Source code for gpiozero.pins.pi

from __future__ import (
    unicode_literals,
    absolute_import,
    print_function,
    division,
    )
str = type('')

import io
from threading import RLock, Lock
from types import MethodType
from collections import defaultdict
try:
    from weakref import ref, WeakMethod
except ImportError:

    from ..compat import WeakMethod
import warnings

try:
    from spidev import SpiDev
except ImportError:
    SpiDev = None

from . import Factory, Pin
from .data import pi_info
from ..exc import (
    PinNoPins,
    PinNonPhysical,
    PinInvalidPin,
    SPIBadArgs,
    SPISoftwareFallback,
    )


SPI_HARDWARE_PINS = {
    0: {
        'clock':  11,
        'mosi':   10,
        'miso':   9,
        'select': (8, 7),
    },
}


[docs]class PiFactory(Factory): """ Abstract base class representing hardware attached to a Raspberry Pi. This forms the base of :class:`~gpiozero.pins.local.LocalPiFactory`. """ def __init__(self): super(PiFactory, self).__init__() self._info = None self.pins = {} self.pin_class = None self.spi_classes = { ('hardware', 'exclusive'): None, ('hardware', 'shared'): None, ('software', 'exclusive'): None, ('software', 'shared'): None, }
[docs] def close(self): for pin in self.pins.values(): pin.close() self.pins.clear()
[docs] def pin(self, spec): n = self._to_gpio(spec) try: pin = self.pins[n] except KeyError: pin = self.pin_class(self, n) self.pins[n] = pin return pin
def _to_gpio(self, spec): """ Converts the pin *spec* to a GPIO port number. """ if not 0 <= spec < 54: raise PinInvalidPin('invalid GPIO port %d specified (range 0..53) ' % spec) return spec def _get_revision(self): raise NotImplementedError def _get_pi_info(self): if self._info is None: self._info = pi_info(self._get_revision()) return self._info
[docs] def spi(self, **spi_args): """ Returns an SPI interface, for the specified SPI *port* and *device*, or for the specified pins (*clock_pin*, *mosi_pin*, *miso_pin*, and *select_pin*). Only one of the schemes can be used; attempting to mix *port* and *device* with pin numbers will raise :exc:`SPIBadArgs`. If the pins specified match the hardware SPI pins (clock on GPIO11, MOSI on GPIO10, MISO on GPIO9, and chip select on GPIO8 or GPIO7), and the spidev module can be imported, a :class:`SPIHardwareInterface` instance will be returned. Otherwise, a :class:`SPISoftwareInterface` will be returned which will use simple bit-banging to communicate. Both interfaces have the same API, support clock polarity and phase attributes, and can handle half and full duplex communications, but the hardware interface is significantly faster (though for many things this doesn't matter). """ spi_args, kwargs = self._extract_spi_args(**spi_args) shared = 'shared' if kwargs.pop('shared', False) else 'exclusive' if kwargs: raise SPIBadArgs( 'unrecognized keyword argument %s' % kwargs.popitem()[0]) for port, pins in SPI_HARDWARE_PINS.items(): if all(( spi_args['clock_pin'] == pins['clock'], spi_args['mosi_pin'] == pins['mosi'], spi_args['miso_pin'] == pins['miso'], spi_args['select_pin'] in pins['select'], )): try: return self.spi_classes[('hardware', shared)]( self, port=port, device=pins['select'].index(spi_args['select_pin']) ) except Exception as e: warnings.warn( SPISoftwareFallback( 'failed to initialize hardware SPI, falling back to ' 'software (error was: %s)' % str(e))) break # Convert all pin arguments to integer GPIO numbers. This is necessary # to ensure the shared-key for shared implementations get matched # correctly, and is a bit of a hack for the pigpio bit-bang # implementation which just wants the pin numbers too. spi_args = { key: pin.number if isinstance(pin, Pin) else pin for key, pin in spi_args.items() } return self.spi_classes[('software', shared)](self, **spi_args)
def _extract_spi_args(self, **kwargs): """ Given a set of keyword arguments, splits it into those relevant to SPI implementations and all the rest. SPI arguments are augmented with defaults and converted into the pin format (from the port/device format) if necessary. Returns a tuple of ``(spi_args, other_args)``. """ dev_defaults = { 'port': 0, 'device': 0, } default_hw = SPI_HARDWARE_PINS[dev_defaults['port']] pin_defaults = { 'clock_pin': default_hw['clock'], 'mosi_pin': default_hw['mosi'], 'miso_pin': default_hw['miso'], 'select_pin': default_hw['select'][dev_defaults['device']], } spi_args = { key: value for (key, value) in kwargs.items() if key in pin_defaults or key in dev_defaults } kwargs = { key: value for (key, value) in kwargs.items() if key not in spi_args } if not spi_args: spi_args = pin_defaults elif set(spi_args) <= set(pin_defaults): spi_args = { key: self._to_gpio(spi_args.get(key, default)) for key, default in pin_defaults.items() } elif set(spi_args) <= set(dev_defaults): spi_args = { key: spi_args.get(key, default) for key, default in dev_defaults.items() } if spi_args['port'] != 0: raise SPIBadArgs('port 0 is the only valid SPI port') selected_hw = SPI_HARDWARE_PINS[spi_args['port']] try: selected_hw['select'][spi_args['device']] except IndexError: raise SPIBadArgs( 'device must be in the range 0..%d' % len(selected_hw['select'])) spi_args = { key: value if key != 'select_pin' else selected_hw['select'][spi_args['device']] for key, value in pin_defaults.items() } else: raise SPIBadArgs( 'you must either specify port and device, or clock_pin, ' 'mosi_pin, miso_pin, and select_pin; combinations of the two ' 'schemes (e.g. port and clock_pin) are not permitted') return spi_args, kwargs
[docs]class PiPin(Pin): """ Abstract base class representing a multi-function GPIO pin attached to a Raspberry Pi. This overrides several methods in the abstract base :class:`~gpiozero.Pin`. Descendents must override the following methods: * :meth:`_get_function` * :meth:`_set_function` * :meth:`_get_state` * :meth:`_call_when_changed` * :meth:`_enable_event_detect` * :meth:`_disable_event_detect` Descendents *may* additionally override the following methods, if applicable: * :meth:`close` * :meth:`output_with_state` * :meth:`input_with_pull` * :meth:`_set_state` * :meth:`_get_frequency` * :meth:`_set_frequency` * :meth:`_get_pull` * :meth:`_set_pull` * :meth:`_get_bounce` * :meth:`_set_bounce` * :meth:`_get_edges` * :meth:`_set_edges` """ def __init__(self, factory, number): super(PiPin, self).__init__() self._factory = factory self._when_changed_lock = RLock() self._when_changed = None self._number = number try: factory.pi_info.physical_pin(repr(self)) except PinNoPins: warnings.warn( PinNonPhysical( 'no physical pins exist for %s' % repr(self))) @property def number(self): return self._number def __repr__(self): return 'GPIO%d' % self._number @property def factory(self): return self._factory def _call_when_changed(self): """ Called to fire the :attr:`when_changed` event handler; override this in descendents if additional (currently redundant) parameters need to be passed. """ method = self.when_changed() if method is None: self.when_changed = None else: method() def _get_when_changed(self): return self._when_changed def _set_when_changed(self, value): with self._when_changed_lock: if value is None: if self._when_changed is not None: self._disable_event_detect() self._when_changed = None else: enabled = self._when_changed is not None # Have to take care, if value is either a closure or a bound # method, not to keep a strong reference to the containing # object if isinstance(value, MethodType): self._when_changed = WeakMethod(value) else: self._when_changed = ref(value) if not enabled: self._enable_event_detect() def _enable_event_detect(self): """ Enables event detection. This is called to activate event detection on pin :attr:`number`, watching for the specified :attr:`edges`. In response, :meth:`_call_when_changed` should be executed. """ raise NotImplementedError def _disable_event_detect(self): """ Disables event detection. This is called to deactivate event detection on pin :attr:`number`. """ raise NotImplementedError