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

I2C framework abstractions in the Linux kernel

The Linux kernel I2C framework is made up of a few data structures, with the most important being as follows:

  • i2c_adapter: Used to abstract the I2C master device. It is used to identify a physical I2C bus.
  • i2c_algorithm: This abstracts the I2C bus transaction interface. Here, transaction means to transfer, such as read or write operations.
  • i2c_client: Used to abstract a slave device sitting on the I2C bus.
  • i2c_driver: The driver of the slave device. It contains a set of specific driving functions to deal with the device.
  • i2c_msg: This is the low-level representation of one segment of an I2C transaction. This data structure defines the device address, the transaction flags (if it's a transmit or receive, for example), a pointer to the data to send/receive, and the size of the data.

Since the scope of this chapter is limited to slave device drivers, we will focus on the last three data structures. However...