Book Image

Mastering Linux Device Driver Development

By : John Madieu
Book Image

Mastering Linux Device Driver Development

By: John Madieu

Overview of this book

Linux is one of the fastest-growing operating systems around the world, and in the last few years, the Linux kernel has evolved significantly to support a wide variety of embedded devices with its improved subsystems and a range of new features. With this book, you’ll find out how you can enhance your skills to write custom device drivers for your Linux operating system. Mastering Linux Device Driver Development provides complete coverage of kernel topics, including video and audio frameworks, that usually go unaddressed. You’ll work with some of the most complex and impactful Linux kernel frameworks, such as PCI, ALSA for SoC, and Video4Linux2, and discover expert tips and best practices along the way. In addition to this, you’ll understand how to make the most of frameworks such as NVMEM and Watchdog. Once you’ve got to grips with Linux kernel helpers, you’ll advance to working with special device types such as Multi-Function Devices (MFD) followed by video and audio device drivers. By the end of this book, you’ll be able to write feature-rich device drivers and integrate them with some of the most complex Linux kernel frameworks, including V4L2 and ALSA for SoC.
Table of Contents (19 chapters)
1
Section 1:Kernel Core Frameworks for Embedded Device Driver Development
6
Section 2: Multimedia and Power Saving in Embedded Linux Systems
13
Section 3: Staying Up to Date with Other Linux Kernel Subsystems

Introduction to machine class drivers

Codec and platform drivers cannot work alone. Machine drivers are responsible for binding them together in order to finish audio information processing. The machine driver class acts as the glue that describes and ties the other component drivers together to form an ALSA sound card device. It manages any machine-specific controls and machine-level audio events (such as turning on an amp at the start of playback). The machine drivers describe and bind the CPU Digital Audio Interfaces (DAIs) and codec drivers together to create the DAI links and the ALSA sound card. The machine driver connects the codec drivers by linking the DAIs exposed by each module (the CPU and codec) described in Chapter 5, ALSA SoC Framework – Leveraging Codec and Platform Class Drivers. It defines the struct snd_soc_dai_link structure and instantiates the sound card, struct snd_soc_card.

Platform and codec drivers are generally reusable, but machine drivers are...