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

[Srinivas Kandagatla]

On 9/8/26 5:25 PM, Charles Keepax wrote:
> 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@xxxxxxxxxxxxxxxx>
>> ---
>> 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

something like this?
-------------------->cut<---------------------------------
if (drv->function->desc->node)
	ret = sdca_parse_function(dev, drv->function);

if (core->hw_ops && core->hw_ops->populate_function)
	ret = core->hw_ops->populate_function(core->sdw, drv->function);

if (ret)
	return ret;

-------------------->cut<---------------------------------

> 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.
+1

--srini
> 
> Thanks,
> Charles