In some case, like a DRM display code for example, it's useful to silently
check whether port node exists at all in a device-tree before proceeding
with parsing of the graph.
This patch adds of_graph_is_present() which returns true if given
device-tree node contains OF graph port.
Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
drivers/of/property.c | 52 +++++++++++++++++++++++++++++++++-------
include/linux/of_graph.h | 6 +++++
2 files changed, 49 insertions(+), 9 deletions(-)
diff --git a/drivers/of/property.c b/drivers/of/property.c
index 6a5760f0d6cd..e12b8b491837 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -29,6 +29,48 @@
#include "of_private.h"
+/**
+ * of_graph_get_first_local_port() - get first local port node
+ * @node: pointer to a local endpoint device_node
+ *
+ * Return: First local port node associated with local endpoint node linked
+ * to @node. Use of_node_put() on it when done.
+ */
+static struct device_node *
+of_graph_get_first_local_port(const struct device_node *node)
+{
+ struct device_node *ports, *port;
+
+ ports = of_get_child_by_name(node, "ports");
+ if (ports)
+ node = ports;
+
+ port = of_get_child_by_name(node, "port");
+ of_node_put(ports);
+
+ return port;
+}
+
+/**
+ * of_graph_is_present() - check graph's presence
+ * @node: pointer to a device_node checked for the graph's presence
+ *
+ * Return: True if @node has a port or ports sub-node, false otherwise.
+ */
+bool of_graph_is_present(const struct device_node *node)
+{
+ struct device_node *local;
+
+ local = of_graph_get_first_local_port(node);
+ if (!local)
+ return false;
+
+ of_node_put(local);
+
+ return true;
+}
+EXPORT_SYMBOL(of_graph_is_present);
+
/**
* of_property_count_elems_of_size - Count the number of elements in a property
*
@@ -608,15 +650,7 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
* parent port node.
*/
if (!prev) {
- struct device_node *node;
-
- node = of_get_child_by_name(parent, "ports");
- if (node)
- parent = node;
-
- port = of_get_child_by_name(parent, "port");
- of_node_put(node);
-
+ port = of_graph_get_first_local_port(parent);
if (!port) {
pr_err("graph: no port node found in %pOF\n", parent);
return NULL;
diff --git a/include/linux/of_graph.h b/include/linux/of_graph.h
index 01038a6aade0..4d7756087b6b 100644
--- a/include/linux/of_graph.h
+++ b/include/linux/of_graph.h
@@ -38,6 +38,7 @@ struct of_endpoint {
child = of_graph_get_next_endpoint(parent, child))
#ifdef CONFIG_OF
+bool of_graph_is_present(const struct device_node *node);
int of_graph_parse_endpoint(const struct device_node *node,
struct of_endpoint *endpoint);
int of_graph_get_endpoint_count(const struct device_node *np);
@@ -56,6 +57,11 @@ struct device_node *of_graph_get_remote_node(const struct device_node *node,
u32 port, u32 endpoint);
#else
+static inline bool of_graph_is_present(const struct device_node *node)
+{
+ return false;
+}
+
static inline int of_graph_parse_endpoint(const struct device_node *node,
struct of_endpoint *endpoint)
{
--
2.26.0
