device property: Add fwnode_graph_get_endpoint_by_id()

fwnode_graph_get_endpoint_by_id() is intended for obtaining local
endpoints by a given local port.

fwnode_graph_get_endpoint_by_id() is slightly different from its OF
counterpart, of_graph_get_endpoint_by_regs(): instead of using -1 as
a value to indicate that a port or an endpoint number does not matter,
it uses flags to look for equal or greater endpoint. The port number
is always fixed. It also returns only remote endpoints that belong
to an available device, a behaviour that can be turned off with a flag.

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

include/linux/property.h

@@ -13,6 +13,7 @@
 #ifndef _LINUX_PROPERTY_H_
 #define _LINUX_PROPERTY_H_
 
+#include <linux/bits.h>
 #include <linux/fwnode.h>
 #include <linux/types.h>
 
@@ -304,6 +305,23 @@ struct fwnode_handle *
 fwnode_graph_get_remote_node(const struct fwnode_handle *fwnode, u32 port,
 			     u32 endpoint);
 
+/*
+ * Fwnode lookup flags
+ *
+ * @FWNODE_GRAPH_ENDPOINT_NEXT: In the case of no exact match, look for the
+ *				closest endpoint ID greater than the specified
+ *				one.
+ * @FWNODE_GRAPH_DEVICE_DISABLED: That the device to which the remote
+ *				  endpoint of the given endpoint belongs to,
+ *				  may be disabled.
+ */
+#define FWNODE_GRAPH_ENDPOINT_NEXT	BIT(0)
+#define FWNODE_GRAPH_DEVICE_DISABLED	BIT(1)
+
+struct fwnode_handle *
+fwnode_graph_get_endpoint_by_id(const struct fwnode_handle *fwnode,
+				u32 port, u32 endpoint, unsigned long flags);
+
 #define fwnode_graph_for_each_endpoint(fwnode, child)			\
 	for (child = NULL;						\
 	     (child = fwnode_graph_get_next_endpoint(fwnode, child)); )