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/*
* 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);
}
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