Book Image

Mastering Embedded Linux Programming

By : Chris Simmonds
Book Image

Mastering Embedded Linux Programming

By: Chris Simmonds

Overview of this book

Mastering Embedded Linux Programming takes you through the product cycle and gives you an in-depth description of the components and options that are available at each stage. You will begin by learning about toolchains, bootloaders, the Linux kernel, and how to configure a root filesystem to create a basic working device. You will then learn how to use the two most commonly used build systems, Buildroot and Yocto, to speed up and simplify the development process. Building on this solid base, the next section considers how to make best use of raw NAND/NOR flash memory and managed flash eMMC chips, including mechanisms for increasing the lifetime of the devices and to perform reliable in-field updates. Next, you need to consider what techniques are best suited to writing applications for your device. We will then see how functions are split between processes and the usage of POSIX threads, which have a big impact on the responsiveness and performance of the final device The closing sections look at the techniques available to developers for profiling and tracing applications and kernel code using perf and ftrace.
Table of Contents (22 chapters)
Mastering Embedded Linux Programming
About the Author
About the Reviewers

Chapter 8. Introducing Device Drivers

Kernel device drivers are the mechanism through which the underlying hardware is exposed to the rest of the system. As a developer of embedded systems, you need to know how device drivers fit into the overall architecture and how to access them from user space programs. Your system will probably have some novel pieces of hardware and you will have to work out a way of accessing them. In many cases, you will find that there are device drivers provided for you and you can achieve everything you want without writing any kernel code. For example, you can manipulate GPIO pins and LEDs using files in sysfs, and there are libraries to access serial buses, including SPI and I2C.

There are many places to find out how to write a device driver, but few to tell you why you would want to and the choices you have in doing so. That is what I want to cover here. However, remember that this is not a book dedicated to writing kernel device drivers and that the information...