UPSTREAM: device property: Add FW type agnostic fwnode_graph_get_remote_node

Add fwnode_graph_get_remote_node() function which is equivalent to
of_graph_get_remote_node() on OF.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
(cherry picked from commit 125ee6b3b0fa920c730b0991e6f083a9f5b1e4c3)
Signed-off-by: Brian J Lovin <brian.j.lovin@intel.com>

BUG=b:64133998
TEST=media device topology shows subdevs registered successfully
TEST=no camera regression

Change-Id: Ic450222819fb987342af9170872b91b0044a181f
Reviewed-on: https://chromium-review.googlesource.com/693679
Commit-Ready: Tomasz Figa <tfiga@chromium.org>
Tested-by: Hyungwoo Yang <hyungwoo.yang@intel.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Jacob Chen <jacob2.chen@rock-chips.com>

Author: Sakari Ailus

drivers/base/property.c

@@ -1142,6 +1142,43 @@ fwnode_graph_get_remote_endpoint(struct fwnode_handle *fwnode)
 }
 EXPORT_SYMBOL_GPL(fwnode_graph_get_remote_endpoint);
 
+/**
+ * fwnode_graph_get_remote_node - get remote parent node for given port/endpoint
+ * @fwnode: pointer to parent fwnode_handle containing graph port/endpoint
+ * @port_id: identifier of the parent port node
+ * @endpoint_id: identifier of the endpoint node
+ *
+ * Return: Remote fwnode handle associated with remote endpoint node linked
+ *	   to @node. Use fwnode_node_put() on it when done.
+ */
+struct fwnode_handle *fwnode_graph_get_remote_node(struct fwnode_handle *fwnode,
+						   u32 port_id, u32 endpoint_id)
+{
+	struct fwnode_handle *endpoint = NULL;
+
+	while ((endpoint = fwnode_graph_get_next_endpoint(fwnode, endpoint))) {
+		struct fwnode_endpoint fwnode_ep;
+		struct fwnode_handle *remote;
+		int ret;
+
+		ret = fwnode_graph_parse_endpoint(endpoint, &fwnode_ep);
+		if (ret < 0)
+			continue;
+
+		if (fwnode_ep.port != port_id || fwnode_ep.id != endpoint_id)
+			continue;
+
+		remote = fwnode_graph_get_remote_port_parent(endpoint);
+		if (!remote)
+			return NULL;
+
+		return fwnode_device_is_available(remote) ? remote : NULL;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(fwnode_graph_get_remote_node);
+
 /**
  * fwnode_graph_parse_endpoint - parse common endpoint node properties
  * @fwnode: pointer to endpoint fwnode_handle

include/linux/property.h

@@ -222,6 +222,8 @@ struct fwnode_handle *fwnode_graph_get_remote_port(
 	struct fwnode_handle *fwnode);
 struct fwnode_handle *fwnode_graph_get_remote_endpoint(
 	struct fwnode_handle *fwnode);
+struct fwnode_handle *fwnode_graph_get_remote_node(struct fwnode_handle *fwnode,
+						   u32 port, u32 endpoint);
 
 int fwnode_graph_parse_endpoint(struct fwnode_handle *fwnode,
 				struct fwnode_endpoint *endpoint);