X-Git-Url: https://git.ayoreis.com/Adafruit_Blinka-hackapet.git/blobdiff_plain/a3770186a94117be56a8d9a8038a2d540bd2884c..1530cf9cbfb008ff6a7e54e695dcb5a34f95d5a4:/src/adafruit_blinka/microcontroller/bcm283x/pulseio/PulseIn.py diff --git a/src/adafruit_blinka/microcontroller/bcm283x/pulseio/PulseIn.py b/src/adafruit_blinka/microcontroller/bcm283x/pulseio/PulseIn.py index 6b86614..4f7ae36 100644 --- a/src/adafruit_blinka/microcontroller/bcm283x/pulseio/PulseIn.py +++ b/src/adafruit_blinka/microcontroller/bcm283x/pulseio/PulseIn.py @@ -1,15 +1,20 @@ +# SPDX-FileCopyrightText: 2021 Melissa LeBlanc-Williams for Adafruit Industries +# +# SPDX-License-Identifier: MIT """Custom PulseIn Class to read PWM signals""" import time import subprocess import os import atexit import random +import struct import sysv_ipc DEBUG = False queues = [] procs = [] + # The message queues live outside of python space, and must be formally cleaned! def final(): """In case the program is cancelled or quit, we need to clean up the PulseIn @@ -25,6 +30,7 @@ def final(): atexit.register(final) + # pylint: disable=c-extension-no-member class PulseIn: """PulseIn Class to read PWM signals""" @@ -45,11 +51,19 @@ class PulseIn: print("Message Queue Key: ", self._mq.key) queues.append(self._mq) except sysv_ipc.ExistentialError: - raise RuntimeError("Message queue creation failed") + raise RuntimeError( + "Message queue creation failed" + ) from sysv_ipc.ExistentialError + + # Check if OS is 64-bit + if struct.calcsize("P") * 8 == 64: # pylint: disable=no-member + libgpiod_filename = "libgpiod_pulsein64" + else: + libgpiod_filename = "libgpiod_pulsein" dir_path = os.path.dirname(os.path.realpath(__file__)) cmd = [ - dir_path + "/libgpiod_pulsein", + dir_path + "/" + libgpiod_filename, "--pulses", str(maxlen), "--queue", @@ -62,30 +76,35 @@ class PulseIn: if DEBUG: print(cmd) - self._process = subprocess.Popen(cmd) + self._process = subprocess.Popen(cmd) # pylint: disable=consider-using-with procs.append(self._process) # wait for it to start up if DEBUG: print("Waiting for startup success message from subprocess") - message = self._wait_receive_msg() + message = self._wait_receive_msg(timeout=0.25) if message[0] != b"!": raise RuntimeError("Could not establish message queue with subprocess") self._paused = False # pylint: disable=redefined-builtin - def _wait_receive_msg(self, timeout=0.25, type=2): + def _wait_receive_msg(self, timeout=0, type=2): """Internal helper that will wait for new messages of a given type, and throw an exception on timeout""" - stamp = time.monotonic() - while (time.monotonic() - stamp) < timeout: - try: - message = self._mq.receive(block=False, type=type) - return message - except sysv_ipc.BusyError: - time.sleep(0.001) # wait a bit then retry! - # uh-oh timed out - raise RuntimeError("Timed out waiting for PulseIn message") + if timeout > 0: + stamp = time.monotonic() + while (time.monotonic() - stamp) < timeout: + try: + message = self._mq.receive(block=False, type=type) + return message + except sysv_ipc.BusyError: + time.sleep(0.001) # wait a bit then retry! + # uh-oh timed out + raise RuntimeError( + "Timed out waiting for PulseIn message. Make sure libgpiod is installed." + ) + message = self._mq.receive(block=True, type=type) + return message # pylint: enable=redefined-builtin