Re: [PATCH v2 05/15] arm64: dts: freescale: imx8mn-var-som: Add support for WM8904 audio codec

[Frank Li <Frank.li@oss.nxp.com>]

On Mon, Jul 06, 2026 at 10:09:47AM +0000, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] The `simple-audio-card,routing` property maps `Microphone Jack` to `IN1L` and `IN1R` but omits the connection to the `MICBIAS` supply, which will leave standard electret microphones unpowered.
> --
>
> commit 78e4da0f71f2e53ae4312cbe5ceecb0f6f2345db
> Author: Stefano Radaelli <stefano.r@variscite.com>
>
> arm64: dts: freescale: imx8mn-var-som: Add support for WM8904 audio codec
>
> This commit adds support for the WM8904 audio codec on the VAR-SOM-MX8MN board.
> It configures the device on the I2C bus, enables the SAI peripheral, and adds a
> simple-audio-card sound node to expose the sound card to the system.
>
> > diff --git a/arch/arm64/boot/dts/freescale/imx8mn-var-som.dtsi b/arch/arm64/boot/dts/freescale/imx8mn-var-som.dtsi
> > index 09146ab763858..e2e04ad2fbb65 100644
> > --- a/arch/arm64/boot/dts/freescale/imx8mn-var-som.dtsi
> > +++ b/arch/arm64/boot/dts/freescale/imx8mn-var-som.dtsi
>
> [ ... ]
>
> > @@ -42,6 +50,34 @@ reg_phy_vddio: regulator-phy-vddio {
> >  		regulator-min-microvolt = <1800000>;
> >  		regulator-max-microvolt = <1800000>;
> >  	};
> > +
> > +	sound {
> > +		compatible = "simple-audio-card";
> > +		simple-audio-card,bitclock-master = <&codec_dai>;
> > +		simple-audio-card,format = "i2s";
> > +		simple-audio-card,frame-master = <&codec_dai>;
> > +		simple-audio-card,mclk-fs = <256>;
> > +		simple-audio-card,name = "wm8904-audio";
> > +		simple-audio-card,routing =
> > +			"Headphone Jack", "HPOUTL",
> > +			"Headphone Jack", "HPOUTR",
> > +			"IN2L", "Line In Jack",
> > +			"IN2R", "Line In Jack",
> > +			"IN1L", "Microphone Jack",
> > +			"IN1R", "Microphone Jack";
> [Severity: Medium]
> Will standard electret microphones remain unpowered with this routing?
>
> The routing maps "Microphone Jack" to "IN1L" and "IN1R", but omits a link to
> the "MICBIAS" supply (e.g., "Microphone Jack", "MICBIAS"). Because "MICBIAS"
> is defined as a DAPM supply widget in the codec driver, DAPM will not enable
> it unless it has an explicit routing link connecting it to the active audio
> path. This could leave the microphone without its required bias voltage when
> recording.

Is this true?

Frank

>
> > +		simple-audio-card,widgets =
> > +			"Microphone", "Microphone Jack",
> > +			"Headphone", "Headphone Jack",
> > +			"Line", "Line In Jack";
> > +
> > +		codec_dai: simple-audio-card,codec {
> > +			sound-dai = <&wm8904>;
> > +		};
>
> --
> Sashiko AI review · https://sashiko.dev/#/patchset/cover.1783330236.git.stefano.r@variscite.com?part=5