Port moisture to gpiod.

grow/moisture.py

@@ -1,6 +1,13 @@
 import time
+import select
+import threading
+from datetime import timedelta
+import atexit
+
+import gpiodevice
+from gpiod import LineSettings
+from gpiod.line import Edge, Bias
 
-import RPi.GPIO as GPIO
 
 MOISTURE_1_PIN = 23
 MOISTURE_2_PIN = 8
@@ -25,46 +32,55 @@ class Moisture(object):
         """
         self._gpio_pin = [MOISTURE_1_PIN, MOISTURE_2_PIN, MOISTURE_3_PIN, MOISTURE_INT_PIN][channel - 1]
 
-        GPIO.setwarnings(False)
-        GPIO.setmode(GPIO.BCM)
-        GPIO.setup(self._gpio_pin, GPIO.IN)
-
         self._count = 0
         self._reading = 0
         self._history = []
         self._history_length = 200
-        self._last_pulse = time.time()
         self._new_data = False
         self._wet_point = wet_point if wet_point is not None else 0.7
         self._dry_point = dry_point if dry_point is not None else 27.6
-        self._time_last_reading = time.time()
+
+        self._last_reading = 0
+
+        self._int, self._offset = gpiodevice.get_pin(self._gpio_pin, f"grow-m-ch{channel}", LineSettings(
+            edge_detection=Edge.RISING, bias=Bias.PULL_DOWN, debounce_period=timedelta(milliseconds=10)
+        ))
+
+        self._poll_thread_event = threading.Event()
+        self._poll_thread = threading.Thread(target=self._thread_poll)
+        self._poll_thread.start()
+
+        atexit.register(self._thread_stop)
+
+    def __del__(self):
+        self._thread_stop()
+
+    def _thread_stop(self):
+        self._poll_thread_event.set()
+        self._poll_thread.join()
+
+    def _thread_poll(self):
+        poll = select.poll()
         try:
-            GPIO.add_event_detect(self._gpio_pin, GPIO.RISING, callback=self._event_handler, bouncetime=1)
-        except RuntimeError as e:
-            if self._gpio_pin == 8:
-                raise RuntimeError("""Unable to set up edge detection on BCM8.
+            poll.register(self._int.fd, select.POLLIN)
+        except TypeError:
+            return
+        while not self._poll_thread_event.wait(1.0):
+            if not poll.poll(0):
+                # No pulses in 1s, this is not a valid reading
+                continue
 
-Please ensure you add the following to /boot/config.txt and reboot:
-
-dtoverlay=spi0-cs,cs0_pin=14 # Re-assign CS0 from BCM 8 so that Grow can use it
-
-""")
-            else:
-                raise e
-
-        self._time_start = time.time()
-
-    def _event_handler(self, pin):
-        self._count += 1
-        self._last_pulse = time.time()
-        if self._time_elapsed >= 1.0:
-            self._reading = self._count / self._time_elapsed
+            # We got pulses, since we waited for 1s we can be relatively
+            # sure the number of pulses is approximately the sensor frequency
+            events = self._int.read_edge_events()
+            self._last_reading = time.time()
+            self._reading = len(events)  # Pulse frequency
             self._history.insert(0, self._reading)
             self._history = self._history[:self._history_length]
-            self._count = 0
-            self._time_last_reading = time.time()
             self._new_data = True
 
+        poll.unregister(self._int.fd)
+
     @property
     def history(self):
         history = []
@@ -76,10 +92,6 @@ dtoverlay=spi0-cs,cs0_pin=14 # Re-assign CS0 from BCM 8 so that Grow can use it
 
         return history
 
-    @property
-    def _time_elapsed(self):
-        return time.time() - self._time_last_reading
-
     def set_wet_point(self, value=None):
         """Set the sensor wet point.
 
@@ -123,7 +135,7 @@ dtoverlay=spi0-cs,cs0_pin=14 # Re-assign CS0 from BCM 8 so that Grow can use it
     @property
     def active(self):
         """Check if the moisture sensor is producing a valid reading."""
-        return (time.time() - self._last_pulse) < 1.0 and self._reading > 0 and self._reading < 28
+        return (time.time() - self._last_reading) <= 1.0 and self._reading > 0 and self._reading < 28
 
     @property
     def new_data(self):