/* * drivers/base/power/runtime.c - Handling dynamic device power management. * * Copyright (c) 2003 Patrick Mochel * Copyright (c) 2003 Open Source Development Lab * */ #include <linux/device.h>#include "power.h"  static void runtime_resume(struct device * dev){	dev_dbg(dev, "resuming\n");	if (!dev->power.power_state)		return;	if (!resume_device(dev))		dev->power.power_state = 0;}  /** *	dpm_runtime_resume - Power one device back on. *	@dev:	Device. * *	Bring one device back to the on state by first powering it *	on, then restoring state. We only operate on devices that aren't *	already on. *	FIXME: We need to handle devices that are in an unknown state. */ void dpm_runtime_resume(struct device * dev){	down(&dpm_sem);	runtime_resume(dev);	up(&dpm_sem);}  /** *	dpm_runtime_suspend - Put one device in low-power state. *	@dev:	Device. *	@state:	State to enter. */ int dpm_runtime_suspend(struct device * dev, pm_message_t state){	int error = 0; 	down(&dpm_sem);	if (dev->power.power_state == state)		goto Done; 	if (dev->power.power_state)		runtime_resume(dev); 	if (!(error = suspend_device(dev, state)))		dev->power.power_state = state; Done:	up(&dpm_sem);	return error;}  /** *	dpm_set_power_state - Update power_state field. *	@dev:	Device. *	@state:	Power state device is in. * *	This is an update mechanism for drivers to notify the core *	what power state a device is in. Device probing code may not *	always be able to tell, but we need accurate information to *	work reliably. */void dpm_set_power_state(struct device * dev, pm_message_t state){	down(&dpm_sem);	dev->power.power_state = state;	up(&dpm_sem);}