On 9/7/26 10:37, 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.
It'd be good to have a link to an example set of DT properties for SDCA.
The way the functions were organized in ACPI is based on a DT-inspired
_DSD mechanism to have nested blocks.
edit: After reaching the last patch I realized there are no such
properties. The main problem is how to deal with board-specific
initialization data, the suggestion to encode all the tables in C seems
limited to me.
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.
I wasn't able to understand that last sentence - and I don't remember
seeing a case with different functions of the same type. It's permitted
by the spec but it'd be fun to manage...
quoted hunk ↗ jump to hunk
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);
};
Erm, this populate_function() callback would not generate any hardware
access, would it? It's really different to hw_init which is supposed to
configure the codec and must run after enumeration.
I am struggling a bit with the 'hw_ops', it's really only a matter of
reading tables from platform firmware, and this could be done without
any dependency on hardware, couldn't it?
quoted hunk ↗ jump to hunk
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;