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Subject[PATCH] of: Make of_find_node_by_path() traverse /aliases for relative paths.
Date
Currently all paths passed to of_find_node_by_path() must begin with a
'/', indicating a full path to the desired node.

Augment the look-up code so that if a path does *not* begin with '/',
the path is used as the name of an /aliases property. The value of
this alias is then used as the full node path to be found.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
---
drivers/of/base.c | 24 +++++++++++++++++++++++-
1 files changed, 23 insertions(+), 1 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 710b53b..e63da9c 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -340,7 +340,10 @@ EXPORT_SYMBOL(of_get_next_child);

/**
* of_find_node_by_path - Find a node matching a full OF path
- * @path: The full path to match
+ * @path: Either the full path to match, or if the path does not
+ * start with '/', the name of a property of the /aliases
+ * node (an alias). In the case of an alias, the node
+ * matching the alias' value will be returned.
*
* Returns a node pointer with refcount incremented, use
* of_node_put() on it when done.
@@ -348,13 +351,32 @@ EXPORT_SYMBOL(of_get_next_child);
struct device_node *of_find_node_by_path(const char *path)
{
struct device_node *np = allnodes;
+ struct device_node *aliases = NULL;

read_lock(&devtree_lock);
+
+ if (path[0] != '/') {
+ aliases = of_find_node_by_path("/aliases");
+ if (!aliases)
+ goto out;
+ path = of_get_property(aliases, path, NULL);
+ /*
+ * The alias must begin with '/', otherwise we could
+ * get stuck in an endless loop and blow out the
+ * stack.
+ */
+ if (!path || path[0] != '/')
+ goto out;
+ }
+
for (; np; np = np->allnext) {
if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
&& of_node_get(np))
break;
}
+out:
+ if (aliases)
+ of_node_put(aliases);
read_unlock(&devtree_lock);
return np;
}
--
1.7.2.3


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