1/*
2 * drivers/base/power/common.c - Common device power management code.
3 *
4 * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
5 *
6 * This file is released under the GPLv2.
7 */
8
9#include <linux/kernel.h>
10#include <linux/device.h>
11#include <linux/export.h>
12#include <linux/slab.h>
13#include <linux/pm_clock.h>
14#include <linux/acpi.h>
15#include <linux/pm_domain.h>
16
17/**
18 * dev_pm_get_subsys_data - Create or refcount power.subsys_data for device.
19 * @dev: Device to handle.
20 *
21 * If power.subsys_data is NULL, point it to a new object, otherwise increment
22 * its reference counter.  Return 0 if new object has been created or refcount
23 * increased, otherwise negative error code.
24 */
25int dev_pm_get_subsys_data(struct device *dev)
26{
27	struct pm_subsys_data *psd;
28
29	psd = kzalloc(sizeof(*psd), GFP_KERNEL);
30	if (!psd)
31		return -ENOMEM;
32
33	spin_lock_irq(&dev->power.lock);
34
35	if (dev->power.subsys_data) {
36		dev->power.subsys_data->refcount++;
37	} else {
38		spin_lock_init(&psd->lock);
39		psd->refcount = 1;
40		dev->power.subsys_data = psd;
41		pm_clk_init(dev);
42		psd = NULL;
43	}
44
45	spin_unlock_irq(&dev->power.lock);
46
47	/* kfree() verifies that its argument is nonzero. */
48	kfree(psd);
49
50	return 0;
51}
52EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data);
53
54/**
55 * dev_pm_put_subsys_data - Drop reference to power.subsys_data.
56 * @dev: Device to handle.
57 *
58 * If the reference counter of power.subsys_data is zero after dropping the
59 * reference, power.subsys_data is removed.
60 */
61void dev_pm_put_subsys_data(struct device *dev)
62{
63	struct pm_subsys_data *psd;
64
65	spin_lock_irq(&dev->power.lock);
66
67	psd = dev_to_psd(dev);
68	if (!psd)
69		goto out;
70
71	if (--psd->refcount == 0)
72		dev->power.subsys_data = NULL;
73	else
74		psd = NULL;
75
76 out:
77	spin_unlock_irq(&dev->power.lock);
78	kfree(psd);
79}
80EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);
81
82/**
83 * dev_pm_domain_attach - Attach a device to its PM domain.
84 * @dev: Device to attach.
85 * @power_on: Used to indicate whether we should power on the device.
86 *
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
90 * should be assigned by the corresponding attach function.
91 *
92 * This function should typically be invoked from subsystem level code during
93 * the probe phase. Especially for those that holds devices which requires
94 * power management through PM domains.
95 *
96 * Callers must ensure proper synchronization of this function with power
97 * management callbacks.
98 *
99 * Returns 0 on successfully attached PM domain or negative error code.
100 */
101int dev_pm_domain_attach(struct device *dev, bool power_on)
102{
103	int ret;
104
105	ret = acpi_dev_pm_attach(dev, power_on);
106	if (ret)
107		ret = genpd_dev_pm_attach(dev);
108
109	return ret;
110}
111EXPORT_SYMBOL_GPL(dev_pm_domain_attach);
112
113/**
114 * dev_pm_domain_detach - Detach a device from its PM domain.
115 * @dev: Device to attach.
116 * @power_off: Used to indicate whether we should power off the device.
117 *
118 * This functions will reverse the actions from dev_pm_domain_attach() and thus
119 * try to detach the @dev from its PM domain. Typically it should be invoked
120 * from subsystem level code during the remove phase.
121 *
122 * Callers must ensure proper synchronization of this function with power
123 * management callbacks.
124 */
125void dev_pm_domain_detach(struct device *dev, bool power_off)
126{
127	if (dev->pm_domain && dev->pm_domain->detach)
128		dev->pm_domain->detach(dev, power_off);
129}
130EXPORT_SYMBOL_GPL(dev_pm_domain_detach);
131