governor_userspace.c
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/*
* linux/drivers/devfreq/governor_simpleondemand.c
*
* Copyright (C) 2011 Samsung Electronics
* MyungJoo Ham <myungjoo.ham@samsung.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/devfreq.h>
#include <linux/pm.h>
#include <linux/mutex.h>
#include "governor.h"
struct userspace_data {
unsigned long user_frequency;
bool valid;
};
static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq)
{
struct userspace_data *data = df->data;
if (!data->valid)
*freq = df->previous_freq; /* No user freq specified yet */
else
*freq = data->user_frequency;
return 0;
}
static ssize_t store_freq(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct devfreq *devfreq = to_devfreq(dev);
struct userspace_data *data;
unsigned long wanted;
int err = 0;
mutex_lock(&devfreq->lock);
data = devfreq->data;
sscanf(buf, "%lu", &wanted);
data->user_frequency = wanted;
data->valid = true;
err = update_devfreq(devfreq);
if (err == 0)
err = count;
mutex_unlock(&devfreq->lock);
return err;
}
static ssize_t show_freq(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct devfreq *devfreq = to_devfreq(dev);
struct userspace_data *data;
int err = 0;
mutex_lock(&devfreq->lock);
data = devfreq->data;
if (data->valid)
err = sprintf(buf, "%lu\n", data->user_frequency);
else
err = sprintf(buf, "undefined\n");
mutex_unlock(&devfreq->lock);
return err;
}
static DEVICE_ATTR(set_freq, 0644, show_freq, store_freq);
static struct attribute *dev_entries[] = {
&dev_attr_set_freq.attr,
NULL,
};
static struct attribute_group dev_attr_group = {
.name = "userspace",
.attrs = dev_entries,
};
static int userspace_init(struct devfreq *devfreq)
{
int err = 0;
struct userspace_data *data = kzalloc(sizeof(struct userspace_data),
GFP_KERNEL);
if (!data) {
err = -ENOMEM;
goto out;
}
data->valid = false;
devfreq->data = data;
err = sysfs_create_group(&devfreq->dev.kobj, &dev_attr_group);
out:
return err;
}
static void userspace_exit(struct devfreq *devfreq)
{
sysfs_remove_group(&devfreq->dev.kobj, &dev_attr_group);
kfree(devfreq->data);
devfreq->data = NULL;
}
const struct devfreq_governor devfreq_userspace = {
.name = "userspace",
.get_target_freq = devfreq_userspace_func,
.init = userspace_init,
.exit = userspace_exit,
.no_central_polling = true,
};