xref: /linux/Documentation/ABI/testing/sysfs-firmware-ofw (revision 3932b9ca55b0be314a36d3e84faff3e823c081f5)
1What:		/sys/firmware/devicetree/*
2Date:		November 2013
3Contact:	Grant Likely <grant.likely@linaro.org>
4Description:
5		When using OpenFirmware or a Flattened Device Tree to enumerate
6		hardware, the device tree structure will be exposed in this
7		directory.
8
9		It is possible for multiple device-tree directories to exist.
10		Some device drivers use a separate detached device tree which
11		have no attachment to the system tree and will appear in a
12		different subdirectory under /sys/firmware/devicetree.
13
14		Userspace must not use the /sys/firmware/devicetree/base
15		path directly, but instead should follow /proc/device-tree
16		symlink. It is possible that the absolute path will change
17		in the future, but the symlink is the stable ABI.
18
19		The /proc/device-tree symlink replaces the devicetree /proc
20		filesystem support, and has largely the same semantics and
21		should be compatible with existing userspace.
22
23		The contents of /sys/firmware/devicetree/ is a
24		hierarchy of directories, one per device tree node. The
25		directory name is the resolved path component name (node
26		name plus address). Properties are represented as files
27		in the directory. The contents of each file is the exact
28		binary data from the device tree.
29