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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7320EC433EF for ; Thu, 27 Jan 2022 20:18:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343953AbiA0USf (ORCPT ); Thu, 27 Jan 2022 15:18:35 -0500 Received: from sin.source.kernel.org ([145.40.73.55]:37644 "EHLO sin.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343965AbiA0USe (ORCPT ); Thu, 27 Jan 2022 15:18:34 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 56F49CE230A for ; Thu, 27 Jan 2022 20:18:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BC5BAC340E4 for ; Thu, 27 Jan 2022 20:18:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643314711; bh=HwcJNC4Xs1PdswWHmb9yiCd8N9H6MoMdl2udx7sPK5g=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=n0H9f+3rWCGYSn+MTwky3Tw4XpfRdM7As76V3+rIJbSYnqYKCpUmiYnyH2s8jaKPv cqOx9cg7uHrcrIz7H4oBK/6deYRIR9Z+pfIseO8IOjnKSAKmNXCfofY26aiZJiwJE0 4LiDzA9vmHKK+KODgDEVTqai35oyGK/IkB6ljjdf7NvWo29zVPBC3p7l3/UgFDi6AG j+6j//N77LSxeFRGWVSyPWjupE5vh/C/mUgNZ5hrHyRr9tiH5RkBjOf6vmSgb87tZq GRljJdAaWOb9I9smphjc/h//gmlZqkwNFuaAzLMoMSrjm1g5riZRdeQywTTX8oO1Lm 2IbMM6M5zpU2g== Received: by mail-qt1-f182.google.com with SMTP id b5so3463389qtq.11 for ; Thu, 27 Jan 2022 12:18:31 -0800 (PST) X-Gm-Message-State: AOAM533yei026pw0V9rrY7OpSmxYYzwTkASvuMcsHlY2Is97NngsM9uT E7btNCu6nuA2VjTSivfAuYXR9I6Zs0mvVHvGKw== X-Google-Smtp-Source: ABdhPJwxjeIoBo2WtSIXzWbRD+IvzUIUZWuJZpaSlcaD7AZPFSsmYDZt39fHEUMzNPEaamJ+GjXhKnlbdlMpYWhhnyw= X-Received: by 2002:ac8:578e:: with SMTP id v14mr4098539qta.345.1643314710815; Thu, 27 Jan 2022 12:18:30 -0800 (PST) MIME-Version: 1.0 References: <20220123172520.48741-1-noralf@tronnes.org> <20220123172520.48741-2-noralf@tronnes.org> <931fab73-3a91-fda0-4af3-b48a1ad3c742@tronnes.org> <20220127093624.6gozbr6gl4ft66fz@houat> In-Reply-To: <20220127093624.6gozbr6gl4ft66fz@houat> From: Rob Herring Date: Thu, 27 Jan 2022 14:18:19 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 1/3] dt-bindings: display: add bindings for MIPI DBI compatible SPI panels To: Maxime Ripard Cc: =?UTF-8?Q?Noralf_Tr=C3=B8nnes?= , Thierry Reding , Sam Ravnborg , Dave Stevenson , David Lechner , devicetree@vger.kernel.org, dri-devel Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Thu, Jan 27, 2022 at 3:36 AM Maxime Ripard wrote: > > Hi Rob, > > On Mon, Jan 24, 2022 at 10:42:37AM -0600, Rob Herring wrote: > > On Mon, Jan 24, 2022 at 10:28 AM Noralf Tr=C3=B8nnes wrote: > > > > > > > > > > > > Den 24.01.2022 17.08, skrev Rob Herring: > > > > On Sun, Jan 23, 2022 at 11:25 AM Noralf Tr=C3=B8nnes wrote: > > > >> > > > >> Add binding for MIPI DBI compatible SPI panels. > > > > > > > > I'm sure we already have MIPI DBI panels. What's this for? > > > > > > > > > > It aims to use one driver to cover all MIPI DBI panels where the > > > controller setup is loaded from userspace in a firmware file. > > > > What's the solution when the user wants a splash screen in the > > bootloader and also wants multiple panels supported? > > > > Also, 1 driver doesn't dictate 1 compatible. A one to many > > relationship is fine and makes the decision entirely the OS's. > > > > > The cover > > > letter points to the discussion where Maxime proposed this: > > > > > > https://lore.kernel.org/dri-devel/20211129093946.xhp22mvdut3m67sc@hou= at/ > > > > The proposal there is: > > > > > compatible =3D "panel-spi"; > > > model =3D "panel-from-random-place-42"; > > > > The same thing can be accomplished with this: > > > > compatible =3D "panel-from-random-place-42", "panel-spi"; > > > > What's the advantage of hijacking 'model'? > > So, the main issue is that a panel is essentially two things: a > controller and the actual panel. > > The controller has an initialization sequence of its own, and part of it > is parameters to match the panel. > > So you can have identical controllers that won't have the same > initialization sequence because they don't have the same panel. > > I was assuming that a compatible would be more about the controller, so > we needed something else, thus "model" We already have cases like that which have "foo,some-panel", "bar,a-ctrlr-i= c". Rob