greybus: connection: remove broken protocol-version handling

Remove the broken legacy protocol-version handling from core and move it
to the legacy driver instead.

Note that version handling has always been broken as legacy protocols
were looked up and bound to connections before the connections were
enabled and version negotiation could take place (over that very
connection). Document that in the legacy driver as well.
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/connection.c

@@ -120,8 +120,6 @@ gb_connection_create(struct gb_host_device *hd, int hd_cport_id,
 	struct gb_connection *connection;
 	struct ida *id_map = &hd->cport_id_map;
 	int ida_start, ida_end;
-	u8 major = 0;
-	u8 minor = 1;
 
 	/*
 	 * If a manifest tries to reuse a cport, reject it.  We
@@ -159,8 +157,6 @@ gb_connection_create(struct gb_host_device *hd, int hd_cport_id,
 	connection->intf = intf;
 
 	connection->protocol_id = protocol_id;
-	connection->major = major;
-	connection->minor = minor;
 
 	connection->bundle = bundle;
 	connection->state = GB_CONNECTION_STATE_DISABLED;

drivers/staging/greybus/connection.h

@@ -39,8 +39,6 @@ struct gb_connection {
 
 	struct gb_protocol		*protocol;
 	u8				protocol_id;
-	u8				major;
-	u8				minor;
 	u8				module_major;
 	u8				module_minor;
 

drivers/staging/greybus/legacy.c

@@ -30,15 +30,25 @@ static int legacy_connection_get_version(struct gb_connection *connection)
 static int legacy_connection_bind_protocol(struct gb_connection *connection)
 {
 	struct gb_protocol *protocol;
+	u8 major, minor;
+
+	/*
+	 * The legacy protocols have always been looked up using a hard-coded
+	 * version of 0.1, despite (or perhaps rather, due to) the fact that
+	 * module version negotiation could not take place until after the
+	 * protocol was bound.
+	 */
+	major = 0;
+	minor = 1;
 
 	protocol = gb_protocol_get(connection->protocol_id,
-				   connection->major,
-				   connection->minor);
+				   major,
+				   minor);
 	if (!protocol) {
 		dev_err(&connection->hd->dev,
 				"protocol 0x%02x version %u.%u not found\n",
 				connection->protocol_id,
-				connection->major, connection->minor);
+				major, minor);
 		return -EPROTONOSUPPORT;
 	}
 	connection->protocol = protocol;