[linux.git] / drivers / cpuidle / driver.c

/*
 * driver.c - driver support
 *
 * (C) 2006-2007 Venkatesh Pallipadi <[email protected]>
 *               Shaohua Li <[email protected]>
 *               Adam Belay <[email protected]>
 *
 * 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;

	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);
Commit	Line	Data
4f86d3a8 LB	1	/*
	2	* driver.c - driver support
	3	*
	4	* (C) 2006-2007 Venkatesh Pallipadi <[email protected]>
	5	* Shaohua Li <[email protected]>
	6	* Adam Belay <[email protected]>
	7	*
	8	* This code is licenced under the GPL.
	9	*/
	10
	11	#include <linux/mutex.h>
	12	#include <linux/module.h>
	13	#include <linux/cpuidle.h>
	14
	15	#include "cpuidle.h"
	16
752138df	17	static struct cpuidle_driver *cpuidle_curr_driver;
4f86d3a8 LB	18	DEFINE_SPINLOCK(cpuidle_driver_lock);
	19
	20	/**
	21	* cpuidle_register_driver - registers a driver
	22	* @drv: the driver
	23	*/
	24	int cpuidle_register_driver(struct cpuidle_driver *drv)
	25	{
	26	if (!drv)
	27	return -EINVAL;
	28
	29	spin_lock(&cpuidle_driver_lock);
	30	if (cpuidle_curr_driver) {
	31	spin_unlock(&cpuidle_driver_lock);
	32	return -EBUSY;
	33	}
	34	cpuidle_curr_driver = drv;
	35	spin_unlock(&cpuidle_driver_lock);
	36
	37	return 0;
	38	}
	39
	40	EXPORT_SYMBOL_GPL(cpuidle_register_driver);
	41
752138df LB	42	/**
	43	* cpuidle_get_driver - return the current driver
	44	*/
	45	struct cpuidle_driver *cpuidle_get_driver(void)
	46	{
	47	return cpuidle_curr_driver;
	48	}
	49	EXPORT_SYMBOL_GPL(cpuidle_get_driver);
	50
4f86d3a8 LB	51	/**
	52	* cpuidle_unregister_driver - unregisters a driver
	53	* @drv: the driver
	54	*/
	55	void cpuidle_unregister_driver(struct cpuidle_driver *drv)
	56	{
c0d64cb0 LB	57	if (drv != cpuidle_curr_driver) {
	58	WARN(1, "invalid cpuidle_unregister_driver(%s)\n",
	59	drv->name);
4f86d3a8	60	return;
c0d64cb0	61	}
4f86d3a8 LB	62
	63	spin_lock(&cpuidle_driver_lock);
	64	cpuidle_curr_driver = NULL;
	65	spin_unlock(&cpuidle_driver_lock);
	66	}
	67
	68	EXPORT_SYMBOL_GPL(cpuidle_unregister_driver);