Re: [PATCH v3 3/3] arm64: dts: exynos7870-j6lte: add Sharp GP2AP070S proximity sensor

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The `i2c_proxm_bus` pinctrl node assigns a hardware alternate pin function (`EXYNOS_PIN_FUNC_3`) to pins that are driven by a software bit-banged `i2c-gpio` device.
--

--- Patch [3]: [PATCH v3 3/3] arm64: dts: exynos7870-j6lte: add Sharp GP2AP070S proximity sensor ---
commit 2279f9b3f632fe5641c2ffa9eb9b410688448a06
Author: Kaustabh Chakraborty <kauschluss@disroot.org>

arm64: dts: exynos7870-j6lte: add Sharp GP2AP070S proximity sensor

This commit adds the devicetree node for the Sharp GP2AP070S proximity sensor
which is connected to a GPIO-driven I2C line, alongside a new fixed regulator
for its VDD supply.

> diff --git a/arch/arm64/boot/dts/exynos/exynos7870-j6lte.dts b/arch/arm64/boot/dts/exynos/exynos7870-j6lte.dts
> index de30d0970336f..dd493138fed6e 100644
> --- a/arch/arm64/boot/dts/exynos/exynos7870-j6lte.dts
> +++ b/arch/arm64/boot/dts/exynos/exynos7870-j6lte.dts
> @@ -73,6 +73,35 @@ key-volup {
>  		};
>  	};
>  
> +	i2c-proximity {
> +		compatible = "i2c-gpio";
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +
> +		pinctrl-names = "default";
> +		pinctrl-0 = <&i2c_proxm_bus>;
> +
> +		sda-gpios = <&gpf4 3 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
> +		scl-gpios = <&gpf4 2 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;

[ ... ]

> @@ -579,6 +624,12 @@ bt_enable: bt-enable-pins {
>  		samsung,pin-pud = <EXYNOS_PIN_PULL_DOWN>;
>  	};
>  

[Severity: Medium]
Is it intentional to configure a hardware alternate function for a bus that
is driven by a software i2c-gpio device?

The i2c-proximity node uses the i2c-gpio driver for software bit-banging, but
the i2c_proxm_bus pinctrl configuration below assigns EXYNOS_PIN_FUNC_3 instead
of a standard GPIO function.

This configuration can cause the pinctrl framework to briefly connect the pins
to a hardware IP block before the GPIO framework requests them and forces them
back to software mode. If the underlying hardware IP is active during this
initialization window, it could drive the lines and lead to transient bus
contention or glitches on the sensor during system probe.

> +	i2c_proxm_bus: i2c-proxm-bus-pins {
> +		samsung,pins = "gpf4-3", "gpf4-2";
> +		samsung,pin-function = <EXYNOS_PIN_FUNC_3>;
> +		samsung,pin-pud = <EXYNOS_PIN_PULL_NONE>;
> +	};
> +

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260731-gp2ap070s-v3-0-d1f5cecf9fe7@disroot.org?part=3