gpio_matrix_keyboard.py

from contextlib import contextmanager

import libevdev
from periphery import GPIO
import time

# 230 69 73 80
gpio_out1 = GPIO("/dev/gpiochip0", 230, "out")
gpio_out2 = GPIO("/dev/gpiochip0", 69, "out")
gpio_out3 = GPIO("/dev/gpiochip0", 73, "out")
gpio_out4 = GPIO("/dev/gpiochip0", 80, "out")


# 68 70 74 75
gpio_in1 = GPIO("/dev/gpiochip0", 68, "in", bias='pull_up')
gpio_in2 = GPIO("/dev/gpiochip0", 70, "in", bias='pull_up')
gpio_in3 = GPIO("/dev/gpiochip0", 74, "in", bias='pull_up')
gpio_in4 = GPIO("/dev/gpiochip0", 75, "in", bias='pull_up')


k = libevdev.EV_KEY
KEYS = [
     k.KEY_1, k.KEY_2, k.KEY_3, k.KEY_0,
     k.KEY_4, k.KEY_5, k.KEY_6, k.KEY_BACK,
     k.KEY_7, k.KEY_8, k.KEY_9, k.KEY_0,
     k.KEY_NUMERIC_STAR, k.KEY_0, k.KEY_NUMERIC_POUND, k.KEY_AGAIN,

]


def write_all_out(value):
    gpio_out1.write(value)
    gpio_out2.write(value)
    gpio_out3.write(value)
    gpio_out4.write(value)


@contextmanager
def open_input_device():
    device = libevdev.Device()
    device.name = 'phone keyboard'
    for key in KEYS:
        device.enable(key)
    try:
        uinput = device.create_uinput_device()
        yield uinput
    finally:
        uinput.close()

def close_all():
    for gpio in [gpio_out1, gpio_out2, gpio_out3, gpio_out4] + [gpio_in1, gpio_in2, gpio_in3, gpio_in4]:
        gpio.close()


def report_key(inp_dev, key):
    print('report key', inp_dev, key)
    press = [libevdev.InputEvent(key, value=1),
             libevdev.InputEvent(libevdev.EV_SYN.SYN_REPORT, value=0)]
    inp_dev.send_events(press)

    release = [libevdev.InputEvent(key, value=0),
               libevdev.InputEvent(libevdev.EV_SYN.SYN_REPORT, value=0)]
    inp_dev.send_events(release)

def loop_once(inp_dev):
    write_all_out(True)

    for idx, out in enumerate([gpio_out1, gpio_out2, gpio_out3, gpio_out4]):
        row = idx << 2
        out.write(False)
        key = None

        if not gpio_in1.read():
            key = KEYS[row | 0]
        if not gpio_in2.read():
            key = KEYS[row | 1]
        if not gpio_in3.read():
            key = KEYS[row | 2]
        if not gpio_in4.read():
            key = KEYS[row | 3]

        out.write(True)

        if key is not None:
            report_key(inp_dev, key)



def main():
    with open_input_device() as inp_dev:
        try:
            while True:
                loop_once(inp_dev)
                time.sleep(1/6)
        except KeyboardInterrupt:
            pass
        finally:
            close_all()


if __name__ == '__main__':
    main()