Re: [PATCH v2 06/17] arm64: dts: imx93-14x14-evk: Add board muxes to select between FlexCAN1 and MQS1

[Chancel Liu <chancel.liu@oss.nxp.com>]

> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] The amplifier enable GPIO for MQS1 is incorrectly modeled as a multiplexer to hijack the pinctrl subsystem.
> --
> 
> --- Patch [6]: [PATCH v2 06/17] arm64: dts: imx93-14x14-evk: Add board muxes to select between FlexCAN1 and MQS1 ---
> commit cd0b6d22bf4426d5f5510c7f3a258a4b50405fb8
> Author: Chancel Liu <chancel.liu@nxp.com>
> 
> arm64: dts: imx93-14x14-evk: Add board muxes to select between FlexCAN1 and MQS1
> 
> FlexCAN1 has pin conflict with MQS1. Add GPIO-controlled board muxes to
> route shared signals between FlexCAN1 and MQS1.
> 
>> diff --git a/arch/arm64/boot/dts/freescale/imx93-14x14-evk.dts b/arch/arm64/boot/dts/freescale/imx93-14x14-evk.dts
>> index ec78c03f4788b..6dcfbca65cbd5 100644
>> --- a/arch/arm64/boot/dts/freescale/imx93-14x14-evk.dts
>> +++ b/arch/arm64/boot/dts/freescale/imx93-14x14-evk.dts
>> @@ -37,6 +37,36 @@ chosen {
>>  		stdout-path = &lpuart1;
>>  	};
>>  
> [ ... ]
>> +	mqs1_amp_en_mux: mux-controller-1 {
>> +		compatible = "gpio-mux";
>> +		#mux-control-cells = <0>;
>> +		#mux-state-cells = <1>;
>> +		mux-gpios = <&pcal6524_2 1 GPIO_ACTIVE_HIGH>;
>> +	};
> 
> [Severity: Medium]
> Is it appropriate to use the gpio-mux binding to control an amplifier enable
> pin?
> 
> Device Tree generally describes the hardware structure. A hardware multiplexer
> routes signals between inputs and outputs, whereas an amplifier enable pin is
> usually a binary control.
> 
> Would it be better to model this with an audio-amplifier or regulator-fixed
> node so that standard power management can dynamically toggle the amplifier
> during audio playback and suspend, rather than statically evaluating it as a
> mux state?
>

That's a good point. I will try to model it with an audio-amplifier device.

Regards,
Chancel Liu