of: Support const and non-const use for to_of_node()

Turn to_of_node() into a macro in order to support both const and
non-const use. Additionally make the fwnode argument to is_of_node() const
as well.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Rob Herring <robh@kernel.org>

1 files changed, 12 insertions, 8 deletions

diff --git a/include/linux/of.h b/include/linux/of.h
index f05c87f0c495..29b7b738b509 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -148,16 +148,20 @@ extern raw_spinlock_t devtree_lock;
 #ifdef CONFIG_OF
 void of_core_init(void);
 
-static inline bool is_of_node(struct fwnode_handle *fwnode)
+static inline bool is_of_node(const struct fwnode_handle *fwnode)
 {
         return !IS_ERR_OR_NULL(fwnode) && fwnode->type == FWNODE_OF;
 }
 
-static inline struct device_node *to_of_node(struct fwnode_handle *fwnode)
-{
-        return is_of_node(fwnode) ?
-                container_of(fwnode, struct device_node, fwnode) : NULL;
-}
+#define to_of_node(__fwnode)                                            \
+        ({                                                              \
+                typeof(__fwnode) __to_of_node_fwnode = (__fwnode);      \
+                                                                        \
+                is_of_node(__to_of_node_fwnode) ?                       \
+                        container_of(__to_of_node_fwnode,               \
+                                     struct device_node, fwnode) :      \
+                        NULL;                                           \
+        })
 
 #define of_fwnode_handle(node)                                          \
         ({                                                              \
@@ -539,12 +543,12 @@ static inline void of_core_init(void)
 {
 }
 
-static inline bool is_of_node(struct fwnode_handle *fwnode)
+static inline bool is_of_node(const struct fwnode_handle *fwnode)
 {
         return false;
 }
 
-static inline struct device_node *to_of_node(struct fwnode_handle *fwnode)
+static inline struct device_node *to_of_node(const struct fwnode_handle *fwnode)
 {
         return NULL;
 }