From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Walleij Subject: Re: [PATCH 1/2] drivers: pinctrl: add driver for Allwinner H5 SoC Date: Thu, 26 Jan 2017 11:03:47 +0100 Message-ID: References: <20161223125001.1176-1-icenowy@aosc.xyz> <1280f095-ab03-93f8-14d2-99d13ba1ce55@arm.com> <20170105224210.wfinfucbpkkd44om@lukather> <38fe3491-457a-f0c5-54fb-9defdcd45045@arm.com> <20170116163124.c5gusyd3j3goivnf@lukather> <87a535d3-1170-c388-ce7d-4921e69f4cab@arm.com> <20170119174144.hiw7lmvdh2tzxtd7@lukather> Reply-To: linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org In-Reply-To: <20170119174144.hiw7lmvdh2tzxtd7@lukather> List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: Maxime Ripard Cc: Andre Przywara , ext Tony Lindgren , Icenowy Zheng , Catalin Marinas , Chen-Yu Tsai , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-gpio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , linux-sunxi List-Id: linux-gpio@vger.kernel.org On Thu, Jan 19, 2017 at 6:41 PM, Maxime Ripard wrote: > That's not true anymore. And while it's true that it reduces the > amount of maintainance on the kernel side and more on the DT side. And > from what you're constantly saying, the thing we can't plan on fixing > / upgrading is the DT, while the kernel is easy to change. > > Which means that if we ever want to fix a non-upgradable DT, the only > way to do that would be to add quirks fixing it in the kernel > itself. Adding more maintainance burden to the kernel. This is a good argument to not put groups and functions into the DT at all. If the following propositions hold: - Functions and group definitions will contain bugs - Those bugs will need to be fixed by changing the buggy definitions - It is hard to change the DTB, it is easy to change the zImage Then by logical deduction the definitions should be in the kernel to minimize maintenance burden. There is a pattern amongst firmware people that they think that they always get the group and function definitions right on first try. As long as there are humans involved in the process, this stance is provedly wrong, just use git log and you will see how much of such bugs we fix, even in drivers and DTSes produced by the vendors themselves. 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 S1753473AbdAZKDv (ORCPT ); Thu, 26 Jan 2017 05:03:51 -0500 Received: from mail-io0-f181.google.com ([209.85.223.181]:36041 "EHLO mail-io0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753359AbdAZKDt (ORCPT ); Thu, 26 Jan 2017 05:03:49 -0500 MIME-Version: 1.0 In-Reply-To: <20170119174144.hiw7lmvdh2tzxtd7@lukather> References: <20161223125001.1176-1-icenowy@aosc.xyz> <1280f095-ab03-93f8-14d2-99d13ba1ce55@arm.com> <20170105224210.wfinfucbpkkd44om@lukather> <38fe3491-457a-f0c5-54fb-9defdcd45045@arm.com> <20170116163124.c5gusyd3j3goivnf@lukather> <87a535d3-1170-c388-ce7d-4921e69f4cab@arm.com> <20170119174144.hiw7lmvdh2tzxtd7@lukather> From: Linus Walleij Date: Thu, 26 Jan 2017 11:03:47 +0100 Message-ID: Subject: Re: [linux-sunxi] [PATCH 1/2] drivers: pinctrl: add driver for Allwinner H5 SoC To: Maxime Ripard Cc: Andre Przywara , ext Tony Lindgren , Icenowy Zheng , Catalin Marinas , Chen-Yu Tsai , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-gpio@vger.kernel.org" , linux-sunxi 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 Thu, Jan 19, 2017 at 6:41 PM, Maxime Ripard wrote: > That's not true anymore. And while it's true that it reduces the > amount of maintainance on the kernel side and more on the DT side. And > from what you're constantly saying, the thing we can't plan on fixing > / upgrading is the DT, while the kernel is easy to change. > > Which means that if we ever want to fix a non-upgradable DT, the only > way to do that would be to add quirks fixing it in the kernel > itself. Adding more maintainance burden to the kernel. This is a good argument to not put groups and functions into the DT at all. If the following propositions hold: - Functions and group definitions will contain bugs - Those bugs will need to be fixed by changing the buggy definitions - It is hard to change the DTB, it is easy to change the zImage Then by logical deduction the definitions should be in the kernel to minimize maintenance burden. There is a pattern amongst firmware people that they think that they always get the group and function definitions right on first try. As long as there are humans involved in the process, this stance is provedly wrong, just use git log and you will see how much of such bugs we fix, even in drivers and DTSes produced by the vendors themselves. Yours, Linus Walleij From mboxrd@z Thu Jan 1 00:00:00 1970 From: linus.walleij@linaro.org (Linus Walleij) Date: Thu, 26 Jan 2017 11:03:47 +0100 Subject: [linux-sunxi] [PATCH 1/2] drivers: pinctrl: add driver for Allwinner H5 SoC In-Reply-To: <20170119174144.hiw7lmvdh2tzxtd7@lukather> References: <20161223125001.1176-1-icenowy@aosc.xyz> <1280f095-ab03-93f8-14d2-99d13ba1ce55@arm.com> <20170105224210.wfinfucbpkkd44om@lukather> <38fe3491-457a-f0c5-54fb-9defdcd45045@arm.com> <20170116163124.c5gusyd3j3goivnf@lukather> <87a535d3-1170-c388-ce7d-4921e69f4cab@arm.com> <20170119174144.hiw7lmvdh2tzxtd7@lukather> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Jan 19, 2017 at 6:41 PM, Maxime Ripard wrote: > That's not true anymore. And while it's true that it reduces the > amount of maintainance on the kernel side and more on the DT side. And > from what you're constantly saying, the thing we can't plan on fixing > / upgrading is the DT, while the kernel is easy to change. > > Which means that if we ever want to fix a non-upgradable DT, the only > way to do that would be to add quirks fixing it in the kernel > itself. Adding more maintainance burden to the kernel. This is a good argument to not put groups and functions into the DT at all. If the following propositions hold: - Functions and group definitions will contain bugs - Those bugs will need to be fixed by changing the buggy definitions - It is hard to change the DTB, it is easy to change the zImage Then by logical deduction the definitions should be in the kernel to minimize maintenance burden. There is a pattern amongst firmware people that they think that they always get the group and function definitions right on first try. As long as there are humans involved in the process, this stance is provedly wrong, just use git log and you will see how much of such bugs we fix, even in drivers and DTSes produced by the vendors themselves. Yours, Linus Walleij