From owner-freebsd-arm@FreeBSD.ORG Wed May 21 20:00:18 2014 Return-Path: Delivered-To: freebsd-arm@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id B92A5809 for ; Wed, 21 May 2014 20:00:18 +0000 (UTC) Received: from mail-la0-x230.google.com (mail-la0-x230.google.com [IPv6:2a00:1450:4010:c03::230]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 44C7A2A55 for ; Wed, 21 May 2014 20:00:18 +0000 (UTC) Received: by mail-la0-f48.google.com with SMTP id mc6so1980837lab.35 for ; Wed, 21 May 2014 13:00:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=stvDxuaXIj2ncsiOGJ5oiqWoTjLfSwBgRoxPHZUS/F0=; b=PWdSKSYq4F8dhED8B32Z/4NKojOVPMcC0pVaOm9ljx+HUhgJuOvJvxLNuVAnLpXY8A +JW7AbZKSASkcrLEkPKJBkKOonosmgWJLsqqfUL7T0GZRcNgSkmmoGyAd9bHio8LWlFx OxXfk7CMvT6Krq9jXAoEfIth8Mm1NXoHd0Mk1JzNYEbpxWtmUPwRaceXxrmcq4cFm3af SlVFafu+gNDmFdfhhd77fLOrB8Xys1Gsau4VPLAVjW1BK88mThkvm9PMbS1oa9abcFYX xPR7e85N4bpPMSoRI4YFEQjKM8zJOsvd1LYXvQHL9NLHE6C+GzFBws4t7vF5oEkIAI0x glNA== MIME-Version: 1.0 X-Received: by 10.152.43.8 with SMTP id s8mr2947450lal.81.1400702416025; Wed, 21 May 2014 13:00:16 -0700 (PDT) Received: by 10.112.230.5 with HTTP; Wed, 21 May 2014 13:00:15 -0700 (PDT) In-Reply-To: <1397618162.1484.26.camel@fbsd-laptop> References: <1397618162.1484.26.camel@fbsd-laptop> Date: Wed, 21 May 2014 17:00:15 -0300 Message-ID: Subject: Re: Plans for standardizing digital/analog I/O? From: Luiz Otavio O Souza To: Brian McGovern Content-Type: text/plain; charset=UTF-8 Cc: "freebsd-arm@freebsd.org" X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 21 May 2014 20:00:18 -0000 On 16 April 2014 00:16, Brian J. McGovern wrote: > This is probably best suited for a more generic list, but given digital > and analog I/O are at the core of many of the ARM based development > boards out there, I figured I'd ask here first... > > Is anyone talking about standardizing the various I/O framworks that > exist/are being built? Or, perhaps more correctly,standardizing the > _interfaces_ to the various I/O frameworks? > > To use the BBB as an example platform, the digital I/O work seems to use > the gpio[ctl] framework, while the ADC uses sysctl under the new/current > driver. I haven't looked at PWM outputs yet. Finally, given that I have > passthrough driver for the various Velleman I/O boards (the 110, 140, > and 167) which allow the application to speak the various protocols to > the boards (not to mention allowing me to plug in 5V and 12V things in > to the 1.8V BBB world without much modification), I'm discovering there > are at least 6 ways to do I/O in my world, and I'm guessing there are a > lot more if I were to keep digging. > > So, I'm curious if anyone is working on or proposing a more generic, or > at least standard, kernel interface to plug in to? Perhaps sysctls are a > way to go, or a set of /dev/hwio/* entries. I'd also be interested in > hearing anyone's thoughts on the matter, should I decide to go off and > build something, either in kernel or user space, to unify these spaces > for the ease of application programming. > -B > Hi Brian, Yes, i do think we could benefit from having such standards for the various I/O options. I have been thinking on this and have some ideas that i would like to see implemented. That being said, i don't know when i will be able to tackle with this. But sure, help is very welcome. Regards, Luiz