soundwire: bus_type: add sdw_master_device support

In the existing SoundWire code, Master Devices are not explicitly
represented - only SoundWire Slave Devices are exposed (the use of
capital letters follows the SoundWire specification conventions).

With the existing code, the bus is handled without using a proper device,
and bus->dev typically points to a platform device. The right thing to
do as discussed in multiple reviews is use a device for each bus.

The sdw_master_device addition is done with minimal internal plumbing
and not exposed externally. The existing API based on
sdw_bus_master_add() and sdw_bus_master_delete() will deal with the
sdw_master_device life cycle, which minimizes changes to existing
drivers.

Note that the Intel code will be modified in follow-up patches (no
impact on any platform since the connection with ASoC is not supported
upstream so far).

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Acked-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20200518174322.31561-5-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 11 insertions, 3 deletions

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index 03d72fa3c190..11cfe435e4a8 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -37,14 +37,21 @@ int sdw_bus_master_add(struct sdw_bus *bus, struct device *parent,
 	struct sdw_master_prop *prop = NULL;
 	int ret;
 
-	if (!bus->dev) {
-		pr_err("SoundWire bus has no device\n");
+	if (!parent) {
+		pr_err("SoundWire parent device is not set\n");
 		return -ENODEV;
 	}
 
 	ret = sdw_get_id(bus);
 	if (ret) {
-		dev_err(bus->dev, "Failed to get bus id\n");
+		dev_err(parent, "Failed to get bus id\n");
+		return ret;
+	}
+
+	ret = sdw_master_device_add(bus, parent, fwnode);
+	if (ret) {
+		dev_err(parent, "Failed to add master device at link %d\n",
+			bus->link_id);
 		return ret;
 	}
 
@@ -161,6 +168,7 @@ static int sdw_delete_slave(struct device *dev, void *data)
 void sdw_bus_master_delete(struct sdw_bus *bus)
 {
 	device_for_each_child(bus->dev, NULL, sdw_delete_slave);
+	sdw_master_device_del(bus);
 
 	sdw_bus_debugfs_exit(bus);
 	ida_free(&sdw_ida, bus->id);