[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.

[[email protected]: address review comments]
[[email protected]: cleanups, build fixes]

Signed-off-by: Ivo van Doorn <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Dmitry Torokhov <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

include/linux/rfkill.h

@@ -0,0 +1,89 @@
+#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

@@ -0,0 +1,24 @@
+#
+# 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

@@ -0,0 +1,6 @@
+#
+# Makefile for the RF switch subsystem.
+#
+
+obj-$(CONFIG_RFKILL)			+= rfkill.o
+obj-$(CONFIG_RFKILL_INPUT)		+= rfkill-input.o

net/rfkill/rfkill-input.c

@@ -0,0 +1,174 @@
+/*
+ * 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 <[email protected]>");
+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);