Re: GPIO inputs on Pis?
- Reply: Dr. Rolf Jansen: "Re: GPIO inputs on Pis?"
- In reply to: Dr. Rolf Jansen: "Re: GPIO inputs on Pis?"
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Date: Tue, 24 Jan 2023 15:35:56 UTC
Thank you -- will check it out. On 1/24/2023 10:35, Dr. Rolf Jansen wrote: >> Am 23.01.2023 um 11:41 schrieb Karl Denninger <karl@denninger.net>: >> >> Is there support somewhere in the 13.x for other than "read current >> state" / "set current state"? >> >> Specifically, there is evidence in the sys/gpio.h header file that I >> can open up a file descriptor and then use select()/read() to grab >> the contents of a ring buffer of some size (presumably >> interrupt-posted) of events since last look, and determine if there's >> anything in there. Provided you're reasonably fast this might be >> enough to, for example, read an optical encoder that has a modest >> pulse rate. >> >> I see apparent review code at https://reviews.freebsd.org/D27398 from >> late 2020, but nothing else I can find digging around; an example >> (assuming it is actually implemented and works) would be helpful >> > See > > https://forums.freebsd.org/threads/gpio-api-general-orange-pi-h3.83950/post-556728 > > And the messages in that thread that follow the one linked above. > > There is a respective thread on this mailing list as well: > > Porting FreeBSD to ARM processors: User Space GPIO Interrupt > programming - GSoC-2018 > <https://lists.freebsd.org/archives/freebsd-arm/2020-November/022740.html> -- Karl Denninger karl@denninger.net /The Market Ticker/ /[S/MIME encrypted email preferred]/