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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>
/**
* 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);
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