linux/drivers/devfreq/devfreq-event.c

494 lines
12 KiB
C

/*
* devfreq-event: a framework to provide raw data and events of devfreq devices
*
* Copyright (C) 2015 Samsung Electronics
* Author: Chanwoo Choi <cw00.choi@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.
*
* This driver is based on drivers/devfreq/devfreq.c.
*/
#include <linux/devfreq-event.h>
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/of.h>
static struct class *devfreq_event_class;
/* The list of all devfreq event list */
static LIST_HEAD(devfreq_event_list);
static DEFINE_MUTEX(devfreq_event_list_lock);
#define to_devfreq_event(DEV) container_of(DEV, struct devfreq_event_dev, dev)
/**
* devfreq_event_enable_edev() - Enable the devfreq-event dev and increase
* the enable_count of devfreq-event dev.
* @edev : the devfreq-event device
*
* Note that this function increase the enable_count and enable the
* devfreq-event device. The devfreq-event device should be enabled before
* using it by devfreq device.
*/
int devfreq_event_enable_edev(struct devfreq_event_dev *edev)
{
int ret = 0;
if (!edev || !edev->desc)
return -EINVAL;
mutex_lock(&edev->lock);
if (edev->desc->ops && edev->desc->ops->enable
&& edev->enable_count == 0) {
ret = edev->desc->ops->enable(edev);
if (ret < 0)
goto err;
}
edev->enable_count++;
err:
mutex_unlock(&edev->lock);
return ret;
}
EXPORT_SYMBOL_GPL(devfreq_event_enable_edev);
/**
* devfreq_event_disable_edev() - Disable the devfreq-event dev and decrease
* the enable_count of the devfreq-event dev.
* @edev : the devfreq-event device
*
* Note that this function decrease the enable_count and disable the
* devfreq-event device. After the devfreq-event device is disabled,
* devfreq device can't use the devfreq-event device for get/set/reset
* operations.
*/
int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
{
int ret = 0;
if (!edev || !edev->desc)
return -EINVAL;
mutex_lock(&edev->lock);
if (edev->enable_count <= 0) {
dev_warn(&edev->dev, "unbalanced enable_count\n");
ret = -EIO;
goto err;
}
if (edev->desc->ops && edev->desc->ops->disable
&& edev->enable_count == 1) {
ret = edev->desc->ops->disable(edev);
if (ret < 0)
goto err;
}
edev->enable_count--;
err:
mutex_unlock(&edev->lock);
return ret;
}
EXPORT_SYMBOL_GPL(devfreq_event_disable_edev);
/**
* devfreq_event_is_enabled() - Check whether devfreq-event dev is enabled or
* not.
* @edev : the devfreq-event device
*
* Note that this function check whether devfreq-event dev is enabled or not.
* If return true, the devfreq-event dev is enabeld. If return false, the
* devfreq-event dev is disabled.
*/
bool devfreq_event_is_enabled(struct devfreq_event_dev *edev)
{
bool enabled = false;
if (!edev || !edev->desc)
return enabled;
mutex_lock(&edev->lock);
if (edev->enable_count > 0)
enabled = true;
mutex_unlock(&edev->lock);
return enabled;
}
EXPORT_SYMBOL_GPL(devfreq_event_is_enabled);
/**
* devfreq_event_set_event() - Set event to devfreq-event dev to start.
* @edev : the devfreq-event device
*
* Note that this function set the event to the devfreq-event device to start
* for getting the event data which could be various event type.
*/
int devfreq_event_set_event(struct devfreq_event_dev *edev)
{
int ret;
if (!edev || !edev->desc)
return -EINVAL;
if (!edev->desc->ops || !edev->desc->ops->set_event)
return -EINVAL;
if (!devfreq_event_is_enabled(edev))
return -EPERM;
mutex_lock(&edev->lock);
ret = edev->desc->ops->set_event(edev);
mutex_unlock(&edev->lock);
return ret;
}
EXPORT_SYMBOL_GPL(devfreq_event_set_event);
/**
* devfreq_event_get_event() - Get {load|total}_count from devfreq-event dev.
* @edev : the devfreq-event device
* @edata : the calculated data of devfreq-event device
*
* Note that this function get the calculated event data from devfreq-event dev
* after stoping the progress of whole sequence of devfreq-event dev.
*/
int devfreq_event_get_event(struct devfreq_event_dev *edev,
struct devfreq_event_data *edata)
{
int ret;
if (!edev || !edev->desc)
return -EINVAL;
if (!edev->desc->ops || !edev->desc->ops->get_event)
return -EINVAL;
if (!devfreq_event_is_enabled(edev))
return -EINVAL;
edata->total_count = edata->load_count = 0;
mutex_lock(&edev->lock);
ret = edev->desc->ops->get_event(edev, edata);
if (ret < 0)
edata->total_count = edata->load_count = 0;
mutex_unlock(&edev->lock);
return ret;
}
EXPORT_SYMBOL_GPL(devfreq_event_get_event);
/**
* devfreq_event_reset_event() - Reset all opeations of devfreq-event dev.
* @edev : the devfreq-event device
*
* Note that this function stop all operations of devfreq-event dev and reset
* the current event data to make the devfreq-event device into initial state.
*/
int devfreq_event_reset_event(struct devfreq_event_dev *edev)
{
int ret = 0;
if (!edev || !edev->desc)
return -EINVAL;
if (!devfreq_event_is_enabled(edev))
return -EPERM;
mutex_lock(&edev->lock);
if (edev->desc->ops && edev->desc->ops->reset)
ret = edev->desc->ops->reset(edev);
mutex_unlock(&edev->lock);
return ret;
}
EXPORT_SYMBOL_GPL(devfreq_event_reset_event);
/**
* devfreq_event_get_edev_by_phandle() - Get the devfreq-event dev from
* devicetree.
* @dev : the pointer to the given device
* @index : the index into list of devfreq-event device
*
* Note that this function return the pointer of devfreq-event device.
*/
struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(struct device *dev,
int index)
{
struct device_node *node;
struct devfreq_event_dev *edev;
if (!dev->of_node)
return ERR_PTR(-EINVAL);
node = of_parse_phandle(dev->of_node, "devfreq-events", index);
if (!node)
return ERR_PTR(-ENODEV);
mutex_lock(&devfreq_event_list_lock);
list_for_each_entry(edev, &devfreq_event_list, node) {
if (edev->dev.parent && edev->dev.parent->of_node == node)
goto out;
}
list_for_each_entry(edev, &devfreq_event_list, node) {
if (!strcmp(edev->desc->name, node->name))
goto out;
}
edev = NULL;
out:
mutex_unlock(&devfreq_event_list_lock);
if (!edev) {
of_node_put(node);
return ERR_PTR(-ENODEV);
}
of_node_put(node);
return edev;
}
EXPORT_SYMBOL_GPL(devfreq_event_get_edev_by_phandle);
/**
* devfreq_event_get_edev_count() - Get the count of devfreq-event dev
* @dev : the pointer to the given device
*
* Note that this function return the count of devfreq-event devices.
*/
int devfreq_event_get_edev_count(struct device *dev)
{
int count;
if (!dev->of_node) {
dev_err(dev, "device does not have a device node entry\n");
return -EINVAL;
}
count = of_property_count_elems_of_size(dev->of_node, "devfreq-events",
sizeof(u32));
if (count < 0) {
dev_err(dev,
"failed to get the count of devfreq-event in %s node\n",
dev->of_node->full_name);
return count;
}
return count;
}
EXPORT_SYMBOL_GPL(devfreq_event_get_edev_count);
static void devfreq_event_release_edev(struct device *dev)
{
struct devfreq_event_dev *edev = to_devfreq_event(dev);
kfree(edev);
}
/**
* devfreq_event_add_edev() - Add new devfreq-event device.
* @dev : the device owning the devfreq-event device being created
* @desc : the devfreq-event device's decriptor which include essential
* data for devfreq-event device.
*
* Note that this function add new devfreq-event device to devfreq-event class
* list and register the device of the devfreq-event device.
*/
struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
struct devfreq_event_desc *desc)
{
struct devfreq_event_dev *edev;
static atomic_t event_no = ATOMIC_INIT(0);
int ret;
if (!dev || !desc)
return ERR_PTR(-EINVAL);
if (!desc->name || !desc->ops)
return ERR_PTR(-EINVAL);
if (!desc->ops->set_event || !desc->ops->get_event)
return ERR_PTR(-EINVAL);
edev = kzalloc(sizeof(struct devfreq_event_dev), GFP_KERNEL);
if (!edev)
return ERR_PTR(-ENOMEM);
mutex_init(&edev->lock);
edev->desc = desc;
edev->enable_count = 0;
edev->dev.parent = dev;
edev->dev.class = devfreq_event_class;
edev->dev.release = devfreq_event_release_edev;
dev_set_name(&edev->dev, "event.%d", atomic_inc_return(&event_no) - 1);
ret = device_register(&edev->dev);
if (ret < 0) {
put_device(&edev->dev);
return ERR_PTR(ret);
}
dev_set_drvdata(&edev->dev, edev);
INIT_LIST_HEAD(&edev->node);
mutex_lock(&devfreq_event_list_lock);
list_add(&edev->node, &devfreq_event_list);
mutex_unlock(&devfreq_event_list_lock);
return edev;
}
EXPORT_SYMBOL_GPL(devfreq_event_add_edev);
/**
* devfreq_event_remove_edev() - Remove the devfreq-event device registered.
* @dev : the devfreq-event device
*
* Note that this function remove the registered devfreq-event device.
*/
int devfreq_event_remove_edev(struct devfreq_event_dev *edev)
{
if (!edev)
return -EINVAL;
WARN_ON(edev->enable_count);
mutex_lock(&devfreq_event_list_lock);
list_del(&edev->node);
mutex_unlock(&devfreq_event_list_lock);
device_unregister(&edev->dev);
return 0;
}
EXPORT_SYMBOL_GPL(devfreq_event_remove_edev);
static int devm_devfreq_event_match(struct device *dev, void *res, void *data)
{
struct devfreq_event_dev **r = res;
if (WARN_ON(!r || !*r))
return 0;
return *r == data;
}
static void devm_devfreq_event_release(struct device *dev, void *res)
{
devfreq_event_remove_edev(*(struct devfreq_event_dev **)res);
}
/**
* devm_devfreq_event_add_edev() - Resource-managed devfreq_event_add_edev()
* @dev : the device owning the devfreq-event device being created
* @desc : the devfreq-event device's decriptor which include essential
* data for devfreq-event device.
*
* Note that this function manages automatically the memory of devfreq-event
* device using device resource management and simplify the free operation
* for memory of devfreq-event device.
*/
struct devfreq_event_dev *devm_devfreq_event_add_edev(struct device *dev,
struct devfreq_event_desc *desc)
{
struct devfreq_event_dev **ptr, *edev;
ptr = devres_alloc(devm_devfreq_event_release, sizeof(*ptr),
GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
edev = devfreq_event_add_edev(dev, desc);
if (IS_ERR(edev)) {
devres_free(ptr);
return ERR_PTR(-ENOMEM);
}
*ptr = edev;
devres_add(dev, ptr);
return edev;
}
EXPORT_SYMBOL_GPL(devm_devfreq_event_add_edev);
/**
* devm_devfreq_event_remove_edev()- Resource-managed devfreq_event_remove_edev()
* @dev : the device owning the devfreq-event device being created
* @edev : the devfreq-event device
*
* Note that this function manages automatically the memory of devfreq-event
* device using device resource management.
*/
void devm_devfreq_event_remove_edev(struct device *dev,
struct devfreq_event_dev *edev)
{
WARN_ON(devres_release(dev, devm_devfreq_event_release,
devm_devfreq_event_match, edev));
}
EXPORT_SYMBOL_GPL(devm_devfreq_event_remove_edev);
/*
* Device attributes for devfreq-event class.
*/
static ssize_t name_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct devfreq_event_dev *edev = to_devfreq_event(dev);
if (!edev || !edev->desc)
return -EINVAL;
return sprintf(buf, "%s\n", edev->desc->name);
}
static DEVICE_ATTR_RO(name);
static ssize_t enable_count_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct devfreq_event_dev *edev = to_devfreq_event(dev);
if (!edev || !edev->desc)
return -EINVAL;
return sprintf(buf, "%d\n", edev->enable_count);
}
static DEVICE_ATTR_RO(enable_count);
static struct attribute *devfreq_event_attrs[] = {
&dev_attr_name.attr,
&dev_attr_enable_count.attr,
NULL,
};
ATTRIBUTE_GROUPS(devfreq_event);
static int __init devfreq_event_init(void)
{
devfreq_event_class = class_create(THIS_MODULE, "devfreq-event");
if (IS_ERR(devfreq_event_class)) {
pr_err("%s: couldn't create class\n", __FILE__);
return PTR_ERR(devfreq_event_class);
}
devfreq_event_class->dev_groups = devfreq_event_groups;
return 0;
}
subsys_initcall(devfreq_event_init);
static void __exit devfreq_event_exit(void)
{
class_destroy(devfreq_event_class);
}
module_exit(devfreq_event_exit);
MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
MODULE_DESCRIPTION("DEVFREQ-Event class support");
MODULE_LICENSE("GPL");