1 What: /sys/class/extcon/.../
2 Date: February 2012
3 Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
4 Description:
5 Provide a place in sysfs for the extcon objects.
6 This allows accessing extcon specific variables.
7 The name of extcon object denoted as ... is the name given
8 with extcon_dev_register.
9
10 One extcon device denotes a single external connector
11 port. An external connector may have multiple cables
12 attached simultaneously. Many of docks, cradles, and
13 accessory cables have such capability. For example,
14 the 30-pin port of Nuri board (/arch/arm/mach-exynos)
15 may have both HDMI and Charger attached, or analog audio,
16 video, and USB cables attached simultaneously.
17
18 If there are cables mutually exclusive with each other,
19 such binary relations may be expressed with extcon_dev's
20 mutually_exclusive array.
21
22 What: /sys/class/extcon/.../name
23 Date: February 2012
24 Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
25 Description:
26 The /sys/class/extcon/.../name shows the name of the extcon
27 object. If the extcon object has an optional callback
28 "show_name" defined, the callback will provide the name with
29 this sysfs node.
30
31 What: /sys/class/extcon/.../state
32 Date: February 2012
33 Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
34 Description:
35 The /sys/class/extcon/.../state shows and stores the cable
36 attach/detach information of the corresponding extcon object.
37 If the extcon object has an optional callback "show_state"
38 defined, the showing function is overridden with the optional
39 callback.
40
41 If the default callback for showing function is used, the
42 format is like this::
43
44 # cat state
45 USB_OTG=1
46 HDMI=0
47 TA=1
48 EAR_JACK=0
49 #
50
51 In this example, the extcon device has USB_OTG and TA
52 cables attached and HDMI and EAR_JACK cables detached.
53
54 In order to update the state of an extcon device, enter a hex
55 state number starting with 0x::
56
57 # echo 0xHEX > state
58
59 This updates the whole state of the extcon device.
60 Inputs of all the methods are required to meet the
61 mutually_exclusive conditions if they exist.
62
63 It is recommended to use this "global" state interface if
64 you need to set the value atomically. The later state
65 interface associated with each cable cannot update
66 multiple cable states of an extcon device simultaneously.
67
68 What: /sys/class/extcon/.../cable.X/name
69 Date: February 2012
70 Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
71 Description:
72 The /sys/class/extcon/.../cable.X/name shows the name of cable
73 "X" (integer between 0 and 31) of an extcon device.
74
75 What: /sys/class/extcon/.../cable.X/state
76 Date: February 2012
77 Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
78 Description:
79 The /sys/class/extcon/.../cable.X/state shows and stores the
80 state of cable "X" (integer between 0 and 31) of an extcon
81 device. The state value is either 0 (detached) or 1
82 (attached).
83
84 What: /sys/class/extcon/.../mutually_exclusive/...
85 Date: December 2011
86 Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
87 Description:
88 Shows the relations of mutually exclusiveness. For example,
89 if the mutually_exclusive array of extcon device is
90 {0x3, 0x5, 0xC, 0x0}, then the output is::
91
92 # ls mutually_exclusive/
93 0x3
94 0x5
95 0xc
96 #
97
98 Note that mutually_exclusive is a sub-directory of the extcon
99 device and the file names under the mutually_exclusive
100 directory show the mutually-exclusive sets, not the contents
101 of the files.
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