This repository contains example device tree overlays for single-board computers running mainline kernels and mainline u-boot.
The goal is to teach how to write device tree overlays, and serve as a point of reference for real-world hardware one may wish to use device tree overlays for.
All overlays are meant to work with real hardware, and can be used as-is with no further modification if one has the necessary hardware configured in the same way as described by one of the overlays.
You will need to have the device tree compiler dtc installed. Please consult
your distribution's manual for how to find and install the correct package.
Your u-boot also needs to be mainline, and compiled with
CONFIG_OF_LIBFDT_OVERLAY enabled. Furthermore, we will assume mainline device
tree bindings here.
Build the overlays with make INCLUDE_DIR=path/to/linux/include. They will be
placed in the folder build. The path to Linux include should be a path to
an extracted Linux source tree's include/, as distributions usually don't
package the dt-bindings headers in their headers packages.
Running make clean will recursively delete build, so don't store anything
other than the built files in it.
Copy the .dtbo files you want to use from the build directory to /boot/dtbo/
and run sudo u-boot-update.
Assuming you are booting with a extlinux/extlinux.conf on your /boot, you
can copy the .dtbo files somewhere into /boot (e.g. /boot/dtbs/overlays)
and specify them in your /boot/extlinux/extlinux.conf as follows:
FDTOVERLAYS /dtbs/overlays/first-overlay.dtbo /dtbs/overlays/second-overlay.dtboIt is the principal author's opinion that hardware descriptions are of dubious copyrightability, due to lacking in individual character. This, however, is not to be misunderstood as legal advice in any way.
The parts of the hardware description that may exhibit individual character, such as comments, label names, etc. are licensed under the MIT license. See LICENSE.txt for details.
It is the principal author's view that one does not need to include the license text if one references these examples during the writing of device trees.
Please read CONTRIBUTING.md before attempting to contribute to this
repository.
We're always happy to help people get the most out of their (mainline) boards! If you want an overlay to be written for a specific piece of hardware, open an issue describing what you're trying to do and we'll try to acquire the hardware ourselves to write an overlay for it.