Re: [PATCH v30 14/30] ASoC: usb: Create SOC USB SND jack kcontrol

[Cezary Rojewski <cezary.rojewski@xxxxxxxxx>]

On 2024-11-06 8:33 PM, Wesley Cheng wrote:
> Expose API for creation of a jack control for notifying of available
> devices that are plugged in/discovered, and that support offloading.  This
> allows for control names to be standardized across implementations of USB
> audio offloading.

...

> +/* SOC USB sound kcontrols */

I'd suggest to use 'SoC' over 'SOC'. The former is predominant in the 
ASoC code.

> +/**
> + * snd_soc_usb_setup_offload_jack() - Create USB offloading jack
> + * @component: USB DPCM backend DAI component
> + * @jack: jack structure to create
> + *
> + * Creates a jack device for notifying userspace of the availability
> + * of an offload capable device.
> + *
> + * Returns 0 on success, negative on error.
> + *
> + */
> +int snd_soc_usb_setup_offload_jack(struct snd_soc_component *component,
> +				   struct snd_soc_jack *jack)
> +{
> +	int ret;
> +
> +	ret = snd_soc_card_jack_new(component->card, "USB Offload Jack",
> +				    SND_JACK_USB, jack);
> +	if (ret < 0) {
> +		dev_err(component->card->dev, "Unable to add USB offload jack: %d\n",
> +			ret);
> +		return ret;
> +	}
> +
> +	ret = snd_soc_component_set_jack(component, jack, NULL);
> +	if (ret) {
> +		dev_err(component->card->dev, "Failed to set jack: %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(snd_soc_usb_setup_offload_jack);

Do we really need this one? Error reporting/handling for both 
invocations above is redundant, the log message should be provided by 
lower-level API. No need to pollute each caller with them. And with that 
part removed, we end up with basic ASoC calls, hardly a new-API candidate.

> +/**
> + * snd_soc_usb_disable_offload_jack() - Disables USB offloading jack
> + * @component: USB DPCM backend DAI component
> + *
> + * Disables the offload jack device, so that further connection events
> + * won't be notified.
> + *
> + * Returns 0 on success, negative on error.
> + *
> + */
> +int snd_soc_usb_disable_offload_jack(struct snd_soc_component *component)
> +{
> +	int ret;
> +
> +	ret = snd_soc_component_set_jack(component, NULL, NULL);
> +	if (ret) {
> +		dev_err(component->card->dev, "Failed to disable jack: %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(snd_soc_usb_disable_offload_jack);

Code duplication. ASoC already provides the API and the logging is 
redundant here.

> +/**
> + * snd_soc_usb_enable_offload_jack() - Enables USB offloading jack
> + * @component: USB DPCM backend DAI component
> + * @jack: offload jack to enable
> + *
> + * Enables the offload jack device, so that further connection events
> + * will be notified.  This is the complement to
> + * snd_soc_usb_disable_offload_jack().
> + *
> + * Returns 0 on success, negative on error.
> + *
> + */
> +int snd_soc_usb_enable_offload_jack(struct snd_soc_component *component,
> +				    struct snd_soc_jack *jack)
> +{
> +	int ret;
> +
> +	ret = snd_soc_component_set_jack(component, jack, NULL);
> +	if (ret) {
> +		dev_err(component->card->dev, "Failed to enable jack: %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(snd_soc_usb_enable_offload_jack);

Ditto.

>   /**
>    * snd_soc_usb_find_priv_data() - Retrieve private data stored
>    * @usbdev: device reference