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=-9.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 3DAD2C64E8A for ; Wed, 2 Dec 2020 12:21:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CCF6B221FE for ; Wed, 2 Dec 2020 12:21:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727331AbgLBMVI (ORCPT ); Wed, 2 Dec 2020 07:21:08 -0500 Received: from mail.kernel.org ([198.145.29.99]:51220 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726817AbgLBMVI (ORCPT ); Wed, 2 Dec 2020 07:21:08 -0500 Date: Wed, 2 Dec 2020 12:19:56 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1606911627; bh=DsrXXY2h/yIcoRTDSQa3tc2wpMVRYr+OV3sf7ETbV58=; h=From:To:Cc:Subject:References:In-Reply-To:From; b=1G14kmIfls6m5J3f769odFT9c818QTKnGGr4LysiyQaqKIbxsw5gJPPsIrd2LMo/w j75duz6xhGrjIgMOrkvqbB5QzjvQ+UdyJf4XzL3+M/+3Kk5iCmYFoTMLQA2d2fyzxj 9n/vLCppCnfMAs8RD6fQov9DDfm7G/h77U1Ej9xo= From: Mark Brown To: Sven Van Asbroeck Cc: "H. Nikolaus Schaller" , Linus Walleij , kernel list , Laurent Pinchart , Discussions about the Letux Kernel , Andreas Kemnade Subject: Re: [BUG] SPI broken for SPI based panel drivers Message-ID: <20201202121956.GA5560@sirena.org.uk> Mail-Followup-To: Sven Van Asbroeck , "H. Nikolaus Schaller" , Linus Walleij , kernel list , Laurent Pinchart , Discussions about the Letux Kernel , Andreas Kemnade References: <4AC29229-9542-4E77-B993-217E29C7E209@goldelico.com> <20201201121620.GB5239@sirena.org.uk> <6283C16F-549C-4463-BC08-E2C1A1D78B2F@goldelico.com> <9380CE00-9CE6-4E0B-B2E1-1B534F85E47D@goldelico.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="CE+1k2dSO48ffgeK" Content-Disposition: inline In-Reply-To: X-Cookie: Sauron is alive in Argentina! User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --CE+1k2dSO48ffgeK Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Dec 01, 2020 at 01:43:36PM -0500, Sven Van Asbroeck wrote: > On Tue, Dec 1, 2020 at 12:13 PM H. Nikolaus Schaller wrote: > > I am not sure if DT maintainers accept that we revert a DT change just to > > handle some change in a driver. Usually they insist on fixing a driver and > > live with the DT. DT is carved in stone or could be ROM... > This is above my paygrade, but I've always assumed that the devicetree ABI > is an in-kernel ABI, i.e. not a userspace ABI. Meaning that it is flexible and > there is no obligation to keep it 100% backwards compatible. Of course Rob > Herring may want to keep it as backwards-compatible as possible, but that's > an altogether different thing from having a userspace-type ABI. It's supposed to be an ABI, though sometimes that gets broken - in a case like this if there's only a very limited set of users relying on something that's going to make things harder to maintain and which don't in practice distribute the kernel separately to the DT then it can make sense to just break the DT since realistically nobody's going to actually notice. On the other hand if people are distributing the kernel separately to the DT then compatibility definitely has to be maintained. --CE+1k2dSO48ffgeK Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAl/HhmsACgkQJNaLcl1U h9CI4gf/WYSrziOVDt0VgkhsyLkPps6cXkjghuRjFYQvSvUxy3Tdk61vCc+YxR5C iAXbjj0di9YynTT+nwnWrOMPeMWMCho94YAU7CCSOoXrVI+IFSMsf3ArPcQRIdEB 5UUdWnOAU9oZ2jlJgST7two9uRieFcKO/opIRLzvh4HHoP8q8etBt95Te773VxA2 2Vpd6bqjNenGBZWj9q/g3e74NDzm8Vny387AmYhjLt6EaI8teSTOo1zgK67zujua mEtuTTZFtpFM5pp2TyIYPDCULet+2KfB9QGXHlIvEnObo4Y/R4iTzWq83Cge9ypG r/sxG5pCNhwYp028Ar0pyYLVLMQqwA== =XtRo -----END PGP SIGNATURE----- --CE+1k2dSO48ffgeK--