| Grant Likely | 75b57ec | 2014-02-20 18:02:11 +0000 | [diff] [blame] | 1 | What: /sys/firmware/devicetree/* |
| 2 | Date: November 2013 |
| 3 | Contact: Grant Likely <grant.likely@linaro.org> |
| 4 | Description: |
| 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. |