Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * linux/drivers/devfreq/governor_simpleondemand.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/slab.h>
13#include <linux/device.h>
14#include <linux/devfreq.h>
15#include <linux/pm.h>
16#include <linux/mutex.h>
17#include "governor.h"
18
19struct userspace_data {
20 unsigned long user_frequency;
21 bool valid;
22};
23
24static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq)
25{
26 struct userspace_data *data = df->data;
27
28 if (data->valid) {
29 unsigned long adjusted_freq = data->user_frequency;
30
31 if (df->max_freq && adjusted_freq > df->max_freq)
32 adjusted_freq = df->max_freq;
33
34 if (df->min_freq && adjusted_freq < df->min_freq)
35 adjusted_freq = df->min_freq;
36
37 *freq = adjusted_freq;
38 } else {
39 *freq = df->previous_freq; /* No user freq specified yet */
40 }
41 return 0;
42}
43
44static ssize_t store_freq(struct device *dev, struct device_attribute *attr,
45 const char *buf, size_t count)
46{
47 struct devfreq *devfreq = to_devfreq(dev);
48 struct userspace_data *data;
49 unsigned long wanted;
50 int err = 0;
51
52
53 mutex_lock(&devfreq->lock);
54 data = devfreq->data;
55
56 sscanf(buf, "%lu", &wanted);
57 data->user_frequency = wanted;
58 data->valid = true;
59 err = update_devfreq(devfreq);
60 if (err == 0)
61 err = count;
62 mutex_unlock(&devfreq->lock);
63 return err;
64}
65
66static ssize_t show_freq(struct device *dev, struct device_attribute *attr,
67 char *buf)
68{
69 struct devfreq *devfreq = to_devfreq(dev);
70 struct userspace_data *data;
71 int err = 0;
72
73 mutex_lock(&devfreq->lock);
74 data = devfreq->data;
75
76 if (data->valid)
77 err = sprintf(buf, "%lu\n", data->user_frequency);
78 else
79 err = sprintf(buf, "undefined\n");
80 mutex_unlock(&devfreq->lock);
81 return err;
82}
83
84static DEVICE_ATTR(set_freq, 0644, show_freq, store_freq);
85static struct attribute *dev_entries[] = {
86 &dev_attr_set_freq.attr,
87 NULL,
88};
89static struct attribute_group dev_attr_group = {
90 .name = "userspace",
91 .attrs = dev_entries,
92};
93
94static int userspace_init(struct devfreq *devfreq)
95{
96 int err = 0;
97 struct userspace_data *data = kzalloc(sizeof(struct userspace_data),
98 GFP_KERNEL);
99
100 if (!data) {
101 err = -ENOMEM;
102 goto out;
103 }
104 data->valid = false;
105 devfreq->data = data;
106
107 err = sysfs_create_group(&devfreq->dev.kobj, &dev_attr_group);
108out:
109 return err;
110}
111
112static void userspace_exit(struct devfreq *devfreq)
113{
114 sysfs_remove_group(&devfreq->dev.kobj, &dev_attr_group);
115 kfree(devfreq->data);
116 devfreq->data = NULL;
117}
118
119const struct devfreq_governor devfreq_userspace = {
120 .name = "userspace",
121 .get_target_freq = devfreq_userspace_func,
122 .init = userspace_init,
123 .exit = userspace_exit,
124 .no_central_polling = true,
125};