Re: [PATCH v3 3/4] arm64: dts: qcom: sc8280xp: add Radxa Dragon Q8B

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] arm64: dts: qcom: missing pinctrl properties on uart2 in dragon-q8b
--

commit 806aef47629e5a5fdf23480747e829d1b21764d6
Author: Xilin Wu <sophon@radxa.com>

arm64: dts: qcom: sc8280xp: add Radxa Dragon Q8B

This commit adds initial device tree support for the Radxa Dragon Q8B
single-board computer based on the Qualcomm Snapdragon 8cx Gen 3 SC8280XP
platform.

> diff --git a/arch/arm64/boot/dts/qcom/sc8280xp-radxa-dragon-q8b.dts b/arch/arm64/boot/dts/qcom/sc8280xp-radxa-dragon-q8b.dts
> new file mode 100644
> index 0000000000000..fd1e29ce83b27
> --- /dev/null
> +++ b/arch/arm64/boot/dts/qcom/sc8280xp-radxa-dragon-q8b.dts
> @@ -0,0 +1,2049 @@

[ ... ]

> +/* E-key Bluetooth */
> +&uart2 {
> +	uart-has-rtscts;
> +	status = "okay";
> +
> +	port {
> +		uart2_ep: endpoint {
> +			remote-endpoint = <&wlan_uart_ep>;
> +		};
> +	};
> +};

[Severity: Medium]
Should the &uart2 node in arch/arm64/boot/dts/qcom/sc8280xp-radxa-dragon-q8b.dts
include pinctrl-0 and pinctrl-names properties?

In arch/arm64/boot/dts/qcom/sc8280xp.dtsi, the base uart2: serial@988000 node
does not define default pinctrl properties:

    uart2: serial@988000 {
        compatible = "qcom,geni-uart";
        reg = <0 0x00988000 0 0x4000>;
        ...
        status = "disabled";
    };

Instead, the pin configuration state qup_uart2_default (for gpio121 CTS,
gpio122 RTS, gpio123 TX, and gpio124 RX) is defined separately under &tlmm in
sc8280xp.dtsi for board device trees to reference.

When qcom_geni_serial probes uart2 for the M.2 E-key Bluetooth interface and
activates resources via pinctrl_bind_pins() and geni_se_resources_on() ->
pinctrl_pm_select_default_state(), the TLMM pins for UART2 will not be muxed
to the qup2 function or configured by Linux without:

    pinctrl-0 = <&qup_uart2_default>;
    pinctrl-names = "default";

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261029-q8b-dts-v3-0-655696dfec45@radxa.com?part=3