2 * drivers/base/power/common.c - Common device power management code.
4 * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
6 * This file is released under the GPLv2.
9 #include <linux/init.h>
10 #include <linux/kernel.h>
11 #include <linux/device.h>
12 #include <linux/export.h>
13 #include <linux/slab.h>
14 #include <linux/pm_clock.h>
17 * dev_pm_get_subsys_data - Create or refcount power.subsys_data for device.
18 * @dev: Device to handle.
20 * If power.subsys_data is NULL, point it to a new object, otherwise increment
21 * its reference counter. Return 1 if a new object has been created, otherwise
22 * return 0 or error code.
24 int dev_pm_get_subsys_data(struct device *dev)
26 struct pm_subsys_data *psd;
29 psd = kzalloc(sizeof(*psd), GFP_KERNEL);
33 spin_lock_irq(&dev->power.lock);
35 if (dev->power.subsys_data) {
36 dev->power.subsys_data->refcount++;
38 spin_lock_init(&psd->lock);
40 dev->power.subsys_data = psd;
46 spin_unlock_irq(&dev->power.lock);
48 /* kfree() verifies that its argument is nonzero. */
53 EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data);
56 * dev_pm_put_subsys_data - Drop reference to power.subsys_data.
57 * @dev: Device to handle.
59 * If the reference counter of power.subsys_data is zero after dropping the
60 * reference, power.subsys_data is removed. Return 1 if that happens or 0
63 int dev_pm_put_subsys_data(struct device *dev)
65 struct pm_subsys_data *psd;
68 spin_lock_irq(&dev->power.lock);
70 psd = dev_to_psd(dev);
76 if (--psd->refcount == 0) {
77 dev->power.subsys_data = NULL;
83 spin_unlock_irq(&dev->power.lock);
87 EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);