From owner-freebsd-hackers@freebsd.org Thu Oct 29 19:31:56 2020 Return-Path: Delivered-To: freebsd-hackers@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 99B8B45BD05 for ; Thu, 29 Oct 2020 19:31:56 +0000 (UTC) (envelope-from jmg@gold.funkthat.com) Received: from gold.funkthat.com (gate2.funkthat.com [208.87.223.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "gate2.funkthat.com", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4CMbDC16YGz4FR9 for ; Thu, 29 Oct 2020 19:31:54 +0000 (UTC) (envelope-from jmg@gold.funkthat.com) Received: from gold.funkthat.com (localhost [127.0.0.1]) by gold.funkthat.com (8.15.2/8.15.2) with ESMTPS id 09TJVqLO024416 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 29 Oct 2020 12:31:52 -0700 (PDT) (envelope-from jmg@gold.funkthat.com) Received: (from jmg@localhost) by gold.funkthat.com (8.15.2/8.15.2/Submit) id 09TJVpvF024415; Thu, 29 Oct 2020 12:31:51 -0700 (PDT) (envelope-from jmg) Date: Thu, 29 Oct 2020 12:31:50 -0700 From: John-Mark Gurney To: Dirk-Willem van Gulik Cc: "freebsd-hackers@freebsd.org" Subject: Re: spigen under uftdi Message-ID: <20201029193150.GK31099@funkthat.com> Mail-Followup-To: Dirk-Willem van Gulik , "freebsd-hackers@freebsd.org" References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: FreeBSD 11.3-STABLE amd64 X-PGP-Fingerprint: D87A 235F FB71 1F3F 55B7 ED9B D5FF 5A51 C0AC 3D65 X-Files: The truth is out there X-URL: https://www.funkthat.com/ X-Resume: https://www.funkthat.com/~jmg/resume.html X-TipJar: bitcoin:13Qmb6AeTgQecazTWph4XasEsP7nGRbAPE X-to-the-FBI-CIA-and-NSA: HI! HOW YA DOIN? can i haz chizburger? User-Agent: Mutt/1.6.1 (2016-04-27) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.4.3 (gold.funkthat.com [127.0.0.1]); Thu, 29 Oct 2020 12:31:53 -0700 (PDT) X-Rspamd-Queue-Id: 4CMbDC16YGz4FR9 X-Spamd-Bar: / Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=none (mx1.freebsd.org: domain of jmg@gold.funkthat.com has no SPF policy when checking 208.87.223.18) smtp.mailfrom=jmg@gold.funkthat.com X-Spamd-Result: default: False [-0.20 / 15.00]; TO_DN_EQ_ADDR_SOME(0.00)[]; ARC_NA(0.00)[]; FREEFALL_USER(0.00)[jmg]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; NEURAL_HAM_MEDIUM(-0.54)[-0.539]; RCVD_TLS_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[funkthat.com]; AUTH_NA(1.00)[]; MID_RHS_MATCH_FROM(0.00)[]; NEURAL_HAM_LONG(-0.36)[-0.364]; TO_MATCH_ENVRCPT_SOME(0.00)[]; NEURAL_HAM_SHORT(-0.50)[-0.499]; RCPT_COUNT_TWO(0.00)[2]; R_SPF_NA(0.00)[no SPF record]; FORGED_SENDER(0.30)[jmg@funkthat.com,jmg@gold.funkthat.com]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:32354, ipnet:208.87.216.0/21, country:US]; FROM_NEQ_ENVFROM(0.00)[jmg@funkthat.com,jmg@gold.funkthat.com]; MAILMAN_DEST(0.00)[freebsd-hackers]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 29 Oct 2020 19:31:56 -0000 Dirk-Willem van Gulik wrote this message on Wed, Oct 28, 2020 at 13:58 +0100: > Various USB based FT2232H usb to rs232 (and cypress CY7C65211) have a variant mode where they support SPI (or I2C). > > I've got this working in a rudimentary way in the uftdi(4) driver. > > But I'd like to have this surface as a 'normal' spigen(4) device. So it works with anything that already works on that device*. > > However - spigen(4) seems very tied to the FDT tree. > > Is this a viable path ? yes, this is possible, but it will require a bit of kernel coding... You need to add code to uftdi, to say that it can attach as to a spibus like one of the other spi drivers does, e.g. gpiospi... As avg said, hints can/should be able to stand in for OFT, BUT, that would only be needed for devices to attach to the spi bus, w/ USB, it should be able to automatically attach a spibus instance to itself when needed... > Or am I better off using the defintions of the ioctl(4) and simply have the uftdi create something like a /dev/uftdi-spi0.0 sort of device ? The advantage of hooking up to the spibus is that other kernel drivers that talk on the spi bus can use it, whereas this method, only userland consumers would be able to use it... -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."