Re: [PATCH v5 5/6] arm64: dts: imx8mm: imx8mp: Add FIO1 DTOs for Data Modul i.MX8M Mini and Plus eDM SBC

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Device Tree node collision and potential I2C address conflict on `io-expander@20`.
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--- Patch [5]: [PATCH v5 5/6] arm64: dts: imx8mm: imx8mp: Add FIO1 DTOs for Data Modul i.MX8M Mini and Plus eDM SBC ---
commit b8816aeaca7378ddfdc8544c5eb07a316a35281c
Author: Marek Vasut <marex@nabladev.com>
Subject: arm64: dts: imx8mm: imx8mp: Add FIO1 DTOs for Data Modul i.MX8M Mini and Plus eDM SBC

This patch adds a Device Tree overlay for the eDM-MOD-iMX8Mm-FIO1 feature 
connector expansion module. It provides additional UARTs, CAN, PWM Beeper, 
I2C, SPI, and GPIO breakout for the Data Modul i.MX8M Mini and Plus eDM SBC.

> diff --git a/arch/arm64/boot/dts/freescale/imx8mm-data-modul-edm-sbc-overlay-edm-mod-imx8mm-fio1.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-data-modul-edm-sbc-overlay-edm-mod-imx8mm-fio1.dtsi
> new file mode 100644
> index 0000000000000..7851ca73ccd8e
> --- /dev/null
> +++ b/arch/arm64/boot/dts/freescale/imx8mm-data-modul-edm-sbc-overlay-edm-mod-imx8mm-fio1.dtsi

[ ... ]

> +&i2c_feature {	/* Feature connector I2C */
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +
> +	gpio_feature: io-expander@20 {
> +		compatible = "nxp,pca9554";
> +		pinctrl-names = "default";
> +		pinctrl-0 = <&pinctrl_gpio_expander>;
> +		reg = <0x20>;

[Severity: High]
Will this overlay conflict with the baseboard when applied to the i.MX8MP?

The i.MX8MP baseboard (arch/arm64/boot/dts/freescale/imx8mp-data-modul-edm-sbc.dts)
unconditionally defines an LVDS IO expander on the same I2C bus:

	gpiolvds: io-expander@20 {
		compatible = "nxp,pca9554";
		reg = <0x20>;
		...
	};

When this overlay is applied, won't gpio_feature: io-expander@20 merge into
gpiolvds: io-expander@20 and silently overwrite properties like gpio-line-names
and interrupt assignments, breaking both configurations?

Additionally, if both the baseboard LVDS PCA9554 and the FIO1 expansion
module PCA9554 are physically present, will they cause a hardware collision 
on the I2C bus at address 0x20 and fail to probe?

> +		#gpio-cells = <2>;
> +		gpio-controller;
> +		#interrupt-cells = <2>;
> +		interrupt-controller;
> +		interrupt-parent = <&gpio4>;
> +		interrupts = <27 IRQ_TYPE_LEVEL_LOW>;

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260716055751.279033-1-marex@nabladev.com?part=5