Pinctrl subsystem and GPIO subsystem

One 、 What is? pinctrl Subsystem and gpio Subsystem

These are both linux Provided by the kernel gpio Development driven framework

pinctrl The subsystem mainly manages the reuse relationship and electrical characteristics of all disciplines

gpio The subsystem is pinctrl The subsystem sets the pin to gpio after , Use api Function operation gpio Of , Such as setting input and output , Set and read pin level status

2.Linux Pinctrl Functions provided by subsystem

    （1） Manage all controllable in the system pin, During system initialization , Enumerate all controllable pin, And identify these pin.

    （2） Manage these pin Reuse of （Multiplexing）. about SOC for , Its pins are configured as ordinary GPIO outside , Several pins can also form a pin group, Travel specific functions .pin control subsystem To manage all pin group.

    （3） Configure these pin Characteristics of . For example, enable or disable... On the pin pull-up、pull-down resistance , Configuration pin driver strength.
 

ref

linux Kernel GPIO Systematic （4）：pinctrl Driven understanding and summary

Pinctrl and GPIO User manual — Sichang communication