Eric Lee / smarc-fsl-linux-kernel

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drivers/devfreq/governor_userspace.c 2.55 KB
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ce26c5bb9   MyungJoo Ham   PM / devfreq: Add... 
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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
  ", data->user_frequency);
  	else
  		err = sprintf(buf, "undefined
  ");
  	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,
  };