diff --git a/arch/arm/boot/dts/overlays/README b/arch/arm/boot/dts/overlays/README index a0488adbf700c1..78b2616399987d 100644 --- a/arch/arm/boot/dts/overlays/README +++ b/arch/arm/boot/dts/overlays/README @@ -490,8 +490,21 @@ Params: Name: iqaudio-dac Info: Configures the IQaudio DAC audio card -Load: dtoverlay=iqaudio-dac -Params: +Load: dtoverlay=iqaudio-dac, +Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec + Digital volume control. Enable with + "dtoverlay=iqaudio-dac,24db_digital_gain" + (The default behaviour is that the Digital + volume control is limited to a maximum of + 0dB. ie. it can attenuate but not provide + gain. For most users, this will be desired + as it will prevent clipping. By appending + the 24db_digital_gain parameter, the Digital + volume control will allow up to 24dB of + gain. If this parameter is enabled, it is the + responsibility of the user to ensure that + the Digital volume control is set to a value + that does not result in clipping/distortion!) Name: iqaudio-dacplus diff --git a/arch/arm/boot/dts/overlays/iqaudio-dac-overlay.dts b/arch/arm/boot/dts/overlays/iqaudio-dac-overlay.dts index 8e8ee0685da38c..0d35c85382bb57 100644 --- a/arch/arm/boot/dts/overlays/iqaudio-dac-overlay.dts +++ b/arch/arm/boot/dts/overlays/iqaudio-dac-overlay.dts @@ -30,10 +30,14 @@ fragment@2 { target = <&sound>; - __overlay__ { + frag2: __overlay__ { compatible = "iqaudio,iqaudio-dac"; i2s-controller = <&i2s>; status = "okay"; }; }; + + __overrides__ { + 24db_digital_gain = <&frag2>,"iqaudio,24db_digital_gain?"; + }; };