upstream: [media] v4l: of: Support empty port nodes

Empty port nodes are allowed but currently unsupported as the
v4l2_of_get_next_endpoint() function assumes that all port nodes have at
least an endpoint. Fix this.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

diff --git a/drivers/media/v4l2-core/v4l2-of.c b/drivers/media/v4l2-core/v4l2-of.c
index 42e3e8a..4c07343 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-of.c
+++ b/drivers/media/v4l2-core/v4l2-of.c
@@ -166,43 +166,51 @@ struct device_node *v4l2_of_get_next_endpoint(const struct device_node *parent,
                                        struct device_node *prev)
 {
        struct device_node *endpoint;
-       struct device_node *port = NULL;
+       struct device_node *port;
 
        if (!parent)
                return NULL;
 
+       /*
+        * Start by locating the port node. If no previous endpoint is specified
+        * search for the first port node, otherwise get the previous endpoint
+        * parent port node.
+        */
        if (!prev) {
                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.
-                */
+
                node = of_get_child_by_name(parent, "ports");
                if (node)
                        parent = node;
 
                port = of_get_child_by_name(parent, "port");
+               of_node_put(node);
 
-               if (port) {
-                       /* Found a port, get an endpoint. */
-                       endpoint = of_get_next_child(port, NULL);
-                       of_node_put(port);
-               } else {
-                       endpoint = NULL;
-               }
-
-               if (!endpoint)
-                       pr_err("%s(): no endpoint nodes specified for %s\n",
+               if (!port) {
+                       pr_err("%s(): no port node found in %s\n",
                               __func__, parent->full_name);
-               of_node_put(node);
+                       return NULL;
+               }
        } else {
                port = of_get_parent(prev);
-               if (!port)
+               if (!port) {
                        /* Hm, has someone given us the root node ?... */
                        return NULL;
+               }
 
-               /* Avoid dropping prev node refcount to 0. */
+               /*
+                * Avoid dropping prev node refcount to 0 when getting the next
+                * child below.
+                */
                of_node_get(prev);
+       }
+
+       while (1) {
+               /*
+                * Now that we have a port node, get the next endpoint by
+                * getting the next child. If the previous endpoint is NULL this
+                * will return the first child.
+                */
                endpoint = of_get_next_child(port, prev);
                if (endpoint) {
                        of_node_put(port);
@@ -210,18 +218,14 @@ struct device_node *v4l2_of_get_next_endpoint(const struct device_node *parent,
                }
 
                /* No more endpoints under this port, try the next one. */
+               prev = NULL;
+
                do {
                        port = of_get_next_child(parent, port);
                        if (!port)
                                return NULL;
                } while (of_node_cmp(port->name, "port"));
-
-               /* Pick up the first endpoint in this port. */
-               endpoint = of_get_next_child(port, NULL);
-               of_node_put(port);
        }
-
-       return endpoint;
 }
 EXPORT_SYMBOL(v4l2_of_get_next_endpoint);