Enable USB audio offloading which allows to play audio via a USB-C
headset with lower power consumption and enabling some other features.

This can be used like the following:

  $ amixer -c0 cset name='USB_RX Audio Mixer MultiMedia1' On
  $ aplay --device=plughw:0,0 test.wav

Compared to regular playback to the USB sound card no xhci-hcd
interrupts appear during playback, instead the ADSP will be handling the
USB transfers.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
---
 arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts b/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
index e115b6a52b299ef663ccfb614785f8f89091f39d..d30912f952db271aa4fbc2570ca04b771ffef3ca 100644
--- a/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
+++ b/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
@@ -1176,6 +1176,22 @@ platform {
 			sound-dai = <&q6routing>;
 		};
 	};
+
+	usb-dai-link {
+		link-name = "USB Playback";
+
+		codec {
+			sound-dai = <&q6usbdai USB_RX>;
+		};
+
+		cpu {
+			sound-dai = <&q6afedai USB_RX>;
+		};
+
+		platform {
+			sound-dai = <&q6routing>;
+		};
+	};
 };
 
 &spi13 {

-- 
2.50.1

On 8/1/25 3:51 PM, Luca Weiss wrote:
> Enable USB audio offloading which allows to play audio via a USB-C
> headset with lower power consumption and enabling some other features.
> 
> This can be used like the following:
> 
>   $ amixer -c0 cset name='USB_RX Audio Mixer MultiMedia1' On
>   $ aplay --device=plughw:0,0 test.wav
> 
> Compared to regular playback to the USB sound card no xhci-hcd
> interrupts appear during playback, instead the ADSP will be handling the
> USB transfers.
> 
> Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
> ---
>  arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts b/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
> index e115b6a52b299ef663ccfb614785f8f89091f39d..d30912f952db271aa4fbc2570ca04b771ffef3ca 100644
> --- a/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
> +++ b/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
> @@ -1176,6 +1176,22 @@ platform {
>  			sound-dai = <&q6routing>;
>  		};
>  	};
> +
> +	usb-dai-link {
> +		link-name = "USB Playback";
> +
> +		codec {
> +			sound-dai = <&q6usbdai USB_RX>;
> +		};
> +
> +		cpu {
> +			sound-dai = <&q6afedai USB_RX>;
> +		};
> +
> +		platform {
> +			sound-dai = <&q6routing>;
> +		};

Because this is SoC component <-> SoC component mapping, this could live
in the SoC dtsi.. but then 7280 is a glorious mess with the firmware
flavors, so I suppose it should stay here..

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Konrad

On Fri Aug 1, 2025 at 4:03 PM CEST, Konrad Dybcio wrote:
> On 8/1/25 3:51 PM, Luca Weiss wrote:
>> Enable USB audio offloading which allows to play audio via a USB-C
>> headset with lower power consumption and enabling some other features.
>> 
>> This can be used like the following:
>> 
>>   $ amixer -c0 cset name='USB_RX Audio Mixer MultiMedia1' On
>>   $ aplay --device=plughw:0,0 test.wav
>> 
>> Compared to regular playback to the USB sound card no xhci-hcd
>> interrupts appear during playback, instead the ADSP will be handling the
>> USB transfers.
>> 
>> Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
>> ---
>>  arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts | 16 ++++++++++++++++
>>  1 file changed, 16 insertions(+)
>> 
>> diff --git a/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts b/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
>> index e115b6a52b299ef663ccfb614785f8f89091f39d..d30912f952db271aa4fbc2570ca04b771ffef3ca 100644
>> --- a/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
>> +++ b/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
>> @@ -1176,6 +1176,22 @@ platform {
>>  			sound-dai = <&q6routing>;
>>  		};
>>  	};
>> +
>> +	usb-dai-link {
>> +		link-name = "USB Playback";
>> +
>> +		codec {
>> +			sound-dai = <&q6usbdai USB_RX>;
>> +		};
>> +
>> +		cpu {
>> +			sound-dai = <&q6afedai USB_RX>;
>> +		};
>> +
>> +		platform {
>> +			sound-dai = <&q6routing>;
>> +		};
>
> Because this is SoC component <-> SoC component mapping, this could live
> in the SoC dtsi.. but then 7280 is a glorious mess with the firmware
> flavors, so I suppose it should stay here..

q6afe definitely doesn't exist on the RB3Gen2 for example with
AudioReach, so yeah... I guess also the sound setup on other (simpler)
platforms can be simplified quite a bit, but it's (unfortunately) not
yet a major concern given the limited number of boards with good and
complete audio support.

>
> Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Thanks!

Regards
Luca

>
> Konrad