src/adafruit_blinka/microcontroller/generic_linux/libgpiod_pin.py

   1 # SPDX-FileCopyrightText: 2021 Melissa LeBlanc-Williams for Adafruit Industries
   2 #
   3 # SPDX-License-Identifier: MIT
   4 """A Pin class for use with libgpiod."""
   5 try:
   6     import gpiod
   7 except ImportError:
   8     raise ImportError(
   9         "libgpiod Python bindings not found, please install and try again! See "
  10         "https://github.com/adafruit/Raspberry-Pi-Installer-Scripts/blob/master/libgpiod.sh"
  11     ) from ImportError
  12
  13
  14 # pylint: disable=too-many-branches,too-many-statements
  15 class Pin:
  16     """Pins dont exist in CPython so...lets make our own!"""
  17
  18     IN = 0
  19     OUT = 1
  20     LOW = 0
  21     HIGH = 1
  22     PULL_NONE = 0
  23     PULL_UP = 1
  24     PULL_DOWN = 2
  25     _CONSUMER = "adafruit_blinka"
  26
  27     id = None
  28     _value = LOW
  29     _mode = IN
  30
  31     def __init__(self, pin_id):
  32         self.id = pin_id
  33         if isinstance(pin_id, tuple):
  34             self._num = int(pin_id[1])
  35             if hasattr(gpiod, "Chip"):
  36                 self._chip = gpiod.Chip(str(pin_id[0]), gpiod.Chip.OPEN_BY_NUMBER)
  37             else:
  38                 self._chip = gpiod.chip(str(pin_id[0]), gpiod.chip.OPEN_BY_NUMBER)
  39         else:
  40             self._num = int(pin_id)
  41             if hasattr(gpiod, "Chip"):
  42                 self._chip = gpiod.Chip("gpiochip0", gpiod.Chip.OPEN_BY_NAME)
  43             else:
  44                 self._chip = gpiod.chip("gpiochip0", gpiod.chip.OPEN_BY_NAME)
  45         self._line = None
  46
  47     def __repr__(self):
  48         return str(self.id)
  49
  50     def __eq__(self, other):
  51         return self.id == other
  52
  53     def init(self, mode=IN, pull=None):
  54         """Initialize the Pin"""
  55         if not self._line:
  56             self._line = self._chip.get_line(int(self._num))
  57             # print("init line: ", self.id, self._line)
  58
  59         if mode is not None:
  60             if mode == self.IN:
  61                 flags = 0
  62                 self._line.release()
  63                 if pull is not None:
  64                     if pull == self.PULL_UP:
  65                         if hasattr(gpiod, "LINE_REQ_FLAG_BIAS_PULL_UP"):
  66                             flags |= gpiod.LINE_REQ_FLAG_BIAS_PULL_UP
  67                         else:
  68                             raise NotImplementedError(
  69                                 "Internal pullups not supported in this version of libgpiod, "
  70                                 "use physical resistor instead!"
  71                             )
  72                     elif pull == self.PULL_DOWN:
  73                         if hasattr(gpiod, "line") and hasattr(
  74                             gpiod, "LINE_REQ_FLAG_BIAS_PULL_DOWN"
  75                         ):
  76                             flags |= gpiod.LINE_REQ_FLAG_BIAS_PULL_DOWN
  77                         else:
  78                             raise NotImplementedError(
  79                                 "Internal pulldowns not supported in this version of libgpiod, "
  80                                 "use physical resistor instead!"
  81                             )
  82                     elif pull == self.PULL_NONE:
  83                         if hasattr(gpiod, "line") and hasattr(
  84                             gpiod, "LINE_REQ_FLAG_BIAS_DISABLE"
  85                         ):
  86                             flags |= gpiod.LINE_REQ_FLAG_BIAS_DISABLE
  87                         else:
  88                             raise NotImplementedError(
  89                                 "Internal pulldowns not supported in this version of libgpiod, "
  90                                 "use physical resistor instead!"
  91                             )
  92                     else:
  93                         raise RuntimeError(f"Invalid pull for pin: {self.id}")
  94
  95                 self._mode = self.IN
  96                 self._line.release()
  97                 if hasattr(gpiod, "LINE_REQ_DIR_IN"):
  98                     self._line.request(
  99                         consumer=self._CONSUMER, type=gpiod.LINE_REQ_DIR_IN, flags=flags
 100                     )
 101                 else:
 102                     config = gpiod.line_request()
 103                     config.consumer = self._CONSUMER
 104                     config.request_type = gpiod.line_request.DIRECTION_INPUT
 105                     self._line.request(config)
 106
 107             elif mode == self.OUT:
 108                 if pull is not None:
 109                     raise RuntimeError("Cannot set pull resistor on output")
 110                 self._mode = self.OUT
 111                 self._line.release()
 112                 if hasattr(gpiod, "LINE_REQ_DIR_OUT"):
 113                     self._line.request(
 114                         consumer=self._CONSUMER, type=gpiod.LINE_REQ_DIR_OUT
 115                     )
 116                 else:
 117                     config = gpiod.line_request()
 118                     config.consumer = self._CONSUMER
 119                     config.request_type = gpiod.line_request.DIRECTION_OUTPUT
 120                     self._line.request(config)
 121             else:
 122                 raise RuntimeError("Invalid mode for pin: %s" % self.id)
 123
 124     def value(self, val=None):
 125         """Set or return the Pin Value"""
 126         if val is None:
 127             return self._line.get_value()
 128
 129         if val in (self.LOW, self.HIGH):
 130             self._value = val
 131             self._line.set_value(val)
 132             return None
 133         raise RuntimeError("Invalid value for pin")