From owner-freebsd-hackers@freebsd.org Tue Dec 20 19:26:27 2016 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id B0900C891ED for ; Tue, 20 Dec 2016 19:26:27 +0000 (UTC) (envelope-from george+freebsd@m5p.com) Received: from mailhost.m5p.com (mailhost.m5p.com [IPv6:2001:418:3fd::f7]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "m5p.com", Issuer "Let's Encrypt Authority X3" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 5155CD5C; Tue, 20 Dec 2016 19:26:27 +0000 (UTC) (envelope-from george+freebsd@m5p.com) Received: from [IPv6:2001:418:3fd::1f] (haymarket.m5p.com [IPv6:2001:418:3fd::1f]) by mailhost.m5p.com (8.15.2/8.15.2) with ESMTP id uBKJQKFq089537; Tue, 20 Dec 2016 14:26:25 -0500 (EST) (envelope-from george+freebsd@m5p.com) Subject: Re: USB ppbus? To: Ian Lepore , freebsd-hackers@freebsd.org References: <35e62a59-556a-68bf-3b9d-017108f12f38@m5p.com> <930e14f6-d8a8-7f50-21b4-6e76c2057f31@selasky.org> <1482259297.48539.30.camel@freebsd.org> From: George Mitchell Message-ID: <7cd409d4-cb49-6384-180b-51e58ca54a66@m5p.com> Date: Tue, 20 Dec 2016 14:26:20 -0500 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <1482259297.48539.30.camel@freebsd.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-3.8 required=10.0 tests=ALL_TRUSTED, RP_MATCHES_RCVD autolearn=unavailable autolearn_force=no version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on mattapan.m5p.com X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.1 (mailhost.m5p.com [IPv6:2001:418:3fd::f7]); Tue, 20 Dec 2016 14:26:26 -0500 (EST) X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 20 Dec 2016 19:26:27 -0000 On 12/20/16 13:41, Ian Lepore wrote: > On Tue, 2016-12-20 at 13:15 -0500, George Mitchell wrote: >> [...] >> Thanks for the response. I think I could kludge the ioctls I want >> into >> ulpt.c by learning more about the USB system works. Possibly. On a >> good day. -- >> George >> > > IMO, ppbus solves a 1990s problem that we don't much have anymore: > multiplexing multiple concurrent (or time-slice-shared) users of a > single parallel port that may have multiple non-printer devices daisy- > chained on it. > > If the only thing you're looking for is the ability to treat some of > the DB25 pins as gpio pins, just adding the ioctls to ulpt.c might be > the way to go. > > Another possiblity, if all you're after is gpio on the end of a usb > wire, is to use an FTDI usb-serial adapter and then use either the > existing ioctl() interface in the uftdi driver (see uftdi(4) manpage), > or libusb and libftdi (I'm not sure the latter has ever been ported to > freebsd). > > -- Ian > [...] Thanks. I need the DB25 Centronics interface on the end of a USB wire, so I guess I'll learn more about the USB system. Musing: Has any other presently defunct company exerted such an influence on computer interfacing over the years than Centronics Data Computer Corporation? (Yes, I know they defined the 36-pin "blue ribbon" interface, and that IBM promulgated the DB25 connector for it, but electrically it was the Centronics interface.) -- George