Book Image

Linux Device Drivers Development

By : John Madieu
Book Image

Linux Device Drivers Development

By: John Madieu

Overview of this book

Linux kernel is a complex, portable, modular and widely used piece of software, running on around 80% of servers and embedded systems in more than half of devices throughout the World. Device drivers play a critical role in how well a Linux system performs. As Linux has turned out to be one of the most popular operating systems used, the interest in developing proprietary device drivers is also increasing steadily. This book will initially help you understand the basics of drivers as well as prepare for the long journey through the Linux Kernel. This book then covers drivers development based on various Linux subsystems such as memory management, PWM, RTC, IIO, IRQ management, and so on. The book also offers a practical approach on direct memory access and network device drivers. By the end of this book, you will be comfortable with the concept of device driver development and will be in a position to write any device driver from scratch using the latest kernel version (v4.13 at the time of writing this book).
Table of Contents (23 chapters)
Free Chapter
1
Introduction to Kernel Development

Device-managed resources – Devres

Devres is a kernel facility helping the developer by automatically freeing the allocated resource in a driver. It simplifies errors handling in init/probe/open functions. With devres, each resource allocator has its managed version that will take care of resource release and freeing for you.

This section heavily relies on the Documentation/driver-model/devres.txt file in the kernel source tree, which deals with the devres API and lists supported functions along with their descriptions.

The memory allocated with resource-managed functions is associated with the device. devres consists of a linked list of arbitrarily sized memory areas associated with a struct device. Each devers resource allocator inserts the allocated resource in the list. The resource remains available until it is manually freed by the code, when the device is detached...