gpiozeroが動かない話

概要

それまで動いていたgpiozeroのプログラムが動かなくなったので修正した．

環境

• Debian GNU/Linux 12
• Python 3.11.2
• gpiozero 2.0

raspi@raspi:~ $ lsb_release -a
No LSB modules are available.
Distributor ID:	Debian
Description:	Debian GNU/Linux 12 (bookworm)
Release:	12
Codename:	bookworm
raspi@raspi:~ $ python --version
Python 3.11.2
raspi@raspi:~ $ pip list | grep gpiozero
gpiozero                           2.0

問題

下のようなプログラムを作成し，実行した．

PWM_org.py

import gpiozero
import sys
from time import sleep

pin = gpiozero.PWMOutputDevice(pin=17, frequency=1000)

while True:
    try:
        for i in range(0, 11, 1):
            pin.value = i / 10
            sleep(1)
    except:
        pin.close()
        sys.exit()

すると下のようなエラーが発生した．

raspi@raspi:~ $ python3 PWM_org.py 
/usr/lib/python3/dist-packages/gpiozero/devices.py:295: PinFactoryFallback: Falling back from lgpio: 'can not open gpiochip'
  warnings.warn(
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/gpiozero/pins/pi.py", line 408, in pin
    pin = self.pins[info]
          ~~~~~~~~~^^^^^^
KeyError: PinInfo(number=11, name='GPIO17', names=frozenset({17, '17', 'BOARD11', 'J8:11', 'BCM17', 'WPI0', 'GPIO17'}), pull='', row=6, col=1, interfaces=frozenset({'', 'gpio', 'spi', 'dpi', 'uart'}))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/raspi/PWM_org.py", line 5, in <module>
    pin = gpiozero.PWMOutputDevice(pin=17, frequency=1000)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/gpiozero/devices.py", line 103, in __call__
    self = super().__call__(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/gpiozero/output_devices.py", line 392, in __init__
    super().__init__(pin, active_high=active_high, initial_value=None,
  File "/usr/lib/python3/dist-packages/gpiozero/output_devices.py", line 74, in __init__
    super().__init__(pin, pin_factory=pin_factory)
  File "/usr/lib/python3/dist-packages/gpiozero/mixins.py", line 75, in __init__
    super().__init__(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/gpiozero/devices.py", line 549, in __init__
    pin = self.pin_factory.pin(pin)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/gpiozero/pins/pi.py", line 410, in pin
    pin = self.pin_class(self, info)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/gpiozero/pins/rpigpio.py", line 101, in __init__
    GPIO.setup(self._number, GPIO.IN, self.GPIO_PULL_UPS[self._pull])
RuntimeError: Cannot determine SOC peripheral base address

Falling back from lgpio: 'can not open gpiochip'このエラーが気になる．

調べたこと

調べてみると同じ現象が発生している模様．
https://raspberrypi.stackexchange.com/questions/148946/lgpio-can-not-open-gpiochip-lgpio-seems-unable-to-open-gpiochip-devices
下のコードを追加することで解決できるとのこと．

import gpiozero.pins.lgpio
import lgpio

def __patched_init(self, chip=None):
    gpiozero.pins.lgpio.LGPIOFactory.__bases__[0].__init__(self)
    chip = 0
    self._handle = lgpio.gpiochip_open(chip)
    self._chip = chip
    self.pin_class = gpiozero.pins.lgpio.LGPIOPin

gpiozero.pins.lgpio.LGPIOFactory.__init__ = __patched_init

(上記コードは https://github.com/gpiozero/gpiozero/issues/1166 より引用)

結論

PWM_org.pyを下のように変更すればよい．

PWM_mod.py

import gpiozero
import sys
from time import sleep

# 追加したコード(ここから)
import gpiozero.pins.lgpio
import lgpio

def __patched_init(self, chip=None):
    gpiozero.pins.lgpio.LGPIOFactory.__bases__[0].__init__(self)
    chip = 0
    self._handle = lgpio.gpiochip_open(chip)
    self._chip = chip
    self.pin_class = gpiozero.pins.lgpio.LGPIOPin

gpiozero.pins.lgpio.LGPIOFactory.__init__ = __patched_init
# 追加したコード(ここまで)

pin = gpiozero.PWMOutputDevice(pin=17, frequency=1000)

while True:
    try:
        for i in range(0, 11, 1):
            pin.value = i / 10
            sleep(1)
    except:
        pin.close()
        sys.exit()

しっかりとPWMの波形を出力している．