Date: Mon, 23 Jan 2023 09:41:45 -0500 From: Karl Denninger <karl@denninger.net> To: "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org> Subject: GPIO inputs on Pis? Message-ID: <0b235f83-7cb3-1d14-7c64-aee7c1c0c23d@denninger.net>
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This is a cryptographically signed message in MIME format. --------------ms000601070800060604040601 Content-Type: multipart/alternative; boundary="------------x2pMdr7LsuFFqjpJMaYDHEJj" --------------x2pMdr7LsuFFqjpJMaYDHEJj Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 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. Thanks in advance! -- Karl Denninger karl@denninger.net /The Market Ticker/ /[S/MIME encrypted email preferred]/ --------------x2pMdr7LsuFFqjpJMaYDHEJj Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit <html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body> <p>Is there support somewhere in the 13.x for other than "read current state" / "set current state"?</p> <p>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>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> <p>Thanks in advance!<br> </p> <div class="moz-signature">-- <br> Karl Denninger<br> <a href="mailto:karl@denninger.net" class="moz-txt-link-freetext">karl@denninger.net</a><br> <i>The Market Ticker</i><br> <font size="-2"><i>[S/MIME encrypted email preferred]</i></font></div> </body> </html> --------------x2pMdr7LsuFFqjpJMaYDHEJj-- --------------ms000601070800060604040601 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature 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