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 
13 static 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 
24 static 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 
38 static 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 
44 static int __init devfreq_powersave_init(void)
45 {
46 	return devfreq_add_governor(&devfreq_powersave);
47 }
48 subsys_initcall(devfreq_powersave_init);
49 
50 static 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 }
60 module_exit(devfreq_powersave_exit);
61 MODULE_LICENSE("GPL");
62