stmhal: Add .value() method to Switch object, to mirror Pin and Signal.

docs/library/pyb.Switch.rst

@@ -8,7 +8,8 @@ A Switch object is used to control a push-button switch.
 Usage::
 
      sw = pyb.Switch()       # create a switch object
-     sw()                    # get state (True if pressed, False otherwise)
+     sw.value()              # get state (True if pressed, False otherwise)
+     sw()                    # shorthand notation to get the switch state
      sw.callback(f)          # register a callback to be called when the
                              #   switch is pressed down
      sw.callback(None)       # remove the callback
@@ -34,6 +35,10 @@ Methods
    Call switch object directly to get its state: ``True`` if pressed down,
    ``False`` otherwise.
 
+.. method:: Switch.value()
+
+   Get the switch state.  Returns `True` if pressed down, otherwise `False`.
+
 .. method:: Switch.callback(fun)
 
    Register the given function to be called when the switch is pressed down.

docs/pyboard/tutorial/switch.rst

@@ -15,12 +15,18 @@ the name ``pyb`` does not exist.
 
 With the switch object you can get its status::
 
-    >>> sw()
+    >>> sw.value()
     False
 
 This will print ``False`` if the switch is not held, or ``True`` if it is held.
 Try holding the USR switch down while running the above command.
 
+There is also a shorthand notation to get the switch status, by "calling" the
+switch object::
+
+    >>> sw()
+    False
+
 Switch callbacks
 ----------------
 

stmhal/usrsw.c

@@ -97,6 +97,12 @@ mp_obj_t pyb_switch_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_
     return switch_get() ? mp_const_true : mp_const_false;
 }
 
+mp_obj_t pyb_switch_value(mp_obj_t self_in) {
+    (void)self_in;
+    return mp_obj_new_bool(switch_get());
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_switch_value_obj, pyb_switch_value);
+
 STATIC mp_obj_t switch_callback(mp_obj_t line) {
     if (MP_STATE_PORT(pyb_switch_callback) != mp_const_none) {
         mp_call_function_0(MP_STATE_PORT(pyb_switch_callback));
@@ -123,6 +129,7 @@ mp_obj_t pyb_switch_callback(mp_obj_t self_in, mp_obj_t callback) {
 STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_switch_callback_obj, pyb_switch_callback);
 
 STATIC const mp_rom_map_elem_t pyb_switch_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_value), MP_ROM_PTR(&pyb_switch_value_obj) },
     { MP_ROM_QSTR(MP_QSTR_callback), MP_ROM_PTR(&pyb_switch_callback_obj) },
 };