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

The concept of power management on Linux-based systems

Power management (PM) entails consuming as little power as possible at any time. There are two types of power management that the operating system must handle: Device Power Management and System Power Management.

  • Device Power Management: This is device specific. It allows a device to be put in a low-power state while the system is running. This may allow, among other things, part of the device not currently in use to be turned off in order to conserve power, such as the keyboard backlight when you are not typing. Individual device power management may be invoked explicitly on devices regardless of the power management activity, or may happen automatically after a device has been idle for a set amount of time. Device power management is an alias for the so-called Runtime Power Management.
  • System Power Management, also known as Sleep States: This enables platforms to enter a system-wide low-power state. In other words...