GPIO Access Denied

[S1L3NTANG3L]

Moonraker is currently not able to access the gpio pins.
[gpio.py:_request_gpio()] - Unable to init gpiochip0:gpio6. Make sure the gpio is not in use by another program or exported by sysfs.
Traceback (most recent call last):
File "/home/biqu/moonraker/moonraker/components/gpio.py", line 84, in _request_gpio
chip = self._get_gpio_chip(pin_params['chip_id'])
File "/home/biqu/moonraker/moonraker/components/gpio.py", line 40, in _get_gpio_chip
chip = self.gpiod.Chip(chip_name, self.gpiod.Chip.OPEN_BY_NAME)
PermissionError: [Errno 13] Permission denied
2022-10-02 13:02:25,273 [moonraker.py:add_warning()] - Failed to load power device [power light_strip_2 ]
Error parsing option (pin) from section [power light_strip_2 ]

[Michelinu]

CB1 uses a custom IO arrangement, check my post here: #14 (comment)

Just take a PC PIN and use my "guide"; I tried with PC8, PC10 and PC15

[S1L3NTANG3L]

Hi thanks for the feedback I tried both the PC pins directly and the SOPine Gpio Alternate. Still getting a permission denied error. What version of the CB1 OS are you running?

2022-10-02 19:28:36,195 [gpio.py:_request_gpio()] - Unable to init gpiochip0:gpio74. Make sure the gpio is not in use by another program or exported by sysfs.
Traceback (most recent call last):
File "/home/biqu/moonraker/moonraker/components/gpio.py", line 84, in _request_gpio
chip = self._get_gpio_chip(pin_params['chip_id'])
File "/home/biqu/moonraker/moonraker/components/gpio.py", line 40, in _get_gpio_chip
chip = self.gpiod.Chip(chip_name, self.gpiod.Chip.OPEN_BY_NAME)
PermissionError: [Errno 13] Permission denied
2022-10-02 19:28:36,195 [moonraker.py:add_warning()] - Failed to load power device [power light_strip_1]
Error parsing option (pin) from section [power light_strip_1]
2022-10-02 19:28:36,197 [gpio.py:_request_gpio()] - Unable to init gpiochip0:gpio79. Make sure the gpio is not in use by another program or exported by sysfs.
Traceback (most recent call last):
File "/home/biqu/moonraker/moonraker/components/gpio.py", line 84, in _request_gpio
chip = self._get_gpio_chip(pin_params['chip_id'])
File "/home/biqu/moonraker/moonraker/components/gpio.py", line 40, in _get_gpio_chip
chip = self.gpiod.Chip(chip_name, self.gpiod.Chip.OPEN_BY_NAME)
PermissionError: [Errno 13] Permission denied

[Michelinu]

I'm using latest Klipper image of CB1 OS, the V2.2.0. I just tried and I have the same problem.
If I set the type as gpio, I get the permission denied error; if I configure it as output_pin in Klipper and then set it up as klipper_device type in Moonraker, it works.

I think that it's just a permission problem. Tried with the solution in this post but it didn't work: Arksine/moonraker#249 (comment)

[S1L3NTANG3L]

Okay so you used the PC pins in klipper?
aka
[output_pin led1_pin]
pin: PC14
pwm: False
value: 0
and
[power light_strip_1] #output_7
type: klipper_device
object_name: output_pin led1_pin

Damn this is a good work around but it still has the downside of not being able to turn the printer on and off :'(

[S1L3NTANG3L]

Hmmm tried Power GPIO permission denied #249 and now the error looks different:
2022-10-02 22:38:09,928 [gpio.py:_request_gpio()] - Unable to init gpiochip0:gpio24. Make sure the gpio is not in use by another program or exported by sysfs.
Traceback (most recent call last):
File "/home/biqu/moonraker/moonraker/components/gpio.py", line 97, in _request_gpio
line.request(**args)
OSError: [Errno 517] Unknown error 517

[Michelinu]

Assuming that you used the Klipper image, so you had the linux MCU host already install or you did it by yourself, you must have:

• In your printer.cfg:

[mcu rpi]
serial: /tmp/klipper_host_mcu

[output_pin led1_pin]
pin: rpi:gpio78

• In your moonraker.conf

[power light_strip_1]
type: klipper_device
object_name: output_pin led1_pin

Just checked and it corresponds: GPIO78 -> GPIO17_PC14 -> PIN n.11
Having a power device in Moonraker gets pretty useless in this case, as you said you won't be able to control it if Klipper is off.

You can try to set it only in your printer.cfg; if it works as expected, you can use it in this way until there will be a fix for Moonraker

[Michelinu]

Hmmm tried Power GPIO permission denied #249 and now the error looks different: 2022-10-02 22:38:09,928 [gpio.py:_request_gpio()] - Unable to init gpiochip0:gpio24. Make sure the gpio is not in use by another program or exported by sysfs. Traceback (most recent call last): File "/home/biqu/moonraker/moonraker/components/gpio.py", line 97, in _request_gpio line.request(**args) OSError: [Errno 517] Unknown error 517

You can't use GPIO24 in our CB1, always follow the table I posted for the GPIO<number> to use

[Michelinu]

I just found the solution.

Add the following lines in your moonraker.conf:

[power my_device]
type: gpio
pin: gpio78

Create a new udev rule as /etc/udev/rules.d/60-gpiod.rules :

# udev rules for gpio port access through libgpiod
SUBSYSTEM=="gpio", KERNEL=="gpiochip[0-4]", GROUP="biqu", MODE="0660"

The solution I posted was using the "gpio" group, that does not exist in our CB1 image.
So by just using "biqu" as group, it works!

[S1L3NTANG3L]

Okay so this and this in combination with this seem to be allowing me to add
[power light_strip_2 ]
type: gpio
pin: gpio74
off_when_shutdown: True
initial_state: off
to my moonraker.conf and not get any error after a system reboot.
I'll quickly just go and check pin voltages and make sure its working.

[Michelinu]

Okay so this and this in combination with this seem to be allowing me to add [power light_strip_2 ] type: gpio pin: gpio74 off_when_shutdown: True initial_state: off to my moonraker.conf and not get any error after a system reboot. I'll quickly just go and check pin voltages and make sure its working.

If you don't get any error, it should work.
I use the CB1 with the Pi4 adapter and I have 1.8V in the PIN when it's "powered".

Remember that GPIO74 -> GPIO22_PC10 -> PIN n.15 in the 40-pin connector

[S1L3NTANG3L]

Lovely I'm also getting around 1.8V output on high.
So the working pins on the M8P are:
GPIO17->PC14->GPIO78
GPIO27->PC12->GPIO76
GPIO22->PC10->GPIO74
GPIO6->PG6->GPIO198
GPIO7->PG8->GPIO200
GPIO23->PC11->GPIO75 -- Error
GPIO24->PC9->GPIO73
GPIO19->PC6->GPIO70
GPIO26->PC15->GPIO79
This is the ones that I quickly tested.

[Michelinu]

Lovely I'm also getting around 1.8V output on high.
So the working pins on the M8P are:
GPIO17->PC14->GPIO78
GPIO27->PC12->GPIO76
GPIO22->PC10->GPIO74
GPIO6->PG6->GPIO198
GPIO23->PC11->GPIO75
GPIO24->PC9->GPIO73
GPIO19->PC6->GPIO70
GPIO26->PC15->GPIO79
This is the ones that I quickly tested.

You already tried more pins than me!
I did the "research" because maybe in the future I would need to use some of them.

The "disappointment" is that people have been asking Biqu/BTT for the GPIO pinout since weeks/months.
There's still nothing of official, except for that scheme I posted that you can find only in M4P user manual but it doesn't tell you what GPIO<number> to use!

[S1L3NTANG3L]

Yeah my little list atleast references the current m8p pinout, weird that 75 aka gpio23 gives a error 16 device busy

[S1L3NTANG3L]

Now I just hope I can use this list on the radxa zero, having the same pinout issue there.

[Michelinu]

You can run sudo cat /sys/kernel/debug/gpio to check if a GPIO is already in use and by which process/service.

In my case gpio75 is used by spi1 CS0

[S1L3NTANG3L]

That's supposed to be gpio8 according to there m8p pinout. This manual is useless. Well I have 8 functioning pins which is more than enough for my purposes. Thanks again for the help

[yzeroy]

Hi all,

pi@Ender:~$ uname -a
Linux Ender 4.9.255-sun50iw9 #1 SMP PREEMPT Tue Mar 1 23:28:34 UTC 2022 aarch64 aarch64 aarch64 GNU/Linux

I wanted to use GPIOs for controling 3D printer relay. And it is finaly fixed by these steps.

Sudo nano /etc/udev/rules.d/60-gpiod.rules
and add
# udev rules for gpio port access through libgpiod
SUBSYSTEM=="gpio", KERNEL=="gpiochip[0-4]", GROUP="USERNAME ", MODE="0660"

Thanks @Michelinu

next
sudo nano /etc/systemd/system/moonraker.service

and add
[Service]
Type=simple
User=username
Group=username

Reboot