309 lines
9.8 KiB
Python
309 lines
9.8 KiB
Python
# vim: set fileencoding=utf-8:
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#
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# GPIO Zero: a library for controlling the Raspberry Pi's GPIO pins
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#
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# Copyright (c) 2016-2021 Dave Jones <dave@waveform.org.uk>
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# Copyright (c) 2020 Ben Nuttall <ben@bennuttall.com>
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# Copyright (c) 2016 Andrew Scheller <github@loowis.durge.org>
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#
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# SPDX-License-Identifier: BSD-3-Clause
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from __future__ import (
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unicode_literals,
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absolute_import,
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print_function,
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division,
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)
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nstr = str
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str = type('')
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import io
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import errno
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import struct
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import warnings
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from collections import defaultdict
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from threading import Lock
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try:
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from time import monotonic
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except ImportError:
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from time import time as monotonic
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try:
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from spidev import SpiDev
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except ImportError:
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SpiDev = None
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from . import SPI
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from .pi import PiFactory, PiPin, SPI_HARDWARE_PINS, spi_port_device
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from .spi import SPISoftwareBus
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from ..devices import Device, SharedMixin
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from ..output_devices import OutputDevice
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from ..exc import DeviceClosed, PinUnknownPi, SPIInvalidClockMode
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def get_pi_revision():
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revision = None
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try:
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with io.open('/proc/device-tree/system/linux,revision', 'rb') as f:
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revision = hex(struct.unpack(nstr('>L'), f.read(4))[0])[2:]
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except IOError as e:
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if e.errno != errno.ENOENT:
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raise e
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with io.open('/proc/cpuinfo', 'r') as f:
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for line in f:
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if line.startswith('Revision'):
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revision = line.split(':')[1].strip().lower()
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if revision is not None:
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overvolted = revision.startswith('100')
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if overvolted:
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revision = revision[-4:]
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return int(revision, base=16)
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raise PinUnknownPi(
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'unable to locate Pi revision in /proc/device-tree or /proc/cpuinfo')
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class LocalPiFactory(PiFactory):
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"""
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Extends :class:`~gpiozero.pins.pi.PiFactory`. Abstract base class
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representing pins attached locally to a Pi. This forms the base class for
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local-only pin interfaces (:class:`~gpiozero.pins.rpigpio.RPiGPIOPin`,
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:class:`~gpiozero.pins.rpio.RPIOPin`, and
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:class:`~gpiozero.pins.native.NativePin`).
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"""
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pins = {}
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_reservations = defaultdict(list)
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_res_lock = Lock()
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def __init__(self):
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super(LocalPiFactory, self).__init__()
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# Override the reservations and pins dict to be this class' attributes.
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# This is a bit of a dirty hack, but ensures that anyone evil enough to
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# mix pin implementations doesn't try and control the same pin with
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# different backends
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self.pins = LocalPiFactory.pins
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self._reservations = LocalPiFactory._reservations
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self._res_lock = LocalPiFactory._res_lock
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def _get_revision(self):
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return get_pi_revision()
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def _get_spi_class(self, shared, hardware):
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return {
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(False, True): LocalPiHardwareSPI,
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(True, True): LocalPiHardwareSPIShared,
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(False, False): LocalPiSoftwareSPI,
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(True, False): LocalPiSoftwareSPIShared,
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}[shared, hardware]
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@staticmethod
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def ticks():
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return monotonic()
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@staticmethod
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def ticks_diff(later, earlier):
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# NOTE: technically the guarantee to always return a positive result
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# cannot be maintained in versions where monotonic() is not available
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# and we fall back to time(). However, in that situation we've no
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# access to a true monotonic source, and no idea how far the clock has
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# skipped back so this is the best we can do anyway.
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return max(0, later - earlier)
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class LocalPiPin(PiPin):
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"""
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Extends :class:`~gpiozero.pins.pi.PiPin`. Abstract base class representing
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a multi-function GPIO pin attached to the local Raspberry Pi.
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"""
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def _call_when_changed(self, ticks=None, state=None):
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"""
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Overridden to provide default ticks from the local Pi factory.
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.. warning::
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The local pin factory uses a seconds-based monotonic value for
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its ticks but you *must not* rely upon this behaviour. Ticks are
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an opaque value that should only be compared with the associated
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:meth:`Factory.ticks_diff` method.
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"""
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super(LocalPiPin, self)._call_when_changed(
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self._factory.ticks() if ticks is None else ticks,
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self.state if state is None else state)
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class LocalPiHardwareSPI(SPI):
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def __init__(self, clock_pin, mosi_pin, miso_pin, select_pin, pin_factory):
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self._port, self._device = spi_port_device(
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clock_pin, mosi_pin, miso_pin, select_pin)
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self._interface = None
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if SpiDev is None:
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raise ImportError('failed to import spidev')
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super(LocalPiHardwareSPI, self).__init__(pin_factory=pin_factory)
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to_reserve = {clock_pin, select_pin}
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if mosi_pin is not None:
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to_reserve.add(mosi_pin)
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if miso_pin is not None:
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to_reserve.add(miso_pin)
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self.pin_factory.reserve_pins(self, *to_reserve)
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self._interface = SpiDev()
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self._interface.open(self._port, self._device)
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self._interface.max_speed_hz = 500000
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def close(self):
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if self._interface is not None:
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self._interface.close()
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self._interface = None
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self.pin_factory.release_all(self)
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super(LocalPiHardwareSPI, self).close()
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@property
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def closed(self):
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return self._interface is None
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def __repr__(self):
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try:
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self._check_open()
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return 'SPI(port=%d, device=%d)' % (self._port, self._device)
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except DeviceClosed:
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return 'SPI(closed)'
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def transfer(self, data):
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"""
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Writes data (a list of integer words where each word is assumed to have
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:attr:`bits_per_word` bits or less) to the SPI interface, and reads an
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equivalent number of words, returning them as a list of integers.
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"""
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return self._interface.xfer2(data)
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def _get_clock_mode(self):
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return self._interface.mode
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def _set_clock_mode(self, value):
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self._interface.mode = value
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def _get_lsb_first(self):
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return self._interface.lsbfirst
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def _set_lsb_first(self, value):
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self._interface.lsbfirst = bool(value)
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def _get_select_high(self):
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return self._interface.cshigh
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def _set_select_high(self, value):
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self._interface.cshigh = bool(value)
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def _get_bits_per_word(self):
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return self._interface.bits_per_word
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def _set_bits_per_word(self, value):
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self._interface.bits_per_word = value
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def _get_rate(self):
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return self._interface.max_speed_hz
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def _set_rate(self, value):
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self._interface.max_speed_hz = int(value)
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class LocalPiSoftwareSPI(SPI):
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def __init__(self, clock_pin, mosi_pin, miso_pin, select_pin, pin_factory):
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self._bus = None
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self._select = None
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super(LocalPiSoftwareSPI, self).__init__(pin_factory=pin_factory)
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try:
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self._clock_phase = False
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self._lsb_first = False
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self._bits_per_word = 8
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self._bus = SPISoftwareBus(clock_pin, mosi_pin, miso_pin)
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self._select = OutputDevice(
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select_pin, active_high=False, pin_factory=pin_factory)
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except:
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self.close()
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raise
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def _conflicts_with(self, other):
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return not (
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isinstance(other, LocalPiSoftwareSPI) and
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(self._select.pin.number != other._select.pin.number)
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)
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def close(self):
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if self._select:
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self._select.close()
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self._select = None
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if self._bus is not None:
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self._bus.close()
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self._bus = None
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super(LocalPiSoftwareSPI, self).close()
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@property
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def closed(self):
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return self._bus is None
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def __repr__(self):
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try:
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self._check_open()
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return 'SPI(clock_pin=%d, mosi_pin=%d, miso_pin=%d, select_pin=%d)' % (
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self._bus.clock.pin.number,
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self._bus.mosi.pin.number,
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self._bus.miso.pin.number,
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self._select.pin.number)
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except DeviceClosed:
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return 'SPI(closed)'
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def transfer(self, data):
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with self._bus.lock:
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self._select.on()
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try:
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return self._bus.transfer(
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data, self._clock_phase, self._lsb_first, self._bits_per_word)
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finally:
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self._select.off()
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def _get_clock_mode(self):
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with self._bus.lock:
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return (not self._bus.clock.active_high) << 1 | self._clock_phase
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def _set_clock_mode(self, value):
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if not (0 <= value < 4):
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raise SPIInvalidClockMode("%d is not a valid clock mode" % value)
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with self._bus.lock:
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self._bus.clock.active_high = not (value & 2)
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self._clock_phase = bool(value & 1)
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def _get_lsb_first(self):
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return self._lsb_first
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def _set_lsb_first(self, value):
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self._lsb_first = bool(value)
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def _get_bits_per_word(self):
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return self._bits_per_word
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def _set_bits_per_word(self, value):
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if value < 1:
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raise ValueError('bits_per_word must be positive')
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self._bits_per_word = int(value)
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def _get_select_high(self):
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return self._select.active_high
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def _set_select_high(self, value):
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with self._bus.lock:
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self._select.active_high = value
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self._select.off()
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class LocalPiHardwareSPIShared(SharedMixin, LocalPiHardwareSPI):
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@classmethod
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def _shared_key(cls, clock_pin, mosi_pin, miso_pin, select_pin,
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pin_factory):
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return (clock_pin, select_pin)
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class LocalPiSoftwareSPIShared(SharedMixin, LocalPiSoftwareSPI):
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@classmethod
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def _shared_key(cls, clock_pin, mosi_pin, miso_pin, select_pin,
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pin_factory):
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return (clock_pin, select_pin)
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