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>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/of.h b/include/linux/of.h
index e2488f5e7cb2..6a7efa242f5e 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -57,6 +57,12 @@ extern struct device_node *of_get_next_child(const struct device_node *node,
         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);