Re: GPIO inputs on Pis?

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 <[email protected]>:
>>
>> 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
[email protected]
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