GPIO for Engineers and Makers
summary
Kernel GPIO moves from fragile global numbers to descriptor-based GPIO with device-tree/ACPI bindings, adds real-device gpiochips, formal IRQ-chip integration, and hardware modes for open drain/open source. The old sysfs CFS interface is deprecated; a new character device ABI (since 4.8) exposes chip/line info, atomic get/set of up to 64 lines, event timestamps, and automatic cleanup on close. Tools and examples (gpiod/yells-gpio) exist and the refactor is merged and working in mainline.
AI-written summary · about
chapters (25)
- 0:00Introduction
- 1:07History
- 4:15Biggest Lies
- 4:47Userspace
- 8:55Descriptors
- 15:18GPIO Ships
- 16:31Open Drain
- 21:42Pin Control
- 25:15GPIO Mode Pitfall
- 27:52GPIO Lock
- 30:37IRQ Domain
- 35:12GPIO Expanders
- 36:02GPIO Hogs
- 37:42Userspace GPIO
- 39:33Random drivers
- 40:07Sisyphus
- 41:34What is good
- 42:26Yellows GPIO
- 43:25GPIO Line Names
- 45:17Reading Line Values
- 46:13Unset Many Lines
- 46:44Multiple Lines
- 47:47One Line
- 48:09Slide Line
- 50:21Questions
related talks
44mNew GPIO Interface for User Space
48mPin Control and GPIO Update
23mGive Me Back My GPIO Persistence Intro to the libgpiod GPIOManager- 23mGive Me Back My GPIO Persistence Intro to the libgpiod GPIOManager
32mlibgpiod V2: New Major Release with a Ton of New Features
19mPinctrl and GPIO - Interactions and Footguns
37mIntroduction to Pin Muxing and GPIO Control Under Linux
12mGPIO across Linux and Zephyr kernels