Pinctrl and GPIO - Interactions and Footguns

Explore the intricate relationship between pinctrl and GPIO subsystems in the Linux Kernel through this informative 19-minute conference talk by ChenYu Tsai from Google LLC. Gain insights into how these two subsystems handle external pins, with pinctrl managing function muxing and electrical characteristics, while GPIO controls generic input/output usage on individual pins. Discover various hardware integration designs and their mapping to kernel subsystems. Delve into the complexities of intertwined implementations, learning about "strict" GPIO pin muxing and its proper handling within the kernel. Examine potential pitfalls in driver implementation using real-world examples from existing in-tree drivers, and understand the consequences of incorrect implementations.