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 # pylint: disable=too-many-branches,too-many-statements
  14 class Pin:
  15     """Pins dont exist in CPython so...lets make our own!"""
  16
  17     IN = 0
  18     OUT = 1
  19     LOW = 0
  20     HIGH = 1
  21     PULL_NONE = 0
  22     PULL_UP = 1
  23     PULL_DOWN = 2
  24     _CONSUMER = "adafruit_blinka"
  25
  26     id = None
  27     _value = LOW
  28     _mode = IN
  29
  30     def __init__(self, pin_id):
  31         self.id = pin_id
  32         if isinstance(pin_id, tuple):
  33             self._num = int(pin_id[1])
  34             if hasattr(gpiod, "Chip"):
  35                 self._chip = gpiod.Chip(str(pin_id[0]), gpiod.Chip.OPEN_BY_NUMBER)
  36             else:
  37                 self._chip = gpiod.chip(str(pin_id[0]), gpiod.chip.OPEN_BY_NUMBER)
  38         else:
  39             self._num = int(pin_id)
  40             if hasattr(gpiod, "Chip"):
  41                 self._chip = gpiod.Chip("gpiochip0", gpiod.Chip.OPEN_BY_NAME)
  42             else:
  43                 self._chip = gpiod.chip("gpiochip0", gpiod.chip.OPEN_BY_NAME)
  44         self._line = None
  45
  46     def __repr__(self):
  47         return str(self.id)
  48
  49     def __eq__(self, other):
  50         return self.id == other
  51
  52     def init(self, mode=IN, pull=None):
  53         """Initialize the Pin"""
  54         if not self._line:
  55             self._line = self._chip.get_line(int(self._num))
  56             # print("init line: ", self.id, self._line)
  57
  58         if mode is not None:
  59             if mode == self.IN:
  60                 flags = 0
  61                 self._line.release()
  62                 if pull is not None:
  63                     if pull == self.PULL_UP:
  64                         if hasattr(gpiod, "line") and hasattr(
  65                             gpiod.line, "BIAS_PULL_UP"
  66                         ):
  67                             config = gpiod.line_request()
  68                             config.consumer = self._CONSUMER
  69                             config.request_type = gpiod.line.BIAS_PULL_UP
  70                             self._line.request(config)
  71                         else:
  72                             self._line.request(
  73                                 consumer=self._CONSUMER,
  74                                 type=gpiod.LINE_REQ_DIR_IN,
  75                                 flags=flags,
  76                             )
  77                             raise NotImplementedError(
  78                                 "Internal pullups not supported in this version of libgpiod, "
  79                                 "use physical resistor instead!"
  80                             )
  81                     elif pull == self.PULL_DOWN:
  82                         if hasattr(gpiod, "line") and hasattr(
  83                             gpiod.line, "BIAS_PULL_DOWN"
  84                         ):
  85                             config = gpiod.line_request()
  86                             config.consumer = self._CONSUMER
  87                             config.request_type = gpiod.line.BIAS_PULL_DOWN
  88                             self._line.request(config)
  89                         else:
  90                             raise NotImplementedError(
  91                                 "Internal pulldowns not supported in this version of libgpiod, "
  92                                 "use physical resistor instead!"
  93                             )
  94                     elif pull == self.PULL_NONE:
  95                         if hasattr(gpiod, "line") and hasattr(
  96                             gpiod.line, "BIAS_DISABLE"
  97                         ):
  98                             config = gpiod.line_request()
  99                             config.consumer = self._CONSUMER
 100                             config.request_type = gpiod.line.BIAS_DISABLE
 101                             self._line.request(config)
 102                     else:
 103                         raise RuntimeError(f"Invalid pull for pin: {self.id}")
 104
 105                 self._mode = self.IN
 106                 self._line.release()
 107                 if hasattr(gpiod, "LINE_REQ_DIR_IN"):
 108                     self._line.request(
 109                         consumer=self._CONSUMER, type=gpiod.LINE_REQ_DIR_IN, flags=flags
 110                     )
 111                 else:
 112                     config = gpiod.line_request()
 113                     config.consumer = self._CONSUMER
 114                     config.request_type = gpiod.line_request.DIRECTION_INPUT
 115                     self._line.request(config)
 116
 117             elif mode == self.OUT:
 118                 if pull is not None:
 119                     raise RuntimeError("Cannot set pull resistor on output")
 120                 self._mode = self.OUT
 121                 self._line.release()
 122                 if hasattr(gpiod, "LINE_REQ_DIR_OUT"):
 123                     self._line.request(
 124                         consumer=self._CONSUMER, type=gpiod.LINE_REQ_DIR_OUT
 125                     )
 126                 else:
 127                     config = gpiod.line_request()
 128                     config.consumer = self._CONSUMER
 129                     config.request_type = gpiod.line_request.DIRECTION_OUTPUT
 130                     self._line.request(config)
 131             else:
 132                 raise RuntimeError("Invalid mode for pin: %s" % self.id)
 133
 134     def value(self, val=None):
 135         """Set or return the Pin Value"""
 136         if val is None:
 137             return self._line.get_value()
 138
 139         if val in (self.LOW, self.HIGH):
 140             self._value = val
 141             self._line.set_value(val)
 142             return None
 143         raise RuntimeError("Invalid value for pin")