common.c
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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>
/**
* 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 1 if a new object has been created, otherwise
* return 0 or 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. Return 1 if that happens or 0
* otherwise.
*/
int dev_pm_put_subsys_data(struct device *dev)
{
struct pm_subsys_data *psd;
int ret = 1;
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;
ret = 0;
}
out:
spin_unlock_irq(&dev->power.lock);
kfree(psd);
return ret;
}
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 attach.
* @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);