i.mx93 m33 core, issues with GPIO interrupt

[Vitus]

playing/debugging  the imx93. I have a simple problem, maybe someone can point to what I do wrong here. I want to create an interrupt with a GPIO state change. I use the drivers from NXP, fsl_rpgio.c/h provided with the SDK for the i.MX93)

First I set the MUX:

    IOMUXC_SetPinMux    (IOMUXC_PAD_I2C1_SDA__GPIO1_IO01, 0U);
    IOMUXC_SetPinConfig (IOMUXC_PAD_I2C1_SDA__GPIO1_IO01, 
                         IOMUXC_PAD_DSE(15U) |
                         IOMUXC_PAD_FSEL1(2U) |
                         IOMUXC_PAD_PD_MASK);  

Then I set up the port

rgpio_pin_config_t pin_config = {
      kRGPIO_DigitalInput,
      0,
  };
  GPIO1->PCNS = 0x0;      /* Set PCNS register value to 0x0 to prepare the RGPIO initialization */
  GPIO1->ICNS = 0x03; 
  RGPIO_PinInit(GPIO1, 1, &pin_config);  //sets PDDR
  RGPIO_SetPinInterruptConfig(GPIO1, 1, kRGPIO_InterruptOutput0, kRGPIO_InterruptRisingEdge); //rising edge interrupt
  NVIC_SetPriority(GPIO1_0_IRQn, 3 /*25*/ /*HAL_GPIO_ISR_PRIORITY*/);
  NVIC_EnableIRQ(GPIO1_0_IRQn);

for the interrupt handler I define (Reserved26 seems to be the General Purpose Input/Output 1 interrupt 0)

void Reserved26_IRQHandler()
{
  RGPIO_ClearPinsInterruptFlags(GPIO1, 0, (1<<1));
}

But the interrupt never comes. Did I overlook sth. obvious?