User Space GPIO Interrupt programming - GSoC-2018

[Ian Lepore]

On Tue, 2020-11-24 at 17:14 -0300, Dr. Rolf Jansen wrote:
> Hello
> 
> Has anything of the GSoC-2018 efforts made it into the current code
> base?
> 
> 
https://wiki.freebsd.org/SummerOfCode2018Projects/UserSpaceGPIOinterrupts
> 
> I installed the recent 13.0-CURRENT snapshot (2020-11-19) on a
> BeagleBone Black which was one of the implementation targets of said
> project, but when running the test tools, I either see cannot
> read/kevent/poll/aio_read - Operation not supported by device or
> Inappropriate ioctl for device.
> 
> Perhaps I need to pull the project’s changes into the kernel by
> myself. However, before this I would like to ask whether it is worth
> the effort.
> 
> Please, can anyone shed some light on this.
> 
> Best regards
> 
> Rolf
> 

I have had that webpage open (but docked) for literally a year,
eternally hoping that I can find time to get to it and somehow get it
committed, or maybe use it as the basis for something to be committed
(I haven't even looked at it close enough to see if it's commit-quality 
code or what).

I'm curious: What particular need do you have for userspace gpio
interrupts?  What would you like the API to look like (do you like the
things listed at that page, or would you prefer something else)?

Interrupts is probably not a good name, because it isn't really going
to act like an interrupt does for kernel code.  It's really just pin-
change notifications delivered to userland.

-- Ian