device connection: Prepare support for firmware described connections

When the connections are defined in firmware, struct
device_connection will have the fwnode member pointing to
the device node (struct fwnode_handle) of the requested
device. The endpoint member for the device names will not be
used at all in that case.
Acked-by: NHans de Goede <hdegoede@redhat.com>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: NJun Li <jun.li@nxp.com>
Tested-by: NJun Li <jun.li@nxp.com>
Signed-off-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/devcon.c

@@ -75,12 +75,36 @@ static struct bus_type *generic_match_buses[] = {
 	NULL,
 };
 
+static int device_fwnode_match(struct device *dev, void *fwnode)
+{
+	return dev_fwnode(dev) == fwnode;
+}
+
+static void *device_connection_fwnode_match(struct device_connection *con)
+{
+	struct bus_type *bus;
+	struct device *dev;
+
+	for (bus = generic_match_buses[0]; bus; bus++) {
+		dev = bus_find_device(bus, NULL, (void *)con->fwnode,
+				      device_fwnode_match);
+		if (dev && !strncmp(dev_name(dev), con->id, strlen(con->id)))
+			return dev;
+
+		put_device(dev);
+	}
+	return NULL;
+}
+
 /* This tries to find the device from the most common bus types by name. */
 static void *generic_match(struct device_connection *con, int ep, void *data)
 {
 	struct bus_type *bus;
 	struct device *dev;
 
+	if (con->fwnode)
+		return device_connection_fwnode_match(con);
+
 	for (bus = generic_match_buses[0]; bus; bus++) {
 		dev = bus_find_device_by_name(bus, NULL, con->endpoint[ep]);
 		if (dev)