Re: [PATCH v2 1/6] dt-bindings: drm/panel-simple: Introduce generic eDP panels

From: Rob Herring <robh@kernel.org>
To: Douglas Anderson <dianders@chromium.org>
Cc: Daniel Vetter <daniel@ffwll.ch>,
	Thierry Reding <thierry.reding@gmail.com>,
	devicetree@vger.kernel.org, Sam Ravnborg <sam@ravnborg.org>,
	David Airlie <airlied@linux.ie>,
	Linus W <linus.walleij@linaro.org>,
	linux-kernel@vger.kernel.org, Maxime Ripard <mripard@kernel.org>,
	Steev Klimaszewski <steev@kali.org>,
	dri-devel@lists.freedesktop.org,
	Thomas Zimmermann <tzimmermann@suse.de>,
	linux-arm-msm@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Bjorn Andersson <bjorn.andersson@linaro.org>
Subject: Re: [PATCH v2 1/6] dt-bindings: drm/panel-simple: Introduce generic eDP panels
Date: Mon, 02 Aug 2021 07:39:43 -0600	[thread overview]
Message-ID: <1627911583.050984.918758.nullmailer@robh.at.kernel.org> (raw)
In-Reply-To: <20210730142537.v2.1.I1116e79d34035338a45c1fc7cdd14a097909c8e0@changeid>

On Fri, 30 Jul 2021 14:26:20 -0700, Douglas Anderson wrote:
> eDP panels generally contain almost everything needed to control them
> in their EDID. This comes from their DP heritage were a computer needs
> to be able to properly control pretty much any DP display that's
> plugged into it.
> 
> The one big issue with eDP panels and the reason that we need a panel
> driver for them is that the power sequencing can be different per
> panel.
> 
> While it is true that eDP panel sequencing can be arbitrarily complex,
> in practice it turns out that many eDP panels are compatible with just
> some slightly different delays. See the contents of the bindings file
> introduced in this patch for some details.
> 
> The fact that eDP panels are 99% probable and that the power
> sequencing (especially power up) can be compatible between many panels
> means that there's a constant desire to plug multiple different panels
> into the same board. This could be for second sourcing purposes or to
> support multiple SKUs (maybe a 11" and a 13", for instance).
> 
> As discussed [1], it should be OK to support this by adding two
> properties to the device tree to specify the delays needed for
> powering up the panel the first time. We'll create a new "edp-panel"
> bindings file and define the two delays that might need to be
> specified. NOTE: in the vast majority of the cases (HPD is hooked up
> and isn't glitchy or is debounced) even these delays aren't needed.
> 
> [1] https://lore.kernel.org/r/CAD=FV=VZYOMPwQZzWdhJGh5cjJWw_EcM-wQVEivZ-bdGXjPrEQ@mail.gmail.com
> 
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---
> 
> Changes in v2:
> - No longer allow fallback to panel-simple.
> - Add "-ms" suffix to delays.
> 
>  .../bindings/display/panel/panel-edp.yaml     | 188 ++++++++++++++++++
>  1 file changed, 188 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/panel/panel-edp.yaml
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/display/panel/panel-edp.example.dt.yaml: bridge@2d: 'aux-bus' does not match any of the regexes: 'pinctrl-[0-9]+'
	From schema: /builds/robherring/linux-dt-review/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.yaml
\ndoc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/patch/1511822

This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit.