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 IIO data structures

The IIO framework is made of a few data structures among which is one representing the IIO device, another one describing this device, and the last one enumerating the channels exposed by the device. An IIO device is represented in the kernel as an instance of struct iio_dev and described by a struct iio_info structure. All the important IIO structures are defined in include/linux/iio/iio.h.

Understanding the struct iio_dev structure

The struct iio_dev structure represents the IIO device, describing the device and its driver. It tells us how many channels are available on the device and what modes the device can operate in (one-shot or triggered buffer, for example). Moreover, this data structure exposes some hooks to be provided by the driver.

This data structure has the following definition:

struct iio_dev {
    [...]
    int            ...