provide default coord_mapping from scanners

kmk/scanners/__init__.py

@@ -24,6 +24,10 @@ class Scanner:
 
     coord_mapping = None
 
+    @property
+    def key_count(self):
+        raise NotImplementedError
+
     def scan_for_changes(self):
         '''
         Scan for key events and return a key report if an event exists.

kmk/scanners/digitalio_matrix.py

@@ -77,8 +77,13 @@ class MatrixScanner(Scanner):
         if self.rollover_cols_every_rows is None:
             self.rollover_cols_every_rows = self.len_rows
 
-        self.len_state_arrays = self.len_cols * self.len_rows
-        self.state = bytearray(self.len_state_arrays)
+        self._key_count = self.len_cols * self.len_rows
+        self.coord_mapping = tuple(range(self.key_count))
+        self.state = bytearray(self.key_count)
+
+    @property
+    def key_count(self):
+        return self._key_count
 
     def scan_for_changes(self):
         '''

kmk/scanners/native_keypad_scanner.py

@@ -16,10 +16,14 @@ class NativeKeypadScanner(Scanner):
         self.keypad = kp
         # for split keyboards, the offset value will be assigned in Split module
         self.offset = 0
-        self.coord_mapping = list(range(len(pin_map)))
+        self.coord_mapping = tuple(range(self.key_count))
 
         self.curr_event = keypad.Event()
 
+    @property
+    def key_count(self):
+        return self.keypad.key_count
+
     def scan_for_changes(self):
         '''
         Scan for key events and return a key report if an event exists.