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
devfreq_powersave_func(struct devfreq * df,unsigned long * freq)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
devfreq_powersave_handler(struct devfreq * devfreq,unsigned int event,void * data)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
devfreq_powersave_init(void)44 static int __init devfreq_powersave_init(void)
45 {
46 return devfreq_add_governor(&devfreq_powersave);
47 }
48 subsys_initcall(devfreq_powersave_init);
49
devfreq_powersave_exit(void)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_DESCRIPTION("DEVFREQ Powersave governor");
62 MODULE_LICENSE("GPL");
63