[PATCH v6 6/8] of: Implement simplified graph binding for single port devices

[Philipp Zabel <p.zabel@pengutronix.de>]

For simple devices with only one port, it can be made implicit.
The endpoint node can be a direct child of the device node.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
---
Changes since v5:
 - Unrolled for-loop in of_graph_get_remote_port_parent
---
 drivers/of/base.c | 42 +++++++++++++++++++++++++++++-------------
 1 file changed, 29 insertions(+), 13 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 715144af..ffd0217 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -2003,7 +2003,8 @@ int of_graph_parse_endpoint(const struct device_node *node,
 	 * It doesn't matter whether the two calls below succeed.
 	 * If they don't then the default value 0 is used.
 	 */
-	of_property_read_u32(port_node, "reg", &endpoint->port);
+	if (port_node && !of_node_cmp(port_node->name, "port"))
+		of_property_read_u32(port_node, "reg", &endpoint->port);
 	of_property_read_u32(node, "reg", &endpoint->id);
 
 	of_node_put(port_node);
@@ -2034,8 +2035,13 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 		struct device_node *node;
 		/*
 		 * It's the first call, we have to find a port subnode
-		 * within this node or within an optional 'ports' node.
+		 * within this node or within an optional 'ports' node,
+		 * or at least a single endpoint.
 		 */
+		endpoint = of_get_child_by_name(parent, "endpoint");
+		if (endpoint)
+			return endpoint;
+
 		node = of_get_child_by_name(parent, "ports");
 		if (node)
 			parent = node;
@@ -2046,8 +2052,6 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 			/* Found a port, get an endpoint. */
 			endpoint = of_get_next_child(port, NULL);
 			of_node_put(port);
-		} else {
-			endpoint = NULL;
 		}
 
 		if (!endpoint)
@@ -2062,6 +2066,10 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 	if (WARN_ONCE(!port, "%s(): endpoint %s has no parent node\n",
 		      __func__, prev->full_name))
 		return NULL;
+	if (port == parent) {
+		of_node_put(port);
+		return NULL;
+	}
 
 	/* Avoid dropping prev node refcount to 0. */
 	of_node_get(prev);
@@ -2097,18 +2105,21 @@ 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_parse_phandle(node, "remote-endpoint", 0);
+	if (!np)
+		return NULL;
 
-	/* 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;
+	np = of_get_next_parent(np);
+	if (!np || of_node_cmp(np->name, "port") != 0)
+		return np;
+
+	np = of_get_next_parent(np);
+	if (!np || of_node_cmp(np->name, "ports") != 0)
+		return np;
+
+	return of_get_next_parent(np);
 }
 EXPORT_SYMBOL(of_graph_get_remote_port_parent);
 
@@ -2127,6 +2138,11 @@ struct device_node *of_graph_get_remote_port(const struct device_node *node)
 	np = of_parse_phandle(node, "remote-endpoint", 0);
 	if (!np)
 		return NULL;
-	return of_get_next_parent(np);
+	np = of_get_next_parent(np);
+	if (of_node_cmp(np->name, "port")) {
+		of_node_put(np);
+		return NULL;
+	}
+	return np;
 }
 EXPORT_SYMBOL(of_graph_get_remote_port);
-- 
1.9.0.rc3