How to safely access the Pi5 GPIO Pins

[sxy-sun]

• pinctrl may or may not cause gpio pin lock on pi5, and once the pin is gone we don't know if we can still bring it back.
• libgpiod does not hold the pin status once it exits. Source So the user can set the pin high or low, but once it exits the status is not held, we cannot use this tool in our case.
• sysfs is deprecated and pinctrl seems to be the future so we loop back to the pin lock situation

[pelwell]

FYI From the source above:

In the Raspberry Pi version of Linux we deliberately disable the returning of GPIOs to inputs when gpioset exits. This differs from upstream Linux, but both versions have (or will soon have) a module parameter to reverse the behaviour.

In the Raspberry Pi downstream kernel, maintaining the previous value is the default (dtparam -h strict_gpiod), while in upstream kernels, reverting to inputs is the default.