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/*
* driver.c - driver support
*
* (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
* Shaohua Li <shaohua.li@intel.com>
* Adam Belay <abelay@novell.com>
*
* This code is licenced under the GPL.
*/
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/cpuidle.h>
#include "cpuidle.h"
static struct cpuidle_driver *cpuidle_curr_driver;
DEFINE_SPINLOCK(cpuidle_driver_lock);
/**
* cpuidle_register_driver - registers a driver
* @drv: the driver
*/
int cpuidle_register_driver(struct cpuidle_driver *drv)
{
if (!drv)
return -EINVAL;
if (cpuidle_disabled())
return -ENODEV;
spin_lock(&cpuidle_driver_lock);
if (cpuidle_curr_driver) {
spin_unlock(&cpuidle_driver_lock);
return -EBUSY;
}
cpuidle_curr_driver = drv;
spin_unlock(&cpuidle_driver_lock);
return 0;
}
EXPORT_SYMBOL_GPL(cpuidle_register_driver);
/**
* cpuidle_get_driver - return the current driver
*/
struct cpuidle_driver *cpuidle_get_driver(void)
{
return cpuidle_curr_driver;
}
EXPORT_SYMBOL_GPL(cpuidle_get_driver);
/**
* cpuidle_unregister_driver - unregisters a driver
* @drv: the driver
*/
void cpuidle_unregister_driver(struct cpuidle_driver *drv)
{
if (drv != cpuidle_curr_driver) {
WARN(1, "invalid cpuidle_unregister_driver(%s)\n",
drv->name);
return;
}
spin_lock(&cpuidle_driver_lock);
cpuidle_curr_driver = NULL;
spin_unlock(&cpuidle_driver_lock);
}
EXPORT_SYMBOL_GPL(cpuidle_unregister_driver);
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