/* * drivers/base/power/common.c - Common device power management code. * * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp. * * This file is released under the GPLv2. */ #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 negative error code. */int dev_pm_domain_attach(struct device *dev, bool power_on){	int ret; 	ret = acpi_dev_pm_attach(dev, power_on);	if (ret)		ret = genpd_dev_pm_attach(dev); 	return ret;}EXPORT_SYMBOL_GPL(dev_pm_domain_attach); /** * 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 thus * try to detach the @dev from its PM domain. Typically it should be invoked * from subsystem level code during the remove phase. * * 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);