src/adafruit_blinka/microcontroller/generic_linux/libgpiod_pin.py

   1 try:
   2     import gpiod
   3 except ImportError:
   4     raise ImportError("libgpiod Python bindings not found, please install and try again! See https://github.com/adafruit/Raspberry-Pi-Installer-Scripts/blob/master/libgpiod.sh")
   5
   6 # Pins dont exist in CPython so...lets make our own!
   7 class Pin:
   8     IN = 0
   9     OUT = 1
  10     LOW = 0
  11     HIGH = 1
  12     PULL_NONE = 0
  13     PULL_UP = 1
  14     PULL_DOWN = 2
  15     _CONSUMER = 'adafruit_blinka'
  16
  17     id = None
  18     _value = LOW
  19     _mode = IN
  20
  21     def __init__(self, pin_number, gpiod_chipname="gpiochip0"):
  22         self.id = int(pin_number)
  23         # FIXME: Presumably this might vary by system:
  24         self._chip = gpiod.Chip(gpiod_chipname, gpiod.Chip.OPEN_BY_NAME)
  25         self._line = None
  26
  27     def __repr__(self):
  28         return str(self.id)
  29
  30     def __eq__(self, other):
  31         return self.id == other
  32
  33     def init(self, mode=IN, pull=None):
  34         if not self._line:
  35             self._line = self._chip.get_line(int(self.id))
  36             print("init line: ", int(self.id), self._line)
  37
  38         if mode != None:
  39             if mode == self.IN:
  40                 flags = 0
  41                 if pull != None:
  42                     if pull == self.PULL_UP:
  43                         flags |= gpiod.LINE_REQ_FLAG_ACTIVE_LOW
  44                     elif pull == self.PULL_DOWN:
  45                         flags |= gpiod.LINE_REQ_FLAG_ACTIVE_HIGH
  46                     else:
  47                         raise RuntimeError("Invalid pull for pin: %s" % self.id)
  48
  49                 self._mode = self.IN
  50                 self._line.release()
  51                 self._line.request(consumer=self._CONSUMER,
  52                                    type=gpiod.LINE_REQ_DIR_IN,
  53                                    flags=flags)
  54
  55             elif mode == self.OUT:
  56                 if pull != None:
  57                     raise RuntimeError("Cannot set pull resistor on output")
  58                 self._mode = self.OUT
  59                 self._line.release()
  60                 self._line.request(consumer=self._CONSUMER,
  61                                    type=gpiod.LINE_REQ_DIR_OUT)
  62
  63             else:
  64                 raise RuntimeError("Invalid mode for pin: %s" % self.id)
  65
  66     def value(self, val=None):
  67         if val != None:
  68             if val in (self.LOW, self.HIGH):
  69                 self._value = val
  70                 self._line.set_value(val)
  71             else:
  72                 raise RuntimeError("Invalid value for pin")
  73         else:
  74             return self._line.get_value()