Book Image

Linux Device Driver Development Cookbook

By : Rodolfo Giometti
Book Image

Linux Device Driver Development Cookbook

By: Rodolfo Giometti

Overview of this book

Linux is a unified kernel that is widely used to develop embedded systems. As Linux has turned out to be one of the most popular operating systems worldwide, the interest in developing proprietary device drivers has also increased. Device drivers play a critical role in how the system performs and ensure that the device works in the manner intended. By exploring several examples on the development of character devices, the technique of managing a device tree, and how to use other kernel internals, such as interrupts, kernel timers, and wait queue, you’ll be able to add proper management for custom peripherals to your embedded system. You’ll begin by installing the Linux kernel and then configuring it. Once you have installed the system, you will learn to use different kernel features and character drivers. You will also cover interrupts in-depth and understand how you can manage them. Later, you will explore the kernel internals required for developing applications. As you approach the concluding chapters, you will learn to implement advanced character drivers and also discover how to write important Linux device drivers. By the end of this book, you will be equipped with the skills you need to write a custom character driver and kernel code according to your requirements.
Table of Contents (14 chapters)
10
Additional Information: Managing Interrupts and Concurrency

Getting application-specific data from a device tree

Now we know how to read a device tree file and how to manage it in userspace. In this recipe, we will see how we can extract the configuration settings it holds within the kernel.

Getting ready

To do our job, we can use all the data stored in the DTB to boot our ESPRESSObin and then use the ESPRESSObin as a system test.

As we know, ESPRESSObin's DTS file is stored in kernel sources at linux/arch/arm64/boot/dts/marvell/armada-3720-espressobin.dts or it can be extracted from the running kernel by executing the dtc command as presented in the following code:

# dtc -I fs -o espressobin-reverted.dts /proc/device-tree/

Now let's take this file apart since we can use...