src/adafruit_blinka/microcontroller/generic_linux/libgpiod/libgpiod_pin_2_x.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 2.x."""
   5 import gpiod
   6
   7
   8 # pylint: disable=too-many-branches,too-many-statements
   9 class Pin:
  10     """Pins dont exist in CPython so...lets make our own!"""
  11
  12     IN = 0
  13     OUT = 1
  14     LOW = 0
  15     HIGH = 1
  16     PULL_NONE = 0
  17     PULL_UP = 1
  18     PULL_DOWN = 2
  19     _CONSUMER = "adafruit_blinka"
  20
  21     id = None
  22     _value = LOW
  23     _mode = IN
  24
  25     _value_map = (gpiod.line.Value.INACTIVE, gpiod.line.Value.ACTIVE)
  26
  27     def __init__(self, pin_id):
  28         self.id = pin_id
  29         chip_id = 0
  30         if isinstance(pin_id, tuple):
  31             chip_id, self._num = pin_id
  32         if isinstance(chip_id, int):
  33             chip_id = f"/dev/gpiochip{chip_id}"
  34         self._chip = gpiod.Chip(chip_id)
  35         self._line_request = None
  36
  37     def __del__(self):
  38         if self._line_request:
  39             self._line_request.release()
  40
  41     def __repr__(self):
  42         return str(self.id)
  43
  44     def __eq__(self, other):
  45         return self.id == other
  46
  47     def init(self, mode=IN, pull=None):
  48         """Initialize the Pin"""
  49         # Input,
  50         if not self._line_request:
  51             line_config = gpiod.LineSettings()
  52
  53             if mode == self.IN:
  54                 line_config.direction = gpiod.line.Direction.INPUT
  55                 if pull is not None:
  56                     if pull == self.PULL_UP:
  57                         line_config.bias = gpiod.line.Bias.PULL_UP
  58                     elif pull == self.PULL_DOWN:
  59                         line_config.bias = gpiod.line.Bias.PULL_DOWN
  60                     elif pull == self.PULL_NONE:
  61                         line_config.bias = gpiod.line.Bias.DISABLED
  62                     else:
  63                         raise RuntimeError(f"Invalid pull for pin: {self.id}")
  64
  65             elif mode == self.OUT:
  66                 if pull is not None:
  67                     raise RuntimeError("Cannot set pull resistor on output")
  68                 line_config.direction = gpiod.line.Direction.OUTPUT
  69
  70             else:
  71                 raise RuntimeError(f"Invalid mode for pin: {self.id}")
  72
  73             self._line_request = self._chip.request_lines(
  74                 {int(self._num): line_config},
  75                 consumer=self._CONSUMER,
  76             )
  77
  78     def value(self, val=None):
  79         """Set or return the Pin Value"""
  80         if val is None:
  81             return bool(self._value_map.index(self._line_request.get_value(self._num)))
  82
  83         if val in (self.LOW, self.HIGH):
  84             self._value = val
  85             self._line_request.set_value(self._num, self._value_map[int(val)])
  86             return None
  87         raise RuntimeError("Invalid value for pin")