drivers/devfreq/governor_performance.c

   1 /*
   2  *  linux/drivers/devfreq/governor_performance.c
   3  *
   4  *  Copyright (C) 2011 Samsung Electronics
   5  *      MyungJoo Ham <myungjoo.ham@samsung.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/devfreq.h>
  13 #include "governor.h"
  14
  15 static int devfreq_performance_func(struct devfreq *df,
  16                                     unsigned long *freq)
  17 {
  18         /*
  19          * target callback should be able to get floor value as
  20          * said in devfreq.h
  21          */
  22         if (!df->max_freq)
  23                 *freq = UINT_MAX;
  24         else
  25                 *freq = df->max_freq;
  26         return 0;
  27 }
  28
  29 static int devfreq_performance_handler(struct devfreq *devfreq,
  30                                 unsigned int event, void *data)
  31 {
  32         int ret = 0;
  33
  34         if (event == DEVFREQ_GOV_START) {
  35                 mutex_lock(&devfreq->lock);
  36                 ret = update_devfreq(devfreq);
  37                 mutex_unlock(&devfreq->lock);
  38         }
  39
  40         return ret;
  41 }
  42
  43 static struct devfreq_governor devfreq_performance = {
  44         .name = "performance",
  45         .get_target_freq = devfreq_performance_func,
  46         .event_handler = devfreq_performance_handler,
  47 };
  48
  49 static int __init devfreq_performance_init(void)
  50 {
  51         return devfreq_add_governor(&devfreq_performance);
  52 }
  53 subsys_initcall(devfreq_performance_init);
  54
  55 static void __exit devfreq_performance_exit(void)
  56 {
  57         int ret;
  58
  59         ret = devfreq_remove_governor(&devfreq_performance);
  60         if (ret)
  61                 pr_err("%s: failed remove governor %d\n", __func__, ret);
  62
  63         return;
  64 }
  65 module_exit(devfreq_performance_exit);