rfkill: rewrite

This patch completely rewrites the rfkill core to address
the following deficiencies:

 * all rfkill drivers need to implement polling where necessary
   rather than having one central implementation

 * updating the rfkill state cannot be done from arbitrary
   contexts, forcing drivers to use schedule_work and requiring
   lots of code

 * rfkill drivers need to keep track of soft/hard blocked
   internally -- the core should do this

 * the rfkill API has many unexpected quirks, for example being
   asymmetric wrt. alloc/free and register/unregister

 * rfkill can call back into a driver from within a function the
   driver called -- this is prone to deadlocks and generally
   should be avoided

 * rfkill-input pointlessly is a separate module

 * drivers need to #ifdef rfkill functions (unless they want to
   depend on or select RFKILL) -- rfkill should provide inlines
   that do nothing if it isn't compiled in

 * the rfkill structure is not opaque -- drivers need to initialise
   it correctly (lots of sanity checking code required) -- instead
   force drivers to pass the right variables to rfkill_alloc()

 * the documentation is hard to read because it always assumes the
   reader is completely clueless and contains way TOO MANY CAPS

 * the rfkill code needlessly uses a lot of locks and atomic
   operations in locked sections

 * fix LED trigger to actually change the LED when the radio state
   changes -- this wasn't done before

Tested-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br> [thinkpad]
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 896 insertions, 0 deletions

diff --git a/net/rfkill/core.c b/net/rfkill/core.c
new file mode 100644
index 000000000000..30a6f8d819b2
--- /dev/null
+++ b/net/rfkill/core.c
@@ -0,0 +1,896 @@
+/*
+ * Copyright (C) 2006 - 2007 Ivo van Doorn
+ * Copyright (C) 2007 Dmitry Torokhov
+ * Copyright 2009 Johannes Berg <johannes@sipsolutions.net>
+ *
+ * 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>
+#include <linux/spinlock.h>
+
+#include "rfkill.h"
+
+#define POLL_INTERVAL		(5 * HZ)
+
+#define RFKILL_BLOCK_HW		BIT(0)
+#define RFKILL_BLOCK_SW		BIT(1)
+#define RFKILL_BLOCK_SW_PREV	BIT(2)
+#define RFKILL_BLOCK_ANY	(RFKILL_BLOCK_HW |\
+				 RFKILL_BLOCK_SW |\
+				 RFKILL_BLOCK_SW_PREV)
+#define RFKILL_BLOCK_SW_SETCALL	BIT(31)
+
+struct rfkill {
+	spinlock_t		lock;
+
+	const char		*name;
+	enum rfkill_type	type;
+
+	unsigned long		state;
+
+	bool			registered;
+	bool			suspended;
+
+	const struct rfkill_ops	*ops;
+	void			*data;
+
+#ifdef CONFIG_RFKILL_LEDS
+	struct led_trigger	led_trigger;
+	const char		*ledtrigname;
+#endif
+
+	struct device		dev;
+	struct list_head	node;
+
+	struct delayed_work	poll_work;
+	struct work_struct	uevent_work;
+	struct work_struct	sync_work;
+};
+#define to_rfkill(d)	container_of(d, struct rfkill, dev)
+
+
+
+MODULE_AUTHOR("Ivo van Doorn <IvDoorn@gmail.com>");
+MODULE_AUTHOR("Johannes Berg <johannes@sipsolutions.net>");
+MODULE_DESCRIPTION("RF switch support");
+MODULE_LICENSE("GPL");
+
+
+/*
+ * The locking here should be made much smarter, we currently have
+ * a bit of a stupid situation because drivers might want to register
+ * the rfkill struct under their own lock, and take this lock during
+ * rfkill method calls -- which will cause an AB-BA deadlock situation.
+ *
+ * To fix that, we need to rework this code here to be mostly lock-free
+ * and only use the mutex for list manipulations, not to protect the
+ * various other global variables. Then we can avoid holding the mutex
+ * around driver operations, and all is happy.
+ */
+static LIST_HEAD(rfkill_list);	/* list of registered rf switches */
+static DEFINE_MUTEX(rfkill_global_mutex);
+
+static unsigned int rfkill_default_state = 1;
+module_param_named(default_state, rfkill_default_state, uint, 0444);
+MODULE_PARM_DESC(default_state,
+		 "Default initial state for all radio types, 0 = radio off");
+
+static struct {
+	bool cur, def;
+} rfkill_global_states[NUM_RFKILL_TYPES];
+
+static unsigned long rfkill_states_default_locked;
+
+static bool rfkill_epo_lock_active;
+
+
+#ifdef CONFIG_RFKILL_LEDS
+static void rfkill_led_trigger_event(struct rfkill *rfkill)
+{
+	struct led_trigger *trigger;
+
+	if (!rfkill->registered)
+		return;
+
+	trigger = &rfkill->led_trigger;
+
+	if (rfkill->state & RFKILL_BLOCK_ANY)
+		led_trigger_event(trigger, LED_OFF);
+	else
+		led_trigger_event(trigger, LED_FULL);
+}
+
+static void rfkill_led_trigger_activate(struct led_classdev *led)
+{
+	struct rfkill *rfkill;
+
+	rfkill = container_of(led->trigger, struct rfkill, led_trigger);
+
+	rfkill_led_trigger_event(rfkill);
+}
+
+const char *rfkill_get_led_trigger_name(struct rfkill *rfkill)
+{
+	return rfkill->led_trigger.name;
+}
+EXPORT_SYMBOL(rfkill_get_led_trigger_name);
+
+void rfkill_set_led_trigger_name(struct rfkill *rfkill, const char *name)
+{
+	BUG_ON(!rfkill);
+
+	rfkill->ledtrigname = name;
+}
+EXPORT_SYMBOL(rfkill_set_led_trigger_name);
+
+static int rfkill_led_trigger_register(struct rfkill *rfkill)
+{
+	rfkill->led_trigger.name = rfkill->ledtrigname
+					? : dev_name(&rfkill->dev);
+	rfkill->led_trigger.activate = rfkill_led_trigger_activate;
+	return led_trigger_register(&rfkill->led_trigger);
+}
+
+static void rfkill_led_trigger_unregister(struct rfkill *rfkill)
+{
+	led_trigger_unregister(&rfkill->led_trigger);
+}
+#else
+static void rfkill_led_trigger_event(struct rfkill *rfkill)
+{
+}
+
+static inline int rfkill_led_trigger_register(struct rfkill *rfkill)
+{
+	return 0;
+}
+
+static inline void rfkill_led_trigger_unregister(struct rfkill *rfkill)
+{
+}
+#endif /* CONFIG_RFKILL_LEDS */
+
+static void rfkill_uevent(struct rfkill *rfkill)
+{
+	if (!rfkill->registered || rfkill->suspended)
+		return;
+
+	kobject_uevent(&rfkill->dev.kobj, KOBJ_CHANGE);
+}
+
+static bool __rfkill_set_hw_state(struct rfkill *rfkill,
+				  bool blocked, bool *change)
+{
+	unsigned long flags;
+	bool prev, any;
+
+	BUG_ON(!rfkill);
+
+	spin_lock_irqsave(&rfkill->lock, flags);
+	prev = !!(rfkill->state & RFKILL_BLOCK_HW);
+	if (blocked)
+		rfkill->state |= RFKILL_BLOCK_HW;
+	else
+		rfkill->state &= ~RFKILL_BLOCK_HW;
+	*change = prev != blocked;
+	any = rfkill->state & RFKILL_BLOCK_ANY;
+	spin_unlock_irqrestore(&rfkill->lock, flags);
+
+	rfkill_led_trigger_event(rfkill);
+
+	return any;
+}
+
+/**
+ * rfkill_set_block - wrapper for set_block method
+ *
+ * @rfkill: the rfkill struct to use
+ * @blocked: the new software state
+ *
+ * Calls the set_block method (when applicable) and handles notifications
+ * etc. as well.
+ */
+static void rfkill_set_block(struct rfkill *rfkill, bool blocked)
+{
+	unsigned long flags;
+	int err;
+
+	/*
+	 * Some platforms (...!) generate input events which affect the
+	 * _hard_ kill state -- whenever something tries to change the
+	 * current software state query the hardware state too.
+	 */
+	if (rfkill->ops->query)
+		rfkill->ops->query(rfkill, rfkill->data);
+
+	spin_lock_irqsave(&rfkill->lock, flags);
+	if (rfkill->state & RFKILL_BLOCK_SW)
+		rfkill->state |= RFKILL_BLOCK_SW_PREV;
+	else
+		rfkill->state &= ~RFKILL_BLOCK_SW_PREV;
+
+	if (blocked)
+		rfkill->state |= RFKILL_BLOCK_SW;
+	else
+		rfkill->state &= ~RFKILL_BLOCK_SW;
+
+	rfkill->state |= RFKILL_BLOCK_SW_SETCALL;
+	spin_unlock_irqrestore(&rfkill->lock, flags);
+
+	if (unlikely(rfkill->dev.power.power_state.event & PM_EVENT_SLEEP))
+		return;
+
+	err = rfkill->ops->set_block(rfkill->data, blocked);
+
+	spin_lock_irqsave(&rfkill->lock, flags);
+	if (err) {
+		/*
+		 * Failed -- reset status to _prev, this may be different
+		 * from what set set _PREV to earlier in this function
+		 * if rfkill_set_sw_state was invoked.
+		 */
+		if (rfkill->state & RFKILL_BLOCK_SW_PREV)
+			rfkill->state |= RFKILL_BLOCK_SW;
+		else
+			rfkill->state &= ~RFKILL_BLOCK_SW;
+	}
+	rfkill->state &= ~RFKILL_BLOCK_SW_SETCALL;
+	rfkill->state &= ~RFKILL_BLOCK_SW_PREV;
+	spin_unlock_irqrestore(&rfkill->lock, flags);
+
+	rfkill_led_trigger_event(rfkill);
+	rfkill_uevent(rfkill);
+}
+
+/**
+ * __rfkill_switch_all - Toggle state of all switches of given type
+ * @type: type of interfaces to be affected
+ * @state: the new state
+ *
+ * This function sets the state of all switches of given type,
+ * unless a specific switch is claimed by userspace (in which case,
+ * that switch is left alone) or suspended.
+ *
+ * Caller must have acquired rfkill_global_mutex.
+ */
+static void __rfkill_switch_all(const enum rfkill_type type, bool blocked)
+{
+	struct rfkill *rfkill;
+
+	rfkill_global_states[type].cur = blocked;
+	list_for_each_entry(rfkill, &rfkill_list, node) {
+		if (rfkill->type != type)
+			continue;
+
+		rfkill_set_block(rfkill, blocked);
+	}
+}
+
+/**
+ * rfkill_switch_all - Toggle state of all switches of given type
+ * @type: type of interfaces to be affected
+ * @state: the new state
+ *
+ * Acquires rfkill_global_mutex and calls __rfkill_switch_all(@type, @state).
+ * Please refer to __rfkill_switch_all() for details.
+ *
+ * Does nothing if the EPO lock is active.
+ */
+void rfkill_switch_all(enum rfkill_type type, bool blocked)
+{
+	mutex_lock(&rfkill_global_mutex);
+
+	if (!rfkill_epo_lock_active)
+		__rfkill_switch_all(type, blocked);
+
+	mutex_unlock(&rfkill_global_mutex);
+}
+
+/**
+ * rfkill_epo - emergency power off all transmitters
+ *
+ * This kicks all non-suspended rfkill devices to RFKILL_STATE_SOFT_BLOCKED,
+ * ignoring everything in its path but rfkill_global_mutex and rfkill->mutex.
+ *
+ * The global state before the EPO is saved and can be restored later
+ * using rfkill_restore_states().
+ */
+void rfkill_epo(void)
+{
+	struct rfkill *rfkill;
+	int i;
+
+	mutex_lock(&rfkill_global_mutex);
+
+	rfkill_epo_lock_active = true;
+	list_for_each_entry(rfkill, &rfkill_list, node)
+		rfkill_set_block(rfkill, true);
+
+	for (i = 0; i < NUM_RFKILL_TYPES; i++) {
+		rfkill_global_states[i].def = rfkill_global_states[i].cur;
+		rfkill_global_states[i].cur = true;
+	}
+	mutex_unlock(&rfkill_global_mutex);
+}
+
+/**
+ * rfkill_restore_states - restore global states
+ *
+ * Restore (and sync switches to) the global state from the
+ * states in rfkill_default_states.  This can undo the effects of
+ * a call to rfkill_epo().
+ */
+void rfkill_restore_states(void)
+{
+	int i;
+
+	mutex_lock(&rfkill_global_mutex);
+
+	rfkill_epo_lock_active = false;
+	for (i = 0; i < NUM_RFKILL_TYPES; i++)
+		__rfkill_switch_all(i, rfkill_global_states[i].def);
+	mutex_unlock(&rfkill_global_mutex);
+}
+
+/**
+ * rfkill_remove_epo_lock - unlock state changes
+ *
+ * Used by rfkill-input manually unlock state changes, when
+ * the EPO switch is deactivated.
+ */
+void rfkill_remove_epo_lock(void)
+{
+	mutex_lock(&rfkill_global_mutex);
+	rfkill_epo_lock_active = false;
+	mutex_unlock(&rfkill_global_mutex);
+}
+
+/**
+ * rfkill_is_epo_lock_active - returns true EPO is active
+ *
+ * Returns 0 (false) if there is NOT an active EPO contidion,
+ * and 1 (true) if there is an active EPO contition, which
+ * locks all radios in one of the BLOCKED states.
+ *
+ * Can be called in atomic context.
+ */
+bool rfkill_is_epo_lock_active(void)
+{
+	return rfkill_epo_lock_active;
+}
+
+/**
+ * rfkill_get_global_sw_state - returns global state for a type
+ * @type: the type to get the global state of
+ *
+ * Returns the current global state for a given wireless
+ * device type.
+ */
+bool rfkill_get_global_sw_state(const enum rfkill_type type)
+{
+	return rfkill_global_states[type].cur;
+}
+
+void rfkill_set_global_sw_state(const enum rfkill_type type, bool blocked)
+{
+	mutex_lock(&rfkill_global_mutex);
+
+	/* don't allow unblock when epo */
+	if (rfkill_epo_lock_active && !blocked)
+		goto out;
+
+	/* too late */
+	if (rfkill_states_default_locked & BIT(type))
+		goto out;
+
+	rfkill_states_default_locked |= BIT(type);
+
+	rfkill_global_states[type].cur = blocked;
+	rfkill_global_states[type].def = blocked;
+ out:
+	mutex_unlock(&rfkill_global_mutex);
+}
+EXPORT_SYMBOL(rfkill_set_global_sw_state);
+
+
+bool rfkill_set_hw_state(struct rfkill *rfkill, bool blocked)
+{
+	bool ret, change;
+
+	ret = __rfkill_set_hw_state(rfkill, blocked, &change);
+
+	if (!rfkill->registered)
+		return ret;
+
+	if (change)
+		schedule_work(&rfkill->uevent_work);
+
+	return ret;
+}
+EXPORT_SYMBOL(rfkill_set_hw_state);
+
+static void __rfkill_set_sw_state(struct rfkill *rfkill, bool blocked)
+{
+	u32 bit = RFKILL_BLOCK_SW;
+
+	/* if in a ops->set_block right now, use other bit */
+	if (rfkill->state & RFKILL_BLOCK_SW_SETCALL)
+		bit = RFKILL_BLOCK_SW_PREV;
+
+	if (blocked)
+		rfkill->state |= bit;
+	else
+		rfkill->state &= ~bit;
+}
+
+bool rfkill_set_sw_state(struct rfkill *rfkill, bool blocked)
+{
+	unsigned long flags;
+	bool prev, hwblock;
+
+	BUG_ON(!rfkill);
+
+	spin_lock_irqsave(&rfkill->lock, flags);
+	prev = !!(rfkill->state & RFKILL_BLOCK_SW);
+	__rfkill_set_sw_state(rfkill, blocked);
+	hwblock = !!(rfkill->state & RFKILL_BLOCK_HW);
+	blocked = blocked || hwblock;
+	spin_unlock_irqrestore(&rfkill->lock, flags);
+
+	if (!rfkill->registered)
+		return blocked;
+
+	if (prev != blocked && !hwblock)
+		schedule_work(&rfkill->uevent_work);
+
+	rfkill_led_trigger_event(rfkill);
+
+	return blocked;
+}
+EXPORT_SYMBOL(rfkill_set_sw_state);
+
+void rfkill_set_states(struct rfkill *rfkill, bool sw, bool hw)
+{
+	unsigned long flags;
+	bool swprev, hwprev;
+
+	BUG_ON(!rfkill);
+
+	spin_lock_irqsave(&rfkill->lock, flags);
+
+	/*
+	 * No need to care about prev/setblock ... this is for uevent only
+	 * and that will get triggered by rfkill_set_block anyway.
+	 */
+	swprev = !!(rfkill->state & RFKILL_BLOCK_SW);
+	hwprev = !!(rfkill->state & RFKILL_BLOCK_HW);
+	__rfkill_set_sw_state(rfkill, sw);
+
+	spin_unlock_irqrestore(&rfkill->lock, flags);
+
+	if (!rfkill->registered)
+		return;
+
+	if (swprev != sw || hwprev != hw)
+		schedule_work(&rfkill->uevent_work);
+
+	rfkill_led_trigger_event(rfkill);
+}
+EXPORT_SYMBOL(rfkill_set_states);
+
+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 const char *rfkill_get_type_str(enum rfkill_type type)
+{
+	switch (type) {
+	case RFKILL_TYPE_WLAN:
+		return "wlan";
+	case RFKILL_TYPE_BLUETOOTH:
+		return "bluetooth";
+	case RFKILL_TYPE_UWB:
+		return "ultrawideband";
+	case RFKILL_TYPE_WIMAX:
+		return "wimax";
+	case RFKILL_TYPE_WWAN:
+		return "wwan";
+	default:
+		BUG();
+	}
+
+	BUILD_BUG_ON(NUM_RFKILL_TYPES != RFKILL_TYPE_WWAN + 1);
+}
+
+static ssize_t rfkill_type_show(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	struct rfkill *rfkill = to_rfkill(dev);
+
+	return sprintf(buf, "%s\n", rfkill_get_type_str(rfkill->type));
+}
+
+static u8 user_state_from_blocked(unsigned long state)
+{
+	if (state & RFKILL_BLOCK_HW)
+		return RFKILL_USER_STATE_HARD_BLOCKED;
+	if (state & RFKILL_BLOCK_SW)
+		return RFKILL_USER_STATE_SOFT_BLOCKED;
+
+	return RFKILL_USER_STATE_UNBLOCKED;
+}
+
+static ssize_t rfkill_state_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct rfkill *rfkill = to_rfkill(dev);
+	unsigned long flags;
+	u32 state;
+
+	spin_lock_irqsave(&rfkill->lock, flags);
+	state = rfkill->state;
+	spin_unlock_irqrestore(&rfkill->lock, flags);
+
+	return sprintf(buf, "%d\n", user_state_from_blocked(state));
+}
+
+static ssize_t rfkill_state_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t count)
+{
+	/*
+	 * The intention was that userspace can only take control over
+	 * a given device when/if rfkill-input doesn't control it due
+	 * to user_claim. Since user_claim is currently unsupported,
+	 * we never support changing the state from userspace -- this
+	 * can be implemented again later.
+	 */
+
+	return -EPERM;
+}
+
+static ssize_t rfkill_claim_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	return sprintf(buf, "%d\n", 0);
+}
+
+static ssize_t rfkill_claim_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t count)
+{
+	return -EOPNOTSUPP;
+}
+
+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|S_IWUSR, 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);
+}
+
+static int rfkill_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct rfkill *rfkill = to_rfkill(dev);
+	unsigned long flags;
+	u32 state;
+	int error;
+
+	error = add_uevent_var(env, "RFKILL_NAME=%s", rfkill->name);
+	if (error)
+		return error;
+	error = add_uevent_var(env, "RFKILL_TYPE=%s",
+			       rfkill_get_type_str(rfkill->type));
+	if (error)
+		return error;
+	spin_lock_irqsave(&rfkill->lock, flags);
+	state = rfkill->state;
+	spin_unlock_irqrestore(&rfkill->lock, flags);
+	error = add_uevent_var(env, "RFKILL_STATE=%d",
+			       user_state_from_blocked(state));
+	return error;
+}
+
+void rfkill_pause_polling(struct rfkill *rfkill)
+{
+	BUG_ON(!rfkill);
+
+	if (!rfkill->ops->poll)
+		return;
+
+	cancel_delayed_work_sync(&rfkill->poll_work);
+}
+EXPORT_SYMBOL(rfkill_pause_polling);
+
+void rfkill_resume_polling(struct rfkill *rfkill)
+{
+	BUG_ON(!rfkill);
+
+	if (!rfkill->ops->poll)
+		return;
+
+	schedule_work(&rfkill->poll_work.work);
+}
+EXPORT_SYMBOL(rfkill_resume_polling);
+
+static int rfkill_suspend(struct device *dev, pm_message_t state)
+{
+	struct rfkill *rfkill = to_rfkill(dev);
+
+	rfkill_pause_polling(rfkill);
+
+	rfkill->suspended = true;
+
+	return 0;
+}
+
+static int rfkill_resume(struct device *dev)
+{
+	struct rfkill *rfkill = to_rfkill(dev);
+	bool cur;
+
+	mutex_lock(&rfkill_global_mutex);
+	cur = rfkill_global_states[rfkill->type].cur;
+	rfkill_set_block(rfkill, cur);
+	mutex_unlock(&rfkill_global_mutex);
+
+	rfkill->suspended = false;
+
+	schedule_work(&rfkill->uevent_work);
+
+	rfkill_resume_polling(rfkill);
+
+	return 0;
+}
+
+static struct class rfkill_class = {
+	.name		= "rfkill",
+	.dev_release	= rfkill_release,
+	.dev_attrs	= rfkill_dev_attrs,
+	.dev_uevent	= rfkill_dev_uevent,
+	.suspend	= rfkill_suspend,
+	.resume		= rfkill_resume,
+};
+
+
+struct rfkill * __must_check rfkill_alloc(const char *name,
+					  struct device *parent,
+					  const enum rfkill_type type,
+					  const struct rfkill_ops *ops,
+					  void *ops_data)
+{
+	struct rfkill *rfkill;
+	struct device *dev;
+
+	if (WARN_ON(!ops))
+		return NULL;
+
+	if (WARN_ON(!ops->set_block))
+		return NULL;
+
+	if (WARN_ON(!name))
+		return NULL;
+
+	if (WARN_ON(type >= NUM_RFKILL_TYPES))
+		return NULL;
+
+	rfkill = kzalloc(sizeof(*rfkill), GFP_KERNEL);
+	if (!rfkill)
+		return NULL;
+
+	spin_lock_init(&rfkill->lock);
+	INIT_LIST_HEAD(&rfkill->node);
+	rfkill->type = type;
+	rfkill->name = name;
+	rfkill->ops = ops;
+	rfkill->data = ops_data;
+
+	dev = &rfkill->dev;
+	dev->class = &rfkill_class;
+	dev->parent = parent;
+	device_initialize(dev);
+
+	return rfkill;
+}
+EXPORT_SYMBOL(rfkill_alloc);
+
+static void rfkill_poll(struct work_struct *work)
+{
+	struct rfkill *rfkill;
+
+	rfkill = container_of(work, struct rfkill, poll_work.work);
+
+	/*
+	 * Poll hardware state -- driver will use one of the
+	 * rfkill_set{,_hw,_sw}_state functions and use its
+	 * return value to update the current status.
+	 */
+	rfkill->ops->poll(rfkill, rfkill->data);
+
+	schedule_delayed_work(&rfkill->poll_work,
+		round_jiffies_relative(POLL_INTERVAL));
+}
+
+static void rfkill_uevent_work(struct work_struct *work)
+{
+	struct rfkill *rfkill;
+
+	rfkill = container_of(work, struct rfkill, uevent_work);
+
+	rfkill_uevent(rfkill);
+}
+
+static void rfkill_sync_work(struct work_struct *work)
+{
+	struct rfkill *rfkill;
+	bool cur;
+
+	rfkill = container_of(work, struct rfkill, sync_work);
+
+	mutex_lock(&rfkill_global_mutex);
+	cur = rfkill_global_states[rfkill->type].cur;
+	rfkill_set_block(rfkill, cur);
+	mutex_unlock(&rfkill_global_mutex);
+}
+
+int __must_check rfkill_register(struct rfkill *rfkill)
+{
+	static unsigned long rfkill_no;
+	struct device *dev = &rfkill->dev;
+	int error;
+
+	BUG_ON(!rfkill);
+
+	mutex_lock(&rfkill_global_mutex);
+
+	if (rfkill->registered) {
+		error = -EALREADY;
+		goto unlock;
+	}
+
+	dev_set_name(dev, "rfkill%lu", rfkill_no);
+	rfkill_no++;
+
+	if (!(rfkill_states_default_locked & BIT(rfkill->type))) {
+		/* first of its kind */
+		BUILD_BUG_ON(NUM_RFKILL_TYPES >
+			sizeof(rfkill_states_default_locked) * 8);
+		rfkill_states_default_locked |= BIT(rfkill->type);
+		rfkill_global_states[rfkill->type].cur =
+			rfkill_global_states[rfkill->type].def;
+	}
+
+	list_add_tail(&rfkill->node, &rfkill_list);
+
+	error = device_add(dev);
+	if (error)
+		goto remove;
+
+	error = rfkill_led_trigger_register(rfkill);
+	if (error)
+		goto devdel;
+
+	rfkill->registered = true;
+
+	if (rfkill->ops->poll) {
+		INIT_DELAYED_WORK(&rfkill->poll_work, rfkill_poll);
+		schedule_delayed_work(&rfkill->poll_work,
+			round_jiffies_relative(POLL_INTERVAL));
+	}
+
+	INIT_WORK(&rfkill->uevent_work, rfkill_uevent_work);
+
+	INIT_WORK(&rfkill->sync_work, rfkill_sync_work);
+	schedule_work(&rfkill->sync_work);
+
+	mutex_unlock(&rfkill_global_mutex);
+	return 0;
+
+ devdel:
+	device_del(&rfkill->dev);
+ remove:
+	list_del_init(&rfkill->node);
+ unlock:
+	mutex_unlock(&rfkill_global_mutex);
+	return error;
+}
+EXPORT_SYMBOL(rfkill_register);
+
+void rfkill_unregister(struct rfkill *rfkill)
+{
+	BUG_ON(!rfkill);
+
+	if (rfkill->ops->poll)
+		cancel_delayed_work_sync(&rfkill->poll_work);
+
+	cancel_work_sync(&rfkill->uevent_work);
+	cancel_work_sync(&rfkill->sync_work);
+
+	rfkill->registered = false;
+
+	device_del(&rfkill->dev);
+
+	mutex_lock(&rfkill_global_mutex);
+	list_del_init(&rfkill->node);
+	mutex_unlock(&rfkill_global_mutex);
+
+	rfkill_led_trigger_unregister(rfkill);
+}
+EXPORT_SYMBOL(rfkill_unregister);
+
+void rfkill_destroy(struct rfkill *rfkill)
+{
+	if (rfkill)
+		put_device(&rfkill->dev);
+}
+EXPORT_SYMBOL(rfkill_destroy);
+
+
+static int __init rfkill_init(void)
+{
+	int error;
+	int i;
+
+	for (i = 0; i < NUM_RFKILL_TYPES; i++)
+		rfkill_global_states[i].def = !rfkill_default_state;
+
+	error = class_register(&rfkill_class);
+	if (error)
+		goto out;
+
+#ifdef CONFIG_RFKILL_INPUT
+	error = rfkill_handler_init();
+	if (error)
+		class_unregister(&rfkill_class);
+#endif
+
+ out:
+	return error;
+}
+subsys_initcall(rfkill_init);
+
+static void __exit rfkill_exit(void)
+{
+#ifdef CONFIG_RFKILL_INPUT
+	rfkill_handler_exit();
+#endif
+	class_unregister(&rfkill_class);
+}
+module_exit(rfkill_exit);