// SPDX-License-Identifier: GPL-2.0 /* * drivers/base/power/common.c - Common device power management code. * * Copyright (C) 2011 Rafael J. Wysocki <[email protected]>, Renesas Electronics Corp. */ #include <linux/kernel.h> #include <linux/device.h> #include <linux/export.h> #include <linux/slab.h> #include <linux/pm_clock.h> #include <linux/acpi.h> #include <linux/pm_domain.h> #include "power.h" /** * dev_pm_get_subsys_data - Create or refcount power.subsys_data for device. * @dev: Device to handle. * * If power.subsys_data is NULL, point it to a new object, otherwise increment * its reference counter. Return 0 if new object has been created or refcount * increased, otherwise negative error code. */ int dev_pm_get_subsys_data(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * dev_pm_put_subsys_data - Drop reference to power.subsys_data. * @dev: Device to handle. * * If the reference counter of power.subsys_data is zero after dropping the * reference, power.subsys_data is removed. */ void dev_pm_put_subsys_data(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * dev_pm_domain_attach - Attach a device to its PM domain. * @dev: Device to attach. * @power_on: Used to indicate whether we should power on the device. * * The @dev may only be attached to a single PM domain. By iterating through * the available alternatives we try to find a valid PM domain for the device. * As attachment succeeds, the ->detach() callback in the struct dev_pm_domain * should be assigned by the corresponding attach function. * * This function should typically be invoked from subsystem level code during * the probe phase. Especially for those that holds devices which requires * power management through PM domains. * * Callers must ensure proper synchronization of this function with power * management callbacks. * * Returns 0 on successfully attached PM domain, or when it is found that the * device doesn't need a PM domain, else a negative error code. */ int dev_pm_domain_attach(struct device *dev, bool power_on) { … } EXPORT_SYMBOL_GPL(…); /** * dev_pm_domain_attach_by_id - Associate a device with one of its PM domains. * @dev: The device used to lookup the PM domain. * @index: The index of the PM domain. * * As @dev may only be attached to a single PM domain, the backend PM domain * provider creates a virtual device to attach instead. If attachment succeeds, * the ->detach() callback in the struct dev_pm_domain are assigned by the * corresponding backend attach function, as to deal with detaching of the * created virtual device. * * This function should typically be invoked by a driver during the probe phase, * in case its device requires power management through multiple PM domains. The * driver may benefit from using the received device, to configure device-links * towards its original device. Depending on the use-case and if needed, the * links may be dynamically changed by the driver, which allows it to control * the power to the PM domains independently from each other. * * Callers must ensure proper synchronization of this function with power * management callbacks. * * Returns the virtual created device when successfully attached to its PM * domain, NULL in case @dev don't need a PM domain, else an ERR_PTR(). * Note that, to detach the returned virtual device, the driver shall call * dev_pm_domain_detach() on it, typically during the remove phase. */ struct device *dev_pm_domain_attach_by_id(struct device *dev, unsigned int index) { … } EXPORT_SYMBOL_GPL(…); /** * dev_pm_domain_attach_by_name - Associate a device with one of its PM domains. * @dev: The device used to lookup the PM domain. * @name: The name of the PM domain. * * For a detailed function description, see dev_pm_domain_attach_by_id(). */ struct device *dev_pm_domain_attach_by_name(struct device *dev, const char *name) { … } EXPORT_SYMBOL_GPL(…); /** * dev_pm_domain_attach_list - Associate a device with its PM domains. * @dev: The device used to lookup the PM domains for. * @data: The data used for attaching to the PM domains. * @list: An out-parameter with an allocated list of attached PM domains. * * This function helps to attach a device to its multiple PM domains. The * caller, which is typically a driver's probe function, may provide a list of * names for the PM domains that we should try to attach the device to, but it * may also provide an empty list, in case the attach should be done for all of * the available PM domains. * * Callers must ensure proper synchronization of this function with power * management callbacks. * * Returns the number of attached PM domains or a negative error code in case of * a failure. Note that, to detach the list of PM domains, the driver shall call * dev_pm_domain_detach_list(), typically during the remove phase. */ int dev_pm_domain_attach_list(struct device *dev, const struct dev_pm_domain_attach_data *data, struct dev_pm_domain_list **list) { … } EXPORT_SYMBOL_GPL(…); /** * dev_pm_domain_detach - Detach a device from its PM domain. * @dev: Device to detach. * @power_off: Used to indicate whether we should power off the device. * * This functions will reverse the actions from dev_pm_domain_attach(), * dev_pm_domain_attach_by_id() and dev_pm_domain_attach_by_name(), thus it * detaches @dev from its PM domain. Typically it should be invoked during the * remove phase, either from subsystem level code or from drivers. * * Callers must ensure proper synchronization of this function with power * management callbacks. */ void dev_pm_domain_detach(struct device *dev, bool power_off) { … } EXPORT_SYMBOL_GPL(…); /** * dev_pm_domain_detach_list - Detach a list of PM domains. * @list: The list of PM domains to detach. * * This function reverse the actions from dev_pm_domain_attach_list(). * Typically it should be invoked during the remove phase from drivers. * * Callers must ensure proper synchronization of this function with power * management callbacks. */ void dev_pm_domain_detach_list(struct dev_pm_domain_list *list) { … } EXPORT_SYMBOL_GPL(…); /** * dev_pm_domain_start - Start the device through its PM domain. * @dev: Device to start. * * This function should typically be called during probe by a subsystem/driver, * when it needs to start its device from the PM domain's perspective. Note * that, it's assumed that the PM domain is already powered on when this * function is called. * * Returns 0 on success and negative error values on failures. */ int dev_pm_domain_start(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * dev_pm_domain_set - Set PM domain of a device. * @dev: Device whose PM domain is to be set. * @pd: PM domain to be set, or NULL. * * Sets the PM domain the device belongs to. The PM domain of a device needs * to be set before its probe finishes (it's bound to a driver). * * This function must be called with the device lock held. */ void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd) { … } EXPORT_SYMBOL_GPL(…); /** * dev_pm_domain_set_performance_state - Request a new performance state. * @dev: The device to make the request for. * @state: Target performance state for the device. * * This function should be called when a new performance state needs to be * requested for a device that is attached to a PM domain. Note that, the * support for performance scaling for PM domains is optional. * * Returns 0 on success and when performance scaling isn't supported, negative * error code on failure. */ int dev_pm_domain_set_performance_state(struct device *dev, unsigned int state) { … } EXPORT_SYMBOL_GPL(…);
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