Date: Tue, 24 Jan 2023 15:35:02 +0000 From: "Dr. Rolf Jansen" <freebsd-rj@cyclaero.com> To: "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org> Cc: Karl Denninger <karl@denninger.net> Subject: Re: GPIO inputs on Pis? Message-ID: <01070185e46b1a6e-ee34b885-1215-45c7-ac18-83320c02cac2-000000@eu-central-1.amazonses.com> In-Reply-To: <0b235f83-7cb3-1d14-7c64-aee7c1c0c23d@denninger.net> References: <0b235f83-7cb3-1d14-7c64-aee7c1c0c23d@denninger.net>
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--Apple-Mail=_A3A27D85-289A-4F7A-9B78-6572DD14D844 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii > Am 23.01.2023 um 11:41 schrieb Karl Denninger <karl@denninger.net>: >=20 > Is there support somewhere in the 13.x for other than "read current = state" / "set current state"? >=20 > 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. >=20 > I see apparent review code at https://reviews.freebsd.org/D27398 = <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 >=20 See = https://forums.freebsd.org/threads/gpio-api-general-orange-pi-h3.83950/pos= t-556728 = <https://forums.freebsd.org/threads/gpio-api-general-orange-pi-h3.83950/po= st-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>= --Apple-Mail=_A3A27D85-289A-4F7A-9B78-6572DD14D844 Content-Transfer-Encoding: 7bit Content-Type: text/html; charset=us-ascii <html><head><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div><blockquote type="cite" class=""><div class="">Am 23.01.2023 um 11:41 schrieb Karl Denninger <<a href="mailto:karl@denninger.net" class="">karl@denninger.net</a>>:</div><br class="Apple-interchange-newline"><div class=""> <meta http-equiv="content-type" content="text/html; charset=UTF-8" class=""> <div class=""><p class="">Is there support somewhere in the 13.x for other than "read current state" / "set current state"?</p><p class="">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.</p><p class="">I see apparent review code at <a class="moz-txt-link-freetext" href="https://reviews.freebsd.org/D27398">https://reviews.freebsd.org/D27398</a>; from late 2020, but nothing else I can find digging around; an example (assuming it is actually implemented and works) would be helpful</p></div></div></blockquote></div>See<div class=""><br class=""></div><div class=""><a href="https://forums.freebsd.org/threads/gpio-api-general-orange-pi-h3.83950/post-556728" class="">https://forums.freebsd.org/threads/gpio-api-general-orange-pi-h3.83950/post-556728</a></div><div class=""><br class=""></div><div class="">And the messages in that thread that follow the one linked above.</div><div class=""><br class=""></div><div class="">There is a respective thread on this mailing list as well:</div><div class=""><br class=""></div><div class=""><a href="https://lists.freebsd.org/archives/freebsd-arm/2020-November/022740.html" class="">Porting FreeBSD to ARM processors: User Space GPIO Interrupt programming - GSoC-2018</a></div></body></html> --Apple-Mail=_A3A27D85-289A-4F7A-9B78-6572DD14D844--
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