You're reading from Mastering Linux Device Driver Development Write custom device drivers to support computer peripherals in Linux operating systems

Product type Paperback

Published in Jan 2021

Publisher Packt

ISBN-13 9781789342048

Length 646 pages

Edition 1st Edition

Languages

C++

Tools

Linux

Concepts

Embedded Systems

Author (1):

John Madieu

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Table of Contents (19) Chapters

Preface

1. Section 1:Kernel Core Frameworks for Embedded Device Driver Development

2. Chapter 1: Linux Kernel Concepts for Embedded Developers FREE CHAPTER

3. Chapter 2: Leveraging the Regmap API and Simplifying the Code

4. Chapter 3: Delving into the MFD Subsystem and Syscon API

5. Chapter 4: Storming the Common Clock Framework

6. Section 2: Multimedia and Power Saving in Embedded Linux Systems

7. Chapter 5: ALSA SoC Framework – Leveraging Codec and Platform Class Drivers

8. Chapter 6: ALSA SoC Framework – Delving into the Machine Class Drivers

9. Chapter 7: Demystifying V4L2 and Video Capture Device Drivers

10. Chapter 8: Integrating with V4L2 Async and Media Controller Frameworks

11. Chapter 9:Leveraging the V4L2 API from the User Space

12. Chapter 10: Linux Kernel Power Management

13. Section 3: Staying Up to Date with Other Linux Kernel Subsystems

14. Chapter 11: Writing PCI Device Drivers

15. Chapter 12: Leveraging the NVMEM Framework

16. Chapter 13: Watchdog Device Drivers

17. Chapter 14: Linux Kernel Debugging Tips and Best Practices

18. Other Books You May Enjoy

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Introducing the MFD subsystem and Syscon APIs

Prior to delving into the syscon framework and its APIs, we will cover MFDs. There are peripherals or hardware blocks exposing more than a single functionality by means of subdevices they embed into them and that are handled by separate subsystems in the kernel. That being said, a subdevice is a dedicated entity in a so-called multifunction device, responsible for a specific task, and managed through a reduced set of registers, in the chip's register map. ADP5520 is a typical example of an MFD device, as it contains a backlight, a keypad, LEDs, and GPIO controllers. Each of these is then considered as a subdevice, and as you can see, each of these falls into a different subsystem. The MFD subsystem, defined in include/linux/mfd/core.h and implemented in drivers/mfd/mfd-core.c, has been created to deal with these devices, allowing the following features: