Linux Device Drivers

Chapter 1. An Introduction to the Linux Kernel

People all around the world are delving into the Linux kernel, mostly to write device drivers. While each driver is different, and you have to know your specific device, many principles and basic techniques are the same from one driver to another. In this book, you’ll learn to write your own device drivers and to hack around in related parts of the kernel. This book covers device-independent programming techniques, without binding the examples to any specific device.

This chapter doesn’t actually get into writing code. However, I’m going to introduce some background concepts about the Linux kernel that you’ll be glad you know later, when we do launch into writing code.

As you learn to write drivers, you will find out a lot about the Linux kernel in general; this may help you understand how your machine works and why things aren’t always as fast as you expect or don’t do quite what you want. We’ll introduce new ideas smoothly, starting off with very simple drivers and building upon them; every new concept will be accompanied by sample code that doesn’t need special hardware to be tested.

The Role of the Driver Writer

As a programmer, you will be able to make your own choices about your driver, choosing an acceptable tradeoff between the programming time required and the flexibility of the result. Though it may appear strange to say that a driver is ``flexible,'' I like this word because it emphasizes that the role of a device driver ...