From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Walleij Subject: Re: [PATCH v5 1/4] gpio: mvebu: Add limited PWM support Date: Mon, 24 Apr 2017 11:15:24 +0200 Message-ID: References: <20170409180931.4884-1-ralph.sennhauser@gmail.com> <20170409180931.4884-2-ralph.sennhauser@gmail.com> <20170412163128.5c985a26@free-electrons.com> <20170412151932.GE7023@lunn.ch> <20170421111952.54978e80@free-electrons.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <20170421111952.54978e80@free-electrons.com> Sender: linux-pwm-owner@vger.kernel.org To: Thomas Petazzoni Cc: Andrew Lunn , Ralph Sennhauser , Thierry Reding , Mark Rutland , Jason Cooper , Alexandre Courbot , Russell King , "linux-pwm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Gregory Clement , "devicetree@vger.kernel.org" , Rob Herring , "linux-gpio@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Sebastian Hesselbarth List-Id: linux-gpio@vger.kernel.org On Fri, Apr 21, 2017 at 11:19 AM, Thomas Petazzoni wrote: > I clearly don't want to block this, but I believe this is a very good > illustration of why stable DT bindings simply don't work. We are > realizing here that having each GPIO bank represented as a separate DT > node doesn't work, because this blinking functionality is not per GPIO > bank, but global to all GPIO banks. > > I am totally fine with compromise, and having things simple first, and > extend them later if needed. But this stable DT binding rule makes this > quite impossible: what is a compromise today might put you in big > troubles tomorrow. Really "stable bindings" I never believed in. It's just a pipe dream. Well they might become stable when the system is "finished" whenever that happens. I think a better rationale is that of the IETF: "rough consensus and running code", make deployed DTs work, if they are not deployed, or only getting deployed together with the kernel, changing the bindings are not a problem. Yours, Linus Walleij From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1167813AbdDXJPu (ORCPT ); Mon, 24 Apr 2017 05:15:50 -0400 Received: from mail-io0-f179.google.com ([209.85.223.179]:33094 "EHLO mail-io0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1167789AbdDXJPc (ORCPT ); Mon, 24 Apr 2017 05:15:32 -0400 MIME-Version: 1.0 In-Reply-To: <20170421111952.54978e80@free-electrons.com> References: <20170409180931.4884-1-ralph.sennhauser@gmail.com> <20170409180931.4884-2-ralph.sennhauser@gmail.com> <20170412163128.5c985a26@free-electrons.com> <20170412151932.GE7023@lunn.ch> <20170421111952.54978e80@free-electrons.com> From: Linus Walleij Date: Mon, 24 Apr 2017 11:15:24 +0200 Message-ID: Subject: Re: [PATCH v5 1/4] gpio: mvebu: Add limited PWM support To: Thomas Petazzoni Cc: Andrew Lunn , Ralph Sennhauser , Thierry Reding , Mark Rutland , Jason Cooper , Alexandre Courbot , Russell King , "linux-pwm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Gregory Clement , "devicetree@vger.kernel.org" , Rob Herring , "linux-gpio@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Sebastian Hesselbarth Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 21, 2017 at 11:19 AM, Thomas Petazzoni wrote: > I clearly don't want to block this, but I believe this is a very good > illustration of why stable DT bindings simply don't work. We are > realizing here that having each GPIO bank represented as a separate DT > node doesn't work, because this blinking functionality is not per GPIO > bank, but global to all GPIO banks. > > I am totally fine with compromise, and having things simple first, and > extend them later if needed. But this stable DT binding rule makes this > quite impossible: what is a compromise today might put you in big > troubles tomorrow. Really "stable bindings" I never believed in. It's just a pipe dream. Well they might become stable when the system is "finished" whenever that happens. I think a better rationale is that of the IETF: "rough consensus and running code", make deployed DTs work, if they are not deployed, or only getting deployed together with the kernel, changing the bindings are not a problem. Yours, Linus Walleij From mboxrd@z Thu Jan 1 00:00:00 1970 From: linus.walleij@linaro.org (Linus Walleij) Date: Mon, 24 Apr 2017 11:15:24 +0200 Subject: [PATCH v5 1/4] gpio: mvebu: Add limited PWM support In-Reply-To: <20170421111952.54978e80@free-electrons.com> References: <20170409180931.4884-1-ralph.sennhauser@gmail.com> <20170409180931.4884-2-ralph.sennhauser@gmail.com> <20170412163128.5c985a26@free-electrons.com> <20170412151932.GE7023@lunn.ch> <20170421111952.54978e80@free-electrons.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Apr 21, 2017 at 11:19 AM, Thomas Petazzoni wrote: > I clearly don't want to block this, but I believe this is a very good > illustration of why stable DT bindings simply don't work. We are > realizing here that having each GPIO bank represented as a separate DT > node doesn't work, because this blinking functionality is not per GPIO > bank, but global to all GPIO banks. > > I am totally fine with compromise, and having things simple first, and > extend them later if needed. But this stable DT binding rule makes this > quite impossible: what is a compromise today might put you in big > troubles tomorrow. Really "stable bindings" I never believed in. It's just a pipe dream. Well they might become stable when the system is "finished" whenever that happens. I think a better rationale is that of the IETF: "rough consensus and running code", make deployed DTs work, if they are not deployed, or only getting deployed together with the kernel, changing the bindings are not a problem. Yours, Linus Walleij