diff options
Diffstat (limited to 'Documentation/devicetree/configfs-overlays.txt')
| -rw-r--r-- | Documentation/devicetree/configfs-overlays.txt | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/Documentation/devicetree/configfs-overlays.txt b/Documentation/devicetree/configfs-overlays.txt new file mode 100644 index 000000000000..5fa43e064307 --- /dev/null +++ b/Documentation/devicetree/configfs-overlays.txt @@ -0,0 +1,31 @@ +Howto use the configfs overlay interface. + +A device-tree configfs entry is created in /config/device-tree/overlays +and and it is manipulated using standard file system I/O. +Note that this is a debug level interface, for use by developers and +not necessarily something accessed by normal users due to the +security implications of having direct access to the kernel's device tree. + +* To create an overlay you mkdir the directory: + + # mkdir /config/device-tree/overlays/foo + +* Either you echo the overlay firmware file to the path property file. + + # echo foo.dtbo >/config/device-tree/overlays/foo/path + +* Or you cat the contents of the overlay to the dtbo file + + # cat foo.dtbo >/config/device-tree/overlays/foo/dtbo + +The overlay file will be applied, and devices will be created/destroyed +as required. + +To remove it simply rmdir the directory. + + # rmdir /config/device-tree/overlays/foo + +The rationalle of the dual interface (firmware & direct copy) is that each is +better suited to different use patterns. The firmware interface is what's +intended to be used by hardware managers in the kernel, while the copy interface +make sense for developers (since it avoids problems with namespaces). |