Documentation/devicetree/overlay-notes.rst

1 .. SPDX-License-Identifier: GPL-2.0
7 This document describes the implementation of the in-kernel
9 companion document to Documentation/devicetree/dynamic-resolution-notes.rst[1]
12 -----------------
17 Since the kernel mainly deals with devices, any new device node that result
18 in an active device should have it created while if the device node is either
23     ---- foo.dts ---------------------------------------------------------------
25 	/dts-v1/;
39     ---- foo.dts ---------------------------------------------------------------
41 The overlay bar.dts,
44     ---- bar.dts - overlay target location by label ----------------------------
45 	/dts-v1/;
54     ---- bar.dts ---------------------------------------------------------------
56 when loaded (and resolved as described in [1]) should result in foo+bar.dts::
58     ---- foo+bar.dts -----------------------------------------------------------
79     ---- foo+bar.dts -----------------------------------------------------------
81 As a result of the overlay, a new device node (bar) has been created
85 If the base DT was not compiled with the -@ option then the "&ocp" label
86 will not be available to resolve the overlay node(s) to the proper location
91 The above bar.dts example modified to use target path syntax is::
93     ---- bar.dts - overlay target location by explicit path --------------------
94 	/dts-v1/;
103     ---- bar.dts ---------------------------------------------------------------
106 Overlay in-kernel API
107 --------------------------------
118 Finally, if you need to remove all overlays in one-go, just call
127 OF_OVERLAY_PRE_REMOVE may store pointers to a device tree node in the overlay
136 are not allowed to store pointers to a device tree node in the overlay