of_graph: add of_graph_get_port_parent()

Linux kernel already has of_graph_get_remote_port_parent(),
but, sometimes we want to get own port parent.
This patch adds of_graph_get_port_parent()

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/of/base.c

@@ -2500,6 +2500,27 @@ struct device_node *of_graph_get_remote_endpoint(const struct device_node *node)
 }
 EXPORT_SYMBOL(of_graph_get_remote_endpoint);
 
+/**
+ * of_graph_get_port_parent() - get port's parent node
+ * @node: pointer to a local endpoint device_node
+ *
+ * Return: device node associated with endpoint node linked
+ *	   to @node. Use of_node_put() on it when done.
+ */
+struct device_node *of_graph_get_port_parent(struct device_node *node)
+{
+	unsigned int depth;
+
+	/* Walk 3 levels up only if there is 'ports' node. */
+	for (depth = 3; depth && node; depth--) {
+		node = of_get_next_parent(node);
+		if (depth == 2 && of_node_cmp(node->name, "ports"))
+			break;
+	}
+	return node;
+}
+EXPORT_SYMBOL(of_graph_get_port_parent);
+
 /**
  * of_graph_get_remote_port_parent() - get remote port's parent node
  * @node: pointer to a local endpoint device_node
@@ -2511,18 +2532,11 @@ struct device_node *of_graph_get_remote_port_parent(
 			       const struct device_node *node)
 {
 	struct device_node *np;
-	unsigned int depth;
 
 	/* Get remote endpoint node. */
 	np = of_graph_get_remote_endpoint(node);
 
-	/* Walk 3 levels up only if there is 'ports' node. */
-	for (depth = 3; depth && np; depth--) {
-		np = of_get_next_parent(np);
-		if (depth == 2 && of_node_cmp(np->name, "ports"))
-			break;
-	}
-	return np;
+	return of_graph_get_port_parent(np);
 }
 EXPORT_SYMBOL(of_graph_get_remote_port_parent);
 

include/linux/of_graph.h

@@ -50,6 +50,7 @@ struct device_node *of_graph_get_endpoint_by_regs(
 		const struct device_node *parent, int port_reg, int reg);
 struct device_node *of_graph_get_remote_endpoint(
 					const struct device_node *node);
+struct device_node *of_graph_get_port_parent(struct device_node *node);
 struct device_node *of_graph_get_remote_port_parent(
 					const struct device_node *node);
 struct device_node *of_graph_get_remote_port(const struct device_node *node);
@@ -88,6 +89,12 @@ static inline struct device_node *of_graph_get_remote_endpoint(
 	return NULL;
 }
 
+static inline struct device_node *of_graph_get_port_parent(
+	struct device_node *node)
+{
+	return NULL;
+}
+
 static inline struct device_node *of_graph_get_remote_port_parent(
 					const struct device_node *node)
 {