Support for rotary encoder

README.rst

@@ -41,9 +41,10 @@ Mopidy-Raspberry-GPIO to your Mopidy configuration file::
     [raspberry-gpio]
     enabled = true
     bcm5 = play_pause,active_low,250
-    bcm6 = volume_down,active_low,250
+    bcm6 = prev,active_low,250
     bcm16 = next,active_low,250
-    bcm20 = volume_up,active_low,250
+    bcm21 = volume_down,active_low,10,rotenc_id=vol,step=1
+    bcm20 = volume_up,active_low,10,rotenc_id=vol,step=1
 
 Each bcmN entry corresponds to the BCM pin of that number.
 

mopidy_raspberry_gpio/frontend.py

@@ -3,6 +3,8 @@
 import pykka
 from mopidy import core
 
+from .rotencoder import RotEncoder
+
 logger = logging.getLogger(__name__)
 
 
@@ -14,6 +16,7 @@ def __init__(self, config, core):
         self.core = core
         self.config = config["raspberry-gpio"]
         self.pin_settings = {}
+        self.rot_encoders = {}
 
         GPIO.setwarnings(False)
         GPIO.setmode(GPIO.BCM)
@@ -33,6 +36,17 @@ def __init__(self, config, core):
                     pull = GPIO.PUD_DOWN
                     edge = GPIO.RISING
 
+                if "rotenc_id" in settings.options:
+                    edge = GPIO.BOTH
+                    rotenc_id = settings.options["rotenc_id"]
+                    encoder = None
+                    if rotenc_id in self.rot_encoders.keys():
+                        encoder = self.rot_encoders[rotenc_id]
+                    else:
+                        encoder = RotEncoder(rotenc_id)
+                        self.rot_encoders[rotenc_id] = encoder
+                    encoder.add_pin(pin, settings.event)
+
                 GPIO.setup(pin, GPIO.IN, pull_up_down=pull)
 
                 GPIO.add_event_detect(
@@ -44,17 +58,30 @@ def __init__(self, config, core):
 
                 self.pin_settings[pin] = settings
 
+        # TODO validate all self.rot_encoders have two pins
+
+    def find_pin_rotenc(self, pin):
+        for encoder in self.rot_encoders.values():
+            if pin in encoder.pins:
+                return encoder
+
     def gpio_event(self, pin):
         settings = self.pin_settings[pin]
-        self.dispatch_input(settings)
+        event = settings.event
+        encoder = self.find_pin_rotenc(pin)
+        if encoder:
+            event = encoder.get_event()
+
+        if event:
+            self.dispatch_input(event, settings.options)
 
-    def dispatch_input(self, settings):
-        handler_name = f"handle_{settings.event}"
+    def dispatch_input(self, event, options):
+        handler_name = f"handle_{event}"
         try:
-            getattr(self, handler_name)(settings.options)
+            getattr(self, handler_name)(options)
         except AttributeError:
             raise RuntimeError(
-                f"Could not find input handler for event: {settings.event}"
+                f"Could not find input handler for event: {event}"
             )
 
     def handle_play_pause(self, config):

mopidy_raspberry_gpio/rotencoder.py

@@ -0,0 +1,51 @@
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class RotEncoder:
+    def __init__(self, rot_id):
+        self.id = rot_id
+        self.pins = []
+        self.events = []
+        self.state = (None, None)
+        self.state_map = {
+            ((False, False), (False, True)): 0,
+            ((False, False), (True, False)): 1,
+            ((False, True), (True, True)): 0,
+            ((False, True), (False, False)): 1,
+            ((True, False), (False, False)): 0,
+            ((True, False), (True, True)): 1,
+            ((True, True), (True, False)): 0,
+            ((True, True), (False, True)): 1,
+        }
+
+    def add_pin(self, pin, event):
+        if len(self.pins) == 2:
+            raise RuntimeError(f"Too many pins for rotary encoder {self.id}!")
+        self.pins.append(pin)
+        self.events.append(event)
+
+    def get_state(self):
+        import RPi.GPIO as GPIO
+
+        level0 = GPIO.input(self.pins[0])
+        level1 = GPIO.input(self.pins[1])
+
+        return (level0, level1)
+
+    def get_direction(self, current, new):
+        return self.state_map[(current, new)]
+
+    def get_event(self):
+        next_state = self.get_state()
+
+        event = None
+        try:
+            direction = self.get_direction(self.state, next_state)
+            event = self.events[direction]
+        except KeyError:
+            pass
+
+        self.state = next_state
+        return event

tests/test_frontend.py

@@ -18,6 +18,8 @@
         "bcm1": deserialize("play_pause,active_low,30"),
         "bcm2": deserialize("volume_up,active_high,30"),
         "bcm3": deserialize("volume_down,active_high,30"),
+        "bcm4": deserialize("volume_down,active_high,250,rotenc_id=vol"),
+        "bcm5": deserialize("volume_up,active_high,250,rotenc_id=vol"),
     }
 }
 
@@ -61,7 +63,7 @@ def test_frontend_handler_dispatch_play_pause():
     schema = ext.get_config_schema()
     settings = schema["bcm1"].deserialize("play_pause,active_low,30")
 
-    frontend.dispatch_input(settings)
+    frontend.dispatch_input(settings.event, settings.options)
 
     stop_mopidy_core()
 
@@ -78,7 +80,7 @@ def test_frontend_handler_dispatch_play_stop():
     schema = ext.get_config_schema()
     settings = schema["bcm1"].deserialize("play_stop,active_low,30")
 
-    frontend.dispatch_input(settings)
+    frontend.dispatch_input(settings.event, settings.options)
 
     stop_mopidy_core()
 
@@ -95,7 +97,7 @@ def test_frontend_handler_dispatch_next():
     schema = ext.get_config_schema()
     settings = schema["bcm1"].deserialize("next,active_low,30")
 
-    frontend.dispatch_input(settings)
+    frontend.dispatch_input(settings.event, settings.options)
 
     stop_mopidy_core()
 
@@ -112,7 +114,7 @@ def test_frontend_handler_dispatch_prev():
     schema = ext.get_config_schema()
     settings = schema["bcm1"].deserialize("prev,active_low,30")
 
-    frontend.dispatch_input(settings)
+    frontend.dispatch_input(settings.event, settings.options)
 
     stop_mopidy_core()
 
@@ -129,7 +131,7 @@ def test_frontend_handler_dispatch_volume_up():
     schema = ext.get_config_schema()
     settings = schema["bcm1"].deserialize("volume_up,active_low,30")
 
-    frontend.dispatch_input(settings)
+    frontend.dispatch_input(settings.event, settings.options)
 
     stop_mopidy_core()
 
@@ -146,7 +148,7 @@ def test_frontend_handler_dispatch_volume_down():
     schema = ext.get_config_schema()
     settings = schema["bcm1"].deserialize("volume_down,active_low,30")
 
-    frontend.dispatch_input(settings)
+    frontend.dispatch_input(settings.event, settings.options)
 
     stop_mopidy_core()
 
@@ -163,7 +165,7 @@ def test_frontend_handler_dispatch_volume_up_custom_step():
     schema = ext.get_config_schema()
     settings = schema["bcm1"].deserialize("volume_up,active_low,30,step=1")
 
-    frontend.dispatch_input(settings)
+    frontend.dispatch_input(settings.event, settings.options)
 
     stop_mopidy_core()
 
@@ -180,7 +182,7 @@ def test_frontend_handler_dispatch_volume_down_custom_step():
     schema = ext.get_config_schema()
     settings = schema["bcm1"].deserialize("volume_down,active_low,30,step=1")
 
-    frontend.dispatch_input(settings)
+    frontend.dispatch_input(settings.event, settings.options)
 
     stop_mopidy_core()
 
@@ -196,3 +198,31 @@ def test_frontend_gpio_event():
     frontend.gpio_event(3)
 
     stop_mopidy_core()
+
+
+@mock.patch("RPi.GPIO.input")
+def test_frontend_rot_encoder_event(patched_input):
+    patched_input.return_value = False
+
+    frontend = frontend_lib.RaspberryGPIOFrontend(
+        dummy_config, dummy_mopidy_core()
+    )
+
+    # Check that transition (False, True) -> (False, False) triggers volume_up
+    encoder = frontend.rot_encoders["vol"]
+    encoder.state = (False, True)
+
+    dispatch_input = mock.Mock()
+    frontend.dispatch_input = dispatch_input
+
+    frontend.gpio_event(4)
+    assert dispatch_input.call_args[0][0] == "volume_up"
+    assert encoder.state == (False, False)
+
+    # Check that we do not submit an event for the invalid transition
+    # (False, False) -> (False, False)
+    dispatch_input.reset_mock()
+    frontend.gpio_event(4)
+    dispatch_input.assert_not_called()
+
+    stop_mopidy_core()

tests/test_rotencoder.py

@@ -0,0 +1,54 @@
+import unittest
+
+from unittest.mock import patch
+from mopidy_raspberry_gpio import RotEncoder
+
+
+class RotEncoderTests(unittest.TestCase):
+    def test_rotenc_init(self):
+        rot_enc = RotEncoder("vol")
+        self.assertTrue(rot_enc.id == "vol")
+        self.assertTrue(((False, False), (False, True)) in rot_enc.state_map)
+
+    def test_get_direction(self):
+        rot_enc = RotEncoder("vol")
+        rot_enc.add_pin(123, "vol_up")
+        rot_enc.add_pin(124, "vol_down")
+
+        dir_down = rot_enc.get_direction((False, False), (False, True))
+        dir_up = rot_enc.get_direction((False, False), (True, False))
+
+        self.assertEqual(dir_up, 1)
+        self.assertEqual(dir_down, 0)
+
+    def test_add_pin_invalid(self):
+        rot_enc = RotEncoder("vol")
+        rot_enc.add_pin(123, "vol_up")
+        rot_enc.add_pin(124, "vol_down")
+
+        with self.assertRaises(RuntimeError):
+            rot_enc.add_pin(124, "vol_down")
+
+    @patch("RPi.GPIO.input")
+    def test_get_event(self, patched_input):
+        # Always return False for GPIO.input
+        patched_input.return_value = False
+
+        rot_enc = RotEncoder("vol")
+        rot_enc.add_pin(123, "vol_down")  # dir 0 => vol_down
+        rot_enc.add_pin(124, "vol_up")  # dir 1 => vol_up
+
+        # from False,True to False,False => dir 1
+        rot_enc.state = (False, True)
+        event = rot_enc.get_event()
+        self.assertEqual(event, "vol_up")
+
+        # from True,False to False,False => dir 0
+        rot_enc.state = (True, False)
+        event = rot_enc.get_event()
+        self.assertEqual(event, "vol_down")
+
+        # from True,True to False,False => None
+        rot_enc.state = (True, True)
+        event = rot_enc.get_event()
+        self.assertEqual(event, None)