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230 lines
6.9 KiB
230 lines
6.9 KiB
// 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 <[email protected]>, 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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