LXR linux/drivers/devfreq/governor

   1/*
   2 *  linux/drivers/devfreq/governor_powersave.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 <linux/module.h>
  14#include "governor.h"
  15
  16static int devfreq_powersave_func(struct devfreq *df,
  17                                  unsigned long *freq)
  18{
  19        /*
  20         * target callback should be able to get ceiling value as
  21         * said in devfreq.h
  22         */
  23        *freq = df->min_freq;
  24        return 0;
  25}
  26
  27static int devfreq_powersave_handler(struct devfreq *devfreq,
  28                                unsigned int event, void *data)
  29{
  30        int ret = 0;
  31
  32        if (event == DEVFREQ_GOV_START) {
  33                mutex_lock(&devfreq->lock);
  34                ret = update_devfreq(devfreq);
  35                mutex_unlock(&devfreq->lock);
  36        }
  37
  38        return ret;
  39}
  40
  41static struct devfreq_governor devfreq_powersave = {
  42        .name = DEVFREQ_GOV_POWERSAVE,
  43        .get_target_freq = devfreq_powersave_func,
  44        .event_handler = devfreq_powersave_handler,
  45};
  46
  47static int __init devfreq_powersave_init(void)
  48{
  49        return devfreq_add_governor(&devfreq_powersave);
  50}
  51subsys_initcall(devfreq_powersave_init);
  52
  53static void __exit devfreq_powersave_exit(void)
  54{
  55        int ret;
  56
  57        ret = devfreq_remove_governor(&devfreq_powersave);
  58        if (ret)
  59                pr_err("%s: failed remove governor %d\n", __func__, ret);
  60
  61        return;
  62}
  63module_exit(devfreq_powersave_exit);
  64MODULE_LICENSE("GPL");
  65