device property: Introduce fwnode_property_get_reference_args

The new fwnode_property_get_reference_args() interface amends the fwnode
property API with the functionality of both of_parse_phandle_with_args()
and __acpi_node_get_property_reference().

The semantics is slightly different: the cells property is ignored on ACPI
as the number of arguments can be explicitly obtained from the firmware
interface.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h
index 7b50ee4edcfc..0c35b6caf0f6 100644
--- a/include/linux/fwnode.h
+++ b/include/linux/fwnode.h
@@ -33,6 +33,20 @@ struct fwnode_endpoint {
 	const struct fwnode_handle *local_fwnode;
 };
 
+#define NR_FWNODE_REFERENCE_ARGS	8
+
+/**
+ * struct fwnode_reference_args - Fwnode reference with additional arguments
+ * @fwnode:- A reference to the base fwnode
+ * @nargs: Number of elements in @args array
+ * @args: Integer arguments on the fwnode
+ */
+struct fwnode_reference_args {
+	struct fwnode_handle *fwnode;
+	unsigned int nargs;
+	unsigned int args[NR_FWNODE_REFERENCE_ARGS];
+};
+
 /**
  * struct fwnode_operations - Operations for fwnode interface
  * @get: Get a reference to an fwnode.
@@ -46,6 +60,7 @@ struct fwnode_endpoint {
  * @get_parent: Return the parent of an fwnode.
  * @get_next_child_node: Return the next child node in an iteration.
  * @get_named_child_node: Return a child node with a given name.
+ * @get_reference_args: Return a reference pointed to by a property, with args
  * @graph_get_next_endpoint: Return an endpoint node in an iteration.
  * @graph_get_remote_endpoint: Return the remote endpoint node of a local
  *			       endpoint node.
@@ -73,6 +88,10 @@ struct fwnode_operations {
 	struct fwnode_handle *
 	(*get_named_child_node)(const struct fwnode_handle *fwnode,
 				const char *name);
+	int (*get_reference_args)(const struct fwnode_handle *fwnode,
+				  const char *prop, const char *nargs_prop,
+				  unsigned int nargs, unsigned int index,
+				  struct fwnode_reference_args *args);
 	struct fwnode_handle *
 	(*graph_get_next_endpoint)(const struct fwnode_handle *fwnode,
 				   struct fwnode_handle *prev);