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 kernel waiting, sleeping, and delay mechanisms

The term sleeping in this section refers to a mechanism by which a task (on behalf of the running kernel code) voluntarily relaxes the processor, with the possibility of another task being scheduled. While simple sleeping would consist of a task sleeping and being awakened after a given duration (to passively delay an operation, for example), there are sleeping mechanisms based on external events (such as data availability). Simple sleeps are implemented in the kernel using dedicated APIs; waking up from such sleeps is implicit (handled by the kernel itself) after the duration expires. The other sleeping mechanism is conditioned on an event and the waking-up is explicit (another task must explicitly wake us up based on a condition, else we sleep forever) unless a sleeping timeout is specified. This mechanism is implemented in the kernel using the concept of wait queues. That said, both sleep APIs and wait queues implement...