2 * linux/drivers/devfreq/governor_simpleondemand.c
4 * Copyright (C) 2011 Samsung Electronics
5 * MyungJoo Ham <myungjoo.ham@samsung.com>
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.
12 #include <linux/slab.h>
13 #include <linux/device.h>
14 #include <linux/devfreq.h>
16 #include <linux/mutex.h>
19 struct userspace_data {
20 unsigned long user_frequency;
24 static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq)
26 struct userspace_data *data = df->data;
29 unsigned long adjusted_freq = data->user_frequency;
31 if (df->max_freq && adjusted_freq > df->max_freq)
32 adjusted_freq = df->max_freq;
34 if (df->min_freq && adjusted_freq < df->min_freq)
35 adjusted_freq = df->min_freq;
37 *freq = adjusted_freq;
39 *freq = df->previous_freq; /* No user freq specified yet */
44 static ssize_t store_freq(struct device *dev, struct device_attribute *attr,
45 const char *buf, size_t count)
47 struct devfreq *devfreq = to_devfreq(dev);
48 struct userspace_data *data;
53 mutex_lock(&devfreq->lock);
56 sscanf(buf, "%lu", &wanted);
57 data->user_frequency = wanted;
59 err = update_devfreq(devfreq);
62 mutex_unlock(&devfreq->lock);
66 static ssize_t show_freq(struct device *dev, struct device_attribute *attr,
69 struct devfreq *devfreq = to_devfreq(dev);
70 struct userspace_data *data;
73 mutex_lock(&devfreq->lock);
77 err = sprintf(buf, "%lu\n", data->user_frequency);
79 err = sprintf(buf, "undefined\n");
80 mutex_unlock(&devfreq->lock);
84 static DEVICE_ATTR(set_freq, 0644, show_freq, store_freq);
85 static struct attribute *dev_entries[] = {
86 &dev_attr_set_freq.attr,
89 static struct attribute_group dev_attr_group = {
94 static int userspace_init(struct devfreq *devfreq)
97 struct userspace_data *data = kzalloc(sizeof(struct userspace_data),
105 devfreq->data = data;
107 err = sysfs_create_group(&devfreq->dev.kobj, &dev_attr_group);
112 static void userspace_exit(struct devfreq *devfreq)
114 sysfs_remove_group(&devfreq->dev.kobj, &dev_attr_group);
115 kfree(devfreq->data);
116 devfreq->data = NULL;
119 const struct devfreq_governor devfreq_userspace = {
121 .get_target_freq = devfreq_userspace_func,
122 .init = userspace_init,
123 .exit = userspace_exit,
124 .no_central_polling = true,