01.07.2020 08:45, Laurent Pinchart пишет:
Hi Dmitry,
Thank you for the patch.
On Wed, Jul 01, 2020 at 05:16:16AM +0300, Dmitry Osipenko wrote:
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
It's not an endpoint.
Alright, somehow I was reading this as a "device_node that contains endpoint (of the graph)". But after re-reading twice I can see that it's not the case.
It should be a "pointer to device_node containing graph port", just like the of_graph_get_remote_node() says it. Thank you :)
- 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);I think this introduces a bug below in the function, where parent is used and is expected to point to the ports node if available. I'd leave this part of the change out, and inline +of_graph_get_first_local_port() in of_graph_is_present().
Good catch! I'll correct this.
Thank you for the review :)