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Subject[PATCH v5 1/6] of_graph: add of_graph_get_local_port()
Date
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 the graph.

This patch adds of_graph_get_local_port() which returns pointer to a local
port node, or NULL if graph isn't specified in a device-tree for a given
device node.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/of/property.c | 32 +++++++++++++++++++++++---------
include/linux/of_graph.h | 7 +++++++
2 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/drivers/of/property.c b/drivers/of/property.c
index 252e4f600155..5dbeccaabb86 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -608,15 +608,7 @@ 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_local_port(parent);
if (!port) {
pr_err("graph: no port node found in %pOF\n", parent);
return NULL;
@@ -765,6 +757,28 @@ struct device_node *of_graph_get_remote_port(const struct device_node *node)
}
EXPORT_SYMBOL(of_graph_get_remote_port);

+/**
+ * of_graph_get_local_port() - get 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.
+ */
+struct device_node *of_graph_get_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;
+}
+EXPORT_SYMBOL(of_graph_get_local_port);
+
int of_graph_get_endpoint_count(const struct device_node *np)
{
struct device_node *endpoint;
diff --git a/include/linux/of_graph.h b/include/linux/of_graph.h
index 01038a6aade0..1fdeb72c7765 100644
--- a/include/linux/of_graph.h
+++ b/include/linux/of_graph.h
@@ -54,6 +54,7 @@ struct device_node *of_graph_get_remote_port_parent(
struct device_node *of_graph_get_remote_port(const struct device_node *node);
struct device_node *of_graph_get_remote_node(const struct device_node *node,
u32 port, u32 endpoint);
+struct device_node *of_graph_get_local_port(const struct device_node *node);
#else

static inline int of_graph_parse_endpoint(const struct device_node *node,
@@ -116,6 +117,12 @@ static inline struct device_node *of_graph_get_remote_node(
return NULL;
}

+static inline struct device_node *of_graph_get_local_port(
+ const struct device_node *node)
+{
+ return NULL;
+}
+
#endif /* CONFIG_OF */

#endif /* __LINUX_OF_GRAPH_H */
--
2.26.0
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