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=-14.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 2067AC47092 for ; Wed, 2 Jun 2021 18:00:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0A77A61DB5 for ; Wed, 2 Jun 2021 18:00:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231189AbhFBSCG (ORCPT ); Wed, 2 Jun 2021 14:02:06 -0400 Received: from mail-ot1-f52.google.com ([209.85.210.52]:43853 "EHLO mail-ot1-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229467AbhFBSCF (ORCPT ); Wed, 2 Jun 2021 14:02:05 -0400 Received: by mail-ot1-f52.google.com with SMTP id i12-20020a05683033ecb02903346fa0f74dso3209520otu.10; Wed, 02 Jun 2021 11:00:20 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=STNHXHQ+81oeK1CksPWVyFVkZuPW4pW3ZP19XpEkSjY=; b=VLmCpGDIDZ5ZfvLjkjOLwX3CMSne+WGDqo5C5hPQA7+CYt6BBCqDJ5Hpl80jum3zzY Poe9CIym6LgJTtgxY66UI8XTRJZuiK2MUbipJNaGs2ttI+JNm9EpMf81+JFxHEKRd289 uJUw3snPyxxTn0kYFgQPl1jIMqfT1TU8OvyVcEs3HlXVPiPQBWAGh8eIIDllRamIk7m5 nVSeJXfZ/zhr873/2GJ/U9NzvOHCEIIwxNrGp8B9k4RTffbQdCcl59FCcTFUNkc65y7S 1xSxoFIPt5gY9AW4D0oG76Ym5jvj1gxaMplNnW0fs1MDOsd6GqXtqsAa8hYSRpBIUWXE fiyA== X-Gm-Message-State: AOAM531GZeFfNeG7kOvp1BfuItEAGu5sVTR36axP0kowBVvMkDJGk7EX KvxLV7hreaBiZyU+5UNsGQ== X-Google-Smtp-Source: ABdhPJw4Wnkkr1ZWBQNe8mwdd924fhfJkTTmphYm16a4o7+93YyM7ubX4h1P3RCN0vdbqFgl/6IyTw== X-Received: by 2002:a9d:6f15:: with SMTP id n21mr12298359otq.154.1622656819618; Wed, 02 Jun 2021 11:00:19 -0700 (PDT) Received: from robh.at.kernel.org (24-155-109-49.dyn.grandenetworks.net. [24.155.109.49]) by smtp.gmail.com with ESMTPSA id q63sm128029oic.15.2021.06.02.11.00.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Jun 2021 11:00:18 -0700 (PDT) Received: (nullmailer pid 3674811 invoked by uid 1000); Wed, 02 Jun 2021 18:00:17 -0000 Date: Wed, 2 Jun 2021 13:00:17 -0500 From: Rob Herring To: Douglas Anderson Cc: Stanislav Lisovskiy , David Airlie , Thierry Reding , robdclark@chromium.org, Andrzej Hajda , Maarten Lankhorst , dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, Rob Herring , linux-kernel@vger.kernel.org, Laurent Pinchart , Steev Klimaszewski , Sam Ravnborg , linux-arm-msm@vger.kernel.org, Neil Armstrong , Bjorn Andersson , Daniel Vetter , Linus W , Jonas Karlman , Lyude Paul , Thierry Reding , Stephen Boyd Subject: Re: [PATCH v8 01/11] dt-bindings: display: simple: List hpd properties in panel-simple Message-ID: <20210602180017.GA3674744@robh.at.kernel.org> References: <20210525000159.3384921-1-dianders@chromium.org> <20210524165920.v8.1.Ieb731d23680db4700cc41fe51ccc73ba0b785fb7@changeid> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210524165920.v8.1.Ieb731d23680db4700cc41fe51ccc73ba0b785fb7@changeid> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Mon, 24 May 2021 17:01:49 -0700, Douglas Anderson wrote: > The HPD (Hot Plug Detect) signal is present in many (probably even > "most") eDP panels. For eDP, this signal isn't actually used for > detecting hot-plugs of the panel but is more akin to a "panel ready" > signal. After you provide power to the panel, panel timing diagrams > typically say that you should wait for HPD to be asserted (or wait a > fixed amount of time) before talking to the panel. > > The panel-simple bindings describes many eDP panels and many of these > panels provide the HPD signal. We should add the HPD-related > properties to the panel-simple bindings. The HPD properties are > actually defined in panel-common.yaml, so adding them here just > documents that they are OK for panels handled by the panel-simple > bindings. > > NOTE: whether or not we'd include HPD properties in the panel node is > more a property of the board design than the panel itself. For most > boards using these eDP panels everything "magically" works without > specifying any HPD properties and that's been why we haven't needed to > allow the HPD properties earlier. On these boards the HPD signal goes > directly to a dedicated "HPD" input to the eDP controller and this > connection doesn't need to be described in the device tree. The only > time the HPD properties are needed in the device tree are if HPD is > hooked up to a GPIO or if HPD is normally on the panel but isn't used > on a given board. That means that if we don't allow the HPD properties > in panel-simple then one could argue that we've got to boot all eDP > panels (or at least all those that someone could conceivably put on a > system where HPD goes to a GPIO or isn't hooked up) from panel-simple. > > Signed-off-by: Douglas Anderson > --- > > Changes in v8: > - Explain better why HPD needs to be in panel-simple in commit msg. > > Changes in v7: > - List hpd properties bindings patch new for v7. > > .../devicetree/bindings/display/panel/panel-simple.yaml | 2 ++ > 1 file changed, 2 insertions(+) > Reviewed-by: Rob Herring