text: /*
   * 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>
  
  #include "rfkill-input.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 long 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 DEFINE_RFKILL_TASK(rfkill_uwb, RFKILL_TYPE_UWB);
  
  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;
  		case KEY_UWB:
  			rfkill_schedule_toggle(&rfkill_uwb);
  			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_MASK(EV_KEY) },
  		.keybit = { [BIT_WORD(KEY_WLAN)] = BIT_MASK(KEY_WLAN) },
  	},
  	{
  		.flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
  		.evbit = { BIT_MASK(EV_KEY) },
  		.keybit = { [BIT_WORD(KEY_BLUETOOTH)] = BIT_MASK(KEY_BLUETOOTH) },
  	},
  	{
  		.flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
  		.evbit = { BIT_MASK(EV_KEY) },
  		.keybit = { [BIT_WORD(KEY_UWB)] = BIT_MASK(KEY_UWB) },
  	},
  	{ }
  };
  
  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);
  