klunky but working with DHT tests

[Adafruit_Blinka-hackapet.git] / src / adafruit_blinka / microcontroller / raspi_23 / pulseio / PulseIn.py

diff --git a/src/adafruit_blinka/microcontroller/raspi_23/pulseio/PulseIn.py b/src/adafruit_blinka/microcontroller/raspi_23/pulseio/PulseIn.py
new file mode 100644 (file)
index 0000000..ef77b74
--- /dev/null
+++ b/src/adafruit_blinka/microcontroller/raspi_23/pulseio/PulseIn.py
@@ -0,0 +1,97 @@
+import array
+import time
+import subprocess
+import os, signal
+import traceback
+import signal
+import sysv_ipc
+import atexit
+import random
+
+DEBUG = False
+queues = []
+procs = []
+
+# The message queues live outside of python space, and must be formally cleaned!
+def final():
+    if DEBUG:
+        print("Cleaning up message queues", queues)
+        print("Cleaning up processes", procs)
+    for q in queues:
+        q.remove()
+    for proc in procs:
+        proc.terminate()
+atexit.register(final)
+
+class PulseIn:
+    def __init__(self, pin, maxlen=2, idle_state=False):
+        self._pin = pin
+        self._maxlen = maxlen
+        self._idle_state = idle_state
+        self._queue_key = random.randint(1, 9999)
+        try:
+            self._mq = sysv_ipc.MessageQueue(None, flags=sysv_ipc.IPC_CREX)
+            if DEBUG:
+                print("Message Queue Key: ", self._mq.key)
+            queues.append(self._mq)
+        except sysv_ipc.ExistentialError:
+            raise RuntimeError("Message queue creation failed")
+
+        cmd = ["/home/pi/libgpiod_pulsein/src/libgpiod_pulsein",
+               "--pulses", str(maxlen),
+               "--queue", str(self._mq.key)]
+        if not idle_state:
+            cmd.append("-i")
+        cmd.append("gpiochip0")
+        cmd.append(str(pin))
+        if DEBUG:
+            print(cmd)
+        
+        self.process = subprocess.Popen(cmd)
+        procs.append(self.process)
+
+        # wait for it to start up
+        if DEBUG:
+            print("Waiting for startup success message from subprocess")
+        message = self._mq.receive(type=2)
+        if message[0] != b'!':
+            raise RuntimeError("Could not establish message queue with subprocess")
+
+
+    def __deinit__(self):
+        print("deinit")
+        
+    # TODO: this doesnt work?
+    def __enter__(self):
+        print("enter")
+        pass # no-op
+
+    # TODO: this doesnt work?
+    def __exit__(self, exc_type, exc_value, tb):
+        print("exit")
+        #self.process.kill()
+
+    def resume(self, trigger_duration=0):
+        if trigger_duration != 0:
+            self._mq.send("t%d" % trigger_duration, True, type=1)
+        else:
+            self._mq.send("r", True, type=1)
+
+    def pause(self):
+        self._mq.send("p", True, type=1)
+
+    def clear(self):
+        self._mq.send("c", True, type=1)
+
+    def popleft(self):
+        self._mq.send("^", True, type=1)
+        message = self._mq.receive(type=2)
+        reply = int(message[0].decode('utf-8'))
+        if reply == -1:
+            reply = None
+        return reply
+
+    def __len__(self):
+        self._mq.send("l", True, type=1)
+        message = self._mq.receive(type=2)
+        return int(message[0].decode('utf-8'))