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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
15/**
16 * dev_pm_get_subsys_data - Create or refcount power.subsys_data for device.
17 * @dev: Device to handle.
18 *
19 * If power.subsys_data is NULL, point it to a new object, otherwise increment
20 * its reference counter. Return 1 if a new object has been created, otherwise
21 * return 0 or error code.
22 */
23int dev_pm_get_subsys_data(struct device *dev)
24{
25 struct pm_subsys_data *psd;
26
27 psd = kzalloc(sizeof(*psd), GFP_KERNEL);
28 if (!psd)
29 return -ENOMEM;
30
31 spin_lock_irq(&dev->power.lock);
32
33 if (dev->power.subsys_data) {
34 dev->power.subsys_data->refcount++;
35 } else {
36 spin_lock_init(&psd->lock);
37 psd->refcount = 1;
38 dev->power.subsys_data = psd;
39 pm_clk_init(dev);
40 psd = NULL;
41 }
42
43 spin_unlock_irq(&dev->power.lock);
44
45 /* kfree() verifies that its argument is nonzero. */
46 kfree(psd);
47
48 return 0;
49}
50EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data);
51
52/**
53 * dev_pm_put_subsys_data - Drop reference to power.subsys_data.
54 * @dev: Device to handle.
55 *
56 * If the reference counter of power.subsys_data is zero after dropping the
57 * reference, power.subsys_data is removed. Return 1 if that happens or 0
58 * otherwise.
59 */
60int dev_pm_put_subsys_data(struct device *dev)
61{
62 struct pm_subsys_data *psd;
63 int ret = 1;
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 ret = 0;
76 }
77
78 out:
79 spin_unlock_irq(&dev->power.lock);
80 kfree(psd);
81
82 return ret;
83}
84EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);
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#include "power.h"
18
19/**
20 * dev_pm_get_subsys_data - Create or refcount power.subsys_data for device.
21 * @dev: Device to handle.
22 *
23 * If power.subsys_data is NULL, point it to a new object, otherwise increment
24 * its reference counter. Return 0 if new object has been created or refcount
25 * increased, otherwise negative error code.
26 */
27int dev_pm_get_subsys_data(struct device *dev)
28{
29 struct pm_subsys_data *psd;
30
31 psd = kzalloc(sizeof(*psd), GFP_KERNEL);
32 if (!psd)
33 return -ENOMEM;
34
35 spin_lock_irq(&dev->power.lock);
36
37 if (dev->power.subsys_data) {
38 dev->power.subsys_data->refcount++;
39 } else {
40 spin_lock_init(&psd->lock);
41 psd->refcount = 1;
42 dev->power.subsys_data = psd;
43 pm_clk_init(dev);
44 psd = NULL;
45 }
46
47 spin_unlock_irq(&dev->power.lock);
48
49 /* kfree() verifies that its argument is nonzero. */
50 kfree(psd);
51
52 return 0;
53}
54EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data);
55
56/**
57 * dev_pm_put_subsys_data - Drop reference to power.subsys_data.
58 * @dev: Device to handle.
59 *
60 * If the reference counter of power.subsys_data is zero after dropping the
61 * reference, power.subsys_data is removed.
62 */
63void dev_pm_put_subsys_data(struct device *dev)
64{
65 struct pm_subsys_data *psd;
66
67 spin_lock_irq(&dev->power.lock);
68
69 psd = dev_to_psd(dev);
70 if (!psd)
71 goto out;
72
73 if (--psd->refcount == 0)
74 dev->power.subsys_data = NULL;
75 else
76 psd = NULL;
77
78 out:
79 spin_unlock_irq(&dev->power.lock);
80 kfree(psd);
81}
82EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);
83
84/**
85 * dev_pm_domain_attach - Attach a device to its PM domain.
86 * @dev: Device to attach.
87 * @power_on: Used to indicate whether we should power on the device.
88 *
89 * The @dev may only be attached to a single PM domain. By iterating through
90 * the available alternatives we try to find a valid PM domain for the device.
91 * As attachment succeeds, the ->detach() callback in the struct dev_pm_domain
92 * should be assigned by the corresponding attach function.
93 *
94 * This function should typically be invoked from subsystem level code during
95 * the probe phase. Especially for those that holds devices which requires
96 * power management through PM domains.
97 *
98 * Callers must ensure proper synchronization of this function with power
99 * management callbacks.
100 *
101 * Returns 0 on successfully attached PM domain or negative error code.
102 */
103int dev_pm_domain_attach(struct device *dev, bool power_on)
104{
105 int ret;
106
107 ret = acpi_dev_pm_attach(dev, power_on);
108 if (ret)
109 ret = genpd_dev_pm_attach(dev);
110
111 return ret;
112}
113EXPORT_SYMBOL_GPL(dev_pm_domain_attach);
114
115/**
116 * dev_pm_domain_detach - Detach a device from its PM domain.
117 * @dev: Device to detach.
118 * @power_off: Used to indicate whether we should power off the device.
119 *
120 * This functions will reverse the actions from dev_pm_domain_attach() and thus
121 * try to detach the @dev from its PM domain. Typically it should be invoked
122 * from subsystem level code during the remove phase.
123 *
124 * Callers must ensure proper synchronization of this function with power
125 * management callbacks.
126 */
127void dev_pm_domain_detach(struct device *dev, bool power_off)
128{
129 if (dev->pm_domain && dev->pm_domain->detach)
130 dev->pm_domain->detach(dev, power_off);
131}
132EXPORT_SYMBOL_GPL(dev_pm_domain_detach);
133
134/**
135 * dev_pm_domain_set - Set PM domain of a device.
136 * @dev: Device whose PM domain is to be set.
137 * @pd: PM domain to be set, or NULL.
138 *
139 * Sets the PM domain the device belongs to. The PM domain of a device needs
140 * to be set before its probe finishes (it's bound to a driver).
141 *
142 * This function must be called with the device lock held.
143 */
144void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd)
145{
146 if (dev->pm_domain == pd)
147 return;
148
149 WARN(pd && device_is_bound(dev),
150 "PM domains can only be changed for unbound devices\n");
151 dev->pm_domain = pd;
152 device_pm_check_callbacks(dev);
153}
154EXPORT_SYMBOL_GPL(dev_pm_domain_set);