Re: [PATCHv8 1/9] devfreq: event: Add new devfreq_event class to provide basic data for devfreq governor

From: Chanwoo Choi
Date: Mon Jan 19 2015 - 05:13:06 EST


Dear Myungjoo,

Following patches need to review from you (DEVFREQ maintainer). Please review these patches.
- [PATCHv8 1/9] devfreq: event: Add new devfreq_event class to provide basic data for devfreq governor
- [PATCHv8 2/9] devfreq: event: Add resource-managed function for devfreq-event device

Best Regards,
Chanwoo Choi

On 01/12/2015 09:34 PM, Chanwoo Choi wrote:
> This patch add new devfreq_event class for devfreq_event device which provide
> raw data (e.g., memory bus utilization/GPU utilization). This raw data from
> devfreq_event data would be used for the governor of devfreq subsystem.
> - devfreq_event device : Provide raw data for governor of existing devfreq device
> - devfreq device : Monitor device state and change frequency/voltage of device
> using the raw data from devfreq_event device
>
> The devfreq subsystem support generic DVFS(Dynamic Voltage/Frequency Scaling)
> for Non-CPU Devices. The devfreq device would dertermine current device state
> using various governor (e.g., ondemand, performance, powersave). After completed
> determination of system state, devfreq device would change the frequency/voltage
> of devfreq device according to the result of governor.
>
> But, devfreq governor must need basic data which indicates current device state.
> Existing devfreq subsystem only consider devfreq device which check current system
> state and determine proper system state using basic data. There is no subsystem
> for device providing basic data to devfreq device.
>
> The devfreq subsystem must need devfreq_event device(data-provider device) for
> existing devfreq device. So, this patch add new devfreq_event class for
> devfreq_event device which read various basic data(e.g, memory bus utilization,
> GPU utilization) and provide measured data to existing devfreq device through
> standard APIs of devfreq_event class.
>
> The following description explains the feature of two kind of devfreq class:
> - devfreq class (existing)
> : devfreq consumer device use raw data from devfreq_event device for
> determining proper current system state and change voltage/frequency
> dynamically using various governors.
>
> - devfreq_event class (new)
> : Provide measured raw data to devfreq device for governor
>
> Cc: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
> Cc: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> Signed-off-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
> ---
> drivers/devfreq/Kconfig | 2 +
> drivers/devfreq/Makefile | 6 +-
> drivers/devfreq/devfreq-event.c | 448 ++++++++++++++++++++++++++++++++++++++++
> drivers/devfreq/event/Kconfig | 16 ++
> drivers/devfreq/event/Makefile | 1 +
> include/linux/devfreq-event.h | 170 +++++++++++++++
> 6 files changed, 642 insertions(+), 1 deletion(-)
> create mode 100644 drivers/devfreq/devfreq-event.c
> create mode 100644 drivers/devfreq/event/Kconfig
> create mode 100644 drivers/devfreq/event/Makefile
> create mode 100644 include/linux/devfreq-event.h
>
> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
> index faf4e70..21f8f17 100644
> --- a/drivers/devfreq/Kconfig
> +++ b/drivers/devfreq/Kconfig
> @@ -87,4 +87,6 @@ config ARM_EXYNOS5_BUS_DEVFREQ
> It reads PPMU counters of memory controllers and adjusts the
> operating frequencies and voltages with OPP support.
>
> +source "drivers/devfreq/event/Kconfig"
> +
> endif # PM_DEVFREQ
> diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
> index 16138c9..c449336 100644
> --- a/drivers/devfreq/Makefile
> +++ b/drivers/devfreq/Makefile
> @@ -1,4 +1,5 @@
> -obj-$(CONFIG_PM_DEVFREQ) += devfreq.o
> +obj-$(CONFIG_PM_DEVFREQ) += devfreq.o
> +obj-$(CONFIG_PM_DEVFREQ_EVENT) += devfreq-event.o
> obj-$(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) += governor_simpleondemand.o
> obj-$(CONFIG_DEVFREQ_GOV_PERFORMANCE) += governor_performance.o
> obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE) += governor_powersave.o
> @@ -7,3 +8,6 @@ obj-$(CONFIG_DEVFREQ_GOV_USERSPACE) += governor_userspace.o
> # DEVFREQ Drivers
> obj-$(CONFIG_ARM_EXYNOS4_BUS_DEVFREQ) += exynos/
> obj-$(CONFIG_ARM_EXYNOS5_BUS_DEVFREQ) += exynos/
> +
> +# DEVFREQ Event Drivers
> +obj-$(CONFIG_PM_DEVFREQ_EVENT) += event/
> diff --git a/drivers/devfreq/devfreq-event.c b/drivers/devfreq/devfreq-event.c
> new file mode 100644
> index 0000000..9ba5ba4
> --- /dev/null
> +++ b/drivers/devfreq/devfreq-event.c
> @@ -0,0 +1,448 @@
> +/*
> + * devfreq-event: a framework to provide raw data and events of devfreq devices
> + *
> + * Copyright (C) 2014 Samsung Electronics
> + * Author: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
> + *
> + * 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) {
> + 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) {
> + edev->enable_count--;
> + } else {
> + dev_warn(&edev->dev, "unbalanced enable_count\n");
> + ret = -EINVAL;
> + goto err;
> + }
> +
> + if (edev->desc->ops && edev->desc->ops->disable) {
> + ret = edev->desc->ops->disable(edev);
> + if (ret < 0) {
> + edev->enable_count++;
> + goto err;
> + }
> + }
> +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 event and total_event 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->event = edata->total_event = 0;
> +
> + mutex_lock(&edev->lock);
> + ret = edev->desc->ops->get_event(edev, edata);
> + mutex_unlock(&edev->lock);
> +
> + if ((edata->total_event <= 0)
> + || (edata->event > edata->total_event)) {
> + edata->event = edata->total_event = 0;
> + ret = -EINVAL;
> + }
> +
> + 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);
> +
> + if (ret < 0)
> + return -EINVAL;
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_reset_event);
> +
> +/**
> + * devfreq_event_get_drvdata() - Return driver-data of devfreq-event dev.
> + * @edev : the devfreq-event device
> + *
> + * Note that this function return the driver-data of devfreq-event device.
> + */
> +void *devfreq_event_get_drvdata(struct devfreq_event_dev *edev)
> +{
> + return edev->desc->driver_data;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_get_drvdata);
> +
> +/**
> + * 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) {
> + dev_err(dev, "device does not have a device node entry\n");
> + return ERR_PTR(-EINVAL);
> + }
> +
> + node = of_parse_phandle(dev->of_node, "devfreq-events", index);
> + if (!node) {
> + dev_err(dev, "failed to get phandle in %s node\n",
> + dev->of_node->full_name);
> + return ERR_PTR(-ENODEV);
> + }
> +
> + mutex_lock(&devfreq_event_list_lock);
> + 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) {
> + dev_err(dev, "unable to get devfreq-event device : %s\n",
> + node->name);
> + 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->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;
> +
> + mutex_lock(&devfreq_event_list_lock);
> + WARN_ON(edev->enable_count);
> + list_del(&edev->node);
> + device_unregister(&edev->dev);
> + mutex_unlock(&devfreq_event_list_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(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@xxxxxxxxxxx>");
> +MODULE_DESCRIPTION("DEVFREQ-Event class support");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/devfreq/event/Kconfig b/drivers/devfreq/event/Kconfig
> new file mode 100644
> index 0000000..1ced42c
> --- /dev/null
> +++ b/drivers/devfreq/event/Kconfig
> @@ -0,0 +1,16 @@
> +menuconfig PM_DEVFREQ_EVENT
> + bool "DEVFREQ-Event device Support"
> + help
> + The devfreq-event device provide the raw data and events which
> + indicate the current state of devfreq-event device. The provided
> + data from devfreq-event device is used to monitor the state of
> + device and determine the suitable size of resource to reduce the
> + wasted resource.
> +
> + The devfreq-event device can support the various type of events
> + (e.g., raw data, utilization, latency, bandwidth). The events
> + may be used by devfreq governor and other subsystem.
> +
> +if PM_DEVFREQ_EVENT
> +
> +endif # PM_DEVFREQ_EVENT
> diff --git a/drivers/devfreq/event/Makefile b/drivers/devfreq/event/Makefile
> new file mode 100644
> index 0000000..dc56005
> --- /dev/null
> +++ b/drivers/devfreq/event/Makefile
> @@ -0,0 +1 @@
> +# Exynos DEVFREQ Event Drivers
> diff --git a/include/linux/devfreq-event.h b/include/linux/devfreq-event.h
> new file mode 100644
> index 0000000..b7363f5
> --- /dev/null
> +++ b/include/linux/devfreq-event.h
> @@ -0,0 +1,170 @@
> +/*
> + * devfreq-event: a framework to provide raw data and events of devfreq devices
> + *
> + * Copyright (C) 2014 Samsung Electronics
> + * Author: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
> + *
> + * 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.
> + */
> +
> +#ifndef __LINUX_DEVFREQ_EVENT_H__
> +#define __LINUX_DEVFREQ_EVENT_H__
> +
> +#include <linux/device.h>
> +
> +/**
> + * struct devfreq_event_dev - the devfreq-event device
> + *
> + * @node : Contain the devfreq-event device that have been registered.
> + * @dev : the device registered by devfreq-event class. dev.parent is
> + * the device using devfreq-event.
> + * @lock : a mutex to protect accessing devfreq-event.
> + * @enable_count: the number of enable function have been called.
> + * @desc : the description for devfreq-event device.
> + *
> + * This structure contains devfreq-event device information.
> + */
> +struct devfreq_event_dev {
> + struct list_head node;
> +
> + struct device dev;
> + struct mutex lock;
> + u32 enable_count;
> +
> + const struct devfreq_event_desc *desc;
> +};
> +
> +/**
> + * struct devfreq_event_data - the devfreq-event data
> + *
> + * @event : the load of devfreq-event device for polling period
> + * @total_event : the total load of devfreq-event device for polling period
> + *
> + * This structure contains the data of devfreq-event device for polling period.
> + */
> +struct devfreq_event_data {
> + unsigned long event;
> + unsigned long total_event;
> +};
> +
> +/**
> + * struct devfreq_event_ops - the operations of devfreq-event device
> + *
> + * @enable : Enable the devfreq-event device.
> + * @disable : Disable the devfreq-event device.
> + * @reset : Reset all setting of the devfreq-event device.
> + * @set_event : Set the specific event type for the devfreq-event device.
> + * @get_event : Get the result of the devfreq-event devie with specific
> + * event type.
> + *
> + * This structure contains devfreq-event device operations which can be
> + * implemented by devfreq-event device drivers.
> + */
> +struct devfreq_event_ops {
> + /* Optional functions */
> + int (*enable)(struct devfreq_event_dev *edev);
> + int (*disable)(struct devfreq_event_dev *edev);
> + int (*reset)(struct devfreq_event_dev *edev);
> +
> + /* Mandatory functions */
> + int (*set_event)(struct devfreq_event_dev *edev);
> + int (*get_event)(struct devfreq_event_dev *edev,
> + struct devfreq_event_data *edata);
> +};
> +
> +/**
> + * struct devfreq_event_desc - the descriptor of devfreq-event device
> + *
> + * @name : the name of devfreq-event device.
> + * @driver_data : the private data for devfreq-event driver.
> + * @ops : the operation to control devfreq-event device.
> + *
> + * Each devfreq-event device is described with a this structure.
> + * This structure contains the various data for devfreq-event device.
> + */
> +struct devfreq_event_desc {
> + const char *name;
> + void *driver_data;
> +
> + struct devfreq_event_ops *ops;
> +};
> +
> +#if defined(CONFIG_PM_DEVFREQ_EVENT)
> +extern int devfreq_event_enable_edev(struct devfreq_event_dev *edev);
> +extern int devfreq_event_disable_edev(struct devfreq_event_dev *edev);
> +extern bool devfreq_event_is_enabled(struct devfreq_event_dev *edev);
> +extern int devfreq_event_set_event(struct devfreq_event_dev *edev);
> +extern int devfreq_event_get_event(struct devfreq_event_dev *edev,
> + struct devfreq_event_data *edata);
> +extern int devfreq_event_reset_event(struct devfreq_event_dev *edev);
> +extern void *devfreq_event_get_drvdata(struct devfreq_event_dev *edev);
> +extern struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(
> + struct device *dev, int index);
> +extern int devfreq_event_get_edev_count(struct device *dev);
> +extern struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
> + struct devfreq_event_desc *desc);
> +extern int devfreq_event_remove_edev(struct devfreq_event_dev *edev);
> +
> +#else
> +static inline int devfreq_event_enable_edev(struct devfreq_event_dev *edev)
> +{
> + return -EINVAL;
> +}
> +
> +static inline int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
> +{
> + return -EINVAL;
> +}
> +
> +static inline bool devfreq_event_is_enabled(struct devfreq_event_dev *edev)
> +{
> + return false;
> +}
> +
> +static inline int devfreq_event_set_event(struct devfreq_event_dev *edev)
> +{
> + return -EINVAL;
> +}
> +
> +static inline int devfreq_event_get_event(struct devfreq_event_dev *edev,
> + struct devfreq_event_data *edata)
> +{
> + return -EINVAL;
> +}
> +
> +static inline int devfreq_event_reset_event(struct devfreq_event_dev *edev)
> +{
> + return -EINVAL;
> +}
> +
> +static inline void *devfreq_event_get_drvdata(struct devfreq_event_dev *edev)
> +{
> + return ERR_PTR(-EINVAL);
> +}
> +
> +static inline struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(
> + struct device *dev, int index)
> +{
> + return ERR_PTR(-EINVAL);
> +}
> +
> +static inline int devfreq_event_get_edev_count(struct device *dev)
> +{
> + return -EINVAL;
> +}
> +
> +static inline struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
> + struct devfreq_event_desc *desc)
> +{
> + return ERR_PTR(-EINVAL);
> +}
> +
> +static inline int devfreq_event_remove_edev(struct devfreq_event_dev *edev)
> +{
> + return -EINVAL;
> +}
> +#endif /* CONFIG_PM_DEVFREQ_EVENT */
> +
> +#endif /* __LINUX_DEVFREQ_EVENT_H__ */
>

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