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/*
* 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,
const 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);
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