Re: [PATCH v2 05/11] ASoC: SDCA: add populate_function hw_op for DT function data

[Charles Keepax <ckeepax@opensource.cirrus.com>]

On Mon, Sep 07, 2026 at 09:37:19AM +0100, Srinivas Kandagatla wrote:
> sdca_parse_function() walks a firmware node, but on DT there is no
> DisCo node -- sdca_lookup_functions() is a no-op and the SDCA
> function descriptors come with a NULL fwnode.
> 
> Add a populate_function hw_op that the class function driver falls
> back to when @function->desc->node is NULL: it fills the caller-owned
> sdca_function_data (entities, clusters, init_table, delays) from the
> codec's static tables, matching by function type.  Leave
> @function->desc alone -- the framework owns the per-instance
> descriptor, so devices with more than one function of the same type
> keep their per-instance SoundWire address.
> 
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@oss.qualcomm.com>
> ---
> diff --git a/sound/soc/sdca/sdca_class_function.c b/sound/soc/sdca/sdca_class_function.c
> index 10a2b031b572..8bca88865a4d 100644
> --- a/sound/soc/sdca/sdca_class_function.c
> +++ b/sound/soc/sdca/sdca_class_function.c
> @@ -329,7 +329,14 @@ static int class_function_probe(struct auxiliary_device *auxdev,
>  	drv->core = core;
>  	drv->function = &sdev->function;
>  
> -	ret = sdca_parse_function(dev, drv->function);
> +	if (drv->function->desc->node) {
> +		ret = sdca_parse_function(dev, drv->function);
> +	} else if (core->hw_ops && core->hw_ops->populate_function) {
> +		ret = core->hw_ops->populate_function(core->sdw, drv->function);
> +	} else {
> +		dev_err(dev, "no firmware node and no populate_function hook\n");
> +		return -ENOENT;
> +	}

Is this the right logic here? I feel like if we have a
populate_function() callback we should call it regardless of if we
have a node. That would help with the use-case where this is
being used to work around bugs in the firmware, and
populate_function() can always call sdca_parse_function() if it
wants too.

Thanks,
Charles