231 lines
6.9 KiB
C
231 lines
6.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* drivers/base/power/common.c - Common device power management code.
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*
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* Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
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*/
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#include <linux/kernel.h>
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#include <linux/device.h>
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#include <linux/export.h>
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#include <linux/slab.h>
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#include <linux/pm_clock.h>
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#include <linux/acpi.h>
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#include <linux/pm_domain.h>
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#include "power.h"
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/**
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* dev_pm_get_subsys_data - Create or refcount power.subsys_data for device.
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* @dev: Device to handle.
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*
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* If power.subsys_data is NULL, point it to a new object, otherwise increment
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* its reference counter. Return 0 if new object has been created or refcount
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* increased, otherwise negative error code.
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*/
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int dev_pm_get_subsys_data(struct device *dev)
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{
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struct pm_subsys_data *psd;
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psd = kzalloc(sizeof(*psd), GFP_KERNEL);
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if (!psd)
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return -ENOMEM;
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spin_lock_irq(&dev->power.lock);
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if (dev->power.subsys_data) {
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dev->power.subsys_data->refcount++;
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} else {
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spin_lock_init(&psd->lock);
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psd->refcount = 1;
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dev->power.subsys_data = psd;
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pm_clk_init(dev);
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psd = NULL;
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}
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spin_unlock_irq(&dev->power.lock);
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/* kfree() verifies that its argument is nonzero. */
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kfree(psd);
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return 0;
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}
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EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data);
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/**
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* dev_pm_put_subsys_data - Drop reference to power.subsys_data.
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* @dev: Device to handle.
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*
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* If the reference counter of power.subsys_data is zero after dropping the
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* reference, power.subsys_data is removed.
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*/
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void dev_pm_put_subsys_data(struct device *dev)
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{
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struct pm_subsys_data *psd;
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spin_lock_irq(&dev->power.lock);
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psd = dev_to_psd(dev);
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if (!psd)
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goto out;
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if (--psd->refcount == 0)
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dev->power.subsys_data = NULL;
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else
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psd = NULL;
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out:
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spin_unlock_irq(&dev->power.lock);
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kfree(psd);
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}
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EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);
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/**
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* dev_pm_domain_attach - Attach a device to its PM domain.
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* @dev: Device to attach.
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* @power_on: Used to indicate whether we should power on the device.
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*
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* The @dev may only be attached to a single PM domain. By iterating through
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* the available alternatives we try to find a valid PM domain for the device.
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* As attachment succeeds, the ->detach() callback in the struct dev_pm_domain
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* should be assigned by the corresponding attach function.
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*
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* This function should typically be invoked from subsystem level code during
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* the probe phase. Especially for those that holds devices which requires
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* power management through PM domains.
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*
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* Callers must ensure proper synchronization of this function with power
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* management callbacks.
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*
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* Returns 0 on successfully attached PM domain, or when it is found that the
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* device doesn't need a PM domain, else a negative error code.
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*/
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int dev_pm_domain_attach(struct device *dev, bool power_on)
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{
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int ret;
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if (dev->pm_domain)
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return 0;
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ret = acpi_dev_pm_attach(dev, power_on);
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if (!ret)
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ret = genpd_dev_pm_attach(dev);
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return ret < 0 ? ret : 0;
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}
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EXPORT_SYMBOL_GPL(dev_pm_domain_attach);
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/**
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* dev_pm_domain_attach_by_id - Associate a device with one of its PM domains.
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* @dev: The device used to lookup the PM domain.
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* @index: The index of the PM domain.
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*
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* As @dev may only be attached to a single PM domain, the backend PM domain
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* provider creates a virtual device to attach instead. If attachment succeeds,
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* the ->detach() callback in the struct dev_pm_domain are assigned by the
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* corresponding backend attach function, as to deal with detaching of the
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* created virtual device.
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*
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* This function should typically be invoked by a driver during the probe phase,
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* in case its device requires power management through multiple PM domains. The
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* driver may benefit from using the received device, to configure device-links
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* towards its original device. Depending on the use-case and if needed, the
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* links may be dynamically changed by the driver, which allows it to control
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* the power to the PM domains independently from each other.
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*
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* Callers must ensure proper synchronization of this function with power
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* management callbacks.
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*
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* Returns the virtual created device when successfully attached to its PM
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* domain, NULL in case @dev don't need a PM domain, else an ERR_PTR().
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* Note that, to detach the returned virtual device, the driver shall call
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* dev_pm_domain_detach() on it, typically during the remove phase.
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*/
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struct device *dev_pm_domain_attach_by_id(struct device *dev,
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unsigned int index)
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{
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if (dev->pm_domain)
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return ERR_PTR(-EEXIST);
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return genpd_dev_pm_attach_by_id(dev, index);
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}
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EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_id);
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/**
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* dev_pm_domain_attach_by_name - Associate a device with one of its PM domains.
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* @dev: The device used to lookup the PM domain.
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* @name: The name of the PM domain.
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*
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* For a detailed function description, see dev_pm_domain_attach_by_id().
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*/
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struct device *dev_pm_domain_attach_by_name(struct device *dev,
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const char *name)
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{
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if (dev->pm_domain)
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return ERR_PTR(-EEXIST);
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return genpd_dev_pm_attach_by_name(dev, name);
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}
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EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_name);
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/**
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* dev_pm_domain_detach - Detach a device from its PM domain.
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* @dev: Device to detach.
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* @power_off: Used to indicate whether we should power off the device.
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*
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* This functions will reverse the actions from dev_pm_domain_attach() and
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* dev_pm_domain_attach_by_id(), thus it detaches @dev from its PM domain.
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* Typically it should be invoked during the remove phase, either from
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* subsystem level code or from drivers.
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*
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* Callers must ensure proper synchronization of this function with power
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* management callbacks.
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*/
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void dev_pm_domain_detach(struct device *dev, bool power_off)
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{
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if (dev->pm_domain && dev->pm_domain->detach)
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dev->pm_domain->detach(dev, power_off);
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}
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EXPORT_SYMBOL_GPL(dev_pm_domain_detach);
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/**
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* dev_pm_domain_start - Start the device through its PM domain.
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* @dev: Device to start.
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*
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* This function should typically be called during probe by a subsystem/driver,
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* when it needs to start its device from the PM domain's perspective. Note
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* that, it's assumed that the PM domain is already powered on when this
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* function is called.
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*
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* Returns 0 on success and negative error values on failures.
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*/
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int dev_pm_domain_start(struct device *dev)
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{
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if (dev->pm_domain && dev->pm_domain->start)
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return dev->pm_domain->start(dev);
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return 0;
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}
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EXPORT_SYMBOL_GPL(dev_pm_domain_start);
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/**
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* dev_pm_domain_set - Set PM domain of a device.
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* @dev: Device whose PM domain is to be set.
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* @pd: PM domain to be set, or NULL.
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*
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* Sets the PM domain the device belongs to. The PM domain of a device needs
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* to be set before its probe finishes (it's bound to a driver).
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*
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* This function must be called with the device lock held.
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*/
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void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd)
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{
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if (dev->pm_domain == pd)
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return;
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WARN(pd && device_is_bound(dev),
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"PM domains can only be changed for unbound devices\n");
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dev->pm_domain = pd;
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device_pm_check_callbacks(dev);
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}
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EXPORT_SYMBOL_GPL(dev_pm_domain_set);
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