Are gpiochip indices (gpiochip0–3) consistent across Linux reboots?

[mfide]

On my SOM module (with Linux v6.12), I have four GPIO chips listed as gpiochip0 through gpiochip3.
I have a feeling that these gpiochip indices are not assigned deterministically across reboots, similar to the issue we previously encountered with Ethernet interface names.

Is this indeed the case? Does the numbering (e.g., gpiochip1 today becoming gpiochip3 after a reboot) depend on the Linux driver or device initialization order during boot?

If so, what’s the recommended way to consistently access a specific GPIO? For example, if our MPU has GPIO1_87, how can I ensure my firmware reliably maps to the same GPIO line across boots, regardless of gpiochipX numbering?

[brgl]

As you figured out: there's no guarantee of the order in which GPIO chip devices are probed. You should typically access them by label. See the output of gpiodetect.