greybus: improve some error messages

Add a few error messages to help explain the reason for failures.
Add a missing space in a message in svc_management().
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/staging/greybus/ap.c

@@ -150,7 +150,7 @@ static void svc_management(struct svc_function_unipro_management *management,
 				management->link_up.interface_id,
 				management->link_up.device_id);
 		if (ret)
-			dev_err(hd->parent, "error %d initializing"
+			dev_err(hd->parent, "error %d initializing "
 				"module %hhu interface %hhu\n",
 				ret, management->link_up.module_id,
 				management->link_up.interface_id);

drivers/staging/greybus/connection.c

@@ -164,6 +164,7 @@ struct gb_connection *gb_connection_create(struct gb_interface *interface,
 
 	INIT_LIST_HEAD(&connection->protocol_links);
 	if (!gb_protocol_get(connection, protocol_id)) {
+		pr_err("protocol 0x%02hhx not found\n", protocol_id);
 		kfree(connection);
 		return NULL;
 	}
@@ -191,6 +192,8 @@ struct gb_connection *gb_connection_create(struct gb_interface *interface,
 
 	retval = device_add(&connection->dev);
 	if (retval) {
+		pr_err("failed to add connection device for cport 0x%04hx\n",
+			cport_id);
 		gb_connection_hd_cport_id_free(connection);
 		gb_protocol_put(connection);
 		put_device(&connection->dev);

drivers/staging/greybus/interface.c

@@ -78,6 +78,8 @@ gb_interface_create(struct gb_module *gmod, u8 interface_id)
 
 	retval = device_add(&interface->dev);
 	if (retval) {
+		pr_err("failed to add interface device for id 0x%02hhx\n",
+			interface_id);
 		kfree(interface);
 		return NULL;
 	}

drivers/staging/greybus/module.c

@@ -100,6 +100,8 @@ struct gb_module *gb_module_create(struct greybus_host_device *hd, u8 module_id)
 
 	retval = device_add(&gmod->dev);
 	if (retval) {
+		pr_err("failed to add module device for id 0x%02hhx\n",
+			module_id);
 		put_device(&gmod->dev);
 		return NULL;
 	}