I'm trying to access an STM32L552 peripheral in a RoT APP (tf-m isolation v1.4 Level 2), but I'm having trouble doing that.

I know that I have to request the peripheral in the YAML file of my partition's manifest, but that request didn't work for me. I filled the required campus and couldn't get access to the peripheral. I'm requesting the peripheral by putting this piece of code in my partition manifest YAML file. Am I missing something? 

.....

   "mmio_regions" : [
    {
      "name": "TFM_PERIPHERAL_TIMER0",
      "permission": "READ-WRITE"
    }

......

Another thing, I am only able to request the TIMER0 and UART peripherals? If I want to access other timers, e.g., TIMER 6 or TIMER 7, am I not allowed to do so?

Cheers,

Cristiano