of: implement of_copy_property

For use in fixups, it can be useful to copy a property verbatim from the
barebox DT to the kernel DT. Add a helper that does just that.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.barebox.org/20230414183545.2039170-1-a.fatoum@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

3 files changed, 27 insertions, 1 deletions

diff --git a/drivers/of/base.c b/drivers/of/base.c
index ea4be9c512..9eaa93b5bb 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -2318,6 +2318,22 @@ struct property *of_rename_property(struct device_node *np,
 	return pp;
 }
 
+struct property *of_copy_property(const struct device_node *src,
+				  const char *propname,
+				  struct device_node *dst)
+{
+	struct property *prop;
+
+	prop = of_find_property(src, propname, NULL);
+	if (!prop)
+		return NULL;
+
+	return of_new_property(dst, propname,
+			       of_property_get_value(prop), prop->length);
+}
+EXPORT_SYMBOL_GPL(of_copy_property);
+
+
 /**
  * of_set_property - create a property for a given node
  * @node - the node
diff --git a/include/of.h b/include/of.h
index b88f39ebfa..106a570418 100644
--- a/include/of.h
+++ b/include/of.h
@@ -152,6 +152,9 @@ extern struct property *__of_new_property(struct device_node *node,
 extern void of_delete_property(struct property *pp);
 extern struct property *of_rename_property(struct device_node *np,
 					   const char *old_name, const char *new_name);
+extern struct property *of_copy_property(const struct device_node *src,
+					 const char *propname,
+					 struct device_node *dst);
 
 extern struct device_node *of_find_node_by_name(struct device_node *from,
 	const char *name);
@@ -577,6 +580,13 @@ static inline struct property *__of_new_property(struct device_node *node,
 	return NULL;
 }
 
+static inline struct property *of_copy_property(const struct device_node *src,
+						const char *propname,
+						struct device_node *dst)
+{
+	return NULL;
+}
+
 static inline void of_delete_property(struct property *pp)
 {
 }
diff --git a/test/self/of_manipulation.c b/test/self/of_manipulation.c
index f7f95fa269..64913ac1ea 100644
--- a/test/self/of_manipulation.c
+++ b/test/self/of_manipulation.c
@@ -63,7 +63,7 @@ static void test_of_basics(struct device_node *root)
 	of_property_write_u32(node2, "property2", 2);
 
 	of_property_write_u32(node1, "property3", 1);
-	of_property_write_u32(node1, "property2", 2);
+	of_copy_property(node2, "property2", node1);
 	of_rename_property(node1, "property3", "property1");
 
 	assert_equal(node1, node2);