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kernel/linux-rt-4.4.41/drivers/devfreq/governor_powersave.c 1.42 KB
5113f6f70   김현기   kernel add
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  /*
   *  linux/drivers/devfreq/governor_powersave.c
   *
   *  Copyright (C) 2011 Samsung Electronics
   *	MyungJoo Ham <myungjoo.ham@samsung.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  
  #include <linux/devfreq.h>
  #include <linux/module.h>
  #include "governor.h"
  
  static int devfreq_powersave_func(struct devfreq *df,
  				  unsigned long *freq)
  {
  	/*
  	 * target callback should be able to get ceiling value as
  	 * said in devfreq.h
  	 */
  	*freq = df->min_freq;
  	return 0;
  }
  
  static int devfreq_powersave_handler(struct devfreq *devfreq,
  				unsigned int event, void *data)
  {
  	int ret = 0;
  
  	if (event == DEVFREQ_GOV_START) {
  		mutex_lock(&devfreq->lock);
  		ret = update_devfreq(devfreq);
  		mutex_unlock(&devfreq->lock);
  	}
  
  	return ret;
  }
  
  static struct devfreq_governor devfreq_powersave = {
  	.name = "powersave",
  	.get_target_freq = devfreq_powersave_func,
  	.event_handler = devfreq_powersave_handler,
  };
  
  static int __init devfreq_powersave_init(void)
  {
  	return devfreq_add_governor(&devfreq_powersave);
  }
  subsys_initcall(devfreq_powersave_init);
  
  static void __exit devfreq_powersave_exit(void)
  {
  	int ret;
  
  	ret = devfreq_remove_governor(&devfreq_powersave);
  	if (ret)
  		pr_err("%s: failed remove governor %d
  ", __func__, ret);
  
  	return;
  }
  module_exit(devfreq_powersave_exit);
  MODULE_LICENSE("GPL");