The Serial Peripheral Interconnect (SPI) bus is a ubiquitous de facto standardfound in many embedded systems produced today. The Linux kernel has longsupported this bus via a comprehensive framework which supports both SPImaster and slave devices. The session will explore the abstractions that theframework provides to expose this hardware to both kernel and userspaceclients. The talk will cover which classes of hardware supported and use casesoutside the scope of the subsystem today. In addition, we will discuss subtlefeatures of the SPI subsystem that may be used to satisfy hardware andperformance requirements in an embedded Linux system.