/* * 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 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, 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);