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Commit b320ff21 authored by Todd Poynor's avatar Todd Poynor Committed by Amit Pundir
Browse files

usb: otg: Temporarily grab wakelock on charger and disconnect events 



Change-Id: If995d4af4adcb08e8369009483f2956ad9627267
Signed-off-by: default avatarTodd Poynor <toddpoynor@google.com>
parent c5348282

drivers/usb/phy/otg-wakelock.c

+56 −77
Original line number Diff line number Diff line
@@ -21,13 +21,15 @@ 
#include <linux/spinlock.h>

#include <linux/usb/otg.h>



#define TEMPORARY_HOLD_TIME	2000



static bool enabled = true;

static struct otg_transceiver *otgwl_xceiv;

static struct notifier_block otgwl_nb;



/*

 * otgwl_spinlock is held while the VBUS lock is grabbed or dropped and the

 * locked field is updated to match.

 * held field is updated to match.

 */



static DEFINE_SPINLOCK(otgwl_spinlock);
@@ -39,51 +41,62 @@ static DEFINE_SPINLOCK(otgwl_spinlock); 
struct otgwl_lock {

	char name[40];

	struct wake_lock wakelock;

	bool locked;

	bool held;

};



/*

 * VBUS present lock.

 * VBUS present lock.  Also used as a timed lock on charger

 * connect/disconnect and USB host disconnect, to allow the system

 * to react to the change in power.

 */



static struct otgwl_lock vbus_lock;



static void otgwl_grab(struct otgwl_lock *lock)

static void otgwl_hold(struct otgwl_lock *lock)

{

	if (!lock->locked) {

	if (!lock->held) {

		wake_lock(&lock->wakelock);

		lock->locked = true;

		lock->held = true;

	}

}



static void otgwl_temporary_hold(struct otgwl_lock *lock)

{

	wake_lock_timeout(&lock->wakelock,

			  msecs_to_jiffies(TEMPORARY_HOLD_TIME));

	lock->held = false;

}



static void otgwl_drop(struct otgwl_lock *lock)

{

	if (lock->locked) {

	if (lock->held) {

		wake_unlock(&lock->wakelock);

		lock->locked = false;

		lock->held = false;

	}

}



static int otgwl_otg_notifications(struct notifier_block *nb,

				   unsigned long event, void *unused)

static void otgwl_handle_event(unsigned long event)

{

	unsigned long irqflags;



	if (!enabled)

		return NOTIFY_OK;



	spin_lock_irqsave(&otgwl_spinlock, irqflags);



	if (!enabled) {

		otgwl_drop(&vbus_lock);

		spin_unlock_irqrestore(&otgwl_spinlock, irqflags);

		return;

	}



	switch (event) {

	case USB_EVENT_VBUS:

	case USB_EVENT_ENUMERATED:

		otgwl_grab(&vbus_lock);

		otgwl_hold(&vbus_lock);

		break;



	case USB_EVENT_NONE:

	case USB_EVENT_ID:

	case USB_EVENT_CHARGER:

		otgwl_drop(&vbus_lock);

		otgwl_temporary_hold(&vbus_lock);

		break;



	default:
@@ -91,71 +104,25 @@ static int otgwl_otg_notifications(struct notifier_block *nb, 
	}



	spin_unlock_irqrestore(&otgwl_spinlock, irqflags);

	return NOTIFY_OK;

}



static void sync_with_xceiv_state(void)

{

	if ((otgwl_xceiv->last_event == USB_EVENT_VBUS) ||

	    (otgwl_xceiv->last_event == USB_EVENT_ENUMERATED))

		otgwl_grab(&vbus_lock);

	else

		otgwl_drop(&vbus_lock);

}



static int init_for_xceiv(void)

static int otgwl_otg_notifications(struct notifier_block *nb,

				   unsigned long event, void *unused)

{

	int rv;



	if (!otgwl_xceiv) {

		otgwl_xceiv = otg_get_transceiver();



		if (!otgwl_xceiv) {

			pr_err("%s: No OTG transceiver found\n", __func__);

			return -ENODEV;

		}



		snprintf(vbus_lock.name, sizeof(vbus_lock.name), "vbus-%s",

			 dev_name(otgwl_xceiv->dev));

		wake_lock_init(&vbus_lock.wakelock, WAKE_LOCK_SUSPEND,

			       vbus_lock.name);



		rv = otg_register_notifier(otgwl_xceiv, &otgwl_nb);



		if (rv) {

			pr_err("%s: otg_register_notifier on transceiver %s"

			       " failed\n", __func__,

			       dev_name(otgwl_xceiv->dev));

			otgwl_xceiv = NULL;

			wake_lock_destroy(&vbus_lock.wakelock);

			return rv;

		}

	}



	return 0;

	otgwl_handle_event(event);

	return NOTIFY_OK;

}



static int set_enabled(const char *val, const struct kernel_param *kp)

{

	unsigned long irqflags;

	int rv = param_set_bool(val, kp);



	if (rv)

		return rv;



	rv = init_for_xceiv();

	if (otgwl_xceiv)

		otgwl_handle_event(otgwl_xceiv->last_event);



	if (rv)

		return rv;



	spin_lock_irqsave(&otgwl_spinlock, irqflags);



	if (enabled)

		sync_with_xceiv_state();

	else

		otgwl_drop(&vbus_lock);



	spin_unlock_irqrestore(&otgwl_spinlock, irqflags);

	return 0;

}
@@ -169,22 +136,34 @@ MODULE_PARM_DESC(enabled, "enable wakelock when VBUS present"); 


static int __init otg_wakelock_init(void)

{

	unsigned long irqflags;

	int ret;



	otgwl_nb.notifier_call = otgwl_otg_notifications;

	otgwl_xceiv = otg_get_transceiver();



	if (!init_for_xceiv()) {

		spin_lock_irqsave(&otgwl_spinlock, irqflags);

	if (!otgwl_xceiv) {

		pr_err("%s: No OTG transceiver found\n", __func__);

		return -ENODEV;

	}



		if (enabled)

			sync_with_xceiv_state();

	snprintf(vbus_lock.name, sizeof(vbus_lock.name), "vbus-%s",

		 dev_name(otgwl_xceiv->dev));

	wake_lock_init(&vbus_lock.wakelock, WAKE_LOCK_SUSPEND,

		       vbus_lock.name);



		spin_unlock_irqrestore(&otgwl_spinlock, irqflags);

	} else {

		enabled = false;

	otgwl_nb.notifier_call = otgwl_otg_notifications;

	ret = otg_register_notifier(otgwl_xceiv, &otgwl_nb);



	if (ret) {

		pr_err("%s: otg_register_notifier on transceiver %s"

		       " failed\n", __func__,

		       dev_name(otgwl_xceiv->dev));

		otgwl_xceiv = NULL;

		wake_lock_destroy(&vbus_lock.wakelock);

		return ret;

	}



	return 0;

	otgwl_handle_event(otgwl_xceiv->last_event);

	return ret;

}



late_initcall(otg_wakelock_init);