# GPIO Zero: a library for controlling the Raspberry Pi's GPIO pins
# Copyright (c) 2016-2019 Dave Jones <dave@waveform.org.uk>
# Copyright (c) 2018 Martchus <martchus@gmx.net>
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
#
# * Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
#
# * Neither the name of the copyright holder nor the names of its contributors
# may be used to endorse or promote products derived from this software
# without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
from __future__ import (
unicode_literals,
absolute_import,
print_function,
division,
)
nstr = str
str = type('')
import io
import errno
import struct
import warnings
from collections import defaultdict
from threading import Lock
try:
from time import monotonic
except ImportError:
from time import time as monotonic
try:
from spidev import SpiDev
except ImportError:
SpiDev = None
from . import SPI
from .pi import PiFactory, PiPin, SPI_HARDWARE_PINS
from .spi import SPISoftwareBus
from ..devices import Device, SharedMixin
from ..output_devices import OutputDevice
from ..exc import DeviceClosed, PinUnknownPi, SPIInvalidClockMode
[docs]class LocalPiFactory(PiFactory):
"""
Extends :class:`~gpiozero.pins.pi.PiFactory`. Abstract base class
representing pins attached locally to a Pi. This forms the base class for
local-only pin interfaces (:class:`~gpiozero.pins.rpigpio.RPiGPIOPin`,
:class:`~gpiozero.pins.rpio.RPIOPin`, and
:class:`~gpiozero.pins.native.NativePin`).
"""
pins = {}
_reservations = defaultdict(list)
_res_lock = Lock()
def __init__(self):
super(LocalPiFactory, self).__init__()
self.spi_classes = {
('hardware', 'exclusive'): LocalPiHardwareSPI,
('hardware', 'shared'): LocalPiHardwareSPIShared,
('software', 'exclusive'): LocalPiSoftwareSPI,
('software', 'shared'): LocalPiSoftwareSPIShared,
}
# Override the reservations and pins dict to be this class' attributes.
# This is a bit of a dirty hack, but ensures that anyone evil enough to
# mix pin implementations doesn't try and control the same pin with
# different backends
self.pins = LocalPiFactory.pins
self._reservations = LocalPiFactory._reservations
self._res_lock = LocalPiFactory._res_lock
def _get_revision(self):
try:
with io.open('/proc/device-tree/system/linux,revision', 'rb') as f:
return struct.unpack(nstr('>L'), f.read(4))[0]
except IOError as e:
if e.errno != errno.ENOENT:
raise e
with io.open('/proc/cpuinfo', 'r') as f:
for line in f:
if line.startswith('Revision'):
revision = line.split(':')[1].strip().lower()
overvolted = revision.startswith('100')
if overvolted:
revision = revision[-4:]
return int(revision, base=16)
raise PinUnknownPi('unable to locate Pi revision in /proc/cpuinfo or /proc/device-tree')
[docs] @staticmethod
def ticks():
return monotonic()
[docs] @staticmethod
def ticks_diff(later, earlier):
# NOTE: technically the guarantee to always return a positive result
# cannot be maintained in versions where monotonic() is not available
# and we fall back to time(). However, in that situation we've no
# access to a true monotonic source, and no idea how far the clock has
# skipped back so this is the best we can do anyway.
return max(0, later - earlier)
[docs]class LocalPiPin(PiPin):
"""
Extends :class:`~gpiozero.pins.pi.PiPin`. Abstract base class representing
a multi-function GPIO pin attached to the local Raspberry Pi.
"""
def _call_when_changed(self, ticks=None, state=None):
"""
Overridden to provide default ticks from the local Pi factory.
.. warning::
The local pin factory uses a seconds-based monotonic value for
its ticks but you *must not* rely upon this behaviour. Ticks are
an opaque value that should only be compared with the associated
:meth:`Factory.ticks_diff` method.
"""
super(LocalPiPin, self)._call_when_changed(
self._factory.ticks() if ticks is None else ticks,
self.state if state is None else state)
class LocalPiHardwareSPI(SPI, Device):
def __init__(self, factory, port, device):
self._port = port
self._device = device
self._interface = None
if SpiDev is None:
raise ImportError('failed to import spidev')
super(LocalPiHardwareSPI, self).__init__()
pins = SPI_HARDWARE_PINS[port]
self.pin_factory.reserve_pins(
self,
pins['clock'],
pins['mosi'],
pins['miso'],
pins['select'][device]
)
self._interface = SpiDev()
self._interface.open(port, device)
self._interface.max_speed_hz = 500000
def close(self):
if self._interface is not None:
self._interface.close()
self._interface = None
self.pin_factory.release_all(self)
super(LocalPiHardwareSPI, self).close()
@property
def closed(self):
return self._interface is None
def __repr__(self):
try:
self._check_open()
return 'SPI(port=%d, device=%d)' % (self._port, self._device)
except DeviceClosed:
return 'SPI(closed)'
def transfer(self, data):
"""
Writes data (a list of integer words where each word is assumed to have
:attr:`bits_per_word` bits or less) to the SPI interface, and reads an
equivalent number of words, returning them as a list of integers.
"""
return self._interface.xfer2(data)
def _get_clock_mode(self):
return self._interface.mode
def _set_clock_mode(self, value):
self._interface.mode = value
def _get_lsb_first(self):
return self._interface.lsbfirst
def _set_lsb_first(self, value):
self._interface.lsbfirst = bool(value)
def _get_select_high(self):
return self._interface.cshigh
def _set_select_high(self, value):
self._interface.cshigh = bool(value)
def _get_bits_per_word(self):
return self._interface.bits_per_word
def _set_bits_per_word(self, value):
self._interface.bits_per_word = value
class LocalPiSoftwareSPI(SPI, OutputDevice):
def __init__(self, factory, clock_pin, mosi_pin, miso_pin, select_pin):
self._bus = None
super(LocalPiSoftwareSPI, self).__init__(select_pin, active_high=False)
try:
self._clock_phase = False
self._lsb_first = False
self._bits_per_word = 8
self._bus = SPISoftwareBus(clock_pin, mosi_pin, miso_pin)
except:
self.close()
raise
def _conflicts_with(self, other):
# XXX Need to refine this
return not (
isinstance(other, LocalPiSoftwareSPI) and
(self.pin.number != other.pin.number)
)
def close(self):
if self._bus is not None:
self._bus.close()
self._bus = None
super(LocalPiSoftwareSPI, self).close()
@property
def closed(self):
return self._bus is None
def __repr__(self):
try:
self._check_open()
return 'SPI(clock_pin=%d, mosi_pin=%d, miso_pin=%d, select_pin=%d)' % (
self._bus.clock.pin.number,
self._bus.mosi.pin.number,
self._bus.miso.pin.number,
self.pin.number)
except DeviceClosed:
return 'SPI(closed)'
def transfer(self, data):
with self._bus.lock:
self.on()
try:
return self._bus.transfer(
data, self._clock_phase, self._lsb_first, self._bits_per_word)
finally:
self.off()
def _get_clock_mode(self):
with self._bus.lock:
return (not self._bus.clock.active_high) << 1 | self._clock_phase
def _set_clock_mode(self, value):
if not (0 <= value < 4):
raise SPIInvalidClockMode("%d is not a valid clock mode" % value)
with self._bus.lock:
self._bus.clock.active_high = not (value & 2)
self._clock_phase = bool(value & 1)
def _get_lsb_first(self):
return self._lsb_first
def _set_lsb_first(self, value):
self._lsb_first = bool(value)
def _get_bits_per_word(self):
return self._bits_per_word
def _set_bits_per_word(self, value):
if value < 1:
raise ValueError('bits_per_word must be positive')
self._bits_per_word = int(value)
def _get_select_high(self):
return self.active_high
def _set_select_high(self, value):
with self._bus.lock:
self.active_high = value
self.off()
class LocalPiHardwareSPIShared(SharedMixin, LocalPiHardwareSPI):
@classmethod
def _shared_key(cls, factory, port, device):
return (port, device)
class LocalPiSoftwareSPIShared(SharedMixin, LocalPiSoftwareSPI):
@classmethod
def _shared_key(cls, factory, clock_pin, mosi_pin, miso_pin, select_pin):
return (select_pin,)