linux/drivers/base/power/runtime.c
Matthias Kaehlcke 11048dcf33 Power Management: use mutexes instead of semaphores
The Power Management code uses semaphores as mutexes.  Use the mutex API
instead of the (binary) semaphores.

Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:01 -07:00

86 lines
1.8 KiB
C

/*
* 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.event)
return;
if (!resume_device(dev))
dev->power.power_state = PMSG_ON;
}
/**
* 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)
{
mutex_lock(&dpm_mtx);
runtime_resume(dev);
mutex_unlock(&dpm_mtx);
}
EXPORT_SYMBOL(dpm_runtime_resume);
/**
* 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;
mutex_lock(&dpm_mtx);
if (dev->power.power_state.event == state.event)
goto Done;
if (dev->power.power_state.event)
runtime_resume(dev);
if (!(error = suspend_device(dev, state)))
dev->power.power_state = state;
Done:
mutex_unlock(&dpm_mtx);
return error;
}
EXPORT_SYMBOL(dpm_runtime_suspend);
#if 0
/**
* 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)
{
mutex_lock(&dpm_mtx);
dev->power.power_state = state;
mutex_unlock(&dpm_mtx);
}
#endif /* 0 */