Dear Maintainer,

Please consider enabling CONFIG_GPIO_SIM=m in the Debian kernel.

gpio-sim is the modern GPIO simulator (the configfs-based successor to the
deprecated gpio-mockup, which is also currently disabled in the Debian kernel).

It allows creating virtual GPIO chips and driving/reading line values entirely
in software, which is the standard mechanism libgpiod and related tools use for
testing without hardware.

Concretely it would let the gpiod-sysfs-proxy package run a real functional
autopkgtest. It is also generally useful for testing libgpiod, gpiod CLI tools
and any software consuming the GPIO character device.

It is a small, self-contained module (drivers/gpio/gpio-sim.c) with no runtime
cost unless manually loaded and depends only on CONFIG_CONFIGFS_FS (already =m)
and the GPIO chardev (already enabled).

Thanks for considering.