Merge pull request #8 from pimoroni/feature/switch-counters

Add method to clear a switch counter

library/ioexpander/__init__.py

@@ -396,6 +396,17 @@ def read_switch_counter(self, pin):
         # The most significant bit encodes the current GPIO state
         return value & 0x7f, value & 0x80 == 0x80
 
+    def clear_switch_counter(self, pin):
+        """Clear the switch count value on a pin to 0."""
+        io_pin = self.get_pin(pin)
+
+        if io_pin.port not in (0, 1):
+            raise ValueError("Pin {} does not support switch counting.".format(pin))
+
+        sw_reg = [REG_SWITCH_P00, REG_SWITCH_P10][io_pin.port] + io_pin.pin
+
+        self.i2c_write8(sw_reg, 0)
+
     def setup_rotary_encoder(self, channel, pin_a, pin_b, pin_c=None, count_microsteps=False):
         """Set up a rotary encoder."""
         channel -= 1

library/tests/test_switch_counter.py

@@ -13,6 +13,11 @@ def test_read_switch_counter(smbus2, ioe):
     assert ioe.read_switch_counter(1) == (2, False)
 
 
+def test_clear_switch_counter(smbus2, ioe):
+    ioe.clear_switch_counter(1)
+    assert smbus2.SMBus(1).i2c_rdwr.called_once()
+
+
 def test_switch_counter_invalid_pin(smbus2, ioe):
     with pytest.raises(ValueError):
         ioe.setup_switch_counter(10)