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

Dealing with platform devices

Before we start writing platform drivers, this section will teach you how and where to instantiate platform devices. Only after that will we delve into the platform driver implementation. Platform device instantiation in the Linux kernel has existed for a long time and has been improved all over the kernel versions, and we will discuss the specificities of each instantiation method in this section.

Allocating and registering platform devices

Since there is no way for platform devices to make themselves known to the system, they must be populated manually and registered with the system along with their resources and private data. In the early platform core days, platform devices were declared in the board file, arch/arm/mach-* (which is arch/arm/mach-imx/mach-imx6q.c for i.MX6), and made known to the kernel with platform_device_add() or platform_device_register(), depending on how each platform device has been allocated.

This leads us to conclude...