Re: [PATCH v33 30/31] ALSA: usb-audio: qcom: Add USB offload route kcontrol

[Wesley Cheng <quic_wcheng@xxxxxxxxxxx>]

Hi Randy,

On 1/16/2025 4:08 PM, Randy Dunlap wrote:
>
> On 1/16/25 3:28 PM, Wesley Cheng wrote:
>> In order to allow userspace/applications know about USB offloading status,
>> expose a sound kcontrol that fetches information about which sound card
>> and PCM index the USB device is mapped to for supporting offloading.  In
>> the USB audio offloading framework, the ASoC BE DAI link is the entity
>> responsible for registering to the SOC USB layer.
>>
>> It is expected for the USB SND offloading driver to add the kcontrol to the
>> sound card associated with the USB audio device.  An example output would
>> look like:
>>
>> tinymix -D 1 get 'USB Offload Playback Route PCM#0'
>> -1, -1 (range -1->255)
>>
>> This example signifies that there is no mapped ASoC path available for the
>> USB SND device.
>>
>> tinymix -D 1 get 'USB Offload Playback Route PCM#0'
>> 0, 0 (range -1->255)
>>
>> This example signifies that the offload path is available over ASoC sound
>> card index#0 and PCM device#0.
>>
>> The USB offload kcontrol will be added in addition to the existing
>> kcontrols identified by the USB SND mixer.  The kcontrols used to modify
>> the USB audio device specific parameters are still valid and expected to be
>> used.  These parameters are not mirrored to the ASoC subsystem.
>>
>> Signed-off-by: Wesley Cheng <quic_wcheng@xxxxxxxxxxx>
>> ---
>>  sound/usb/Kconfig                  |  10 ++
>>  sound/usb/qcom/Makefile            |   4 +
>>  sound/usb/qcom/mixer_usb_offload.c | 158 +++++++++++++++++++++++++++++
>>  sound/usb/qcom/mixer_usb_offload.h |  17 ++++
>>  sound/usb/qcom/qc_audio_offload.c  |   2 +
>>  5 files changed, 191 insertions(+)
>>  create mode 100644 sound/usb/qcom/mixer_usb_offload.c
>>  create mode 100644 sound/usb/qcom/mixer_usb_offload.h
>>
>> diff --git a/sound/usb/qcom/mixer_usb_offload.c b/sound/usb/qcom/mixer_usb_offload.c
>> new file mode 100644
>> index 000000000000..2696eb145ef5
>> --- /dev/null
>> +++ b/sound/usb/qcom/mixer_usb_offload.c
>> @@ -0,0 +1,158 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (c) 2022-2025 Qualcomm Innovation Center, Inc. All rights reserved.
>> + */
>> +
>> +#include <linux/usb.h>
>> +
> [snip]
>
>> +
>> +/**
>> + * snd_usb_offload_create_ctl() - Add USB offload bounded mixer
>> + * @chip - USB SND chip device
> Use ':' instead of '-'.


So to clarify, the ':' separator should be used for both structs and function descriptions?  Just want to clarify, so I can fix them in all the spots.


Thanks

Wesley Cheng