SPI chip select on WP77xx


Hello Forum,
I have added a WiFi card with SPI to a WP77xx module and it is running. The spisvc example module was used to combine the wifi driver with the SPI driver, which worked straight forward.
The problem is, that the chip select signal (on GPIO 2) is not used by the SPI driver, though it seems to be configured in the DTS file (mdm9607-wp76xx.dtsi).

                    spi1_cs0_active: cs0_active {
                            /* CS */
                            mux {
                                    pins = "gpio2";
                                    function = "blsp_spi3";

So my question: How can I tell the SPI driver to use the GPIO 2 pin as chip select?