Re: [PATCH v2 3/3] arm64: dts: qcom: qcs6490-rb3gen2: Add LVDS display overlay

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:
- [Medium] The introduced 'lontium,lt9211c' compatible string is unsupported by the driver and dt-bindings, and lacks a fallback.
- [Medium] The introduced 'boe,dv215fhm-r01' compatible string is unsupported and lacks a fallback.
- [Medium] The reset GPIO for the LT9211C bridge lacks a pinctrl configuration.
--

--- Patch [3]: [PATCH v2 3/3] arm64: dts: qcom: qcs6490-rb3gen2: Add LVDS display overlay ---
commit f8ec082b3378414f04ce77574b9aa99cf0a7904b
Author: Vishnu Saini <vishnu.saini@oss.qualcomm.com>

arm64: dts: qcom: qcs6490-rb3gen2: Add LVDS display overlay

The QCS6490 RB3 Gen2 industrial mezzanine supports LVDS display output
using the Lontium LT9211C DSI-to-LVDS bridge as an alternative to the
default HDMI output via the LT9611UXC bridge.

> diff --git a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2-industrial-mezzanine-lvds-boe,dv215fhm-r01.dtso b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2-industrial-mezzanine-lvds-boe,dv215fhm-r01.dtso
> new file mode 100644
> index 0000000000000..8e60b8631169a
> --- /dev/null
> +++ b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2-industrial-mezzanine-lvds-boe,dv215fhm-r01.dtso
> @@ -0,0 +1,105 @@
[ ... ]
> +&{/} {
> +	model = "Qualcomm Technologies, Inc. Industrial RB3gen2 LVDS";
> +
> +	hdmi-connector {
> +		status = "disabled";
> +	};
> +
> +	panel_lvds: panel-lvds {
> +		compatible = "boe,dv215fhm-r01";

[Severity: Medium]
Is this compatible string supported by the panel-simple driver?

Without a generic fallback or an explicit panel-timing node in the DT, will
the DRM panel driver fail to attach and leave the display non-functional?

> +		power-supply = <&lcd_disp_bias>;
> +
> +		status = "okay";
[ ... ]
> +&i2c1 {
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +
> +	status = "okay";
> +
> +	lvds_bridge: lvds-bridge@29 {
> +		compatible = "lontium,lt9211c";

[Severity: Medium]
Does the upstream lontium-lt9211 driver support the "c" suffix in this
compatible string?

If not, would it be better to provide a fallback like "lontium,lt9211" so
device matching does not fail and the display pipeline can initialize?

> +		reg = <0x29>;
> +		reset-gpios = <&tlmm 117 GPIO_ACTIVE_HIGH>;

[Severity: Medium]
Does this reset GPIO need a corresponding pinctrl configuration (pinctrl-names,
pinctrl-0)?

On Qualcomm platforms, if the bootloader leaves the pin in an alternate
function, asserting the reset GPIO might not propagate to the physical pad,
causing the bridge to silently fail to come out of reset.

> +		vccio-supply = <&vreg_l18b_1p8>;
> +
> +		status = "okay";
[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260813-lvds-support-v2-0-6b11035e8ab0@oss.qualcomm.com?part=3