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@kernel.org Signed-off-by: Dmitry Osipenko digetx@gmail.com --- 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) {