[NET]: rfkill: add support for input key to control wireless radio

The RF kill patch that provides infrastructure for implementing
switches controlling radio states on various network and other cards.

[dtor@insightbb.com: address review comments]
[akpm@linux-foundation.org: cleanups, build fixes]
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/rfkill.h

+#ifndef __RFKILL_H
+#define __RFKILL_H
+
+/*
+ * Copyright (C) 2006 Ivo van Doorn
+ * Copyright (C) 2007 Dmitry Torokhov
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the
+ * Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/device.h>
+
+/**
+ * enum rfkill_type - type of rfkill switch.
+ * RFKILL_TYPE_WLAN: switch is no a Wireless network devices.
+ * RFKILL_TYPE_BlUETOOTH: switch is on a bluetooth device.
+ * RFKILL_TYPE_IRDA: switch is on an infrared devices.
+ */
+enum rfkill_type {
+	RFKILL_TYPE_WLAN = 0,
+	RFKILL_TYPE_BLUETOOTH = 1,
+	RFKILL_TYPE_IRDA = 2,
+	RFKILL_TYPE_MAX = 3,
+};
+
+enum rfkill_state {
+	RFKILL_STATE_OFF	= 0,
+	RFKILL_STATE_ON		= 1,
+};
+
+/**
+ * struct rfkill - rfkill control structure.
+ * @name: Name of the switch.
+ * @type: Radio type which the button controls, the value stored
+ *	here should be a value from enum rfkill_type.
+ * @state: State of the switch (on/off).
+ * @user_claim: Set when the switch is controlled exlusively by userspace.
+ * @mutex: Guards switch state transitions
+ * @data: Pointer to the RF button drivers private data which will be
+ *	passed along when toggling radio state.
+ * @toggle_radio(): Mandatory handler to control state of the radio.
+ * @dev: Device structure integrating the switch into device tree.
+ * @node: Used to place switch into list of all switches known to the
+ *	the system.
+ *
+ * This structure represents a RF switch located on a network device.
+ */
+struct rfkill {
+	char *name;
+	enum rfkill_type type;
+
+	enum rfkill_state state;
+	bool user_claim;
+
+	struct mutex mutex;
+
+	void *data;
+	int (*toggle_radio)(void *data, enum rfkill_state state);
+
+	struct device dev;
+	struct list_head node;
+};
+#define to_rfkill(d)	container_of(d, struct rfkill, dev)
+
+struct rfkill *rfkill_allocate(struct device *parent, enum rfkill_type type);
+void rfkill_free(struct rfkill *rfkill);
+int rfkill_register(struct rfkill *rfkill);
+void rfkill_unregister(struct rfkill *rfkill);
+
+void rfkill_switch_all(enum rfkill_type type, enum rfkill_state state);
+
+#endif /* RFKILL_H */

net/Kconfig

@@ -225,6 +225,8 @@ source "net/ieee80211/Kconfig"
 
 endmenu
 
+source "net/rfkill/Kconfig"
+
 endif   # if NET
 endmenu # Networking
 

net/Makefile

@@ -51,6 +51,7 @@ obj-$(CONFIG_IEEE80211)		+= ieee80211/
 obj-$(CONFIG_TIPC)		+= tipc/
 obj-$(CONFIG_NETLABEL)		+= netlabel/
 obj-$(CONFIG_IUCV)		+= iucv/
+obj-$(CONFIG_RFKILL)		+= rfkill/
 
 ifeq ($(CONFIG_NET),y)
 obj-$(CONFIG_SYSCTL)		+= sysctl_net.o

net/rfkill/Kconfig

+#
+# RF switch subsystem configuration
+#
+menuconfig RFKILL
+	tristate "RF switch subsystem support"
+	help
+	  Say Y here if you want to have control over RF switches
+	  found on many WiFi, Bluetooth and IRDA cards.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rfkill.
+
+config RFKILL_INPUT
+	tristate "Input layer to RF switch connector"
+	depends on RFKILL && INPUT
+	help
+	  Say Y here if you want kernel automatically toggle state
+	  of RF switches on and off when user presses appropriate
+	  button or a key on the keyboard. Without this module you
+	  need a some kind of userspace application to control
+	  state of the switches.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rfkill-input.

net/rfkill/Makefile

+#
+# Makefile for the RF switch subsystem.
+#
+
+obj-$(CONFIG_RFKILL)			+= rfkill.o
+obj-$(CONFIG_RFKILL_INPUT)		+= rfkill-input.o

net/rfkill/rfkill-input.c

+/*
+ * Input layer to RF Kill interface connector
+ *
+ * Copyright (c) 2007 Dmitry Torokhov
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/input.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+#include <linux/init.h>
+#include <linux/rfkill.h>
+
+MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
+MODULE_DESCRIPTION("Input layer to RF switch connector");
+MODULE_LICENSE("GPL");
+
+struct rfkill_task {
+	struct work_struct work;
+	enum rfkill_type type;
+	struct mutex mutex; /* ensures that task is serialized */
+	spinlock_t lock; /* for accessing last and desired state */
+	unsigned long last; /* last schedule */
+	enum rfkill_state desired_state; /* on/off */
+	enum rfkill_state current_state; /* on/off */
+};
+
+static void rfkill_task_handler(struct work_struct *work)
+{
+	struct rfkill_task *task = container_of(work, struct rfkill_task, work);
+	enum rfkill_state state;
+
+	mutex_lock(&task->mutex);
+
+	/*
+	 * Use temp variable to fetch desired state to keep it
+	 * consistent even if rfkill_schedule_toggle() runs in
+	 * another thread or interrupts us.
+	 */
+	state = task->desired_state;
+
+	if (state != task->current_state) {
+		rfkill_switch_all(task->type, state);
+		task->current_state = state;
+	}
+
+	mutex_unlock(&task->mutex);
+}
+
+static void rfkill_schedule_toggle(struct rfkill_task *task)
+{
+	unsigned int flags;
+
+	spin_lock_irqsave(&task->lock, flags);
+
+	if (time_after(jiffies, task->last + msecs_to_jiffies(200))) {
+		task->desired_state = !task->desired_state;
+		task->last = jiffies;
+		schedule_work(&task->work);
+	}
+
+	spin_unlock_irqrestore(&task->lock, flags);
+}
+
+#define DEFINE_RFKILL_TASK(n, t)			\
+	struct rfkill_task n = {			\
+		.work = __WORK_INITIALIZER(n.work,	\
+				rfkill_task_handler),	\
+		.type = t,				\
+		.mutex = __MUTEX_INITIALIZER(n.mutex),	\
+		.lock = __SPIN_LOCK_UNLOCKED(n.lock),	\
+		.desired_state = RFKILL_STATE_ON,	\
+		.current_state = RFKILL_STATE_ON,	\
+	}
+
+static DEFINE_RFKILL_TASK(rfkill_wlan, RFKILL_TYPE_WLAN);
+static DEFINE_RFKILL_TASK(rfkill_bt, RFKILL_TYPE_BLUETOOTH);
+
+static void rfkill_event(struct input_handle *handle, unsigned int type,
+		        unsigned int code, int down)
+{
+	if (type == EV_KEY && down == 1) {
+		switch (code) {
+		case KEY_WLAN:
+			rfkill_schedule_toggle(&rfkill_wlan);
+			break;
+		case KEY_BLUETOOTH:
+			rfkill_schedule_toggle(&rfkill_bt);
+			break;
+		default:
+			break;
+		}
+	}
+}
+
+static int rfkill_connect(struct input_handler *handler, struct input_dev *dev,
+			  const struct input_device_id *id)
+{
+	struct input_handle *handle;
+	int error;
+
+	handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL);
+	if (!handle)
+		return -ENOMEM;
+
+	handle->dev = dev;
+	handle->handler = handler;
+	handle->name = "rfkill";
+
+	error = input_register_handle(handle);
+	if (error)
+		goto err_free_handle;
+
+	error = input_open_device(handle);
+	if (error)
+		goto err_unregister_handle;
+
+	return 0;
+
+ err_unregister_handle:
+	input_unregister_handle(handle);
+ err_free_handle:
+	kfree(handle);
+	return error;
+}
+
+static void rfkill_disconnect(struct input_handle *handle)
+{
+	input_close_device(handle);
+	input_unregister_handle(handle);
+	kfree(handle);
+}
+
+static const struct input_device_id rfkill_ids[] = {
+	{
+		.flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
+		.evbit = { BIT(EV_KEY) },
+		.keybit = { [LONG(KEY_WLAN)] = BIT(KEY_WLAN) },
+	},
+	{
+		.flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
+		.evbit = { BIT(EV_KEY) },
+		.keybit = { [LONG(KEY_BLUETOOTH)] = BIT(KEY_BLUETOOTH) },
+	},
+	{ }
+};
+
+static struct input_handler rfkill_handler = {
+	.event =	rfkill_event,
+	.connect =	rfkill_connect,
+	.disconnect =	rfkill_disconnect,
+	.name =		"rfkill",
+	.id_table =	rfkill_ids,
+};
+
+static int __init rfkill_handler_init(void)
+{
+	return input_register_handler(&rfkill_handler);
+}
+
+static void __exit rfkill_handler_exit(void)
+{
+	input_unregister_handler(&rfkill_handler);
+	flush_scheduled_work();
+}
+
+module_init(rfkill_handler_init);
+module_exit(rfkill_handler_exit);

net/rfkill/rfkill.c

+/*
+ * Copyright (C) 2006 Ivo van Doorn
+ * Copyright (C) 2007 Dmitry Torokhov
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the
+ * Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/workqueue.h>
+#include <linux/capability.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/rfkill.h>
+
+MODULE_AUTHOR("Ivo van Doorn <IvDoorn@gmail.com>");
+MODULE_VERSION("1.0");
+MODULE_DESCRIPTION("RF switch support");
+MODULE_LICENSE("GPL");
+
+static LIST_HEAD(rfkill_list);	/* list of registered rf switches */
+static DEFINE_MUTEX(rfkill_mutex);
+
+static enum rfkill_state rfkill_states[RFKILL_TYPE_MAX];
+
+static int rfkill_toggle_radio(struct rfkill *rfkill,
+				enum rfkill_state state)
+{
+	int retval;
+
+	retval = mutex_lock_interruptible(&rfkill->mutex);
+	if (retval)
+		return retval;
+
+	if (state != rfkill->state) {
+		retval = rfkill->toggle_radio(rfkill->data, state);
+		if (!retval)
+			rfkill->state = state;
+	}
+
+	mutex_unlock(&rfkill->mutex);
+	return retval;
+}
+
+/**
+ * rfkill_switch_all - Toggle state of all switches of given type
+ * @type: type of interfaces to be affeceted
+ * @state: the new state
+ *
+ * This function toggles state of all switches of given type unless
+ * a specific switch is claimed by userspace in which case it is
+ * left alone.
+ */
+
+void rfkill_switch_all(enum rfkill_type type, enum rfkill_state state)
+{
+	struct rfkill *rfkill;
+
+	mutex_lock(&rfkill_mutex);
+
+	rfkill_states[type] = state;
+
+	list_for_each_entry(rfkill, &rfkill_list, node) {
+		if (!rfkill->user_claim)
+			rfkill_toggle_radio(rfkill, state);
+	}
+
+	mutex_unlock(&rfkill_mutex);
+}
+EXPORT_SYMBOL(rfkill_switch_all);
+
+static ssize_t rfkill_name_show(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	struct rfkill *rfkill = to_rfkill(dev);
+
+	return sprintf(buf, "%s\n", rfkill->name);
+}
+
+static ssize_t rfkill_type_show(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	struct rfkill *rfkill = to_rfkill(dev);
+	const char *type;
+
+	switch (rfkill->type) {
+	case RFKILL_TYPE_WLAN:
+		type = "wlan";
+		break;
+	case RFKILL_TYPE_BLUETOOTH:
+		type = "bluetooth";
+		break;
+	case RFKILL_TYPE_IRDA:
+		type = "irda";
+		break;
+	default:
+		BUG();
+	}
+
+	return sprintf(buf, "%s\n", type);
+}
+
+static ssize_t rfkill_state_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct rfkill *rfkill = to_rfkill(dev);
+
+	return sprintf(buf, "%d\n", rfkill->state);
+}
+
+static ssize_t rfkill_state_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t count)
+{
+	struct rfkill *rfkill = to_rfkill(dev);
+	unsigned int state = simple_strtoul(buf, NULL, 0);
+	int error;
+
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	error = rfkill_toggle_radio(rfkill,
+			state ? RFKILL_STATE_ON : RFKILL_STATE_OFF);
+	if (error)
+		return error;
+
+	return count;
+}
+
+static ssize_t rfkill_claim_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct rfkill *rfkill = to_rfkill(dev);
+
+	return sprintf(buf, "%d", rfkill->user_claim);
+}
+
+static ssize_t rfkill_claim_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t count)
+{
+	struct rfkill *rfkill = to_rfkill(dev);
+	bool claim = !!simple_strtoul(buf, NULL, 0);
+	int error;
+
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	/*
+	 * Take the global lock to make sure the kernel is not in
+	 * the middle of rfkill_switch_all
+	 */
+	error = mutex_lock_interruptible(&rfkill_mutex);
+	if (error)
+		return error;
+
+	if (rfkill->user_claim != claim) {
+		if (!claim)
+			rfkill_toggle_radio(rfkill,
+					    rfkill_states[rfkill->type]);
+		rfkill->user_claim = claim;
+	}
+
+	mutex_unlock(&rfkill_mutex);
+
+	return count;
+}
+
+static struct device_attribute rfkill_dev_attrs[] = {
+	__ATTR(name, S_IRUGO, rfkill_name_show, NULL),
+	__ATTR(type, S_IRUGO, rfkill_type_show, NULL),
+	__ATTR(state, S_IRUGO, rfkill_state_show, rfkill_state_store),
+	__ATTR(claim, S_IRUGO|S_IWUSR, rfkill_claim_show, rfkill_claim_store),
+	__ATTR_NULL
+};
+
+static void rfkill_release(struct device *dev)
+{
+	struct rfkill *rfkill = to_rfkill(dev);
+
+	kfree(rfkill);
+	module_put(THIS_MODULE);
+}
+
+#ifdef CONFIG_PM
+static int rfkill_suspend(struct device *dev, pm_message_t state)
+{
+	struct rfkill *rfkill = to_rfkill(dev);
+
+	if (dev->power.power_state.event != state.event) {
+		if (state.event == PM_EVENT_SUSPEND) {
+			mutex_lock(&rfkill->mutex);
+
+			if (rfkill->state == RFKILL_STATE_ON)
+				rfkill->toggle_radio(rfkill->data,
+						     RFKILL_STATE_OFF);
+
+			mutex_unlock(&rfkill->mutex);
+		}
+
+		dev->power.power_state = state;
+	}
+
+	return 0;
+}
+
+static int rfkill_resume(struct device *dev)
+{
+	struct rfkill *rfkill = to_rfkill(dev);
+
+	if (dev->power.power_state.event != PM_EVENT_ON) {
+		mutex_lock(&rfkill->mutex);
+
+		if (rfkill->state == RFKILL_STATE_ON)
+			rfkill->toggle_radio(rfkill->data, RFKILL_STATE_ON);
+
+		mutex_unlock(&rfkill->mutex);
+	}
+
+	dev->power.power_state = PMSG_ON;
+	return 0;
+}
+#else
+#define rfkill_suspend NULL
+#define rfkill_resume NULL
+#endif
+
+static struct class rfkill_class = {
+	.name		= "rfkill",
+	.dev_release	= rfkill_release,
+	.dev_attrs	= rfkill_dev_attrs,
+	.suspend	= rfkill_suspend,
+	.resume		= rfkill_resume,
+};
+
+static int rfkill_add_switch(struct rfkill *rfkill)
+{
+	int retval;
+
+	retval = mutex_lock_interruptible(&rfkill_mutex);
+	if (retval)
+		return retval;
+
+	retval = rfkill_toggle_radio(rfkill, rfkill_states[rfkill->type]);
+	if (retval)
+		goto out;
+
+	list_add_tail(&rfkill->node, &rfkill_list);
+
+ out:
+	mutex_unlock(&rfkill_mutex);
+	return retval;
+}
+
+static void rfkill_remove_switch(struct rfkill *rfkill)
+{
+	mutex_lock(&rfkill_mutex);
+	list_del_init(&rfkill->node);
+	rfkill_toggle_radio(rfkill, RFKILL_STATE_OFF);
+	mutex_unlock(&rfkill_mutex);
+}
+
+/**
+ * rfkill_allocate - allocate memory for rfkill structure.
+ * @parent: device that has rf switch on it
+ * @type: type of the switch (wlan, bluetooth, irda)
+ *
+ * This function should be called by the network driver when it needs
+ * rfkill structure. Once the structure is allocated the driver shoud
+ * finish its initialization by setting name, private data, enable_radio
+ * and disable_radio methods and then register it with rfkill_register().
+ * NOTE: If registration fails the structure shoudl be freed by calling
+ * rfkill_free() otherwise rfkill_unregister() should be used.
+ */
+struct rfkill *rfkill_allocate(struct device *parent, enum rfkill_type type)
+{
+	struct rfkill *rfkill;
+	struct device *dev;
+
+	rfkill = kzalloc(sizeof(struct rfkill), GFP_KERNEL);
+	if (rfkill)
+		return NULL;
+
+	mutex_init(&rfkill->mutex);
+	INIT_LIST_HEAD(&rfkill->node);
+	rfkill->type = type;
+
+	dev = &rfkill->dev;
+	dev->class = &rfkill_class;
+	dev->parent = parent;
+	device_initialize(dev);
+
+	__module_get(THIS_MODULE);
+
+	return rfkill;
+}
+EXPORT_SYMBOL(rfkill_allocate);
+
+/**
+ * rfkill_free - Mark rfkill structure for deletion
+ * @rfkill: rfkill structure to be destroyed
+ *
+ * Decrements reference count of rfkill structure so it is destoryed.
+ * Note that rfkill_free() should _not_ be called after rfkill_unregister().
+ */
+void rfkill_free(struct rfkill *rfkill)
+{
+	if (rfkill)
+		put_device(&rfkill->dev);
+}
+EXPORT_SYMBOL(rfkill_free);
+
+/**
+ * rfkill_register - Register a rfkill structure.
+ * @rfkill: rfkill structure to be registered
+ *
+ * This function should be called by the network driver when the rfkill
+ * structure needs to be registered. Immediately from registration the
+ * switch driver should be able to service calls to toggle_radio.
+ */
+int rfkill_register(struct rfkill *rfkill)
+{
+	static atomic_t rfkill_no = ATOMIC_INIT(0);
+	struct device *dev = &rfkill->dev;
+	int error;
+
+	if (!rfkill->toggle_radio)
+		return -EINVAL;
+
+	error = rfkill_add_switch(rfkill);
+	if (error)
+		return error;
+
+	snprintf(dev->bus_id, sizeof(dev->bus_id),
+		 "rfkill%ld", (long)atomic_inc_return(&rfkill_no) - 1);
+
+	error = device_add(dev);
+	if (error) {
+		rfkill_remove_switch(rfkill);
+		return error;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(rfkill_register);
+
+/**
+ * rfkill_unregister - Uegister a rfkill structure.
+ * @rfkill: rfkill structure to be unregistered
+ *
+ * This function should be called by the network driver during device
+ * teardown to destroy rfkill structure. Note that rfkill_free() should
+ * _not_ be called after rfkill_unregister().
+ */
+void rfkill_unregister(struct rfkill *rfkill)
+{
+	device_del(&rfkill->dev);
+	rfkill_remove_switch(rfkill);
+	put_device(&rfkill->dev);
+}
+EXPORT_SYMBOL(rfkill_unregister);
+
+/*
+ * Rfkill module initialization/deinitialization.
+ */
+static int __init rfkill_init(void)
+{
+	int error;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(rfkill_states); i++)
+		rfkill_states[i] = RFKILL_STATE_ON;
+
+	error = class_register(&rfkill_class);
+	if (error) {
+		printk(KERN_ERR "rfkill: unable to register rfkill class\n");
+		return error;
+	}
+
+	return 0;
+}
+
+static void __exit rfkill_exit(void)
+{
+	class_unregister(&rfkill_class);
+}
+
+module_init(rfkill_init);
+module_exit(rfkill_exit);