[PATCH v4 06/15] soundwire: add support for sdw_slave_type

[Pierre-Louis Bossart]

Currently the bus does not have any explicit support for master
devices.

First add explicit support for sdw_slave_type and error checks if this type
is not set.

In follow-up patches we can add support for the sdw_md_type (md==Master
Device), following the Grey Bus example.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
---
 drivers/soundwire/bus_type.c       | 16 ++++++++++++----
 drivers/soundwire/slave.c          |  7 ++++++-
 include/linux/soundwire/sdw_type.h |  6 ++++++
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/drivers/soundwire/bus_type.c b/drivers/soundwire/bus_type.c
index 9a0fd3ee1014..bbdedce5eb26 100644
--- a/drivers/soundwire/bus_type.c
+++ b/drivers/soundwire/bus_type.c
@@ -49,13 +49,21 @@ int sdw_slave_modalias(const struct sdw_slave *slave, char *buf, size_t size)
 
 static int sdw_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
-	struct sdw_slave *slave = to_sdw_slave_device(dev);
+	struct sdw_slave *slave;
 	char modalias[32];
 
-	sdw_slave_modalias(slave, modalias, sizeof(modalias));
+	if (is_sdw_slave(dev)) {
+		slave = to_sdw_slave_device(dev);
+
+		sdw_slave_modalias(slave, modalias, sizeof(modalias));
 
-	if (add_uevent_var(env, "MODALIAS=%s", modalias))
-		return -ENOMEM;
+		if (add_uevent_var(env, "MODALIAS=%s", modalias))
+			return -ENOMEM;
+	} else {
+		/* only Slave device type supported */
+		dev_warn(dev, "uevent for unknown Soundwire type\n");
+		return -EINVAL;
+	}
 
 	return 0;
 }
diff --git a/drivers/soundwire/slave.c b/drivers/soundwire/slave.c
index 48a513680db6..c87267f12a3b 100644
--- a/drivers/soundwire/slave.c
+++ b/drivers/soundwire/slave.c
@@ -14,6 +14,11 @@ static void sdw_slave_release(struct device *dev)
 	kfree(slave);
 }
 
+struct device_type sdw_slave_type = {
+	.name =		"sdw_slave",
+	.release =	sdw_slave_release,
+};
+
 static int sdw_slave_add(struct sdw_bus *bus,
 			 struct sdw_slave_id *id, struct fwnode_handle *fwnode)
 {
@@ -41,9 +46,9 @@ static int sdw_slave_add(struct sdw_bus *bus,
 			     id->class_id, id->unique_id);
 	}
 
-	slave->dev.release = sdw_slave_release;
 	slave->dev.bus = &sdw_bus_type;
 	slave->dev.of_node = of_node_get(to_of_node(fwnode));
+	slave->dev.type = &sdw_slave_type;
 	slave->bus = bus;
 	slave->status = SDW_SLAVE_UNATTACHED;
 	slave->dev_num = 0;
diff --git a/include/linux/soundwire/sdw_type.h b/include/linux/soundwire/sdw_type.h
index 7d4bc6a979bf..c681b3426478 100644
--- a/include/linux/soundwire/sdw_type.h
+++ b/include/linux/soundwire/sdw_type.h
@@ -5,6 +5,12 @@
 #define __SOUNDWIRE_TYPES_H
 
 extern struct bus_type sdw_bus_type;
+extern struct device_type sdw_slave_type;
+
+static inline int is_sdw_slave(const struct device *dev)
+{
+	return dev->type == &sdw_slave_type;
+}
 
 #define to_sdw_slave_driver(_drv) \
 	container_of(_drv, struct sdw_driver, driver)
-- 
2.20.1