of: Add helpers for finding device nodes which have a given property
This commit adds a routine for finding a device node which has a
certain property. The contents of the property are not taken into
account, merely the presence or absence of the property.
Based on that routine, we add a for_each_ macro for iterating over all
nodes that have a certain property.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 7c79e94..4f884a3 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -329,6 +329,41 @@
EXPORT_SYMBOL(of_find_compatible_node);
/**
+ * of_find_node_with_property - Find a node which has a property with
+ * the given name.
+ * @from: The node to start searching from or NULL, the node
+ * you pass will not be searched, only the next one
+ * will; typically, you pass what the previous call
+ * returned. of_node_put() will be called on it
+ * @prop_name: The name of the property to look for.
+ *
+ * Returns a node pointer with refcount incremented, use
+ * of_node_put() on it when done.
+ */
+struct device_node *of_find_node_with_property(struct device_node *from,
+ const char *prop_name)
+{
+ struct device_node *np;
+ struct property *pp;
+
+ read_lock(&devtree_lock);
+ np = from ? from->allnext : allnodes;
+ for (; np; np = np->allnext) {
+ for (pp = np->properties; pp != 0; pp = pp->next) {
+ if (of_prop_cmp(pp->name, prop_name) == 0) {
+ of_node_get(np);
+ goto out;
+ }
+ }
+ }
+out:
+ of_node_put(from);
+ read_unlock(&devtree_lock);
+ return np;
+}
+EXPORT_SYMBOL(of_find_node_with_property);
+
+/**
* of_match_node - Tell if an device_node has a matching of_match structure
* @matches: array of of device match structures to search in
* @node: the of device structure to match against