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/*
* linux/drivers/devfreq/governor_userspace.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 <linux/module.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 = data->user_frequency;
else
*freq = df->previous_freq; /* No user freq specified yet */
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 const struct attribute_group dev_attr_group = {
.name = DEVFREQ_GOV_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)
{
/*
* Remove the sysfs entry, unless this is being called after
* device_del(), which should have done this already via kobject_del().
*/
if (devfreq->dev.kobj.sd)
sysfs_remove_group(&devfreq->dev.kobj, &dev_attr_group);
kfree(devfreq->data);
devfreq->data = NULL;
}
static int devfreq_userspace_handler(struct devfreq *devfreq,
unsigned int event, void *data)
{
int ret = 0;
switch (event) {
case DEVFREQ_GOV_START:
ret = userspace_init(devfreq);
break;
case DEVFREQ_GOV_STOP:
userspace_exit(devfreq);
break;
default:
break;
}
return ret;
}
static struct devfreq_governor devfreq_userspace = {
.name = "userspace",
.get_target_freq = devfreq_userspace_func,
.event_handler = devfreq_userspace_handler,
};
static int __init devfreq_userspace_init(void)
{
return devfreq_add_governor(&devfreq_userspace);
}
subsys_initcall(devfreq_userspace_init);
static void __exit devfreq_userspace_exit(void)
{
int ret;
ret = devfreq_remove_governor(&devfreq_userspace);
if (ret)
pr_err("%s: failed remove governor %d\n", __func__, ret);
return;
}
module_exit(devfreq_userspace_exit);
MODULE_LICENSE("GPL");
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