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

Regulator Framework

A regulator is an electronic device that supplies power to other devices. Devices powered by regulators are called consumers. One said they consume power provided by regulators. Most regulators can enable and disable their output and some can also control their output voltage or current. The driver should expose those capabilities to consumers by means of specific functions and data structures, which we will discuss in this chapter.

The chip that physically provides regulators is called a Power Management Integrated Circuit (PMIC):

The Linux regulator framework has been designed to interface and control voltage and current regulators. It is divided into four separate interfaces, as follows:

  • A regulator drivers interface for regulator PMIC drivers. The structure of this interface can be found in include/linux/regulator/driver.h.
  • A consumer interface for device...