/* * 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; 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);