From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johan Hovold Subject: Re: [PATCH] gpiolib: debugfs: display gpios requested as irq only Date: Tue, 19 May 2015 17:39:40 +0200 Message-ID: <20150519153940.GP28127@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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-la0-f47.google.com ([209.85.215.47]:35089 "EHLO mail-la0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752408AbbESPjl (ORCPT ); Tue, 19 May 2015 11:39:41 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Linus Walleij Cc: "Grygorii.Strashko@linaro.org" , Johan Hovold , Alexandre Courbot , "linux-gpio@vger.kernel.org" , "linux-kernel@vger.kernel.org" On Tue, May 19, 2015 at 04:12:35PM +0200, Linus Walleij wrote: > On Mon, May 18, 2015 at 5:17 PM, Grygorii.Strashko@linaro.org > wrote: > > On 05/18/2015 06:08 PM, Johan Hovold wrote: > > >> GPIOs 160-191, platform/4805d000.gpio, gpio: > >> gpio-171 ( ) in hi IRQ-209 > > > > In general agree, but i propose to do it as > > GPIOs 160-191, platform/4805d000.gpio, gpio: > > gpio-171 ((null) ) in hi IRQ-209 > > > > My intention is - this interface could be considered as more or less stable, so > > it is better to add additional information at the end of each line to avoid > > potential breakage of User space SW (test/debug scripts). > > 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: "The fact that something is documented (whether correctly or not) has absolutely _zero_ impact on anything at all. What makes something an ABI is that it's useful and available. The only way something isn't an ABI is by _explicitly_ making sure that it's not available even by mistake in a stable form for binary use. Example: kernel internal data structures and function calls. We make sure that you simply _cannot_ make a binary that works across kernel versions. That is the only way for an ABI to not form." https://lwn.net/Articles/309298/ In this case, it could be worked around by providing another debugfs file with gpios used as IRQs, I guess. Johan