0001 What: /sys/class/extcon/.../
0002 Date: February 2012
0003 Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
0004 Description:
0005 Provide a place in sysfs for the extcon objects.
0006 This allows accessing extcon specific variables.
0007 The name of extcon object denoted as ... is the name given
0008 with extcon_dev_register.
0009
0010 One extcon device denotes a single external connector
0011 port. An external connector may have multiple cables
0012 attached simultaneously. Many of docks, cradles, and
0013 accessory cables have such capability. For example,
0014 the 30-pin port of Nuri board (/arch/arm/mach-exynos)
0015 may have both HDMI and Charger attached, or analog audio,
0016 video, and USB cables attached simultaneously.
0017
0018 If there are cables mutually exclusive with each other,
0019 such binary relations may be expressed with extcon_dev's
0020 mutually_exclusive array.
0021
0022 What: /sys/class/extcon/.../name
0023 Date: February 2012
0024 Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
0025 Description:
0026 The /sys/class/extcon/.../name shows the name of the extcon
0027 object. If the extcon object has an optional callback
0028 "show_name" defined, the callback will provide the name with
0029 this sysfs node.
0030
0031 What: /sys/class/extcon/.../state
0032 Date: February 2012
0033 Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
0034 Description:
0035 The /sys/class/extcon/.../state shows and stores the cable
0036 attach/detach information of the corresponding extcon object.
0037 If the extcon object has an optional callback "show_state"
0038 defined, the showing function is overridden with the optional
0039 callback.
0040
0041 If the default callback for showing function is used, the
0042 format is like this::
0043
0044 # cat state
0045 USB_OTG=1
0046 HDMI=0
0047 TA=1
0048 EAR_JACK=0
0049 #
0050
0051 In this example, the extcon device has USB_OTG and TA
0052 cables attached and HDMI and EAR_JACK cables detached.
0053
0054 In order to update the state of an extcon device, enter a hex
0055 state number starting with 0x::
0056
0057 # echo 0xHEX > state
0058
0059 This updates the whole state of the extcon device.
0060 Inputs of all the methods are required to meet the
0061 mutually_exclusive conditions if they exist.
0062
0063 It is recommended to use this "global" state interface if
0064 you need to set the value atomically. The later state
0065 interface associated with each cable cannot update
0066 multiple cable states of an extcon device simultaneously.
0067
0068 What: /sys/class/extcon/.../cable.X/name
0069 Date: February 2012
0070 Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
0071 Description:
0072 The /sys/class/extcon/.../cable.X/name shows the name of cable
0073 "X" (integer between 0 and 31) of an extcon device.
0074
0075 What: /sys/class/extcon/.../cable.X/state
0076 Date: February 2012
0077 Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
0078 Description:
0079 The /sys/class/extcon/.../cable.X/state shows and stores the
0080 state of cable "X" (integer between 0 and 31) of an extcon
0081 device. The state value is either 0 (detached) or 1
0082 (attached).
0083
0084 What: /sys/class/extcon/.../mutually_exclusive/...
0085 Date: December 2011
0086 Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
0087 Description:
0088 Shows the relations of mutually exclusiveness. For example,
0089 if the mutually_exclusive array of extcon device is
0090 {0x3, 0x5, 0xC, 0x0}, then the output is::
0091
0092 # ls mutually_exclusive/
0093 0x3
0094 0x5
0095 0xc
0096 #
0097
0098 Note that mutually_exclusive is a sub-directory of the extcon
0099 device and the file names under the mutually_exclusive
0100 directory show the mutually-exclusive sets, not the contents
0101 of the files.
