Book Image

Linux Device Driver Development - Second Edition

By : John Madieu
Book Image

Linux Device Driver Development - Second Edition

By: John Madieu

Overview of this book

Linux is by far the most-used kernel on embedded systems. Thanks to its subsystems, the Linux kernel supports almost all of the application fields in the industrial world. This updated second edition of Linux Device Driver Development is a comprehensive introduction to the Linux kernel world and the different subsystems that it is made of, and will be useful for embedded developers from any discipline. You'll learn how to configure, tailor, and build the Linux kernel. Filled with real-world examples, the book covers each of the most-used subsystems in the embedded domains such as GPIO, direct memory access, interrupt management, and I2C/SPI device drivers. This book will show you how Linux abstracts each device from a hardware point of view and how a device is bound to its driver(s). You’ll also see how interrupts are propagated in the system as the book covers the interrupt processing mechanisms in-depth and describes every kernel structure and API involved. This new edition also addresses how not to write device drivers using user space libraries for GPIO clients, I2C, and SPI drivers. By the end of this Linux book, you’ll be able to write device drivers for most of the embedded devices out there.
Table of Contents (23 chapters)
1
Section 1 -Linux Kernel Development Basics
6
Section 2 - Linux Kernel Platform Abstraction and Device Drivers
12
Section 3 - Making the Most out of Your Hardware
18
Section 4 - Misc Kernel Subsystems for the Embedded World

Introduction to LDM data structures

The Linux device model introduced device hierarchy. It is built on top of a few data structures. Among these is the bus, which is represented in the kernel as an instance of struct bus_type; the device driver, which is represented by a struct device_driver structure; and the device, which is the last element and is represented as an instance of the struct device structure. In this section, we will introduce all those structures and learn how they interact each with other.

The bus data structure

A bus is a channel link between devices and the processor. The hardware entity that manages the bus and exports its protocol to devices is called the bus controller. For example, the USB controller provides USB support, while the I2C controller provides I2C bus support. However, the bus controller, being a device on its own, must be registered like any device. It will be the parent of the devices that need to sit on this bus. In other words, every device...