Interrupts on GPIO (on RPI, specifically, but also in general)

[Jason Thorpe <thorpej%me.com@localhost>]

There seems to be support for interrupts on GPIO, but no in-tree examples of how it’s used, programming patterns, etc.

Anyone have any solid examples?

Context: I have a device I’m building that is going to have some buttons, a switch or two, and a rotary encoder for input.  Path of least resistance is to use an AVR and an existing software library for said AVR to emulate a USB keyboard (the “throw more hardware at the problem” approach).  But I have enough GPIO pins on the Raspberry Pi for the task and I loathe to make the PCB more complicated than it has to be, so I’m considering writing an interrupt-driven “gpiokbd” driver that would allow me to map GPIO input pin interrupts to a configurable set of “wskbd” input events.  I could poll, but I *really* don’t want too, and if I’m forced down that path, then I’d almost rather use the AVR solution.

I found Manuel Bouyer’s chart plotter driver that uses this on Github, but it seems to have some FDT conditionals, as well…

Just looking for guidance here… don’t want to go down the rabbit hole only to have it be a fruitless exercise.

Thx.

-- thorpej