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