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") and hasattr(
  66                             gpiod.line, "BIAS_PULL_UP"
  67                         ):
  68                             config = gpiod.line_request()
  69                             config.consumer = self._CONSUMER
  70                             config.request_type = gpiod.line.BIAS_PULL_UP
  71                             self._line.request(config)
  72                         else:
  73                             self._line.request(
  74                                 consumer=self._CONSUMER,
  75                                 type=gpiod.LINE_REQ_DIR_IN,
  76                                 flags=flags,
  77                             )
  78                             raise NotImplementedError(
  79                                 "Internal pullups not supported in this version of libgpiod, "
  80                                 "use physical resistor instead!"
  81                             )
  82                     elif pull == self.PULL_DOWN:
  83                         if hasattr(gpiod, "line") and hasattr(
  84                             gpiod.line, "BIAS_PULL_DOWN"
  85                         ):
  86                             config = gpiod.line_request()
  87                             config.consumer = self._CONSUMER
  88                             config.request_type = gpiod.line.BIAS_PULL_DOWN
  89                             self._line.request(config)
  90                         else:
  91                             raise NotImplementedError(
  92                                 "Internal pulldowns not supported in this version of libgpiod, "
  93                                 "use physical resistor instead!"
  94                             )
  95                     elif pull == self.PULL_NONE:
  96                         if hasattr(gpiod, "line") and hasattr(
  97                             gpiod.line, "BIAS_DISABLE"
  98                         ):
  99                             config = gpiod.line_request()
 100                             config.consumer = self._CONSUMER
 101                             config.request_type = gpiod.line.BIAS_DISABLE
 102                             self._line.request(config)
 103                     else:
 104                         raise RuntimeError(f"Invalid pull for pin: {self.id}")
 105
 106                 self._mode = self.IN
 107                 self._line.release()
 108                 if hasattr(gpiod, "LINE_REQ_DIR_IN"):
 109                     self._line.request(
 110                         consumer=self._CONSUMER, type=gpiod.LINE_REQ_DIR_IN, flags=flags
 111                     )
 112                 else:
 113                     config = gpiod.line_request()
 114                     config.consumer = self._CONSUMER
 115                     config.request_type = gpiod.line_request.DIRECTION_INPUT
 116                     self._line.request(config)
 117
 118             elif mode == self.OUT:
 119                 if pull is not None:
 120                     raise RuntimeError("Cannot set pull resistor on output")
 121                 self._mode = self.OUT
 122                 self._line.release()
 123                 if hasattr(gpiod, "LINE_REQ_DIR_OUT"):
 124                     self._line.request(
 125                         consumer=self._CONSUMER, type=gpiod.LINE_REQ_DIR_OUT
 126                     )
 127                 else:
 128                     config = gpiod.line_request()
 129                     config.consumer = self._CONSUMER
 130                     config.request_type = gpiod.line_request.DIRECTION_OUTPUT
 131                     self._line.request(config)
 132             else:
 133                 raise RuntimeError("Invalid mode for pin: %s" % self.id)
 134
 135     def value(self, val=None):
 136         """Set or return the Pin Value"""
 137         if val is None:
 138             return self._line.get_value()
 139
 140         if val in (self.LOW, self.HIGH):
 141             self._value = val
 142             self._line.set_value(val)
 143             return None
 144         raise RuntimeError("Invalid value for pin")