Documentation/ABI/testing/sysfs-class-extcon

Source file repositories/reference/linux-study-clean/Documentation/ABI/testing/sysfs-class-extcon

File Facts

System
Linux kernel
Corpus path
Documentation/ABI/testing/sysfs-class-extcon
Extension
[no extension]
Size
3461 bytes
Lines
102
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: Documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

What:		/sys/class/extcon/.../
Date:		February 2012
Contact:	MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
		Provide a place in sysfs for the extcon objects.
		This allows accessing extcon specific variables.
		The name of extcon object denoted as ... is the name given
		with extcon_dev_register.

		One extcon device denotes a single external connector
		port. An external connector may have multiple cables
		attached simultaneously. Many of docks, cradles, and
		accessory cables have such capability. For example,
		the 30-pin port of Nuri board (/arch/arm/mach-exynos)
		may have both HDMI and Charger attached, or analog audio,
		video, and USB cables attached simultaneously.

		If there are cables mutually exclusive with each other,
		such binary relations may be expressed with extcon_dev's
		mutually_exclusive array.

What:		/sys/class/extcon/.../name
Date:		February 2012
Contact:	MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
		The /sys/class/extcon/.../name shows the name of the extcon
		object. If the extcon object has an optional callback
		"show_name" defined, the callback will provide the name with
		this sysfs node.

What:		/sys/class/extcon/.../state
Date:		February 2012
Contact:	MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
		The /sys/class/extcon/.../state shows and stores the cable
		attach/detach information of the corresponding extcon object.
		If the extcon object has an optional callback "show_state"
		defined, the showing function is overridden with the optional
		callback.

		If the default callback for showing function is used, the
		format is like this::

		    # cat state
		    USB_OTG=1
		    HDMI=0
		    TA=1
		    EAR_JACK=0
		    #

		In this example, the extcon device has USB_OTG and TA
		cables attached and HDMI and EAR_JACK cables detached.

		In order to update the state of an extcon device, enter a hex
		state number starting with 0x::

		    # echo 0xHEX > state

		This updates the whole state of the extcon device.
		Inputs of all the methods are required to meet the
		mutually_exclusive conditions if they exist.

		It is recommended to use this "global" state interface if
		you need to set the value atomically. The later state
		interface associated with each cable cannot update
		multiple cable states of an extcon device simultaneously.

What:		/sys/class/extcon/.../cable.X/name
Date:		February 2012
Contact:	MyungJoo Ham <myungjoo.ham@samsung.com>

Annotation

Implementation Notes