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Description:

gpiochip2 0.9.3

Contents

Features
Requirements
Examples

Pythonic API for Linux’s gpiochip chardev ABI v2.

Features

Manage multiple GPIO lines at the same time, with bit operation affecting the
entire line group at once (|=, &=, ^=).
Get file event notification of timestamped line events (rising edge, falling
edge).
Get file event notifications (select, poll, epoll…) of gpiochip-level and
line-level events.
Control line parameters (pull-up, pull-down, active-low, debouncing, …).
Pure python module: no compilation needed, not limited to CPython.

Requirements

Linux >=5.10.0 for GPIO chardev ABI v2
python stdlib >=3.7.10 (not tested with earlier versions, they may work)

Examples
Warning: this example is not meant to be executed as-is. Depending on what
is connected to the GPIO lines used here (which is entirely board-dependent),
this could cause all sort of problems, including permanent hardware damage.
This is only to be taken as a quick overview of this module’s API.
from gpiochip2 import GPIOChip, GPIO_V2_LINE_FLAG, EXPECT_PRECONFIGURED
with GPIOChip('/dev/gpiochip0', 'w+b') as gpiochip:
# Get information about the gpio chip itself
gpiochip.getInfo()
# Get information about line 20
gpiochip.getLineInfo(20)
with gpiochip.openLines(
line_list=[20, 21, 26],
flags=GPIO_V2_LINE_FLAG.OUTPUT,
consumer='sample-name'.encode('ascii'),
flags_dict={
# Line 26 is an input and produces event on falling edges
2: GPIO_V2_LINE_FLAG.INPUT | GPIO_V2_LINE_FLAG.EDGE_FALLING,
},
default_dict={
# Drive line 20 low immediately on opening
0: False,
},
# Expect the GPIO lines to be correctly preconfigured (ex: by board-
# specific firmware or devicetree).
expect_preconfigured=EXPECT_PRECONFIGURED.DIRECTION,
expect_preconfigured_dict={
# Expect line 26 to have its edge detection preconfigured
# in addition to its direction
2: EXPECT_PRECONFIGURED.DIRECTION | EXPECT_PRECONFIGURED.EDGE,
},
) as gpio_lines:
# Read lines state
value = gpio_lines.value
# Change lines state
gpio_lines.value = 0b11
# Set line 21
gpio_lines |= 2 # 1 << 1
# Clear line 20
gpio_lines &= 1 # 1 << 0
# Read event
lines.getEvent()
Notes on bit operations:
gpio_lines.lines |= some_mask will read then write the GPIO, while
gpio_lines |= some_mask only needs to write, making it more efficient.
The same applies to &=, but not to other operators.
See also the examples directory for more realistic code.