LXR linux/drivers/devfreq/governor

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  linux/drivers/devfreq/governor_powersave.c
   4 *
   5 *  Copyright (C) 2011 Samsung Electronics
   6 *      MyungJoo Ham <myungjoo.ham@samsung.com>
   7 */
   8
   9#include <linux/devfreq.h>
  10#include <linux/module.h>
  11#include "governor.h"
  12
  13static int devfreq_powersave_func(struct devfreq *df,
  14                                  unsigned long *freq)
  15{
  16        /*
  17         * target callback should be able to get ceiling value as
  18         * said in devfreq.h
  19         */
  20        *freq = DEVFREQ_MIN_FREQ;
  21        return 0;
  22}
  23
  24static int devfreq_powersave_handler(struct devfreq *devfreq,
  25                                unsigned int event, void *data)
  26{
  27        int ret = 0;
  28
  29        if (event == DEVFREQ_GOV_START) {
  30                mutex_lock(&devfreq->lock);
  31                ret = update_devfreq(devfreq);
  32                mutex_unlock(&devfreq->lock);
  33        }
  34
  35        return ret;
  36}
  37
  38static struct devfreq_governor devfreq_powersave = {
  39        .name = DEVFREQ_GOV_POWERSAVE,
  40        .get_target_freq = devfreq_powersave_func,
  41        .event_handler = devfreq_powersave_handler,
  42};
  43
  44static int __init devfreq_powersave_init(void)
  45{
  46        return devfreq_add_governor(&devfreq_powersave);
  47}
  48subsys_initcall(devfreq_powersave_init);
  49
  50static void __exit devfreq_powersave_exit(void)
  51{
  52        int ret;
  53
  54        ret = devfreq_remove_governor(&devfreq_powersave);
  55        if (ret)
  56                pr_err("%s: failed remove governor %d\n", __func__, ret);
  57
  58        return;
  59}
  60module_exit(devfreq_powersave_exit);
  61MODULE_LICENSE("GPL");
  62