		else
418			ret = rbtn_rfkill_init(device);
419		break;
420	default:
421		ret = -EINVAL;
422		break;
423	}
424	if (ret)
425		rbtn_acquire(device, false);
426
427	return ret;
428}
429
430static void rbtn_remove(struct acpi_device *device)
431{
432	struct rbtn_data *rbtn_data = device->driver_data;
433
434	switch (rbtn_data->type) {
435	case RBTN_TOGGLE:
436		rbtn_input_exit(rbtn_data);
437		break;
438	case RBTN_SLIDER:
439		rbtn_rfkill_exit(device);
440		break;
441	default:
442		break;
443	}
444
445	rbtn_acquire(device, false);
446}
447
448static void rbtn_notify(struct acpi_device *device, u32 event)
449{
450	struct rbtn_data *rbtn_data = device->driver_data;
451
452	/*
453	 * Some BIOSes send a notification at resume.
454	 * Ignore it to prevent unwanted input events.
455	 */
456	if (rbtn_data->suspended) {
457		dev_dbg(&device->dev, "ACPI notification ignored\n");
458		return;
459	}
460
461	if (event != 0x80) {
462		dev_info(&device->dev, "Received unknown event (0x%x)\n",
463			 event);
464		return;
465	}
466
467	switch (rbtn_data->type) {
468	case RBTN_TOGGLE:
469		rbtn_input_event(rbtn_data);
470		break;
471	case RBTN_SLIDER:
472		rbtn_rfkill_event(device);
473		atomic_notifier_call_chain(&rbtn_chain_head, event, device);
474		break;
475	default:
476		break;
477	}
478}
479
480
481/*
482 * module functions
483 */
484
485module_acpi_driver(rbtn_driver);
486
487module_param(auto_remove_rfkill, bool, 0444);
488
489MODULE_PARM_DESC(auto_remove_rfkill, "Automatically remove rfkill devices when "
490				     "other modules start receiving events "
491				     "from this module and re-add them when "
492				     "the last module stops receiving events "
493				     "(default true)");
494MODULE_DEVICE_TABLE(acpi, rbtn_ids);
495MODULE_DESCRIPTION("Dell Airplane Mode Switch driver");
496MODULE_AUTHOR("Pali Rohár <pali@kernel.org>");
497MODULE_LICENSE("GPL");