binman: Add an entry method for getting the default filename

Various entry implementations provide a way to obtain the default filename
for an entry. But at present there is no base-class implementation for
this function. Add one so that the API is defined.

Signed-off-by: Simon Glass <sjg@chromium.org>

tools/binman/entry.py

@@ -160,6 +160,9 @@ class Entry(object):
         self.align_end = fdt_util.GetInt(self._node, 'align-end')
         self.offset_unset = fdt_util.GetBool(self._node, 'offset-unset')
 
+    def GetDefaultFilename(self):
+        return None
+
     def AddMissingProperties(self):
         """Add new properties to the device tree as needed for this entry"""
         for prop in ['offset', 'size', 'image-pos']:

tools/binman/entry_test.py

@@ -65,6 +65,11 @@ class TestEntry(unittest.TestCase):
         sub_entry = entry.Entry(None, None, sub_node, read_node=False)
         self.assertEqual('root.subnode', sub_entry.GetUniqueName())
 
+    def testGetDefaultFilename(self):
+        """Trivial test for this base class function"""
+        import entry
+        base_entry = entry.Entry(None, None, None, read_node=False)
+        self.assertIsNone(base_entry.GetDefaultFilename())
 
 if __name__ == "__main__":
     unittest.main()