add support for potentiometers

kmk/modules/potentiometer.py

@@ -0,0 +1,103 @@
+import busio
+from analogio import AnalogIn
+from supervisor import ticks_ms
+
+from kmk.modules import Module
+
+class BasePotentiometer:
+    
+    def __init__(self, is_inverted=False):
+        self.is_inverted = is_inverted
+        self.read_pin = None
+        self._state = None
+        self._direction = None
+        self._pos = 0.0
+        self._timestamp = ticks_ms()
+        
+        # callback function on events. Needs to be defined externally
+        self.on_move_do = None
+        
+    def get_state(self):
+        return {
+            'direction': self.is_inverted and -self._direction or self._direction,
+            'position': self.is_inverted and -self._pos or self._pos,
+            'velocity': self._velocity,
+        }
+        
+    def update_state(self):
+        new_state = self.read_pin.value
+        
+        self._direction = 0
+        
+        if new_state != self._state:
+            # movement detected!
+            # Debounce...
+            
+            # AnalogRead always reports 16 bit values
+            # convert to percentage and round to hundreths
+            new_pos = round(new_state / 0xFFFF, 2)
+            
+            if new_pos != self._pos:
+                self._pos = new_pos
+            
+                if new_state > self._state:
+                    self._direction = 1
+                else:
+                    self._direction = -1
+                    
+                if self.on_move_do is not None:
+                    self.on_move_do(self.get_state())
+              
+class GPIOPotentiometer(BasePotentiometer):
+    def __init__(self, pin, move_callback, is_inverted = False):
+        super().__init__(is_inverted)
+        self.read_pin = AnalogIn(pin)
+        self.update_state()
+        self.cb = move_callback
+
+    def on_move_do(self, state):
+        self.cb(state)
+        
+class PotentiometerHandler(Module):
+    def __init__(self):
+        self.potentiometers = []
+        self.pins = None
+    
+    def on_runtime_enable(self, keyboard):
+        return
+
+    def on_runtime_disable(self, keyboard):
+        return
+
+    def during_bootup(self, keyboard):
+        if self.pins:
+            for args in enumerate(self.pins):
+                self.potentiometers.append( GPIOPotentiometer(*args) )
+        return
+    
+    def before_matrix_scan(self, keyboard):
+        '''
+        Return value will be injected as an extra matrix update
+        '''
+        for encoder in self.encoders:
+            encoder.update_state()
+
+        return keyboard
+
+    def after_matrix_scan(self, keyboard):
+        '''
+        Return value will be replace matrix update if supplied
+        '''
+        return
+
+    def before_hid_send(self, keyboard):
+        return
+
+    def after_hid_send(self, keyboard):
+        return
+
+    def on_powersave_enable(self, keyboard):
+        return
+
+    def on_powersave_disable(self, keyboard):
+        return