How about CM3?


This guide first explains the boot process and how Device Tree is used to describe attached hardware; these are essential things to understand when designing with the Compute Module. It then provides a worked example of attaching an I2C and an SPI peripheral to a CMIO (or CMIO V3 for CM3) Board and creating the Device Tree files necessary to make both peripherals work under Linux, starting from a vanilla Raspberry Pi OS image.


Compute Module 3 Launch! - Raspberry Pi

BCM283x Boot process

Device Tree


ARM Linux Device Tree

Device Tree Surce and Compilation

Device Tree Debugging