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#
# Copyright 2020 Ettus Research, a National Instruments Brand
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
"""
Access to GPIOs via libgpiod
"""
import contextlib
import gpiod
@contextlib.contextmanager
def request_gpio(line, direction):
"""
Context manager for a GPIO line
"""
line.request(consumer='mpm', type=direction)
try:
yield line
finally:
line.release()
class Gpio:
"""
Class for accessing a named GPIO line via libgpiod
"""
INPUT = gpiod.LINE_REQ_DIR_IN
OUTPUT = gpiod.LINE_REQ_DIR_OUT
FALLING_EDGE = gpiod.LINE_REQ_EV_FALLING_EDGE
def __init__(self, name, direction=INPUT, default_val=None):
self._direction = direction
self._line = gpiod.find_line(name)
self._out_value = False
if self._line is None:
raise RuntimeError('failed to find gpio with name %s' % name)
if default_val is not None and direction == Gpio.OUTPUT:
self.set(default_val)
def get(self):
"""
Read the value of this GPIO
"""
if self._direction == self.OUTPUT:
return self._out_value
with request_gpio(self._line, self._direction) as gpio:
return bool(gpio.get_value())
def set(self, value):
"""
Set the value of this GPIO
"""
with request_gpio(self._line, self._direction) as gpio:
gpio.set_value(int(value))
self._out_value = bool(value)
def event_wait(self):
"""
Wait for an event to happen on this line
"""
with request_gpio(self._line, self._direction) as gpio:
while True:
if gpio.event_wait(sec=1):
return True
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