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

The concept behind major and minor

Character devices are populated in the /dev directory. Do note that they are not only files present in that directory. A character device file is recognizable to its type, which we can display thanks to the ls -l command. Major and minor identify and tie the devices with the drivers. Let's see how it works, by listing the content of the /dev directory (ls -l /dev):

[...]
drwxr-xr-x 2 root root 160 Mar 21 08:57 input
crw-r----- 1 root kmem 1, 2 Mar 21 08:57 kmem
lrwxrwxrwx 1 root root 28 Mar 21 08:57 log -> /run/systemd/journal/dev-log
crw-rw---- 1 root disk 10, 237 Mar 21 08:57 loop-control
brw-rw---- 1 root disk 7, 0 Mar 21 08:57 loop0
brw-rw---- 1 root disk 7, 1 Mar 21 08:57 loop1
brw-rw---- 1 root disk 7, 2 Mar 21 08:57 loop2
brw-rw---- 1 root disk 7, 3 Mar 21 08:57 loop3

Given the preceding excerpt, the first character of the first...