Chapter 5: Understanding and Leveraging the Device Tree

The device tree is an easy-to-read hardware description file, with a JSON-like formatting style. It is a simple tree structure where devices are represented by nodes and their properties. These properties can either be empty (that is, just the key to describe Boolean values) or key-value pairs, where the value can contain an arbitrary byte stream. This chapter is a simple introduction to device trees. Every kernel subsystem or framework has its own device tree binding, and we will talk about those specific bindings when we deal with the relevant topics.

The device tree originated from Open Firmware (OF), which is a standard endorsed by computer companies, and whose main purpose is to define interfaces for computer firmware systems. That said, you can find out more about device tree specification at http://www.devicetree.org/. Therefore, this chapter will cover the basics of the device tree, including the following:

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