# \[PATCH v2 05/11\] ASoC: SDCA: add populate\_function hw\_op for DT function data

- From: Srinivas Kandagatla \<hidden\>
- Date: 2026-09-07 08:38:36 
- List: linux-devicetree
- Page: https://ratatoskr.run/linux-devicetree/2026/09/17523627
- Thread: https://ratatoskr.run/linux-sound/2026/09/17523622/t.md

```text
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 <redacted>
---
 include/sound/sdca_class.h           | 6 ++++++
 sound/soc/sdca/sdca_class_function.c | 9 ++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/include/sound/sdca_class.h b/include/sound/sdca_class.h
index 3342937d09fd..3a1b6d65048f 100644
--- a/include/sound/sdca_class.h
+++ b/include/sound/sdca_class.h
@@ -26,9 +26,15 @@ struct sdca_function_data;
  *           before the class regmap is created and before the slave is
  *           ATTACHED; callers needing bus I/O must sdw_slave_wait_for_init()
  *           first.
+ * @populate_function: fill @function (entities, clusters, init_table, ...)
+ *           from static tables in place of sdca_parse_function() on
+ *           DT/non-DisCo platforms.  Must leave @function->desc alone.
+ *           Return 0 on success or a negative errno.  May be NULL.
  */
 struct sdca_class_hw_ops {
 	int (*hw_init)(struct sdw_slave *slave);
+	int (*populate_function)(struct sdw_slave *slave,
+				 struct sdca_function_data *function);
 };
 
 struct sdca_class_drv {
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;
+	}
 	if (ret)
 		return ret;
 
-- 
2.53.0

```