Chapter 8. Device Driver Basics

In this chapter

• Device Driver Concepts page 190

• Module Utilities page 199

• Driver Methods page 205

• Bringing It All Together page 209

• Device Drivers and the GPL page 211

• Chapter Summary page 211

One of the more challenging aspects of system design is partitioning functionality in a rational manner. The familiar device driver model found in UNIX and Linux provides a natural partitioning of functionality between your application code and hardware or kernel devices. In this chapter, we develop an understanding of this model and the basics of Linux device driver architecture. After reading this chapter, you will have a solid foundation for continuing your study of device drivers using one of the excellent texts listed at the end of this chapter.

This chapter begins by presenting Linux device driver concepts and the build system for drivers within the kernel source tree. We examine the Linux device driver architecture and present a simple working example driver. We introduce the user space utilities for loading and unloading kernel modules.^[1] We present a simple application to illustrate the interface between applications and device drivers. We conclude this chapter with a discussion of device drivers and the GNU Public License.

^[1] The terms module and device driver are used here interchangeably.