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=-8.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 8D9ECC4707E for ; Sat, 22 May 2021 10:34:45 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 43E18611CB for ; Sat, 22 May 2021 10:34:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 43E18611CB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6548A6E197; Sat, 22 May 2021 10:34:44 +0000 (UTC) Received: from mail-lj1-x235.google.com (mail-lj1-x235.google.com [IPv6:2a00:1450:4864:20::235]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8618B6E197 for ; Sat, 22 May 2021 10:34:41 +0000 (UTC) Received: by mail-lj1-x235.google.com with SMTP id v5so26943647ljg.12 for ; Sat, 22 May 2021 03:34:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=GYUGb+Vmff9gIUFyntVd0FDSDvGjX/ufL9sA1nyH3vE=; b=BoJ8q46zkHwgiqwqQriO/CkcH2ITeLf1ezMGx+UzZ8wDLGLO89xIOlJochoYDjDjWD VKfN6KnYmFLB6KSnYwg+92T2S7iOLUicG+XA/VkwSPkDfLa0WoMwqCiNkWhUogFjad74 m6WXkkfcz9fq/r+HAtrmj/7OmM2bIeWOW1c7iMm5v8+ZHPQBbU5g2oeV2FQZj8sFlhI5 Vxayp7bWj1GlHkAtIK5GTCSwY8mn0K8RTEfO50R/b0+ozUyYoiTomGDigFs5riqELBa5 Y8zobRoz3tuQhl8Kc5/PykT1s7cppXe7/V2Hke6tIKBaDMkyYY23avqaiUk98xQ5gFcU 2B+A== 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=GYUGb+Vmff9gIUFyntVd0FDSDvGjX/ufL9sA1nyH3vE=; b=pjtzkXYAhXmF/qBtbEL5az+BGHx6C3q/fCcYayrIFL/1n0mJchAM+dTaS55ymecxe0 UBPRiIMgCR43qTCAWX/HUobTm2neNV8mZWhumGdwYuDNjPV0zzW4zjvY9zELRKvgMO5L oWlMozZUEciNyGumShqtOYNUNQudg/Zo1lv5/DsphnAAMKet+hSXYa8fLiI91A/8Uafb nduFS4ZExnb3EK0oQwlxm6QnklTJaV47KYEA1AZ6gEejlqhurf1WZ0cesHnHsYgkSNIG A65SstBo/W9wgbppcXWiUa63VEawKzxNl2qpLV4DEndOMUIrDZXFYKvBcyx0D9f5AL9Z KFrg== X-Gm-Message-State: AOAM532A2GFZ+G/D3KsmN9FDC2PJdS0jrM91WC3HmPpaD/8+eog+Sx/b j5ct95BoZBWEzFxVJ4wxyZ453wTB+jNwIydDDk9pig== X-Google-Smtp-Source: ABdhPJz+ibDLMNP419ZZFrjVh+qJ+I+wQfZgaVgBBcDbk/aF9PHnxGEBejFwxuPQTBjJzM6NkcCaBX514iUfRyBvKSw= X-Received: by 2002:a2e:889a:: with SMTP id k26mr9933011lji.438.1621679679967; Sat, 22 May 2021 03:34:39 -0700 (PDT) MIME-Version: 1.0 References: <20210517200907.1459182-1-dianders@chromium.org> <20210517130450.v7.4.I787c9ba09ed5ce12500326ded73a4f7c9265b1b3@changeid> In-Reply-To: <20210517130450.v7.4.I787c9ba09ed5ce12500326ded73a4f7c9265b1b3@changeid> From: Linus Walleij Date: Sat, 22 May 2021 12:34:28 +0200 Message-ID: Subject: Re: [PATCH v7 04/10] drm: Introduce the DP AUX bus To: Douglas Anderson Content-Type: text/plain; charset="UTF-8" X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Neil Armstrong , David Airlie , "open list:DRM PANEL DRIVERS" , Bjorn Andersson , Andrzej Hajda , Laurent Pinchart , Sam Ravnborg , Rob Clark , Stanislav Lisovskiy , Thierry Reding , Thomas Zimmermann , Jonas Karlman , MSM , Stephen Boyd , Steev Klimaszewski , Jernej Skrabec , Rajeev Nandan , linux-kernel Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Mon, May 17, 2021 at 10:09 PM Douglas Anderson wrote: > Historically "simple" eDP panels have been handled by panel-simple > which is a basic platform_device. In the device tree, the panel node > was at the top level and not connected to anything else. > > Let's change it so that, instead, panels can be represented as being > children of the "DP AUX bus". Essentially we're saying that the > hierarchy that we're going to represent is the "control" connections > between devices. The DP AUX bus is a control bus provided by an eDP > controller (the parent) and consumed by a device like a panel (the > child). > > The primary incentive here is to cleanly provide the panel driver the > ability to communicate over the AUX bus while handling lifetime issues > properly. The panel driver may want the AUX bus for controlling the > backlight or querying the panel's EDID. > > The idea for this bus's design was hashed out over IRC [1]. > > [1] https://people.freedesktop.org/~cbrill/dri-log/?channel=dri-devel&date=2021-05-11 > > Cc: Laurent Pinchart > Cc: Lyude Paul > Cc: Rajeev Nandan > Suggested-by: Laurent Pinchart > Signed-off-by: Douglas Anderson I like the concept and the general idea behind this, clean and helpful design. Acked-by: Linus Walleij Yours, Linus Walleij