drivers/base/power/common.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * drivers/base/power/common.c - Common device power management code.
  *
  * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, 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)
 {
 	struct pm_subsys_data *psd;

 	psd = kzalloc(sizeof(*psd), GFP_KERNEL);
 	if (!psd)
 		return -ENOMEM;

 	spin_lock_irq(&dev->power.lock);

 	if (dev->power.subsys_data) {
 		dev->power.subsys_data->refcount++;
 	} else {
 		spin_lock_init(&psd->lock);
 		psd->refcount = 1;
 		dev->power.subsys_data = psd;
 		pm_clk_init(dev);
 		psd = NULL;
 	}

 	spin_unlock_irq(&dev->power.lock);

 	/* kfree() verifies that its argument is nonzero. */
 	kfree(psd);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data);

 /**
  * 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)
 {
 	struct pm_subsys_data *psd;

 	spin_lock_irq(&dev->power.lock);

 	psd = dev_to_psd(dev);
 	if (!psd)
 		goto out;

 	if (--psd->refcount == 0)
 		dev->power.subsys_data = NULL;
 	else
 		psd = NULL;

  out:
 	spin_unlock_irq(&dev->power.lock);
 	kfree(psd);
 }
 EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);

 /**
  * 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)
 {
 	int ret;

 	if (dev->pm_domain)
 		return 0;

 	ret = acpi_dev_pm_attach(dev, power_on);
 	if (!ret)
 		ret = genpd_dev_pm_attach(dev);

 	return ret < 0 ? ret : 0;
 }
 EXPORT_SYMBOL_GPL(dev_pm_domain_attach);

 /**
  * 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)
 {
 	if (dev->pm_domain)
 		return ERR_PTR(-EEXIST);

 	return genpd_dev_pm_attach_by_id(dev, index);
 }
 EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_id);

 /**
  * 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)
 {
 	if (dev->pm_domain)
 		return ERR_PTR(-EEXIST);

 	return genpd_dev_pm_attach_by_name(dev, name);
 }
 EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_name);

 /**
  * 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() and
  * dev_pm_domain_attach_by_id(), 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)
 {
 	if (dev->pm_domain && dev->pm_domain->detach)
 		dev->pm_domain->detach(dev, power_off);
 }
 EXPORT_SYMBOL_GPL(dev_pm_domain_detach);

 /**
  * 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)
 {
 	if (dev->pm_domain == pd)
 		return;

 	WARN(pd && device_is_bound(dev),
 	     "PM domains can only be changed for unbound devices\n");
 	dev->pm_domain = pd;
 	device_pm_check_callbacks(dev);
 }
 EXPORT_SYMBOL_GPL(dev_pm_domain_set);
	// SPDX-License-Identifier: GPL-2.0
	/*
	* drivers/base/power/common.c - Common device power management code.
	*
	* Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, 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)
	{
	struct pm_subsys_data *psd;

	psd = kzalloc(sizeof(*psd), GFP_KERNEL);
	if (!psd)
	return -ENOMEM;

	spin_lock_irq(&dev->power.lock);

	if (dev->power.subsys_data) {
	dev->power.subsys_data->refcount++;
	} else {
	spin_lock_init(&psd->lock);
	psd->refcount = 1;
	dev->power.subsys_data = psd;
	pm_clk_init(dev);
	psd = NULL;
	}

	spin_unlock_irq(&dev->power.lock);

	/* kfree() verifies that its argument is nonzero. */
	kfree(psd);

	return 0;
	}
	EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data);

	/**
	* 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)
	{
	struct pm_subsys_data *psd;

	spin_lock_irq(&dev->power.lock);

	psd = dev_to_psd(dev);
	if (!psd)
	goto out;

	if (--psd->refcount == 0)
	dev->power.subsys_data = NULL;
	else
	psd = NULL;

	out:
	spin_unlock_irq(&dev->power.lock);
	kfree(psd);
	}
	EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);

	/**
	* 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)
	{
	int ret;

	if (dev->pm_domain)
	return 0;

	ret = acpi_dev_pm_attach(dev, power_on);
	if (!ret)
	ret = genpd_dev_pm_attach(dev);

	return ret < 0 ? ret : 0;
	}
	EXPORT_SYMBOL_GPL(dev_pm_domain_attach);

	/**
	* 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)
	{
	if (dev->pm_domain)
	return ERR_PTR(-EEXIST);

	return genpd_dev_pm_attach_by_id(dev, index);
	}
	EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_id);

	/**
	* 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)
	{
	if (dev->pm_domain)
	return ERR_PTR(-EEXIST);

	return genpd_dev_pm_attach_by_name(dev, name);
	}
	EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_name);

	/**
	* 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() and
	* dev_pm_domain_attach_by_id(), 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)
	{
	if (dev->pm_domain && dev->pm_domain->detach)
	dev->pm_domain->detach(dev, power_off);
	}
	EXPORT_SYMBOL_GPL(dev_pm_domain_detach);

	/**
	* 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)
	{
	if (dev->pm_domain == pd)
	return;

	WARN(pd && device_is_bound(dev),
	"PM domains can only be changed for unbound devices\n");
	dev->pm_domain = pd;
	device_pm_check_callbacks(dev);
	}
	EXPORT_SYMBOL_GPL(dev_pm_domain_set);