[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>

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 <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);