OF-nodes, Fwnodes, Swnodes, Devlinks, Properties - Understanding How Devices Are Modeled in Linux

Explore the evolution and current state of device modeling in the Linux kernel through this 40-minute conference talk that demystifies the complex landscape of device configuration mechanisms. Learn how the Linux kernel driver model has evolved to incorporate multiple approaches for passing device configuration data to platform drivers, including firmware-based methods like device-tree and ACPI, as well as kernel-based approaches such as board-files, MFD, and auxiliary drivers. Understand the distinctions between various APIs including OF routines, fwnode interfaces, and generic device properties, while discovering the role of software nodes in the device model. Gain clarity on when to use each API and how device properties function within the broader kernel architecture. Examine the historical progression from legacy custom platform data structures through the introduction of open-firmware APIs to their generalization into firmware nodes and other fwnode implementations, culminating in the modern generic device property API. Discover how devlinks integrate into this model to manage provider-consumer relationships between devices and ensure proper probe ordering. Designed for beginner to intermediate level developers, this presentation provides essential knowledge for understanding how device configuration should be properly handled in kernel development, addressing common confusion points that less experienced driver developers encounter when navigating the multiple available mechanisms for device property access.