[PATCH v2 6/7] of_graph: add for_each_of_port() / for_each_of_endpoint_in_port()

[Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>]

From: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>

OF graph indicates each devices connection. It already has
for_each_endpoint_of_node() which is for-loop for each endpoint.
But, some driver needs for-loop for each port[s], and for-loop for
each endpoint in port[s]. This patch adds for_each_of_port()
and for_each_of_endpoint_in_port() for this purpose.

And it also adds for_each_of_endpoint() which is similar to
for_each_endpoint_of_node(). The difference is it can catch port
handle during for-loop.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
---
 drivers/of/base.c        | 62 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/of_graph.h | 28 ++++++++++++++++++++++
 2 files changed, 90 insertions(+)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index a085961..a39d483 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -2249,6 +2249,68 @@ struct device_node *of_graph_get_top_port(struct device *dev)
 EXPORT_SYMBOL(of_graph_get_top_port);
 
 /**
+ * of_graph_get_next_port() - get next port node
+ * @parent: pointer to the parent device node
+ * @prev: previous endpoint node, or NULL to get first
+ *
+ * Return: An 'endpoint' node pointer with refcount incremented. Refcount
+ * of the passed @prev node is decremented.
+ */
+struct device_node *of_graph_get_next_port(const struct device_node *parent,
+					   struct device_node *prev)
+{
+	struct device_node *port;
+	struct device_node *node;
+
+	if (!parent)
+		return NULL;
+
+	node = of_get_child_by_name(parent, "ports");
+	if (node)
+		parent = node;
+
+	/*
+	 * Start by locating the port node. If no previous endpoint is specified
+	 * search for the first port node, otherwise get the previous endpoint
+	 * parent port node.
+	 */
+	if (!prev) {
+		port = of_get_child_by_name(parent, "port");
+		if (!port)
+			pr_err("%s(): no port node found in %s\n",
+			       __func__, parent->full_name);
+	} else {
+		do {
+			port = of_get_next_child(parent, prev);
+			if (!port)
+				break;
+		} while (of_node_cmp(port->name, "port"));
+	}
+
+	of_node_put(node);
+
+	return port;
+}
+EXPORT_SYMBOL(of_graph_get_next_port);
+
+/**
+ * of_graph_get_next_endpoint_in_port() - get next endpoint node in port
+ * @parent: pointer to the parent device node
+ * @prev: previous endpoint node, or NULL to get first
+ *
+ * Return: An 'endpoint' node pointer with refcount incremented. Refcount
+ * of the passed @prev node is decremented.
+ */
+struct device_node *of_graph_get_next_endpoint_in_port(const struct device_node *port,
+					       struct device_node *prev)
+{
+	if (!port)
+		return NULL;
+
+	return of_get_next_child(port, prev);
+}
+
+/**
  * of_graph_get_next_endpoint() - get next endpoint node
  * @parent: pointer to the parent device node
  * @prev: previous endpoint node, or NULL to get first
diff --git a/include/linux/of_graph.h b/include/linux/of_graph.h
index 35e9a6e..c88b676 100644
--- a/include/linux/of_graph.h
+++ b/include/linux/of_graph.h
@@ -30,6 +30,16 @@ struct of_endpoint {
 	const struct device_node *local_node;
 };
 
+#define for_each_of_port(parent, port) \
+	for (port = of_graph_get_next_port(parent, NULL); port != NULL; \
+	     port = of_graph_get_next_port(parent, port))
+#define for_each_of_endpoint_in_port(port, ep) \
+	for (ep = of_graph_get_next_endpoint_in_port(port, NULL); ep != NULL; \
+	     ep = of_graph_get_next_endpoint_in_port(port, ep))
+#define for_each_of_endpoint(parent, port, ep) \
+	for_each_of_port(parent, port) \
+		for_each_of_endpoint_in_port(port, ep)
+
 /**
  * for_each_endpoint_of_node - iterate over every endpoint in a device node
  * @parent: parent device node containing ports and endpoints
@@ -49,6 +59,10 @@ int of_graph_parse_endpoint(const struct device_node *node,
 bool of_graph_port_type_is(struct device_node *port, char *type);
 struct device_node *of_graph_get_port_by_id(struct device_node *node, u32 id);
 struct device_node *of_graph_get_top_port(struct device *dev);
+struct device_node *of_graph_get_next_port(const struct device_node *parent,
+					struct device_node *prev);
+struct device_node *of_graph_get_next_endpoint_in_port(const struct device_node *port,
+						struct device_node *prev);
 struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 					struct device_node *previous);
 struct device_node *of_graph_get_endpoint_by_regs(
@@ -78,6 +92,20 @@ static inline struct device_node *of_graph_get_port_by_id(
 	return NULL;
 }
 
+static inline struct device_node *of_graph_get_next_port(
+					const struct device_node *parent,
+					struct device_node *prev)
+{
+	return NULL;
+}
+
+static inline struct device_node *of_graph_get_next_endpoint_in_port(
+					const struct device_node *port,
+					struct device_node *prev)
+{
+	return NULL;
+}
+
 static inline struct device_node *of_graph_get_next_endpoint(
 					const struct device_node *parent,
 					struct device_node *previous)
-- 
1.9.1