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
|
/*
* drivers/base/power/sysfs.c - sysfs entries for device PM
*/
#include <linux/device.h>
#include <linux/string.h>
#include "power.h"
/**
* state - Control current power state of device
*
* show() returns the current power state of the device. '0' indicates
* the device is on. Other values (1-3) indicate the device is in a low
* power state.
*
* store() sets the current power state, which is an integer value
* between 0-3. If the device is on ('0'), and the value written is
* greater than 0, then the device is placed directly into the low-power
* state (via its driver's ->suspend() method).
* If the device is currently in a low-power state, and the value is 0,
* the device is powered back on (via the ->resume() method).
* If the device is in a low-power state, and a different low-power state
* is requested, the device is first resumed, then suspended into the new
* low-power state.
*/
static ssize_t state_show(struct device * dev, struct device_attribute *attr, char * buf)
{
return sprintf(buf, "%u\n", dev->power.power_state.event);
}
static ssize_t state_store(struct device * dev, struct device_attribute *attr, const char * buf, size_t n)
{
pm_message_t state;
char * rest;
int error = 0;
state.event = simple_strtoul(buf, &rest, 10);
if (*rest)
return -EINVAL;
if (state.event)
error = dpm_runtime_suspend(dev, state);
else
dpm_runtime_resume(dev);
return error ? error : n;
}
static DEVICE_ATTR(state, 0644, state_show, state_store);
/*
* 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";
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[] = {
&dev_attr_state.attr,
&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);
}
|
