linux-kernel - Re: [PATCH v6 1/2] arm64: dts: qcom: x1e78100-t14s: add hpd gpio to dp controller

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Message-ID: <aJCyBbwNjZvTHnjT@hovoldconsulting.com>
Date: Mon, 4 Aug 2025 15:13:41 +0200
From: Johan Hovold <johan@...nel.org>
To: Christopher Obbard <christopher.obbard@...aro.org>
Cc: Douglas Anderson <dianders@...omium.org>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Jessica Zhang <quic_jesszhan@...cinc.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konradybcio@...nel.org>,
	Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
	linux-arm-msm@...r.kernel.org,
	Rui Miguel Silva <rui.silva@...aro.org>,
	Abel Vesa <abel.vesa@...aro.org>, devicetree@...r.kernel.org
Subject: Re: [PATCH v6 1/2] arm64: dts: qcom: x1e78100-t14s: add hpd gpio to
 dp controller

On Thu, Jul 31, 2025 at 09:51:26PM +0100, Christopher Obbard wrote:
> The eDP controller has an HPD GPIO. Describe it in the device tree
> for the generic T14s model, as the HPD GPIO is used in both the
> OLED and LCD models which inherit this device tree.

> @@ -5779,6 +5779,11 @@ tlmm: pinctrl@...0000 {
>  			gpio-ranges = <&tlmm 0 0 239>;
>  			wakeup-parent = <&pdc>;
>  
> +			edp_hpd_active: edp-hpd-active-state {

The node name and label needs an index as this SoC has two edp hpd pins
as I already pointed out.

> +				pins = "gpio119";
> +				function = "edp0_hot";

And you also need to configure the bias somewhere as you should not rely
on the firmware having configured things for you (as I also pointed out
before).

On my T14s the internal pull-up has been disabled.

> +			};

Johan