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 
16 static 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 = DEVFREQ_MIN_FREQ;
24 	return 0;
25 }
26 
27 static 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 
41 static 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 
47 static int __init devfreq_powersave_init(void)
48 {
49 	return devfreq_add_governor(&devfreq_powersave);
50 }
51 subsys_initcall(devfreq_powersave_init);
52 
53 static 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 }
63 module_exit(devfreq_powersave_exit);
64 MODULE_LICENSE("GPL");
65