# Device tree addons: describing non-discoverable addon boards and connectors

DevFeed: [Device tree addons: describing non-discoverable addon boards and connectors](<https://devfeed.tech/articles/device-tree-addons-describing-non-discoverable-addon-boards-and-connectors-52994.md>)

Original publisher: [Read original article](<https://bootlin.com/blog/device-tree-addons-describing-non-discoverable-addon-boards-and-connectors/>)

Author: Hervé Codina

Published: 2026-09-18T15:04:56Z

Content type: article

Language: en

Sources: [Bootlin](<https://devfeed.tech/sources/bootlin.md>)

Topics: [Embedded Systems](<https://devfeed.tech/topics/embedded-systems.md>), [Embedded Software Dev](<https://devfeed.tech/topics/embedded-software-dev.md>), [Hardware](<https://devfeed.tech/topics/hardware.md>), [Raspberry Pi](<https://devfeed.tech/topics/raspberry-pi.md>)

Tags: [board](<https://devfeed.tech/tags/board.md>), [connectors](<https://devfeed.tech/tags/connectors.md>), [device-tree](<https://devfeed.tech/tags/device-tree.md>), [embedded](<https://devfeed.tech/tags/embedded.md>), [embedded-devices](<https://devfeed.tech/tags/embedded-devices.md>), [kernel](<https://devfeed.tech/tags/kernel.md>), [raspberry-pi](<https://devfeed.tech/tags/raspberry-pi.md>), [technical](<https://devfeed.tech/tags/technical.md>)

## AI overview

This article introduces device tree addons, a proposed way to describe non-discoverable addon boards and their connectors for embedded systems. It explains the limitations of device tree overlays, outlines coldplug and hotplug use cases, presents a practical example, and describes testing and upstream contribution.

## Source excerpt

Lots of embedded devices exist that have a connector for addon boards: BeagleBone Black Capes and Raspberry Pi Hats are just some common de facto standards, each with a whole ecosystem of base boards and addon boards that can be mixed and matched in countless ways. Most of them are based on embedded System-on-Chips, and ... Continue reading "Device tree addons: describing non-discoverable addon boards and connectors"