core: ofnode: add of_graph parsing helpers

Add a mostly complete list of ofnode analogs of of_graph
parsing helpers.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>

include/dm/ofnode_graph.h

@@ -0,0 +1,90 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2025 Svyatoslav Ryhel <clamor95@gmail.com>
+ */
+
+#ifndef _DM_OFNODE_GRAPH_H
+#define _DM_OFNODE_GRAPH_H
+
+#include <dm/of.h>
+
+/**
+ * ofnode_graph_get_endpoint_count() - get the number of endpoints in a device ofnode
+ * @parent: ofnode to the device containing ports and endpoints
+ *
+ * Return: count of endpoint of this device ofnode
+ */
+unsigned int ofnode_graph_get_endpoint_count(ofnode parent);
+
+/**
+ * ofnode_graph_get_port_count() - get the number of port in a device or ports ofnode
+ * @parent: ofnode to the device or ports node
+ *
+ * Return: count of port of this device or ports node
+ */
+unsigned int ofnode_graph_get_port_count(ofnode parent);
+
+/**
+ * ofnode_graph_get_port_by_id() - get the port matching a given id
+ * @parent: parent ofnode
+ * @id: id of the port
+ *
+ * Return: ofnode in given port.
+ */
+ofnode ofnode_graph_get_port_by_id(ofnode parent, u32 id);
+
+/**
+ * ofnode_graph_get_endpoint_by_regs() - get the endpoint matching a given id
+ * @parent: parent ofnode
+ * @reg_id: id of the port
+ * @id: id for the endpoint
+ *
+ * Return: ofnode in given endpoint or NULL if not found.
+ * reg and port_reg are ignored when they are -1.
+ */
+ofnode ofnode_graph_get_endpoint_by_regs(ofnode parent, u32 reg_id, u32 id);
+
+/**
+ * ofnode_graph_get_remote_endpoint() - get remote endpoint node
+ * @endoint: ofnode of a local endpoint
+ *
+ * Return: Remote endpoint ofnode linked with local endpoint.
+ */
+ofnode ofnode_graph_get_remote_endpoint(ofnode endpoint);
+
+/**
+ * ofnode_graph_get_port_parent() - get port's parent node
+ * @endpoint: ofnode of a local endpoint
+ *
+ * Return: device ofnode associated with endpoint
+ */
+ofnode ofnode_graph_get_port_parent(ofnode endpoint);
+
+/**
+ * ofnode_graph_get_remote_port_parent() - get remote port's parent ofnode
+ * @endoint: ofnode of a local endpoint
+ *
+ * Return: device ofnode associated with endpoint linked to local endpoint.
+ */
+ofnode ofnode_graph_get_remote_port_parent(ofnode endpoint);
+
+/**
+ * ofnode_graph_get_remote_port() - get remote port ofnode
+ * @endoint: ofnode of a local endpoint
+ *
+ * Return: port ofnode associated with remote endpoint node linked
+ * to local endpoint.
+ */
+ofnode ofnode_graph_get_remote_port(ofnode endpoint);
+
+/**
+ * ofnode_graph_get_remote_node() - get remote parent ofnode for given port/endpoint
+ * @parent: parent ofnode containing graph port/endpoint
+ * @port: identifier (value of reg property) of the parent port ofnode
+ * @endpoint: identifier (value of reg property) of the endpoint ofnode
+ *
+ * Return: device ofnode associated with endpoint linked to local endpoint.
+ */
+ofnode ofnode_graph_get_remote_node(ofnode parent, u32 port, u32 endpoint);
+
+#endif