[mirror_ubuntu-bionic-kernel.git] / drivers / platform / x86 / dell-rbtn.c

/*
    Dell Airplane Mode Switch driver
    Copyright (C) 2014-2015  Pali Rohár <pali.rohar@gmail.com>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
*/

#include <linux/module.h>
#include <linux/acpi.h>
#include <linux/rfkill.h>
#include <linux/input.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");
Commit	Line	Data
817a5cdb PR	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
	21	enum rbtn_type {
	22	RBTN_UNKNOWN,
	23	RBTN_TOGGLE,
	24	RBTN_SLIDER,
	25	};
	26
	27	struct rbtn_data {
	28	enum rbtn_type type;
	29	struct rfkill *rfkill;
	30	struct input_dev *input_dev;
ff865123	31	bool suspended;
817a5cdb PR	32	};
	33
	34
	35	/*
	36	* acpi functions
	37	*/
	38
	39	static 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
	60	static 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
	72	static 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 = &param;
	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
	95	static 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
107	static int rbtn_rfkill_set_block(void *data, bool blocked)
108	{
109	/* NOTE: setting soft rfkill state is not supported */
110	return -EINVAL;
111	}
112
a63693a0	113	static const struct rfkill_ops rbtn_ops = {
817a5cdb PR	114	.query = rbtn_rfkill_query,
	115	.set_block = rbtn_rfkill_set_block,
	116	};
	117
	118	static 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
	146	static 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
	158	static 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
	171	static 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
195	static 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
201	static 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
214	static int rbtn_add(struct acpi_device *device);
215	static int rbtn_remove(struct acpi_device *device);
216	static void rbtn_notify(struct acpi_device *device, u32 event);
217
218	static const struct acpi_device_id rbtn_ids[] = {
219	{ "DELRBTN", 0 },
220	{ "DELLABCE", 0 },
4d340c6b AL	221
	222	/*
	223	* This driver can also handle the "DELLABC6" device that
5d4be5f2 AL	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".
4d340c6b	227	*
5d4be5f2 AL	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.
4d340c6b AL	245	*/
4d340c6b AL	246
817a5cdb PR	247	{ "", 0 },
	248	};
	249
ff865123 GM	250	#ifdef CONFIG_PM_SLEEP
	251	static 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
	258	static 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
	268	static 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
	293	static SIMPLE_DEV_PM_OPS(rbtn_pm_ops, rbtn_suspend, rbtn_resume);
	294
817a5cdb PR	295	static struct acpi_driver rbtn_driver = {
	296	.name = "dell-rbtn",
	297	.ids = rbtn_ids,
ff865123	298	.drv.pm = &rbtn_pm_ops,
817a5cdb PR	299	.ops = {
	300	.add = rbtn_add,
	301	.remove = rbtn_remove,
	302	.notify = rbtn_notify,
	303	},
	304	.owner = THIS_MODULE,
	305	};
	306
	307
b05ffc95 PR	308	/*
	309	* notifier export functions
	310	*/
	311
	312	static bool auto_remove_rfkill = true;
	313
	314	static ATOMIC_NOTIFIER_HEAD(rbtn_chain_head);
	315
	316	static 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
	328	static 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
	345	int 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	}
	369	EXPORT_SYMBOL_GPL(dell_rbtn_notifier_register);
	370
	371	int 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	}
385	EXPORT_SYMBOL_GPL(dell_rbtn_notifier_unregister);
386
387
817a5cdb PR	388	/*
	389	* acpi driver functions
	390	*/
	391
	392	static 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:
b05ffc95 PR	422	if (auto_remove_rfkill && rbtn_chain_head.head)
	423	ret = 0;
	424	else
	425	ret = rbtn_rfkill_init(device);
817a5cdb PR	426	break;
	427	default:
	428	ret = -EINVAL;
	429	}
	430
	431	return ret;
	432
	433	}
	434
	435	static 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
	456	static void rbtn_notify(struct acpi_device *device, u32 event)
	457	{
	458	struct rbtn_data *rbtn_data = device->driver_data;
	459
ff865123 GM	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
817a5cdb PR	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);
b05ffc95	481	atomic_notifier_call_chain(&rbtn_chain_head, event, device);
817a5cdb PR	482	break;
	483	default:
	484	break;
	485	}
	486	}
	487
	488
	489	/*
	490	* module functions
	491	*/
	492
	493	module_acpi_driver(rbtn_driver);
	494
b05ffc95 PR	495	module_param(auto_remove_rfkill, bool, 0444);
	496
	497	MODULE_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)");
817a5cdb PR	502	MODULE_DEVICE_TABLE(acpi, rbtn_ids);
	503	MODULE_DESCRIPTION("Dell Airplane Mode Switch driver");
	504	MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
	505	MODULE_LICENSE("GPL");