[PATCH 04/11] soundwire: slave: lookup SDCA version and functions

[Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>]

From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>

Use SDCA helpers to get the basic information and store it in the
slave context. The information will be optionally be used in codec
drivers to register sub-devices for each Function.

When platforms are not based on ACPI the helpers do absolutely
nothing.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@xxxxxxxxxxxxxxx>
Signed-off-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>
---
 drivers/soundwire/Kconfig |  1 +
 drivers/soundwire/slave.c | 14 ++++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/drivers/soundwire/Kconfig b/drivers/soundwire/Kconfig
index 4d8f3b7024ae..f66f869dff2e 100644
--- a/drivers/soundwire/Kconfig
+++ b/drivers/soundwire/Kconfig
@@ -6,6 +6,7 @@
 menuconfig SOUNDWIRE
 	tristate "SoundWire support"
 	depends on ACPI || OF
+	depends on SND_SOC_SDCA_OPTIONAL
 	help
 	  SoundWire is a 2-Pin interface with data and clock line ratified
 	  by the MIPI Alliance. SoundWire is used for transporting data
diff --git a/drivers/soundwire/slave.c b/drivers/soundwire/slave.c
index f1a4df6cfebd..97cf8bcca047 100644
--- a/drivers/soundwire/slave.c
+++ b/drivers/soundwire/slave.c
@@ -5,6 +5,7 @@
 #include <linux/of.h>
 #include <linux/soundwire/sdw.h>
 #include <linux/soundwire/sdw_type.h>
+#include <sound/sdca.h>
 #include "bus.h"
 #include "sysfs_local.h"
 
@@ -70,6 +71,17 @@ int sdw_slave_add(struct sdw_bus *bus,
 	list_add_tail(&slave->node, &bus->slaves);
 	mutex_unlock(&bus->bus_lock);
 
+	/*
+	 * The Soundwire driver probe may optionally register SDCA
+	 * sub-devices, one per Function. This means the information
+	 * on the SDCA revision and the number/type of Functions need
+	 * to be extracted from platform firmware before the SoundWire
+	 * driver probe, and as a consequence before the SoundWire
+	 * device_register() below.
+	 */
+	sdca_lookup_interface_revision(slave);
+	sdca_lookup_functions(slave);
+
 	ret = device_register(&slave->dev);
 	if (ret) {
 		dev_err(bus->dev, "Failed to add slave: ret %d\n", ret);
@@ -259,3 +271,5 @@ int sdw_of_find_slaves(struct sdw_bus *bus)
 
 	return 0;
 }
+
+MODULE_IMPORT_NS(SND_SOC_SDCA);
-- 
2.43.0