// SPDX-License-Identifier: GPL-2.0-only/* *  linux/drivers/devfreq/governor_userspace.c * *  Copyright (C) 2011 Samsung Electronics *	MyungJoo Ham <myungjoo.ham@samsung.com> */ #include <linux/slab.h>#include <linux/device.h>#include <linux/devfreq.h>#include <linux/devfreq-governor.h>#include <linux/kstrtox.h>#include <linux/pm.h>#include <linux/mutex.h>#include <linux/module.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->governor_data; 	if (data->valid)		*freq = data->user_frequency;	else		*freq = df->previous_freq; /* No user freq specified yet */ 	return 0;} static ssize_t set_freq_store(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; 	err = kstrtoul(buf, 0, &wanted);	if (err)		return err; 	mutex_lock(&devfreq->lock);	data = devfreq->governor_data; 	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 set_freq_show(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->governor_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_RW(set_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_obj(struct userspace_data); 	if (!data) {		err = -ENOMEM;		goto out;	}	data->valid = false;	devfreq->governor_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->governor_data);	devfreq->governor_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 = DEVFREQ_GOV_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_DESCRIPTION("DEVFREQ Userspace governor");MODULE_LICENSE("GPL");