Hello Stefan, > there are neither gpio-line-names defined for this GPIO expander nor the > SOC. Are there no GPIOs which can be accessed from userspace? The carrier board schematic is here: https://www.variscite.com/wp-content/uploads/2023/01/symphony-board_VAR-SOM-MX93.pdf All the pin headers are mapped to specific functions. On the other, already mainlined device-trees, that are based on the same "Symphony" carrier board, there are however gpio-keys for three buttons: gpio-keys { compatible = "gpio-keys"; key-back { label = "Back"; gpios = <&pca9534 1 GPIO_ACTIVE_LOW>; linux,code = <KEY_BACK>; }; key-home { label = "Home"; gpios = <&pca9534 2 GPIO_ACTIVE_LOW>; linux,code = <KEY_HOME>; }; key-menu { label = "Menu"; gpios = <&pca9534 3 GPIO_ACTIVE_LOW>; linux,code = <KEY_MENU>; }; }; I can add that in v5. Thanks, Mathieu