From patchwork Mon Jun 7 17:05:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Douglas Anderson X-Patchwork-Id: 12304103 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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 9EB07C4743F for ; Mon, 7 Jun 2021 17:07:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 89EC460FF2 for ; Mon, 7 Jun 2021 17:07:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231685AbhFGRJK (ORCPT ); Mon, 7 Jun 2021 13:09:10 -0400 Received: from mail-pl1-f173.google.com ([209.85.214.173]:41888 "EHLO mail-pl1-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231656AbhFGRJK (ORCPT ); Mon, 7 Jun 2021 13:09:10 -0400 Received: by mail-pl1-f173.google.com with SMTP id o12so5678416plk.8 for ; Mon, 07 Jun 2021 10:07:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=dQE2oc4ck1yBx8OjbWi1jB5697iDZ6Jcz+Jq90YnWDE=; b=BRHM24dXb9WdBH3AF7IEEdq5qZGZPbGeXoUVu78XEfchuxuyufLLfG7W4v0ZiQA8Dy i7nO9xhzjYiBMja5Zr43QEFJeeeqyYZErxY2sVXgFe8yqkhc4x4+r662ossOOHA56BS1 pRzPqoE6FFJ22C3liFwTJKwnKLckezI1tsHck= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=dQE2oc4ck1yBx8OjbWi1jB5697iDZ6Jcz+Jq90YnWDE=; b=aZhrrIcGBESA2TvtEtSedYFH34nIwmq9IgLvfgFDUUPw2RYncUDtgKXLwm4DamAjG6 XzUxkQ4LdAuZbf7ij4vX4/BvZCM/TPr46cXYC3LD40qjg6g7Rz1JQdbTKx4DNHO4Utze ferQ/HXcTet2HSMZgMcNompFjTS0EMgMQpQ2se81mQA+BgdKnXJMVO+yyUs8p3uVp9Tb 7uk4NVoF0r3lnv70En0+AZ7sCEuCZ3YVIiD8oJA1ptDgkkUUvlOwgOcCltxuJczI2kdL lfKfHt83O0/y6cYP5pV3cZRKZBtf8YQkqI5RStVrH75U/pJCkwhz8OI8jAeclMYfCp0Z HkYA== X-Gm-Message-State: AOAM533hFthpAX9+ADGYG0d/TJ8CFM7sCj5YaG1+CZd6n+lr0OWu0ibG DdHQTHtLB2RxJB9EN4dJ1yK2rw== X-Google-Smtp-Source: ABdhPJyWrV1oYCT31s6fWz03UksAA2NhnlHdmI7OV5MP8ziAx7Ta1SgfnVY80ymWu7sQMnlDsAomtQ== X-Received: by 2002:a17:90a:1641:: with SMTP id x1mr139302pje.114.1623085578464; Mon, 07 Jun 2021 10:06:18 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:201:f656:ffce:6348:a42a]) by smtp.gmail.com with ESMTPSA id fs24sm12897639pjb.6.2021.06.07.10.06.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Jun 2021 10:06:18 -0700 (PDT) From: Douglas Anderson To: Andrzej Hajda , Neil Armstrong , Laurent Pinchart , Jonas Karlman , Sam Ravnborg Cc: Linus W , robdclark@chromium.org, Maarten Lankhorst , Stanislav Lisovskiy , Steev Klimaszewski , linux-arm-msm@vger.kernel.org, Bjorn Andersson , Thierry Reding , Lyude Paul , dri-devel@lists.freedesktop.org, Stephen Boyd , Douglas Anderson , Rob Herring , Daniel Vetter , David Airlie , Rob Herring , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v9 02/11] dt-bindings: drm: Introduce the DP AUX bus Date: Mon, 7 Jun 2021 10:05:46 -0700 Message-Id: <20210607100234.v9.2.Id3c048d22e72a9f90084a543b5b4e3f43bc9ab62@changeid> X-Mailer: git-send-email 2.32.0.rc1.229.g3e70b5a671-goog In-Reply-To: <20210607170555.4006050-1-dianders@chromium.org> References: <20210607170555.4006050-1-dianders@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org We want to be able to list an eDP panel as a child of an eDP controller node to represent the fact that the panel is connected to the controller's DP AUX bus. Though the panel and the controller are connected in several ways, the DP AUX bus is the primary control interface between the two and thus makes the most sense to model in device tree hierarchy. Listing a panel in this way makes it possible for the panel driver to easily get access to the DP AUX bus that it resides on, which can be useful to help in auto-detecting the panel and for turning on various bits. NOTE: historically eDP panels were _not_ listed under their controller but were listed at the top level of the device tree. This will still be supported for backward compatibility (and while DP controller drivers are adapted to support the new DT syntax) but should be considered deprecated since there is no downside to listing the panel under the controller. For now, the DP AUX bus bindings will only support an eDP panel underneath. It's possible it could be extended to allow having a DP connector under it in the future. NOTE: there is no "Example" in this bindings file. Yikes! This avoids duplicating the same example lots of places. See users of the aux bus (like ti-sn65dsi86) for examples. 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 Signed-off-by: Douglas Anderson Reviewed-by: Rob Herring Reviewed-by: Linus Walleij --- Changes in v9: - Commit message now notes aux-bus yaml won't have an "Example". Changes in v8: - Separate DP AUX bus binding is new for v8. .../bindings/display/dp-aux-bus.yaml | 37 +++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 Documentation/devicetree/bindings/display/dp-aux-bus.yaml diff --git a/Documentation/devicetree/bindings/display/dp-aux-bus.yaml b/Documentation/devicetree/bindings/display/dp-aux-bus.yaml new file mode 100644 index 000000000000..5e4afe9f98fb --- /dev/null +++ b/Documentation/devicetree/bindings/display/dp-aux-bus.yaml @@ -0,0 +1,37 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/display/dp-aux-bus.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: DisplayPort AUX bus + +maintainers: + - Douglas Anderson + +description: + DisplayPort controllers provide a control channel to the sinks that + are hooked up to them. This is the DP AUX bus. Over the DP AUX bus + we can query properties about a sink and also configure it. In + particular, DP sinks support DDC over DP AUX which allows tunneling + a standard I2C DDC connection over the AUX channel. + + To model this relationship, DP sinks should be placed as children + of the DP controller under the "aux-bus" node. + + At the moment, this binding only handles the eDP case. It is + possible it will be extended in the future to handle the DP case. + For DP, presumably a connector would be listed under the DP AUX + bus instead of a panel. + +properties: + $nodename: + const: "aux-bus" + + panel: + $ref: panel/panel-common.yaml# + +additionalProperties: false + +required: + - panel