From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 897ABC41514 for ; Sat, 31 Aug 2019 06:48:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5C3722377D for ; Sat, 31 Aug 2019 06:48:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kemnade.info header.i=@kemnade.info header.b="d7bhxDGR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726360AbfHaGs6 (ORCPT ); Sat, 31 Aug 2019 02:48:58 -0400 Received: from mail.andi.de1.cc ([85.214.55.253]:37274 "EHLO mail.andi.de1.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725899AbfHaGs6 (ORCPT ); Sat, 31 Aug 2019 02:48:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=kemnade.info; s=20180802; h=Content-Transfer-Encoding:Content-Type: MIME-Version:References:In-Reply-To:Message-ID:Subject:Cc:To:From:Date:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=rnTIfzRXS5Ir3AL9qhqZWwty0d60IscoDBzfov0jLUU=; b=d7bhxDGRoaRHuEc26WzHmmVfC/ ogQzkqh7yDgFK/luVkUpsOeqKZJ0qCMSmiDP5qL5Wrb/Y3R7XL4mkd6+Vpr6mMNM0n4wdoyGE9dZz dugfTMV43zOzVFZzKnCYLvrCC1eAjpJk6TMBiL9sb2TY+1miRmCEERIAiSk685qrv2ZE=; Received: from p5dc58eeb.dip0.t-ipconnect.de ([93.197.142.235] helo=aktux) by mail.andi.de1.cc with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1i3xBs-0007Yb-VQ; Sat, 31 Aug 2019 08:48:53 +0200 Date: Sat, 31 Aug 2019 08:48:52 +0200 From: Andreas Kemnade To: Linus Walleij Cc: Discussions about the Letux Kernel , Rob Herring , Mark Rutland , devicetree , Linux-OMAP , Tony Lindgren , Linux Kernel Mailing List , stable , linux-spi , Mark Brown , =?UTF-8?B?QmVub8OudA==?= Cousson Subject: Re: [Letux-kernel] [PATCH 2/2] DTS: ARM: gta04: introduce legacy spi-cs-high to make display work again Message-ID: <20190831084852.5e726cfa@aktux> In-Reply-To: References: <8ae7cf816b22ef9cecee0d789fcf9e8a06495c39.1562597164.git.hns@goldelico.com> <20190724194259.GA25847@bogus> <2EA06398-E45B-481B-9A26-4DD2E043BF9C@goldelico.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Mon, 5 Aug 2019 12:29:19 +0200 Linus Walleij wrote: > On Fri, Jul 26, 2019 at 12:43 AM Rob Herring wrote: > > On Thu, Jul 25, 2019 at 12:23 AM H. Nikolaus Schaller wrote: > > > > I tried to convince Linus that this is the right way but he convinced > > > me that a fix that handles all cases does not exist. > > > > > > There seem to be embedded devices with older DTB (potentially in ROM) > > > which provide a plain 0 value for a gpios definition. And either with > > > or without spi-cs-high. > > > > > > Since "0" is the same as "GPIO_ACTIVE_HIGH", the absence of > > > spi-cs-high was and must be interpreted as active low for these > > > devices. This leads to the inversion logic in code. > > > > > > AFAIR it boils down to the question if gpiolib and the bindings > > > should still support such legacy devices with out-of tree DTB, > > > but force in-tree DTS to add the legacy spi-cs-high property. > > > > > > Or if we should fix the 2 or 3 cases of in-tree legacy cases > > > and potentially break out-of tree DTBs. > > > > If it is small number of platforms, then the kernel could handle those > > cases explicitly as needed. > > > > > IMHO it is more general to keep the out-of-tree DTBs working > > > and "fix" what we can control (in-tree DTS). > > > > If we do this, then we need to not call spi-cs-high legacy because > > we're stuck with it forever. > > I agree. The background on it is here: > https://lkml.org/lkml/2019/4/2/4 > > Not using the negatively defined (i.e. if it is no there, the line is > by default active low) spi-cs-high would break > PowerPC, who were AFAICT using this to ship devices. > is this thing now just waiting for someone to do a s/legacy//? Regards, Andreas