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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 B2E7EC43603 for ; Mon, 16 Dec 2019 10:37:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 919A520725 for ; Mon, 16 Dec 2019 10:37:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727319AbfLPKhN (ORCPT ); Mon, 16 Dec 2019 05:37:13 -0500 Received: from mail-oi1-f196.google.com ([209.85.167.196]:34103 "EHLO mail-oi1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727099AbfLPKhN (ORCPT ); Mon, 16 Dec 2019 05:37:13 -0500 Received: by mail-oi1-f196.google.com with SMTP id l136so3120636oig.1; Mon, 16 Dec 2019 02:37:12 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=mzy4MnymQY4e/i55C6UvU1p3HJsy+cqrBB14goXu6lk=; b=IU+d7/o3X5XYfrYR5T/YNjK8ZwHunxRL5adryOvae6nd89nyibJf9IxlTFFxcLMdDW Oll8CuUznqAMmoea5bKzkcxZIKhN6D/DYTsOVLQ7HXLAIonRCjAScCus5gop/m5bTywK mFRoNoPNmTyFoti2mdbnJf4WLnJIYyNElWWEz81JFncQE+2W2a+2ALyLIx0DIO96fteq AHDoLjc5bGGjaxOgCifd5Rbk4MB8zIDBk6yL2K8O53mw/xCLYblgs6oZzjtI4cO8GIaC 9nb5d9Djjx++U71+OxewRMF7DrnzIlj3OqtX2oeMqvnK6uTrs4bVryyGdei2Q/qpwV/L GF6w== X-Gm-Message-State: APjAAAVo0gGTYwZAVaP45M8WlDEwG17KLF3GgQMeNbN+8XHD7UIqcynw yu8RT6UjZgjPZhYCq0KlER7+CRqeA+troWsU6P4= X-Google-Smtp-Source: APXvYqyHX4rBGNEDa6Z3oYE/ISGuH6mr8Na6Ob2WcaWaHKza4vXUSA+tgVsU4U16CGSh2bQ13Wtg76nuZkSsQK4FqgY= X-Received: by 2002:aca:36c5:: with SMTP id d188mr9559143oia.54.1576492632030; Mon, 16 Dec 2019 02:37:12 -0800 (PST) MIME-Version: 1.0 References: <20190911192502.16609-1-kieran.bingham+renesas@ideasonboard.com> <70b94265-69f3-d18f-1b67-b5b814723b1b@cogentembedded.com> <20190913082129.lvusbp6pbcayqh5r@verge.net.au> <20190913090359.GC29992@pendragon.ideasonboard.com> <2eeacacc-f190-4ba8-32bc-b4103b41db46@ideasonboard.com> <20191213004812.GA27328@pendragon.ideasonboard.com> <19cb3d1c-6910-4bec-13bb-adb875ddd077@ideasonboard.com> In-Reply-To: <19cb3d1c-6910-4bec-13bb-adb875ddd077@ideasonboard.com> From: Geert Uytterhoeven Date: Mon, 16 Dec 2019 11:37:00 +0100 Message-ID: Subject: Re: [PATCH] drm: rcar-du: Add r8a77980 support To: Kieran Bingham , Laurent Pinchart Cc: Simon Horman , Sergei Shtylyov , Linux-Renesas , David Airlie , Daniel Vetter , "open list:DRM DRIVERS FOR RENESAS" , open list Content-Type: text/plain; charset="UTF-8" Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org Hi Kieran, Laurent, On Mon, Dec 16, 2019 at 10:47 AM Kieran Bingham wrote: > On 13/12/2019 00:48, Laurent Pinchart wrote: > > On Mon, Dec 09, 2019 at 12:41:07PM +0000, Kieran Bingham wrote: > >> On 13/09/2019 10:03, Laurent Pinchart wrote: > >>> On Fri, Sep 13, 2019 at 10:21:29AM +0200, Simon Horman wrote: > >>>> On Thu, Sep 12, 2019 at 01:00:41PM +0300, Sergei Shtylyov wrote: > >>>>> On 11.09.2019 22:25, Kieran Bingham wrote: > >>>>> > >>>>>> Add direct support for the r8a77980 (V3H). > >>>>>> > >>>>>> The V3H shares a common, compatible configuration with the r8a77970 > >>>>>> (V3M) so that device info structure is reused. > >>>>> > >>>>> Do we really need to add yet another compatible in this case? > >>>>> I just added r8a77970 to the compatible prop in the r8a77980 DT. That's why > >>>>> a patch like this one didn't get posted by me. > >>>> > >>>> The reason for having per-SoC compat strings is that the IP blocks > >>>> are not versioned and while we can observe that there are similarities > >>>> between, f.e. the DU on the r8a77970 and r8a77980, we can't be certain that > >>>> differences may not emerge at some point. By having per-SoC compat strings > >>>> we have the flexibility for the driver to address any such differences as > >>>> the need arises. > >>>> > >>>> My recollection is that this scheme has been adopted for non-versioned > >>>> Renesas IP blocks since June 2015 and uses of this scheme well before that. > >>> > >>> Sure, but we could use > >>> > >>> compatible = "renesas,du-r8a77980", "renesas,du-r8a77970"; > > We already do in arch/arm64/boot/dts/renesas/r8a77980.dtsi. > > However that is the *only* non r8a77980 reference in the file so it, > itself looks *very* much out of place. > > > Furthermore, the main purpose of this patch is that we clearly document > the driver as supporting the r8a77980 in the bindings (No mention that > you must use the ..970 binding), yet in actual fact - the driver could > not currently support loading a device with the following compatible: > > compatible = "renesas,du-r8a77980"; > > > >>> in DT without updating the driver. If the r8a77980 turns out to be > >>> different, we'll then update the driver without a need to modify DT. I'm > >>> fine either way, so > >>> > >>> Reviewed-by: Laurent Pinchart > >> > >> Thanks, > >> > >> This patch has an RB tag from you, and Simon, but alas I don't believe > >> it has been picked up in your drm/du/next branch. > >> > >> Is this patch acceptable? Or do I need to repost? > > > > Could you just confirm I should apply this patch, and not go for the > > alternative proposal above ? > > I believe the alternative proposal above is what we have today isn't it? > > > Yes, I do believe we should apply this patch. +1. I'm waiting for the driver part to go upstream, so I can apply the DTS patch. Note that this will lead to a messy situation in LTS, as the DTS patch will likely be backported, so the driver part must be backported, too. > I'm going to assume you haven't read the other arguments on this thread > so I'll paste them here: Thanks for recollecting! ;-) Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds