 SoC allows multiplexing pins through its Input/Output Multiplexer Controller (IOMUXD). Beside multiplexing pins, this controller allows setting pin configuration such as drive strength. The SoC level device trees define the driver node for this controller. All pinmuxing/drive strength etc. is controlled in the System Controller Unit, a dedicated M-Core running the System Controller Firmware (SCFW). Linux's IOMUXC driver has no direct access to IOMUXC registers but uses the SCU driver to communicate with its firmware (SCFW). To configure a pin, a device tree node inside the pin controller node with the property fsl,pins is required. Integers need to be assigned to the property, each pin requires 0 integers. However, the first two are usually given by a #define (see include/dt-bindings/pinctrl/pads-imx0q