from __future__ import (
unicode_literals,
absolute_import,
print_function,
division,
)
str = type('')
import io
import warnings
from collections import defaultdict
from threading import Lock
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):
"""
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):
# Cache the result as we can reasonably assume it won't change during
# runtime (this is LocalPin after all; descendents that deal with
# remote Pis should inherit from Pin instead)
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 revision
raise PinUnknownPi('unable to locate Pi revision in /proc/cpuinfo')
[docs]class LocalPiPin(PiPin):
"""
Abstract base class representing a multi-function GPIO pin attached to the
local Raspberry Pi.
"""
pass
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:
try:
self._interface.close()
finally:
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:
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,)