of: back-porting v4l2 graph bindings

This patch is back-porting the generic _portion_ of
fd9fdb78a9bf85b94fb2190c82ff280c8f8375cc to 3.10

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

diff --git a/drivers/of/base.c b/drivers/of/base.c
index a6f584a7f4a13f2842663c98d807e9b38b2cf89f..4caad01b6feca685a0c47510bbdd49ea6a20a5f2 100644 (file)
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1703,3 +1703,123 @@ const char *of_prop_next_string(struct property *prop, const char *cur)
        return curv;
 }
 EXPORT_SYMBOL_GPL(of_prop_next_string);
+
+/**
+ * of_graph_get_next_endpoint() - get next endpoint node
+ * @parent: pointer to the parent device node
+ * @prev: previous endpoint node, or NULL to get first
+ *
+ * Return: An 'endpoint' node pointer with refcount incremented. Refcount
+ * of the passed @prev node is not decremented, the caller have to use
+ * of_node_put() on it when done.
+ */
+struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
+                                       struct device_node *prev)
+{
+       struct device_node *endpoint;
+       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;
+
+               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) {
+                       pr_err("%s(): no port node found in %s\n",
+                              __func__, parent->full_name);
+                       return NULL;
+               }
+       } else {
+               port = of_get_parent(prev);
+               if (WARN_ONCE(!port, "%s(): endpoint %s has no parent node\n",
+                             __func__, prev->full_name))
+                       return NULL;
+
+               /*
+                * 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);
+                       return endpoint;
+               }
+
+               /* 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"));
+       }
+}
+EXPORT_SYMBOL(of_graph_get_next_endpoint);
+
+/**
+ * of_graph_get_remote_port_parent() - get remote port's parent node
+ * @node: pointer to a local endpoint device_node
+ *
+ * Return: Remote device node associated with remote endpoint node linked
+ *        to @node. Use of_node_put() on it when done.
+ */
+struct device_node *of_graph_get_remote_port_parent(
+                              const struct device_node *node)
+{
+       struct device_node *np;
+       unsigned int depth;
+
+       /* Get remote endpoint node. */
+       np = of_parse_phandle(node, "remote-endpoint", 0);
+
+       /* Walk 3 levels up only if there is 'ports' node. */
+       for (depth = 3; depth && np; depth--) {
+               np = of_get_next_parent(np);
+               if (depth == 2 && of_node_cmp(np->name, "ports"))
+                       break;
+       }
+       return np;
+}
+EXPORT_SYMBOL(of_graph_get_remote_port_parent);
+
+/**
+ * of_graph_get_remote_port() - get remote port node
+ * @node: pointer to a local endpoint device_node
+ *
+ * Return: Remote port node associated with remote endpoint node linked
+ *        to @node. Use of_node_put() on it when done.
+ */
+struct device_node *of_graph_get_remote_port(const struct device_node *node)
+{
+       struct device_node *np;
+
+       /* Get remote endpoint node. */
+       np = of_parse_phandle(node, "remote-endpoint", 0);
+       if (!np)
+               return NULL;
+       return of_get_next_parent(np);
+}
+EXPORT_SYMBOL(of_graph_get_remote_port);

diff --git a/include/linux/of_graph.h b/include/linux/of_graph.h
new file mode 100644 (file)
index 0000000..3bbeb60
--- /dev/null
+++ b/include/linux/of_graph.h
@@ -0,0 +1,46 @@
+/*
+ * OF graph binding parsing helpers
+ *
+ * Copyright (C) 2012 - 2013 Samsung Electronics Co., Ltd.
+ * Author: Sylwester Nawrocki <s.nawrocki@samsung.com>
+ *
+ * Copyright (C) 2012 Renesas Electronics Corp.
+ * Author: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ */
+#ifndef __LINUX_OF_GRAPH_H
+#define __LINUX_OF_GRAPH_H
+
+#ifdef CONFIG_OF
+struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
+                                       struct device_node *previous);
+struct device_node *of_graph_get_remote_port_parent(
+                                       const struct device_node *node);
+struct device_node *of_graph_get_remote_port(const struct device_node *node);
+#else
+
+static inline struct device_node *of_graph_get_next_endpoint(
+                                       const struct device_node *parent,
+                                       struct device_node *previous)
+{
+       return NULL;
+}
+
+static inline struct device_node *of_graph_get_remote_port_parent(
+                                       const struct device_node *node)
+{
+       return NULL;
+}
+
+static inline struct device_node *of_graph_get_remote_port(
+                                       const struct device_node *node)
+{
+       return NULL;
+}
+
+#endif /* CONFIG_OF */
+
+#endif /* __LINUX_OF_GRAPH_H */