Re: [PATCH v1 07/15] arm64: dts: freescale: imx8mn-var-som: Rework WiFi/BT and add legacy dts

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:
- [High] The removal of the Broadcom WiFi node from `imx8mn-var-som.dtsi` silently breaks WiFi support on the downstream imx8mn-rve-gateway board.
- [Medium] Incomplete reversion of IW61x pinmux changes in the legacy device tree.
- [Low] Unnecessary `#address-cells` and `#size-cells` properties are left in `usdhc1`, which will trigger dtc warnings for boards without a WiFi child node.
--

commit 5a726be8cbb43e633eba48d88581647aae4f82ba
Author: Stefano Radaelli <stefano.r@variscite.com>

arm64: dts: freescale: imx8mn-var-som: Rework WiFi/BT and add legacy dts

The VAR-SOM-MX8MN currently integrates the NXP IW61x wireless module,
providing WiFi over SDIO and Bluetooth over UART.

Move the wireless module configuration out of the base
imx8mn-var-som.dtsi and provide dedicated variant includes.

> diff --git a/arch/arm64/boot/dts/freescale/imx8mn-var-som-symphony-legacy.dts b/arch/arm64/boot/dts/freescale/imx8mn-var-som-symphony-legacy.dts
> new file mode 100644
> index 0000000000000..5998ebcef4740
> --- /dev/null
> +++ b/arch/arm64/boot/dts/freescale/imx8mn-var-som-symphony-legacy.dts
> @@ -0,0 +1,19 @@
[ ... ]
> +&bluetooth_iw61x {
> +	status = "disabled";
> +};
> +
> +&iw61x_pwrseq {
> +	status = "disabled";
> +};
> +
> +&usdhc1 {
> +	/delete-property/ mmc-pwrseq;
> +};

[Severity: Medium]
Does this leave unintended pin configurations active for the legacy board?

Since this file includes imx8mn-var-som-symphony.dts, it inherits the
pinctrl properties from imx8mn-var-som-wifi-bt-iw61x.dtsi:

&usdhc1 {
	pinctrl-0 = <&pinctrl_usdhc1>, <&pinctrl_wifi>;
	pinctrl-1 = <&pinctrl_usdhc1_100mhz>, <&pinctrl_wifi>;
	pinctrl-2 = <&pinctrl_usdhc1_200mhz>, <&pinctrl_wifi>;
};

Should this legacy file also override the pinctrl properties to remove
<&pinctrl_wifi> and <&pinctrl_bt> from usdhc1 and uart2 to prevent
hardware conflicts on GPIO2_IO6, GPIO2_IO10, and GPIO2_IO20?

> diff --git a/arch/arm64/boot/dts/freescale/imx8mn-var-som.dtsi b/arch/arm64/boot/dts/freescale/imx8mn-var-som.dtsi
> index ac22dd3e65421..ff5f658b33ded 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mn-var-som.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8mn-var-som.dtsi
> @@ -371,7 +371,6 @@ &usbotg1 {
>  	status = "okay";
>  };
>  
> -/* WIFI */
>  &usdhc1 {
>  	#address-cells = <1>;
>  	#size-cells = <0>;

[Severity: Low]
Will leaving these properties here trigger avoid_unnecessary_addr_size dtc
warnings for boards without a WiFi child node?

Since the wifi@1 child node is removed below, usdhc1 no longer has any child
nodes for boards using the new IW61x module.

> @@ -383,11 +382,6 @@ &usdhc1 {
>  	non-removable;
>  	keep-power-in-suspend;
>  	status = "okay";
> -
> -	brcmf: wifi@1 {
> -		reg = <1>;
> -		compatible = "brcm,bcm4329-fmac";
> -	};
>  };

[Severity: High]
Does removing the Broadcom WiFi node from the shared SOM dtsi silently break
WiFi support on downstream carrier boards?

Looking at arch/arm64/boot/dts/freescale/imx8mn-rve-gateway.dts, it includes
imx8mn-var-som.dtsi but was not updated to include a Wi-Fi variant include. 
Will the brcmfmac driver fail to bind to the device tree node for the gateway
board, breaking DT-dependent configurations?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/cover.1783067947.git.stefano.r@variscite.com?part=7