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

Chapter 14: Introduction to the Linux Device Model

Until version 2.5, the Linux kernel had no way to describe and manage objects, and its code reusability was not as enhanced as it is now. In other words, there was no device topology, nor organization as we know it is in sysfs nowadays. There was no information on subsystem relationships, nor on how the system is put together. Then came the Linux Device Model (LDM), which introduced the following features:

  • The concept of classes. They are used to group devices of the same type or that expose the same functionalities (for example, mice and keyboards are both input devices).
  • Communication with the user space through a virtual filesystem, allowing you to manage and enumerate devices and the properties they expose from user space.
  • Object life cycle management using reference counting.
  • A power management facility, allowing you to handle the order in which devices should shut down.
  • The reusability of the code. Classes...