Mastering Linux Device Driver Development

Cover
Title Page
Copyright and Credits
About Packt
Contributors
Table of Contents
Preface
Section 1:Kernel Core Frameworks for Embedded Device Driver Development
Chapter 01: Linux Kernel Concepts for Embedded Developers
	Technical requirements
	The kernel locking API and shared objects
		Spinlocks
		Mutexes
		The try-lock method
		Waiting, sensing, and blocking in the Linux kernel
	Work deferring mechanisms
		SoftIRQs
		Tasklets
		Workqueues
		Workqueues – a new generation
	Linux kernel interrupt management
		Designing an interrupt handler
	Summary
Chapter 02: Leveraging the Regmap API and Simplifying the Code
	Technical requirements
	Introduction to regmap and its data structures – I2C, SPI, and MMIO
		Accessing device registers
		Quick recap on Linux kernel IRQ management
		Regmap IRQ API and data structures
	Summary
Chapter 03: Delving into the MFD Subsystem and Syscon API
	Technical requirements
	Introducing the MFD subsystem and Syscon APIs
	Device tree binding for MFD devices
	Understanding Syscon and simple-mfd
		Introducing simple-mfd
	Summary
Chapter 04: Storming the Common Clock Framework
	Technical requirements
	CCF data structures and interfaces
		Understanding struct clk_hw and its dependencies
		Registering/unregistering the clock provider
		Exposing clocks to others (in detail)
	Writing a clock provider driver
		Providing clock ops
		Putting it all together – global overview
		Grabbing and releasing clocks
		Preparing/unpreparing clocks
		Rate functions
		Parent functions
		Putting it all together
Section 2: Multimedia and Power Saving in Embedded Linux Systems
Chapter 05: ALSA SoC Framework – Leveraging Codec and Platform Class Drivers
	Technical requirements
	Introduction to ASoC
		ASoC Digital Audio Interface
		ASoC sub-elements
	Writing codec class drivers
		Codec DAI and PCM (AKA DSP) configurations
		The concept of controls
		The concept of DAPM
	Writing the platform class driver
		The CPU DAI driver
		The platform DMA driver AKA PCM DMA driver
	Summary
Chapter 06: ALSA SoC Framework – Delving into the Machine Class Drivers
	Technical requirements
	Introduction to machine class drivers
		The DAI link
	Machine routing consideration
		Codec pins
		Board connectors
		Machine routing
	Clocking and formatting considerations
	Sound card registration
	Leveraging the simple-card machine driver
		Codec-less sound cards
	Summary
Chapter 07: Demystifying V4L2 and Video Capture Device Drivers
	Technical requirements
	Framework architecture and the main data structures
		Initializing and registering a V4L2 device
	Introducing video device drivers – the bridge driver
		Initializing and registering the video device
		Video device file operations
		V4L2 ioctl handling
		The videobuf2 interface and APIs
	The concept of sub-devices
		Sub-device initialization
		Sub-device operations
		Traditional sub-device (un)registration
	V4L2 controls infrastructure
		A word about control inheritance
	Summary
Chapter 08: Integrating with V4L2 Async and Media Controller Frameworks
	Technical requirements
	The V4L2 async interface and the concept of graph binding
		Graph binding
		The V4L2 async and graph-oriented API
		V4L2 async
	The Linux media controller framework
		The media controller abstraction model
		Integrating media controller support in the driver
		Media controller from user space
	Summary
Chapter 09: Leveraging the V4L2 API from the User Space
	Technical requirements
	Introduction to V4L2 from user space
		The V4L2 user space API
	Video device opening and property management
		Querying the device capabilities
	Buffer management
		Image (buffer) format
		Requesting buffers
		Enqueueing the buffer and enabling streaming
		Dequeuing buffers
	V4L2 user space tools
		Using v4l2-ctl
		Debugging V4L2 in user space
	Summary
Chapter 10: Linux Kernel Power Management
	Technical requirements
	The concept of power management on Linux-based systems
		Runtime power management
		System power management sleep states
	Adding power management capabilities to device drivers
		Implementing runtime PM capability
		System suspend and resume sequences
		Implementing system sleep capability
	Being a source of system wakeup
		Wakeup source and sysfs (or debugfs)
		The IRQF_NO_SUSPEND flag
	Summary
Section 3: Staying Up to Date with Other Linux Kernel Subsystems
Chapter 11: Writing PCI Device Drivers
	Technical requirements
	Introduction to PCI buses and interfaces
		Terminology
		PCI bus enumeration, device configuration, and addressing
		PCI address spaces
		Interrupt distribution
	The Linux kernel PCI subsystem and data structures
		PCI data structures
		Overview of the PCI driver structure
	PCI and Direct Memory Access (DMA)
		PCI coherent (aka consistent) mapping
		Streaming DMA mapping
	Summary
Chapter 12: Leveraging the NVMEM Framework
	Technical requirements
	Introducing NVMEM data structures and APIs
	Writing the NVMEM provider driver
		NVMEM device (un)registration
		Implementing NVMEM read/write callbacks
		Device tree bindings for NVMEM providers
	NVMEM consumer driver APIs
		NVMEM in user space
	Summary
Chapter 13: Watchdog Device Drivers
	Technical requirements
	Watchdog data structures and APIs
		Registering/unregistering a watchdog device
		Handling pretimeouts and governors
		GPIO-based watchdogs
	The watchdog user space interface
		Starting and stopping the watchdog
		Getting watchdog capabilities and identity
		Setting and getting the timeout and pretimeout
		Getting the (boot/reboot) status
		The watchdog sysfs interface
	Summary
Chapter 14: Linux Kernel Debugging Tips and Best Practices
	Technical requirements
	Understanding the Linux kernel release process
	Linux kernel development tips
		Message printing
	Linux kernel tracing and performance analysis
		Using Ftrace to instrument the code
	Linux kernel debugging tips
		Oops and panic analysis
		Using objdump to identify the faulty code line in the kernel module
	Summary
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Index