1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
|
/*
* drivers/base/power/sysfs.c - sysfs entries for device PM
*/
#include <linux/device.h>
#include <linux/string.h>
#include <linux/pm_runtime.h>
#include "power.h"
/*
* control - Report/change current runtime PM setting of the device
*
* Runtime power management of a device can be blocked with the help of
* this attribute. All devices have one of the following two values for
* the power/control file:
*
* + "auto\n" to allow the device to be power managed at run time;
* + "on\n" to prevent the device from being power managed at run time;
*
* The default for all devices is "auto", which means that devices may be
* subject to automatic power management, depending on their drivers.
* Changing this attribute to "on" prevents the driver from power managing
* the device at run time. Doing that while the device is suspended causes
* it to be woken up.
*
* wakeup - Report/change current wakeup option for device
*
* Some devices support "wakeup" events, which are hardware signals
* used to activate devices from suspended or low power states. Such
* devices have one of three values for the sysfs power/wakeup file:
*
* + "enabled\n" to issue the events;
* + "disabled\n" not to do so; or
* + "\n" for temporary or permanent inability to issue wakeup.
*
* (For example, unconfigured USB devices can't issue wakeups.)
*
* Familiar examples of devices that can issue wakeup events include
* keyboards and mice (both PS2 and USB styles), power buttons, modems,
* "Wake-On-LAN" Ethernet links, GPIO lines, and more. Some events
* will wake the entire system from a suspend state; others may just
* wake up the device (if the system as a whole is already active).
* Some wakeup events use normal IRQ lines; other use special out
* of band signaling.
*
* It is the responsibility of device drivers to enable (or disable)
* wakeup signaling as part of changing device power states, respecting
* the policy choices provided through the driver model.
*
* Devices may not be able to generate wakeup events from all power
* states. Also, the events may be ignored in some configurations;
* for example, they might need help from other devices that aren't
* active, or which may have wakeup disabled. Some drivers rely on
* wakeup events internally (unless they are disabled), keeping
* their hardware in low power modes whenever they're unused. This
* saves runtime power, without requiring system-wide sleep states.
*/
static const char enabled[] = "enabled";
static const char disabled[] = "disabled";
#ifdef CONFIG_PM_RUNTIME
static const char ctrl_auto[] = "auto";
static const char ctrl_on[] = "on";
static ssize_t control_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
return sprintf(buf, "%s\n",
dev->power.runtime_auto ? ctrl_auto : ctrl_on);
}
static ssize_t control_store(struct device * dev, struct device_attribute *attr,
const char * buf, size_t n)
{
char *cp;
int len = n;
cp = memchr(buf, '\n', n);
if (cp)
len = cp - buf;
if (len == sizeof ctrl_auto - 1 && strncmp(buf, ctrl_auto, len) == 0)
pm_runtime_allow(dev);
else if (len == sizeof ctrl_on - 1 && strncmp(buf, ctrl_on, len) == 0)
pm_runtime_forbid(dev);
else
return -EINVAL;
return n;
}
static DEVICE_ATTR(control, 0644, control_show, control_store);
#endif
static ssize_t
wake_show(struct device * dev, struct device_attribute *attr, char * buf)
{
return sprintf(buf, "%s\n", device_can_wakeup(dev)
? (device_may_wakeup(dev) ? enabled : disabled)
: "");
}
static ssize_t
wake_store(struct device * dev, struct device_attribute *attr,
const char * buf, size_t n)
{
char *cp;
int len = n;
if (!device_can_wakeup(dev))
return -EINVAL;
cp = memchr(buf, '\n', n);
if (cp)
len = cp - buf;
if (len == sizeof enabled - 1
&& strncmp(buf, enabled, sizeof enabled - 1) == 0)
device_set_wakeup_enable(dev, 1);
else if (len == sizeof disabled - 1
&& strncmp(buf, disabled, sizeof disabled - 1) == 0)
device_set_wakeup_enable(dev, 0);
else
return -EINVAL;
return n;
}
static DEVICE_ATTR(wakeup, 0644, wake_show, wake_store);
static struct attribute * power_attrs[] = {
#ifdef CONFIG_PM_RUNTIME
&dev_attr_control.attr,
#endif
&dev_attr_wakeup.attr,
NULL,
};
static struct attribute_group pm_attr_group = {
.name = "power",
.attrs = power_attrs,
};
int dpm_sysfs_add(struct device * dev)
{
return sysfs_create_group(&dev->kobj, &pm_attr_group);
}
void dpm_sysfs_remove(struct device * dev)
{
sysfs_remove_group(&dev->kobj, &pm_attr_group);
}
|
