Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * drivers/base/power/sysfs.c - sysfs entries for device PM | |
3 | */ | |
4 | ||
5 | #include <linux/device.h> | |
8c65b4a6 | 6 | #include <linux/string.h> |
1da177e4 LT |
7 | #include "power.h" |
8 | ||
0ac85241 DB |
9 | /* |
10 | * wakeup - Report/change current wakeup option for device | |
11 | * | |
12 | * Some devices support "wakeup" events, which are hardware signals | |
13 | * used to activate devices from suspended or low power states. Such | |
14 | * devices have one of three values for the sysfs power/wakeup file: | |
15 | * | |
16 | * + "enabled\n" to issue the events; | |
17 | * + "disabled\n" not to do so; or | |
18 | * + "\n" for temporary or permanent inability to issue wakeup. | |
19 | * | |
20 | * (For example, unconfigured USB devices can't issue wakeups.) | |
21 | * | |
22 | * Familiar examples of devices that can issue wakeup events include | |
23 | * keyboards and mice (both PS2 and USB styles), power buttons, modems, | |
24 | * "Wake-On-LAN" Ethernet links, GPIO lines, and more. Some events | |
25 | * will wake the entire system from a suspend state; others may just | |
26 | * wake up the device (if the system as a whole is already active). | |
27 | * Some wakeup events use normal IRQ lines; other use special out | |
28 | * of band signaling. | |
29 | * | |
30 | * It is the responsibility of device drivers to enable (or disable) | |
31 | * wakeup signaling as part of changing device power states, respecting | |
32 | * the policy choices provided through the driver model. | |
33 | * | |
34 | * Devices may not be able to generate wakeup events from all power | |
35 | * states. Also, the events may be ignored in some configurations; | |
36 | * for example, they might need help from other devices that aren't | |
37 | * active, or which may have wakeup disabled. Some drivers rely on | |
38 | * wakeup events internally (unless they are disabled), keeping | |
39 | * their hardware in low power modes whenever they're unused. This | |
40 | * saves runtime power, without requiring system-wide sleep states. | |
41 | */ | |
42 | ||
43 | static const char enabled[] = "enabled"; | |
44 | static const char disabled[] = "disabled"; | |
45 | ||
46 | static ssize_t | |
47 | wake_show(struct device * dev, struct device_attribute *attr, char * buf) | |
48 | { | |
49 | return sprintf(buf, "%s\n", device_can_wakeup(dev) | |
50 | ? (device_may_wakeup(dev) ? enabled : disabled) | |
51 | : ""); | |
52 | } | |
53 | ||
54 | static ssize_t | |
55 | wake_store(struct device * dev, struct device_attribute *attr, | |
56 | const char * buf, size_t n) | |
57 | { | |
58 | char *cp; | |
59 | int len = n; | |
60 | ||
61 | if (!device_can_wakeup(dev)) | |
62 | return -EINVAL; | |
63 | ||
64 | cp = memchr(buf, '\n', n); | |
65 | if (cp) | |
66 | len = cp - buf; | |
67 | if (len == sizeof enabled - 1 | |
68 | && strncmp(buf, enabled, sizeof enabled - 1) == 0) | |
69 | device_set_wakeup_enable(dev, 1); | |
70 | else if (len == sizeof disabled - 1 | |
71 | && strncmp(buf, disabled, sizeof disabled - 1) == 0) | |
72 | device_set_wakeup_enable(dev, 0); | |
73 | else | |
74 | return -EINVAL; | |
75 | return n; | |
76 | } | |
77 | ||
78 | static DEVICE_ATTR(wakeup, 0644, wake_show, wake_store); | |
79 | ||
80 | ||
1da177e4 | 81 | static struct attribute * power_attrs[] = { |
0ac85241 | 82 | &dev_attr_wakeup.attr, |
1da177e4 LT |
83 | NULL, |
84 | }; | |
85 | static struct attribute_group pm_attr_group = { | |
86 | .name = "power", | |
87 | .attrs = power_attrs, | |
88 | }; | |
89 | ||
90 | int dpm_sysfs_add(struct device * dev) | |
91 | { | |
92 | return sysfs_create_group(&dev->kobj, &pm_attr_group); | |
93 | } | |
94 | ||
95 | void dpm_sysfs_remove(struct device * dev) | |
96 | { | |
97 | sysfs_remove_group(&dev->kobj, &pm_attr_group); | |
98 | } |