base/power/common.c

1 // SPDX-License-Identifier: GPL-2.0
3  * drivers/base/power/common.c - Common device power management code.
15 #include "power.h"
18  * dev_pm_get_subsys_data - Create or refcount power.subsys_data for device.
21  * If power.subsys_data is NULL, point it to a new object, otherwise increment
31 		return -ENOMEM;  in dev_pm_get_subsys_data()
33 	spin_lock_irq(&dev->power.lock);  in dev_pm_get_subsys_data()
35 	if (dev->power.subsys_data) {  in dev_pm_get_subsys_data()
36 		dev->power.subsys_data->refcount++;  in dev_pm_get_subsys_data()
38 		spin_lock_init(&psd->lock);  in dev_pm_get_subsys_data()
39 		psd->refcount = 1;  in dev_pm_get_subsys_data()
40 		dev->power.subsys_data = psd;  in dev_pm_get_subsys_data()
45 	spin_unlock_irq(&dev->power.lock);  in dev_pm_get_subsys_data()
55  * dev_pm_put_subsys_data - Drop reference to power.subsys_data.
58  * If the reference counter of power.subsys_data is zero after dropping the
59  * reference, power.subsys_data is removed.
65 	spin_lock_irq(&dev->power.lock);  in dev_pm_put_subsys_data()
71 	if (--psd->refcount == 0)  in dev_pm_put_subsys_data()
72 		dev->power.subsys_data = NULL;  in dev_pm_put_subsys_data()
77 	spin_unlock_irq(&dev->power.lock);  in dev_pm_put_subsys_data()
83  * dev_pm_domain_attach - Attach a device to its PM domain.
85  * @power_on: Used to indicate whether we should power on the device.
87  * The @dev may only be attached to a single PM domain. By iterating through
88  * the available alternatives we try to find a valid PM domain for the device.
89  * As attachment succeeds, the ->detach() callback in the struct dev_pm_domain
94  * power management through PM domains.
96  * Callers must ensure proper synchronization of this function with power
99  * Returns 0 on successfully attached PM domain, or when it is found that the
100  * device doesn't need a PM domain, else a negative error code.
106 	if (dev->pm_domain)  in dev_pm_domain_attach()
118  * dev_pm_domain_attach_by_id - Associate a device with one of its PM domains.
119  * @dev: The device used to lookup the PM domain.
120  * @index: The index of the PM domain.
122  * As @dev may only be attached to a single PM domain, the backend PM domain
124  * the ->detach() callback in the struct dev_pm_domain are assigned by the
129  * in case its device requires power management through multiple PM domains. The
130  * driver may benefit from using the received device, to configure device-links
131  * towards its original device. Depending on the use-case and if needed, the
133  * the power to the PM domains independently from each other.
135  * Callers must ensure proper synchronization of this function with power
139  * domain, NULL in case @dev don't need a PM domain, else an ERR_PTR().
146 	if (dev->pm_domain)  in dev_pm_domain_attach_by_id()
147 		return ERR_PTR(-EEXIST);  in dev_pm_domain_attach_by_id()
154  * dev_pm_domain_attach_by_name - Associate a device with one of its PM domains.
155  * @dev: The device used to lookup the PM domain.
156  * @name: The name of the PM domain.
163 	if (dev->pm_domain)  in dev_pm_domain_attach_by_name()
164 		return ERR_PTR(-EEXIST);  in dev_pm_domain_attach_by_name()
171  * dev_pm_domain_detach - Detach a device from its PM domain.
173  * @power_off: Used to indicate whether we should power off the device.
177  * detaches @dev from its PM domain.  Typically it should be invoked during the
180  * Callers must ensure proper synchronization of this function with power
185 	if (dev->pm_domain && dev->pm_domain->detach)  in dev_pm_domain_detach()
186 		dev->pm_domain->detach(dev, power_off);  in dev_pm_domain_detach()
191  * dev_pm_domain_start - Start the device through its PM domain.
195  * when it needs to start its device from the PM domain's perspective. Note
196  * that, it's assumed that the PM domain is already powered on when this
203 	if (dev->pm_domain && dev->pm_domain->start)  in dev_pm_domain_start()
204 		return dev->pm_domain->start(dev);  in dev_pm_domain_start()
211  * dev_pm_domain_set - Set PM domain of a device.
212  * @dev: Device whose PM domain is to be set.
213  * @pd: PM domain to be set, or NULL.
215  * Sets the PM domain the device belongs to. The PM domain of a device needs
222 	if (dev->pm_domain == pd)  in dev_pm_domain_set()
227 	dev->pm_domain = pd;  in dev_pm_domain_set()