Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Thu, 25 Mar 2021 18:09:07 -0600
From:   Rob Herring <robh@kernel.org>
To:     Douglas Anderson <dianders@chromium.org>
Cc:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        Sam Ravnborg <sam@ravnborg.org>, robdclark@chromium.org,
        Daniel Vetter <daniel@ffwll.ch>,
        dri-devel@lists.freedesktop.org, David Airlie <airlied@linux.ie>,
        devicetree@vger.kernel.org, swboyd@chromium.org,
        linux-arm-msm@vger.kernel.org, Steev Klimaszewski <steev@kali.org>,
        eballetbo@gmail.com, Andy Gross <agross@kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        drinkcat@chromium.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 1/3] dt-bindings: display: simple: Add the panel on
 sc7180-trogdor-pompom
Message-ID: <20210326000907.GA1965415@robh.at.kernel.org>
References: <20210316140707.RFC.1.I3a21995726282f1e9fcb70da5eb96f19ed96634f@changeid>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20210316140707.RFC.1.I3a21995726282f1e9fcb70da5eb96f19ed96634f@changeid>
Precedence: bulk

On Tue, Mar 16, 2021 at 02:08:19PM -0700, Douglas Anderson wrote:
> The sc7180-trogdor-pompom board might be attached to any number of a
> pile of eDP panels. At the moment I'm told that the list might include:
> - KD KD116N21-30NV-A010
> - KD KD116N09-30NH-A016
> - Starry 2081116HHD028001-51D
> - Sharp LQ116M1JW10
> 
> It should be noted that while the EDID programmed in the first 3
> panels indicates that they should run with exactly the same timing (to
> keep things simple), the 4th panel not only needs different timing but
> has a different resolution.
> 
> As is true in general with eDP panels, we can figure out which panel
> we have and all the info needed to drive its pixel clock by reading
> the EDID. However, we can do this only after we've powered the panel
> on. Powering on the panels requires following the timing diagram in
> each panel's datasheet which specifies delays between certain
> actions. This means that, while we can be quite dynamic about handling
> things we can't just totally skip out on describing the panel like we
> could do if it was connected to an external-facing DP port.

Is this a 'standard' eDP connector? AFAICT, there does seem to be 
such a thing. I've said in the past I'd be okay with a edp-connector 
node. If that needs just the "HPD absent delay" property, I think that 
would be okay. It's just a never ending stream of new properties with 
each new panel that I don't want to see.

Rob