Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755900AbbEUOeE (ORCPT ); Thu, 21 May 2015 10:34:04 -0400 Received: from mail-lb0-f170.google.com ([209.85.217.170]:33063 "EHLO mail-lb0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754189AbbEUOeB (ORCPT ); Thu, 21 May 2015 10:34:01 -0400 Date: Thu, 21 May 2015 16:34:01 +0200 From: Johan Hovold To: Linus Walleij Cc: Johan Hovold , "Grygorii.Strashko@linaro.org" , Alexandre Courbot , "linux-gpio@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] gpiolib: debugfs: display gpios requested as irq only Message-ID: <20150521143401.GB30660@localhost> References: <1431696321-7257-1-git-send-email-grygorii.strashko@linaro.org> <20150518110214.GC28127@localhost> <5559E3C0.1040207@linaro.org> <20150518150815.GH28127@localhost> <555A0299.3030803@linaro.org> <20150519153940.GP28127@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1608 Lines: 44 On Wed, May 20, 2015 at 09:21:16AM +0200, Linus Walleij wrote: > On Tue, May 19, 2015 at 5:39 PM, Johan Hovold wrote: > > On Tue, May 19, 2015 at 04:12:35PM +0200, Linus Walleij wrote: > > >> What? If I wanted a stable interface I would use sysfs and document > >> the ABI in Documentation/ABI/*. > >> > >> debugfs is not ABI. > > > > As I mentioned in my response to Grygorii, not everyone -- and most > > notably apparently not even Linus Torvalds -- agrees on this: > > Yeah I was sloppy I guess. > > What I mean, precisely is that sysfs is ABI, whether documented or > not. > > Even debugfs is actually blurry, as per > Documentation/filesystems/debugfs.txt: > > "The debugfs filesystem is also intended to not serve as a stable > ABI to user space; in theory, there are no stability constraints placed on > files exported there. The real world is not always so simple, though [1]; > even debugfs interfaces are best designed with the idea that they will need > to be maintained forever." > > But I haven't been bitten by it yet so that's why I allow some poetic > license. Yes, and the [1] reference in that quote is the LWN article I referred to. I also see you already "broke" that ABI in a similar way in 2013 with d468bf9ecaab ("gpio: add API to be strict about GPIO IRQ usage") by adding the IRQ field. Your call. :) Johan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/