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#55 Edited PinApi.__close__ so that output pins are not set to 0 when leaving context manager. #56

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#55 Edited PinApi.__close__ so that output pins are not set to 0 when leaving context manager. #56

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144 changes: 70 additions & 74 deletions quick2wire/gpio.py
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Original file line number Diff line number Diff line change
Expand Up @@ -18,11 +18,11 @@ def gpio_admin(subcommand, pin, pull=None):

Out = "out"
In = "in"

Rising = "rising"
Falling = "falling"
Both = "both"

PullDown = "pulldown"
PullUp = "pullup"

Expand All @@ -32,56 +32,56 @@ class PinAPI(object):
def __init__(self, bank, index):
self._bank = bank
self._index = index

@property
def index(self):
return self._index

@property
def bank(self):
return self._bank

def __enter__(self):
self.open()
return self

def __exit__(self, exc_type, exc_value, traceback):
self.close()
value = property(lambda p: p.get(),
lambda p,v: p.set(v),

value = property(lambda p: p.get(),
lambda p,v: p.set(v),
doc="""The value of the pin: 1 if the pin is high, 0 if the pin is low.""")


class PinBankAPI(object):
def __getitem__(self, n):
if 0 < n < len(self):
raise ValueError("no pin index {n} out of range", n=n)
return self.pin(n)

def write(self):
pass

def read(self):
pass



class Pin(PinAPI):
"""Controls a GPIO pin."""

__trigger__ = EDGE

def __init__(self, bank, index, soc_pin_number, direction=In, interrupt=None, pull=None):
"""Creates a pin

Parameters:
user_pin_number -- the identity of the pin used to create the derived class.
soc_pin_number -- the pin on the header to control, identified by the SoC pin number.
direction -- (optional) the direction of the pin, either In or Out.
interrupt -- (optional)
pull -- (optional)

Raises:
IOError -- could not export the pin (if direction is given)
"""
Expand All @@ -91,81 +91,77 @@ def __init__(self, bank, index, soc_pin_number, direction=In, interrupt=None, pu
self._direction = direction
self._interrupt = interrupt
self._pull = pull


@property
def soc_pin_number(self):
return self._soc_pin_number

def open(self):
gpio_admin("export", self.soc_pin_number, self._pull)
self._file = open(self._pin_path("value"), "r+")
self._write("direction", self._direction)
if self._direction == In:
self._write("edge", self._interrupt if self._interrupt is not None else "none")

def close(self):
if not self.closed:
if self.direction == Out:
self.value = 0
self._file.close()
self._file = None
self._write("direction", In)
self._write("edge", "none")
gpio_admin("unexport", self.soc_pin_number)

def get(self):
"""The current value of the pin: 1 if the pin is high or 0 if the pin is low.

The value can only be set if the pin's direction is Out.
Raises:

Raises:
IOError -- could not read or write the pin's value.
"""
self._check_open()
self._file.seek(0)
v = self._file.read()
return int(v) if v else 0

def set(self, new_value):
self._check_open()
if self._direction != Out:
raise ValueError("not an output pin")
self._file.seek(0)
self._file.write(str(int(new_value)))
self._file.flush()

@property
def direction(self):
"""The direction of the pin: either In or Out.

The value of the pin can only be set if its direction is Out.

Raises:
IOError -- could not set the pin's direction.
"""
return self._direction

@direction.setter
def direction(self, new_value):
self._write("direction", new_value)
self._direction = new_value
@property

@property
def interrupt(self):
"""The interrupt property specifies what event (if any) will raise an interrupt.
One of:

One of:
Rising -- voltage changing from low to high
Falling -- voltage changing from high to low
Both -- voltage changing in either direction
None -- interrupts are not raised

Raises:
IOError -- could not read or set the pin's interrupt trigger
"""
return self._interrupt

@interrupt.setter
def interrupt(self, new_value):
self._write("edge", new_value)
Expand All @@ -174,33 +170,33 @@ def interrupt(self, new_value):
@property
def pull(self):
return self._pull

def fileno(self):
"""Return the underlying file descriptor. Useful for select, epoll, etc."""
return self._file.fileno()

@property
def closed(self):
"""Returns if this pin is closed"""
return self._file is None or self._file.closed

def _check_open(self):
if self.closed:
raise IOError(str(self) + " is closed")

def _write(self, filename, value):
with open(self._pin_path(filename), "w+") as f:
f.write(value)

def _pin_path(self, filename=""):
return "/sys/devices/virtual/gpio/gpio%i/%s" % (self.soc_pin_number, filename)

def __repr__(self):
return self.__module__ + "." + str(self)

def __str__(self):
return "{type}({index})".format(
type=self.__class__.__name__,
type=self.__class__.__name__,
index=self.index)


Expand All @@ -212,14 +208,14 @@ def __init__(self, index_to_soc_fn, count=None):
super(PinBank,self).__init__()
self._index_to_soc = index_to_soc_fn
self._count = count

def pin(self, index, *args, **kwargs):
return Pin(self, index, self._index_to_soc(index), *args, **kwargs)

@property
def has_len(self):
return self._count is not None

def __len__(self):
if self._count is not None:
return self._count
Expand Down Expand Up @@ -249,49 +245,49 @@ def by_revision(d):
# Maps header pin numbers to SoC GPIO numbers
# See http://elinux.org/RPi_Low-level_peripherals
#
# Note: - header pins are numbered from 1, SoC GPIO from zero
# Note: - header pins are numbered from 1, SoC GPIO from zero
# - the Pi documentation identifies some header pins as GPIO0,
# GPIO1, etc., but these are not the same as the SoC GPIO
# numbers.

_pi_header_1_pins = {
3: by_revision({1:0, 2:2}),
5: by_revision({1:1, 2:3}),
7: 4,
8: 14,
10: 15,
11: 17,
12: 18,
13: by_revision({1:21, 2:27}),
15: 22,
16: 23,
18: 24,
19: 10,
21: 9,
22: 25,
23: 11,
3: by_revision({1:0, 2:2}),
5: by_revision({1:1, 2:3}),
7: 4,
8: 14,
10: 15,
11: 17,
12: 18,
13: by_revision({1:21, 2:27}),
15: 22,
16: 23,
18: 24,
19: 10,
21: 9,
22: 25,
23: 11,
24: 8,
26: 7
}

_pi_gpio_pins = [_pi_header_1_pins[i] for i in [11, 12, 13, 15, 16, 18, 22, 7]]


def lookup(pin_mapping, i):
try:
if i >= 0:
return pin_mapping[i]
except LookupError:
pass

raise IndexError(str(i) + " is not a valid pin index")

def map_with(pin_mapping):
return lambda i: lookup(pin_mapping,i)


pi_broadcom_soc = PinBank(lambda p: p)
pi_header_1 = PinBank(map_with(_pi_header_1_pins))
pins = PinBank(map_with(_pi_gpio_pins), len(_pi_gpio_pins))


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