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>

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>
Michael Ellerman · Paul Mackerras
1 parent ae564c63b8
Showing 2 changed files with 41 additions and 0 deletions Side-by-side Diff
drivers/of/base.c
include/linux/of.h
@@ -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
@@ -57,6 +57,12 @@
 	for (child = of_get_next_child(parent, NULL); child != NULL; \
 	     child = of_get_next_child(parent, child))
  
+extern struct device_node *of_find_node_with_property(
+	struct device_node *from, const char *prop_name);
+#define for_each_node_with_property(dn, prop_name) \
+	for (dn = of_find_node_with_property(NULL, prop_name); dn; \
+	     dn = of_find_node_with_property(dn, prop_name))
+
 extern struct property *of_find_property(const struct device_node *np,
 					 const char *name,
 					 int *lenp);
...	...	@@ -329,6 +329,41 @@
329	329	EXPORT_SYMBOL(of_find_compatible_node);
330	330
331	331	/**
	332	+ * of_find_node_with_property - Find a node which has a property with
	333	+ * the given name.
	334	+ * @from: The node to start searching from or NULL, the node
	335	+ * you pass will not be searched, only the next one
	336	+ * will; typically, you pass what the previous call
	337	+ * returned. of_node_put() will be called on it
	338	+ * @prop_name: The name of the property to look for.
	339	+ *
	340	+ * Returns a node pointer with refcount incremented, use
	341	+ * of_node_put() on it when done.
	342	+ */
	343	+struct device_node of_find_node_with_property(struct device_node from,
	344	+ const char *prop_name)
	345	+{
	346	+ struct device_node *np;
	347	+ struct property *pp;
	348	+
	349	+ read_lock(&devtree_lock);
	350	+ np = from ? from->allnext : allnodes;
	351	+ for (; np; np = np->allnext) {
	352	+ for (pp = np->properties; pp != 0; pp = pp->next) {
	353	+ if (of_prop_cmp(pp->name, prop_name) == 0) {
	354	+ of_node_get(np);
	355	+ goto out;
	356	+ }
	357	+ }
	358	+ }
	359	+out:
	360	+ of_node_put(from);
	361	+ read_unlock(&devtree_lock);
	362	+ return np;
	363	+}
	364	+EXPORT_SYMBOL(of_find_node_with_property);
	365	+
	366	+/**
332	367	* of_match_node - Tell if an device_node has a matching of_match structure
333	368	* @matches: array of of device match structures to search in
334	369	* @node: the of device structure to match against
...	...	@@ -57,6 +57,12 @@
57	57	for (child = of_get_next_child(parent, NULL); child != NULL; \
58	58	child = of_get_next_child(parent, child))
59	59
	60	+extern struct device_node *of_find_node_with_property(
	61	+ struct device_node from, const char prop_name);
	62	+#define for_each_node_with_property(dn, prop_name) \
	63	+ for (dn = of_find_node_with_property(NULL, prop_name); dn; \
	64	+ dn = of_find_node_with_property(dn, prop_name))
	65	+
60	66	extern struct property of_find_property(const struct device_node np,
61	67	const char *name,
62	68	int *lenp);