Re: [PATCH v5 4/4] arm64: dts: realtek: Add GPIO support for RTD1625

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Device Tree mapping conflict where two distinct GPIO controllers claim the exact same pins from the `isom_pinctrl` controller.
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commit ca40dcb33ea07a0408e101ec08ff651fed48479b
Author: Yu-Chun Lin <eleanor.lin@realtek.com>

arm64: dts: realtek: Add GPIO support for RTD1625

This commit adds the GPIO nodes for the Realtek RTD1625 SoC.
It configures multiple GPIO controllers and establishes their 
pin controller mapping ranges.

> diff --git a/arch/arm64/boot/dts/realtek/kent.dtsi b/arch/arm64/boot/dts/realtek/kent.dtsi
> index 8d4293cd4c036..228b82dfdb7ac 100644
> --- a/arch/arm64/boot/dts/realtek/kent.dtsi
> +++ b/arch/arm64/boot/dts/realtek/kent.dtsi
> @@ -151,6 +151,37 @@ uart0: serial@7800 {
>  				status = "disabled";
>  			};
>  
> +			gpio: gpio@31000 {
> +				compatible = "realtek,rtd1625-iso-gpio";
> +				reg = <0x31000 0x398>;
> +				gpio-controller;
> +				gpio-ranges = <&isom_pinctrl 0 0 2>,
> +					      <&ve4_pinctrl 2 0 6>,
> +					      <&iso_pinctrl 8 0 4>,
[ ... ]
> +					      <&iso_pinctrl 26 4 2>,
> +					      <&isom_pinctrl 28 2 2>,
[ ... ]
> +			iso_m_gpio: gpio@89100 {
> +				compatible = "realtek,rtd1625-isom-gpio";
> +				reg = <0x89100 0x30>;
> +				gpio-controller;
> +				gpio-ranges = <&isom_pinctrl 0 0 4>;

[Severity: Medium]
Is it intended for both the gpio@31000 and iso_m_gpio controllers to claim
the exact same pins from the isom_pinctrl controller?

Looking at gpio@31000, it maps pins 0-1 and 2-3 from isom_pinctrl. Down here
in iso_m_gpio, the gpio-ranges property identically maps isom_pinctrl pins 0,
1, 2, and 3.

Could this cause unexpected behavior in the pinctrl subsystem? Functions like
pinctrl_find_gpio_range_from_pin() strictly return the first matched range,
which might silently shadow the other controller's reverse lookups. Also, if
both controllers attempt to request the same pin via pinctrl_gpio_request(),
would the second request fail because the pin will be marked as already in-use?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260702090115.2564318-1-eleanor.lin@realtek.com?part=4