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

Configuring CPU pins for specific peripherals

As the device driver developer, this task is really important because to be able to talk with external devices (or internal ones but with external signal lines) we must be sure that each CPU pin is properly configured to talk with these external signals. In this recipe, we will look at how we can use the device tree to configure CPU pins.

How to do it...

Just as a simple example, let's try to modify the pin configuration for our ESPRESSObin.

  1. First of all, we should take a look at the current configuration by looking at sysfs in the /sys/bus/platform/drivers/mvebu-uart/ directory, where we verify that only one UART is currently enabled:
# ls /sys/bus/platform/drivers/mvebu...