Re: [PATCH 1/3] arm64: dts: qcom: lemans-evk: Add LVDS display overlay

[Dmitry Baryshkov]

On Sun, Jul 19, 2026 at 11:35:06PM +0530, Vishnu Saini wrote:
> The Lemans EVK IFP mezzanine supports LVDS display output using the
> Lontium LT9211C DSI-to-LVDS bridge. The bridge is connected to the
> DSI0 output and drives a dual-channel 1920x1080 LVDS panel in
> VESA-24 mapping.
> 
> Add a DTBO overlay, lemans-evk-lvds-boe,dv215fhm-r01.dtso, that wires
> up the LT9211C bridge on I2C1 (address 0x2d) with reset on GPIO37,
> a panel-lvds node describing the 476x268mm 1080p panel timing, and
> an LCD display bias regulator supplied through the GPIO expander.
> DSI power is provided by vreg_s4a.
> 
> The overlay is built as a composite DTB combining the base
> lemans-evk.dtb, the IFP mezzanine overlay, and this LVDS overlay.
> 
> Signed-off-by: Vishnu Saini <vishnu.saini@xxxxxxxxxxxxxxxx>
> ---
>  arch/arm64/boot/dts/qcom/Makefile                  |   4 +
>  .../dts/qcom/lemans-evk-lvds-boe,dv215fhm-r01.dtso | 127 +++++++++++++++++++++
>  2 files changed, 131 insertions(+)
> 
> +	model = "Qualcomm Technologies, Inc. Lemans-evk Mezzanine Lvds";

EVK, LVDS.

> +
> +	panel_lvds: panel-lvds {
> +		compatible = "boe,dv215fhm-r01", "panel-lvds";

Thinking about it, does your panel have EDID? Is it readable from the
device via the I2C bus?

My major concern is that if the user changes the LVDS panel, they'd need
a new DTBO.

Would it make sense to implement EDID-based handling (like it's done in
panel-edp)?

> +		data-mapping = "vesa-24";
> +		width-mm = <476>;
> +		height-mm = <268>;
> +		power-supply = <&lcd_disp_bias>;
> +		status = "okay";
> +
> +		panel-timing {
> +			clock-frequency = <148500000>;
> +			hactive = <1920>;
> +			vactive = <1080>;
> +			hfront-porch = <88>;
> +			hback-porch = <148>;
> +			hsync-len = <44>;
> +			vfront-porch = <4>;
> +			vback-porch = <36>;
> +			vsync-len = <5>;
> +			de-active = <1>;
> +		};

[..]

> +
> +&i2c1 {
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +	pinctrl-names = "default";
> +	pinctrl-0 = <&qup_i2c1_default>;
> +	status = "okay";

Empty lines before the status property (here and later).

> +

-- 
With best wishes
Dmitry