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https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git
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96c52d3e59
Replace tool examples with use case examples drawn from the tools. Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
55 lines
1.7 KiB
Python
Executable File
55 lines
1.7 KiB
Python
Executable File
#!/usr/bin/env python3
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# SPDX-License-Identifier: GPL-2.0-or-later
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# SPDX-FileCopyrightText: 2023 Kent Gibson <warthog618@gmail.com>
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"""Minimal example of asynchronously watching for edges on a single line."""
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import gpiod
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import select
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from datetime import timedelta
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from gpiod.line import Bias, Edge
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def edge_type_str(event):
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if event.event_type is event.Type.RISING_EDGE:
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return "Rising"
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if event.event_type is event.Type.FALLING_EDGE:
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return "Falling"
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return "Unknown"
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def async_watch_line_value(chip_path, line_offset):
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# Assume a button connecting the pin to ground,
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# so pull it up and provide some debounce.
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with gpiod.request_lines(
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chip_path,
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consumer="async-watch-line-value",
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config={
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line_offset: gpiod.LineSettings(
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edge_detection=Edge.BOTH,
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bias=Bias.PULL_UP,
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debounce_period=timedelta(milliseconds=10),
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)
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},
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) as request:
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poll = select.poll()
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poll.register(request.fd, select.POLLIN)
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while True:
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# Other fds could be registered with the poll and be handled
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# separately using the return value (fd, event) from poll()
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poll.poll()
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for event in request.read_edge_events():
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print(
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"offset: {} type: {:<7} event #{}".format(
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event.line_offset, edge_type_str(event), event.line_seqno
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)
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)
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if __name__ == "__main__":
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try:
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async_watch_line_value("/dev/gpiochip0", 5)
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except OSError as ex:
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print(ex, "\nCustomise the example configuration to suit your situation")
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