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154 lines
4.1 KiB
154 lines
4.1 KiB
/*
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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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* This file is released under the GPLv2.
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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 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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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;
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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_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 thus
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* try to detach the @dev from its PM domain. Typically it should be invoked
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* from subsystem level code during the remove phase.
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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_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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