diff --git a/drivers/base/power/Makefile b/drivers/base/power/Makefile
index 911208b..3ce3519 100644
--- a/drivers/base/power/Makefile
+++ b/drivers/base/power/Makefile
@@ -1,5 +1,6 @@
 obj-$(CONFIG_PM)	+= sysfs.o
 obj-$(CONFIG_PM_SLEEP)	+= main.o
+obj-$(CONFIG_PM_RUNTIME)	+= runtime.o
 obj-$(CONFIG_PM_TRACE_RTC)	+= trace.o
 
 ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 1b1a786..8699001 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -21,6 +21,7 @@
 #include <linux/kallsyms.h>
 #include <linux/mutex.h>
 #include <linux/pm.h>
+#include <linux/pm_runtime.h>
 #include <linux/resume-trace.h>
 #include <linux/rwsem.h>
 #include <linux/interrupt.h>
@@ -49,6 +50,16 @@
 static bool transition_started;
 
 /**
+ * device_pm_init - Initialize the PM-related part of a device object
+ * @dev: Device object being initialized.
+ */
+void device_pm_init(struct device *dev)
+{
+	dev->power.status = DPM_ON;
+	pm_runtime_init(dev);
+}
+
+/**
  *	device_pm_lock - lock the list of active devices used by the PM core
  */
 void device_pm_lock(void)
@@ -105,6 +116,7 @@
 	mutex_lock(&dpm_list_mtx);
 	list_del_init(&dev->power.entry);
 	mutex_unlock(&dpm_list_mtx);
+	pm_runtime_remove(dev);
 }
 
 /**
@@ -512,6 +524,7 @@
 			mutex_unlock(&dpm_list_mtx);
 
 			device_complete(dev, state);
+			pm_runtime_put_noidle(dev);
 
 			mutex_lock(&dpm_list_mtx);
 		}
@@ -757,7 +770,14 @@
 		dev->power.status = DPM_PREPARING;
 		mutex_unlock(&dpm_list_mtx);
 
-		error = device_prepare(dev, state);
+		pm_runtime_get_noresume(dev);
+		if (pm_runtime_barrier(dev) && device_may_wakeup(dev)) {
+			/* Wake-up requested during system sleep transition. */
+			pm_runtime_put_noidle(dev);
+			error = -EBUSY;
+		} else {
+			error = device_prepare(dev, state);
+		}
 
 		mutex_lock(&dpm_list_mtx);
 		if (error) {
diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index c7cb4fc..b8fa1aa 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -1,7 +1,14 @@
-static inline void device_pm_init(struct device *dev)
-{
-	dev->power.status = DPM_ON;
-}
+#ifdef CONFIG_PM_RUNTIME
+
+extern void pm_runtime_init(struct device *dev);
+extern void pm_runtime_remove(struct device *dev);
+
+#else /* !CONFIG_PM_RUNTIME */
+
+static inline void pm_runtime_init(struct device *dev) {}
+static inline void pm_runtime_remove(struct device *dev) {}
+
+#endif /* !CONFIG_PM_RUNTIME */
 
 #ifdef CONFIG_PM_SLEEP
 
@@ -16,23 +23,33 @@
 	return container_of(entry, struct device, power.entry);
 }
 
+extern void device_pm_init(struct device *dev);
 extern void device_pm_add(struct device *);
 extern void device_pm_remove(struct device *);
 extern void device_pm_move_before(struct device *, struct device *);
 extern void device_pm_move_after(struct device *, struct device *);
 extern void device_pm_move_last(struct device *);
 
-#else /* CONFIG_PM_SLEEP */
+#else /* !CONFIG_PM_SLEEP */
+
+static inline void device_pm_init(struct device *dev)
+{
+	pm_runtime_init(dev);
+}
+
+static inline void device_pm_remove(struct device *dev)
+{
+	pm_runtime_remove(dev);
+}
 
 static inline void device_pm_add(struct device *dev) {}
-static inline void device_pm_remove(struct device *dev) {}
 static inline void device_pm_move_before(struct device *deva,
 					 struct device *devb) {}
 static inline void device_pm_move_after(struct device *deva,
 					struct device *devb) {}
 static inline void device_pm_move_last(struct device *dev) {}
 
-#endif
+#endif /* !CONFIG_PM_SLEEP */
 
 #ifdef CONFIG_PM
 
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
new file mode 100644
index 0000000..38556f6
--- /dev/null
+++ b/drivers/base/power/runtime.c
@@ -0,0 +1,1011 @@
+/*
+ * drivers/base/power/runtime.c - Helper functions for device run-time PM
+ *
+ * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/sched.h>
+#include <linux/pm_runtime.h>
+#include <linux/jiffies.h>
+
+static int __pm_runtime_resume(struct device *dev, bool from_wq);
+static int __pm_request_idle(struct device *dev);
+static int __pm_request_resume(struct device *dev);
+
+/**
+ * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
+ * @dev: Device to handle.
+ */
+static void pm_runtime_deactivate_timer(struct device *dev)
+{
+	if (dev->power.timer_expires > 0) {
+		del_timer(&dev->power.suspend_timer);
+		dev->power.timer_expires = 0;
+	}
+}
+
+/**
+ * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
+ * @dev: Device to handle.
+ */
+static void pm_runtime_cancel_pending(struct device *dev)
+{
+	pm_runtime_deactivate_timer(dev);
+	/*
+	 * In case there's a request pending, make sure its work function will
+	 * return without doing anything.
+	 */
+	dev->power.request = RPM_REQ_NONE;
+}
+
+/**
+ * __pm_runtime_idle - Notify device bus type if the device can be suspended.
+ * @dev: Device to notify the bus type about.
+ *
+ * This function must be called under dev->power.lock with interrupts disabled.
+ */
+static int __pm_runtime_idle(struct device *dev)
+	__releases(&dev->power.lock) __acquires(&dev->power.lock)
+{
+	int retval = 0;
+
+	dev_dbg(dev, "__pm_runtime_idle()!\n");
+
+	if (dev->power.runtime_error)
+		retval = -EINVAL;
+	else if (dev->power.idle_notification)
+		retval = -EINPROGRESS;
+	else if (atomic_read(&dev->power.usage_count) > 0
+	    || dev->power.disable_depth > 0
+	    || dev->power.runtime_status != RPM_ACTIVE)
+		retval = -EAGAIN;
+	else if (!pm_children_suspended(dev))
+		retval = -EBUSY;
+	if (retval)
+		goto out;
+
+	if (dev->power.request_pending) {
+		/*
+		 * If an idle notification request is pending, cancel it.  Any
+		 * other pending request takes precedence over us.
+		 */
+		if (dev->power.request == RPM_REQ_IDLE) {
+			dev->power.request = RPM_REQ_NONE;
+		} else if (dev->power.request != RPM_REQ_NONE) {
+			retval = -EAGAIN;
+			goto out;
+		}
+	}
+
+	dev->power.idle_notification = true;
+
+	if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_idle) {
+		spin_unlock_irq(&dev->power.lock);
+
+		dev->bus->pm->runtime_idle(dev);
+
+		spin_lock_irq(&dev->power.lock);
+	}
+
+	dev->power.idle_notification = false;
+	wake_up_all(&dev->power.wait_queue);
+
+ out:
+	dev_dbg(dev, "__pm_runtime_idle() returns %d!\n", retval);
+
+	return retval;
+}
+
+/**
+ * pm_runtime_idle - Notify device bus type if the device can be suspended.
+ * @dev: Device to notify the bus type about.
+ */
+int pm_runtime_idle(struct device *dev)
+{
+	int retval;
+
+	spin_lock_irq(&dev->power.lock);
+	retval = __pm_runtime_idle(dev);
+	spin_unlock_irq(&dev->power.lock);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(pm_runtime_idle);
+
+/**
+ * __pm_runtime_suspend - Carry out run-time suspend of given device.
+ * @dev: Device to suspend.
+ * @from_wq: If set, the function has been called via pm_wq.
+ *
+ * Check if the device can be suspended and run the ->runtime_suspend() callback
+ * provided by its bus type.  If another suspend has been started earlier, wait
+ * for it to finish.  If an idle notification or suspend request is pending or
+ * scheduled, cancel it.
+ *
+ * This function must be called under dev->power.lock with interrupts disabled.
+ */
+int __pm_runtime_suspend(struct device *dev, bool from_wq)
+	__releases(&dev->power.lock) __acquires(&dev->power.lock)
+{
+	struct device *parent = NULL;
+	bool notify = false;
+	int retval = 0;
+
+	dev_dbg(dev, "__pm_runtime_suspend()%s!\n",
+		from_wq ? " from workqueue" : "");
+
+ repeat:
+	if (dev->power.runtime_error) {
+		retval = -EINVAL;
+		goto out;
+	}
+
+	/* Pending resume requests take precedence over us. */
+	if (dev->power.request_pending
+	    && dev->power.request == RPM_REQ_RESUME) {
+		retval = -EAGAIN;
+		goto out;
+	}
+
+	/* Other scheduled or pending requests need to be canceled. */
+	pm_runtime_cancel_pending(dev);
+
+	if (dev->power.runtime_status == RPM_SUSPENDED)
+		retval = 1;
+	else if (dev->power.runtime_status == RPM_RESUMING
+	    || dev->power.disable_depth > 0
+	    || atomic_read(&dev->power.usage_count) > 0)
+		retval = -EAGAIN;
+	else if (!pm_children_suspended(dev))
+		retval = -EBUSY;
+	if (retval)
+		goto out;
+
+	if (dev->power.runtime_status == RPM_SUSPENDING) {
+		DEFINE_WAIT(wait);
+
+		if (from_wq) {
+			retval = -EINPROGRESS;
+			goto out;
+		}
+
+		/* Wait for the other suspend running in parallel with us. */
+		for (;;) {
+			prepare_to_wait(&dev->power.wait_queue, &wait,
+					TASK_UNINTERRUPTIBLE);
+			if (dev->power.runtime_status != RPM_SUSPENDING)
+				break;
+
+			spin_unlock_irq(&dev->power.lock);
+
+			schedule();
+
+			spin_lock_irq(&dev->power.lock);
+		}
+		finish_wait(&dev->power.wait_queue, &wait);
+		goto repeat;
+	}
+
+	dev->power.runtime_status = RPM_SUSPENDING;
+
+	if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_suspend) {
+		spin_unlock_irq(&dev->power.lock);
+
+		retval = dev->bus->pm->runtime_suspend(dev);
+
+		spin_lock_irq(&dev->power.lock);
+		dev->power.runtime_error = retval;
+	} else {
+		retval = -ENOSYS;
+	}
+
+	if (retval) {
+		dev->power.runtime_status = RPM_ACTIVE;
+		pm_runtime_cancel_pending(dev);
+		dev->power.deferred_resume = false;
+
+		if (retval == -EAGAIN || retval == -EBUSY) {
+			notify = true;
+			dev->power.runtime_error = 0;
+		}
+	} else {
+		dev->power.runtime_status = RPM_SUSPENDED;
+
+		if (dev->parent) {
+			parent = dev->parent;
+			atomic_add_unless(&parent->power.child_count, -1, 0);
+		}
+	}
+	wake_up_all(&dev->power.wait_queue);
+
+	if (dev->power.deferred_resume) {
+		dev->power.deferred_resume = false;
+		__pm_runtime_resume(dev, false);
+		retval = -EAGAIN;
+		goto out;
+	}
+
+	if (notify)
+		__pm_runtime_idle(dev);
+
+	if (parent && !parent->power.ignore_children) {
+		spin_unlock_irq(&dev->power.lock);
+
+		pm_request_idle(parent);
+
+		spin_lock_irq(&dev->power.lock);
+	}
+
+ out:
+	dev_dbg(dev, "__pm_runtime_suspend() returns %d!\n", retval);
+
+	return retval;
+}
+
+/**
+ * pm_runtime_suspend - Carry out run-time suspend of given device.
+ * @dev: Device to suspend.
+ */
+int pm_runtime_suspend(struct device *dev)
+{
+	int retval;
+
+	spin_lock_irq(&dev->power.lock);
+	retval = __pm_runtime_suspend(dev, false);
+	spin_unlock_irq(&dev->power.lock);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(pm_runtime_suspend);
+
+/**
+ * __pm_runtime_resume - Carry out run-time resume of given device.
+ * @dev: Device to resume.
+ * @from_wq: If set, the function has been called via pm_wq.
+ *
+ * Check if the device can be woken up and run the ->runtime_resume() callback
+ * provided by its bus type.  If another resume has been started earlier, wait
+ * for it to finish.  If there's a suspend running in parallel with this
+ * function, wait for it to finish and resume the device.  Cancel any scheduled
+ * or pending requests.
+ *
+ * This function must be called under dev->power.lock with interrupts disabled.
+ */
+int __pm_runtime_resume(struct device *dev, bool from_wq)
+	__releases(&dev->power.lock) __acquires(&dev->power.lock)
+{
+	struct device *parent = NULL;
+	int retval = 0;
+
+	dev_dbg(dev, "__pm_runtime_resume()%s!\n",
+		from_wq ? " from workqueue" : "");
+
+ repeat:
+	if (dev->power.runtime_error) {
+		retval = -EINVAL;
+		goto out;
+	}
+
+	pm_runtime_cancel_pending(dev);
+
+	if (dev->power.runtime_status == RPM_ACTIVE)
+		retval = 1;
+	else if (dev->power.disable_depth > 0)
+		retval = -EAGAIN;
+	if (retval)
+		goto out;
+
+	if (dev->power.runtime_status == RPM_RESUMING
+	    || dev->power.runtime_status == RPM_SUSPENDING) {
+		DEFINE_WAIT(wait);
+
+		if (from_wq) {
+			if (dev->power.runtime_status == RPM_SUSPENDING)
+				dev->power.deferred_resume = true;
+			retval = -EINPROGRESS;
+			goto out;
+		}
+
+		/* Wait for the operation carried out in parallel with us. */
+		for (;;) {
+			prepare_to_wait(&dev->power.wait_queue, &wait,
+					TASK_UNINTERRUPTIBLE);
+			if (dev->power.runtime_status != RPM_RESUMING
+			    && dev->power.runtime_status != RPM_SUSPENDING)
+				break;
+
+			spin_unlock_irq(&dev->power.lock);
+
+			schedule();
+
+			spin_lock_irq(&dev->power.lock);
+		}
+		finish_wait(&dev->power.wait_queue, &wait);
+		goto repeat;
+	}
+
+	if (!parent && dev->parent) {
+		/*
+		 * Increment the parent's resume counter and resume it if
+		 * necessary.
+		 */
+		parent = dev->parent;
+		spin_unlock_irq(&dev->power.lock);
+
+		pm_runtime_get_noresume(parent);
+
+		spin_lock_irq(&parent->power.lock);
+		/*
+		 * We can resume if the parent's run-time PM is disabled or it
+		 * is set to ignore children.
+		 */
+		if (!parent->power.disable_depth
+		    && !parent->power.ignore_children) {
+			__pm_runtime_resume(parent, false);
+			if (parent->power.runtime_status != RPM_ACTIVE)
+				retval = -EBUSY;
+		}
+		spin_unlock_irq(&parent->power.lock);
+
+		spin_lock_irq(&dev->power.lock);
+		if (retval)
+			goto out;
+		goto repeat;
+	}
+
+	dev->power.runtime_status = RPM_RESUMING;
+
+	if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_resume) {
+		spin_unlock_irq(&dev->power.lock);
+
+		retval = dev->bus->pm->runtime_resume(dev);
+
+		spin_lock_irq(&dev->power.lock);
+		dev->power.runtime_error = retval;
+	} else {
+		retval = -ENOSYS;
+	}
+
+	if (retval) {
+		dev->power.runtime_status = RPM_SUSPENDED;
+		pm_runtime_cancel_pending(dev);
+	} else {
+		dev->power.runtime_status = RPM_ACTIVE;
+		if (parent)
+			atomic_inc(&parent->power.child_count);
+	}
+	wake_up_all(&dev->power.wait_queue);
+
+	if (!retval)
+		__pm_request_idle(dev);
+
+ out:
+	if (parent) {
+		spin_unlock_irq(&dev->power.lock);
+
+		pm_runtime_put(parent);
+
+		spin_lock_irq(&dev->power.lock);
+	}
+
+	dev_dbg(dev, "__pm_runtime_resume() returns %d!\n", retval);
+
+	return retval;
+}
+
+/**
+ * pm_runtime_resume - Carry out run-time resume of given device.
+ * @dev: Device to suspend.
+ */
+int pm_runtime_resume(struct device *dev)
+{
+	int retval;
+
+	spin_lock_irq(&dev->power.lock);
+	retval = __pm_runtime_resume(dev, false);
+	spin_unlock_irq(&dev->power.lock);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(pm_runtime_resume);
+
+/**
+ * pm_runtime_work - Universal run-time PM work function.
+ * @work: Work structure used for scheduling the execution of this function.
+ *
+ * Use @work to get the device object the work is to be done for, determine what
+ * is to be done and execute the appropriate run-time PM function.
+ */
+static void pm_runtime_work(struct work_struct *work)
+{
+	struct device *dev = container_of(work, struct device, power.work);
+	enum rpm_request req;
+
+	spin_lock_irq(&dev->power.lock);
+
+	if (!dev->power.request_pending)
+		goto out;
+
+	req = dev->power.request;
+	dev->power.request = RPM_REQ_NONE;
+	dev->power.request_pending = false;
+
+	switch (req) {
+	case RPM_REQ_NONE:
+		break;
+	case RPM_REQ_IDLE:
+		__pm_runtime_idle(dev);
+		break;
+	case RPM_REQ_SUSPEND:
+		__pm_runtime_suspend(dev, true);
+		break;
+	case RPM_REQ_RESUME:
+		__pm_runtime_resume(dev, true);
+		break;
+	}
+
+ out:
+	spin_unlock_irq(&dev->power.lock);
+}
+
+/**
+ * __pm_request_idle - Submit an idle notification request for given device.
+ * @dev: Device to handle.
+ *
+ * Check if the device's run-time PM status is correct for suspending the device
+ * and queue up a request to run __pm_runtime_idle() for it.
+ *
+ * This function must be called under dev->power.lock with interrupts disabled.
+ */
+static int __pm_request_idle(struct device *dev)
+{
+	int retval = 0;
+
+	if (dev->power.runtime_error)
+		retval = -EINVAL;
+	else if (atomic_read(&dev->power.usage_count) > 0
+	    || dev->power.disable_depth > 0
+	    || dev->power.runtime_status == RPM_SUSPENDED
+	    || dev->power.runtime_status == RPM_SUSPENDING)
+		retval = -EAGAIN;
+	else if (!pm_children_suspended(dev))
+		retval = -EBUSY;
+	if (retval)
+		return retval;
+
+	if (dev->power.request_pending) {
+		/* Any requests other then RPM_REQ_IDLE take precedence. */
+		if (dev->power.request == RPM_REQ_NONE)
+			dev->power.request = RPM_REQ_IDLE;
+		else if (dev->power.request != RPM_REQ_IDLE)
+			retval = -EAGAIN;
+		return retval;
+	}
+
+	dev->power.request = RPM_REQ_IDLE;
+	dev->power.request_pending = true;
+	queue_work(pm_wq, &dev->power.work);
+
+	return retval;
+}
+
+/**
+ * pm_request_idle - Submit an idle notification request for given device.
+ * @dev: Device to handle.
+ */
+int pm_request_idle(struct device *dev)
+{
+	unsigned long flags;
+	int retval;
+
+	spin_lock_irqsave(&dev->power.lock, flags);
+	retval = __pm_request_idle(dev);
+	spin_unlock_irqrestore(&dev->power.lock, flags);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(pm_request_idle);
+
+/**
+ * __pm_request_suspend - Submit a suspend request for given device.
+ * @dev: Device to suspend.
+ *
+ * This function must be called under dev->power.lock with interrupts disabled.
+ */
+static int __pm_request_suspend(struct device *dev)
+{
+	int retval = 0;
+
+	if (dev->power.runtime_error)
+		return -EINVAL;
+
+	if (dev->power.runtime_status == RPM_SUSPENDED)
+		retval = 1;
+	else if (atomic_read(&dev->power.usage_count) > 0
+	    || dev->power.disable_depth > 0)
+		retval = -EAGAIN;
+	else if (dev->power.runtime_status == RPM_SUSPENDING)
+		retval = -EINPROGRESS;
+	else if (!pm_children_suspended(dev))
+		retval = -EBUSY;
+	if (retval < 0)
+		return retval;
+
+	pm_runtime_deactivate_timer(dev);
+
+	if (dev->power.request_pending) {
+		/*
+		 * Pending resume requests take precedence over us, but we can
+		 * overtake any other pending request.
+		 */
+		if (dev->power.request == RPM_REQ_RESUME)
+			retval = -EAGAIN;
+		else if (dev->power.request != RPM_REQ_SUSPEND)
+			dev->power.request = retval ?
+						RPM_REQ_NONE : RPM_REQ_SUSPEND;
+		return retval;
+	} else if (retval) {
+		return retval;
+	}
+
+	dev->power.request = RPM_REQ_SUSPEND;
+	dev->power.request_pending = true;
+	queue_work(pm_wq, &dev->power.work);
+
+	return 0;
+}
+
+/**
+ * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
+ * @data: Device pointer passed by pm_schedule_suspend().
+ *
+ * Check if the time is right and execute __pm_request_suspend() in that case.
+ */
+static void pm_suspend_timer_fn(unsigned long data)
+{
+	struct device *dev = (struct device *)data;
+	unsigned long flags;
+	unsigned long expires;
+
+	spin_lock_irqsave(&dev->power.lock, flags);
+
+	expires = dev->power.timer_expires;
+	/* If 'expire' is after 'jiffies' we've been called too early. */
+	if (expires > 0 && !time_after(expires, jiffies)) {
+		dev->power.timer_expires = 0;
+		__pm_request_suspend(dev);
+	}
+
+	spin_unlock_irqrestore(&dev->power.lock, flags);
+}
+
+/**
+ * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
+ * @dev: Device to suspend.
+ * @delay: Time to wait before submitting a suspend request, in milliseconds.
+ */
+int pm_schedule_suspend(struct device *dev, unsigned int delay)
+{
+	unsigned long flags;
+	int retval = 0;
+
+	spin_lock_irqsave(&dev->power.lock, flags);
+
+	if (dev->power.runtime_error) {
+		retval = -EINVAL;
+		goto out;
+	}
+
+	if (!delay) {
+		retval = __pm_request_suspend(dev);
+		goto out;
+	}
+
+	pm_runtime_deactivate_timer(dev);
+
+	if (dev->power.request_pending) {
+		/*
+		 * Pending resume requests take precedence over us, but any
+		 * other pending requests have to be canceled.
+		 */
+		if (dev->power.request == RPM_REQ_RESUME) {
+			retval = -EAGAIN;
+			goto out;
+		}
+		dev->power.request = RPM_REQ_NONE;
+	}
+
+	if (dev->power.runtime_status == RPM_SUSPENDED)
+		retval = 1;
+	else if (dev->power.runtime_status == RPM_SUSPENDING)
+		retval = -EINPROGRESS;
+	else if (atomic_read(&dev->power.usage_count) > 0
+	    || dev->power.disable_depth > 0)
+		retval = -EAGAIN;
+	else if (!pm_children_suspended(dev))
+		retval = -EBUSY;
+	if (retval)
+		goto out;
+
+	dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
+	mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
+
+ out:
+	spin_unlock_irqrestore(&dev->power.lock, flags);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(pm_schedule_suspend);
+
+/**
+ * pm_request_resume - Submit a resume request for given device.
+ * @dev: Device to resume.
+ *
+ * This function must be called under dev->power.lock with interrupts disabled.
+ */
+static int __pm_request_resume(struct device *dev)
+{
+	int retval = 0;
+
+	if (dev->power.runtime_error)
+		return -EINVAL;
+
+	if (dev->power.runtime_status == RPM_ACTIVE)
+		retval = 1;
+	else if (dev->power.runtime_status == RPM_RESUMING)
+		retval = -EINPROGRESS;
+	else if (dev->power.disable_depth > 0)
+		retval = -EAGAIN;
+	if (retval < 0)
+		return retval;
+
+	pm_runtime_deactivate_timer(dev);
+
+	if (dev->power.request_pending) {
+		/* If non-resume request is pending, we can overtake it. */
+		dev->power.request = retval ? RPM_REQ_NONE : RPM_REQ_RESUME;
+		return retval;
+	} else if (retval) {
+		return retval;
+	}
+
+	dev->power.request = RPM_REQ_RESUME;
+	dev->power.request_pending = true;
+	queue_work(pm_wq, &dev->power.work);
+
+	return retval;
+}
+
+/**
+ * pm_request_resume - Submit a resume request for given device.
+ * @dev: Device to resume.
+ */
+int pm_request_resume(struct device *dev)
+{
+	unsigned long flags;
+	int retval;
+
+	spin_lock_irqsave(&dev->power.lock, flags);
+	retval = __pm_request_resume(dev);
+	spin_unlock_irqrestore(&dev->power.lock, flags);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(pm_request_resume);
+
+/**
+ * __pm_runtime_get - Reference count a device and wake it up, if necessary.
+ * @dev: Device to handle.
+ * @sync: If set and the device is suspended, resume it synchronously.
+ *
+ * Increment the usage count of the device and if it was zero previously,
+ * resume it or submit a resume request for it, depending on the value of @sync.
+ */
+int __pm_runtime_get(struct device *dev, bool sync)
+{
+	int retval = 1;
+
+	if (atomic_add_return(1, &dev->power.usage_count) == 1)
+		retval = sync ? pm_runtime_resume(dev) : pm_request_resume(dev);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(__pm_runtime_get);
+
+/**
+ * __pm_runtime_put - Decrement the device's usage counter and notify its bus.
+ * @dev: Device to handle.
+ * @sync: If the device's bus type is to be notified, do that synchronously.
+ *
+ * Decrement the usage count of the device and if it reaches zero, carry out a
+ * synchronous idle notification or submit an idle notification request for it,
+ * depending on the value of @sync.
+ */
+int __pm_runtime_put(struct device *dev, bool sync)
+{
+	int retval = 0;
+
+	if (atomic_dec_and_test(&dev->power.usage_count))
+		retval = sync ? pm_runtime_idle(dev) : pm_request_idle(dev);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(__pm_runtime_put);
+
+/**
+ * __pm_runtime_set_status - Set run-time PM status of a device.
+ * @dev: Device to handle.
+ * @status: New run-time PM status of the device.
+ *
+ * If run-time PM of the device is disabled or its power.runtime_error field is
+ * different from zero, the status may be changed either to RPM_ACTIVE, or to
+ * RPM_SUSPENDED, as long as that reflects the actual state of the device.
+ * However, if the device has a parent and the parent is not active, and the
+ * parent's power.ignore_children flag is unset, the device's status cannot be
+ * set to RPM_ACTIVE, so -EBUSY is returned in that case.
+ *
+ * If successful, __pm_runtime_set_status() clears the power.runtime_error field
+ * and the device parent's counter of unsuspended children is modified to
+ * reflect the new status.  If the new status is RPM_SUSPENDED, an idle
+ * notification request for the parent is submitted.
+ */
+int __pm_runtime_set_status(struct device *dev, unsigned int status)
+{
+	struct device *parent = dev->parent;
+	unsigned long flags;
+	bool notify_parent = false;
+	int error = 0;
+
+	if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
+		return -EINVAL;
+
+	spin_lock_irqsave(&dev->power.lock, flags);
+
+	if (!dev->power.runtime_error && !dev->power.disable_depth) {
+		error = -EAGAIN;
+		goto out;
+	}
+
+	if (dev->power.runtime_status == status)
+		goto out_set;
+
+	if (status == RPM_SUSPENDED) {
+		/* It always is possible to set the status to 'suspended'. */
+		if (parent) {
+			atomic_add_unless(&parent->power.child_count, -1, 0);
+			notify_parent = !parent->power.ignore_children;
+		}
+		goto out_set;
+	}
+
+	if (parent) {
+		spin_lock_irq(&parent->power.lock);
+
+		/*
+		 * It is invalid to put an active child under a parent that is
+		 * not active, has run-time PM enabled and the
+		 * 'power.ignore_children' flag unset.
+		 */
+		if (!parent->power.disable_depth
+		    && !parent->power.ignore_children
+		    && parent->power.runtime_status != RPM_ACTIVE) {
+			error = -EBUSY;
+		} else {
+			if (dev->power.runtime_status == RPM_SUSPENDED)
+				atomic_inc(&parent->power.child_count);
+		}
+
+		spin_unlock_irq(&parent->power.lock);
+
+		if (error)
+			goto out;
+	}
+
+ out_set:
+	dev->power.runtime_status = status;
+	dev->power.runtime_error = 0;
+ out:
+	spin_unlock_irqrestore(&dev->power.lock, flags);
+
+	if (notify_parent)
+		pm_request_idle(parent);
+
+	return error;
+}
+EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
+
+/**
+ * __pm_runtime_barrier - Cancel pending requests and wait for completions.
+ * @dev: Device to handle.
+ *
+ * Flush all pending requests for the device from pm_wq and wait for all
+ * run-time PM operations involving the device in progress to complete.
+ *
+ * Should be called under dev->power.lock with interrupts disabled.
+ */
+static void __pm_runtime_barrier(struct device *dev)
+{
+	pm_runtime_deactivate_timer(dev);
+
+	if (dev->power.request_pending) {
+		dev->power.request = RPM_REQ_NONE;
+		spin_unlock_irq(&dev->power.lock);
+
+		cancel_work_sync(&dev->power.work);
+
+		spin_lock_irq(&dev->power.lock);
+		dev->power.request_pending = false;
+	}
+
+	if (dev->power.runtime_status == RPM_SUSPENDING
+	    || dev->power.runtime_status == RPM_RESUMING
+	    || dev->power.idle_notification) {
+		DEFINE_WAIT(wait);
+
+		/* Suspend, wake-up or idle notification in progress. */
+		for (;;) {
+			prepare_to_wait(&dev->power.wait_queue, &wait,
+					TASK_UNINTERRUPTIBLE);
+			if (dev->power.runtime_status != RPM_SUSPENDING
+			    && dev->power.runtime_status != RPM_RESUMING
+			    && !dev->power.idle_notification)
+				break;
+			spin_unlock_irq(&dev->power.lock);
+
+			schedule();
+
+			spin_lock_irq(&dev->power.lock);
+		}
+		finish_wait(&dev->power.wait_queue, &wait);
+	}
+}
+
+/**
+ * pm_runtime_barrier - Flush pending requests and wait for completions.
+ * @dev: Device to handle.
+ *
+ * Prevent the device from being suspended by incrementing its usage counter and
+ * if there's a pending resume request for the device, wake the device up.
+ * Next, make sure that all pending requests for the device have been flushed
+ * from pm_wq and wait for all run-time PM operations involving the device in
+ * progress to complete.
+ *
+ * Return value:
+ * 1, if there was a resume request pending and the device had to be woken up,
+ * 0, otherwise
+ */
+int pm_runtime_barrier(struct device *dev)
+{
+	int retval = 0;
+
+	pm_runtime_get_noresume(dev);
+	spin_lock_irq(&dev->power.lock);
+
+	if (dev->power.request_pending
+	    && dev->power.request == RPM_REQ_RESUME) {
+		__pm_runtime_resume(dev, false);
+		retval = 1;
+	}
+
+	__pm_runtime_barrier(dev);
+
+	spin_unlock_irq(&dev->power.lock);
+	pm_runtime_put_noidle(dev);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(pm_runtime_barrier);
+
+/**
+ * __pm_runtime_disable - Disable run-time PM of a device.
+ * @dev: Device to handle.
+ * @check_resume: If set, check if there's a resume request for the device.
+ *
+ * Increment power.disable_depth for the device and if was zero previously,
+ * cancel all pending run-time PM requests for the device and wait for all
+ * operations in progress to complete.  The device can be either active or
+ * suspended after its run-time PM has been disabled.
+ *
+ * If @check_resume is set and there's a resume request pending when
+ * __pm_runtime_disable() is called and power.disable_depth is zero, the
+ * function will wake up the device before disabling its run-time PM.
+ */
+void __pm_runtime_disable(struct device *dev, bool check_resume)
+{
+	spin_lock_irq(&dev->power.lock);
+
+	if (dev->power.disable_depth > 0) {
+		dev->power.disable_depth++;
+		goto out;
+	}
+
+	/*
+	 * Wake up the device if there's a resume request pending, because that
+	 * means there probably is some I/O to process and disabling run-time PM
+	 * shouldn't prevent the device from processing the I/O.
+	 */
+	if (check_resume && dev->power.request_pending
+	    && dev->power.request == RPM_REQ_RESUME) {
+		/*
+		 * Prevent suspends and idle notifications from being carried
+		 * out after we have woken up the device.
+		 */
+		pm_runtime_get_noresume(dev);
+
+		__pm_runtime_resume(dev, false);
+
+		pm_runtime_put_noidle(dev);
+	}
+
+	if (!dev->power.disable_depth++)
+		__pm_runtime_barrier(dev);
+
+ out:
+	spin_unlock_irq(&dev->power.lock);
+}
+EXPORT_SYMBOL_GPL(__pm_runtime_disable);
+
+/**
+ * pm_runtime_enable - Enable run-time PM of a device.
+ * @dev: Device to handle.
+ */
+void pm_runtime_enable(struct device *dev)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->power.lock, flags);
+
+	if (dev->power.disable_depth > 0)
+		dev->power.disable_depth--;
+	else
+		dev_warn(dev, "Unbalanced %s!\n", __func__);
+
+	spin_unlock_irqrestore(&dev->power.lock, flags);
+}
+EXPORT_SYMBOL_GPL(pm_runtime_enable);
+
+/**
+ * pm_runtime_init - Initialize run-time PM fields in given device object.
+ * @dev: Device object to initialize.
+ */
+void pm_runtime_init(struct device *dev)
+{
+	spin_lock_init(&dev->power.lock);
+
+	dev->power.runtime_status = RPM_SUSPENDED;
+	dev->power.idle_notification = false;
+
+	dev->power.disable_depth = 1;
+	atomic_set(&dev->power.usage_count, 0);
+
+	dev->power.runtime_error = 0;
+
+	atomic_set(&dev->power.child_count, 0);
+	pm_suspend_ignore_children(dev, false);
+
+	dev->power.request_pending = false;
+	dev->power.request = RPM_REQ_NONE;
+	dev->power.deferred_resume = false;
+	INIT_WORK(&dev->power.work, pm_runtime_work);
+
+	dev->power.timer_expires = 0;
+	setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
+			(unsigned long)dev);
+
+	init_waitqueue_head(&dev->power.wait_queue);
+}
+
+/**
+ * pm_runtime_remove - Prepare for removing a device from device hierarchy.
+ * @dev: Device object being removed from device hierarchy.
+ */
+void pm_runtime_remove(struct device *dev)
+{
+	__pm_runtime_disable(dev, false);
+
+	/* Change the status back to 'suspended' to match the initial status. */
+	if (dev->power.runtime_status == RPM_ACTIVE)
+		pm_runtime_set_suspended(dev);
+}