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Release 4.17 drivers/devfreq/devfreq-event.c

Directory: drivers/devfreq
/*
 * 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/export.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; }

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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; }

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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; }

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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; }

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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; }

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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; }

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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; }

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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 %pOF node\n", dev->of_node); return count; } return count; }

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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); }

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/** * 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(-1); 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)); 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; }

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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; }

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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; }

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static void devm_devfreq_event_release(struct device *dev, void *res) { devfreq_event_remove_edev(*(struct devfreq_event_dev **)res); }

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/** * 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; }

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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)); }

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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); }

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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); }

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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; }

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subsys_initcall(devfreq_event_init);

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Directory: drivers/devfreq
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