Take a look at the Arduino board package and/or Zephyr devicetree for one of the nRF52832 boards. You may be able to use one as is or may need to change the PIN numbers (for SPI, I2C, etc) to match your custom board.
I haven’t done a custom board from scratch, only modified a “Generic nRF5” (nRF51802) board for a custom nRF51802 board. It worked fine for most functions (GPIO, I2C, SPI) that I tried.
Curious - Any particular reason you’re using a nRF52832 and not nRF52840 or nRF52833?
Arduino:
macOS - variant.h / variant.cpp in
/Users/<username>/.platformio/packages/framework-arduinoadafruitnrf52/variants/feather_nrf52832
Zephyr RTOS:
for example, one of the nrf52832 boards,
/zephyr/boards/arm/nrf52832_mdk/nrf52832_mdk.dts
Zephyr Board Porting Guide:
https://docs.zephyrproject.org/latest/guides/porting/board_porting.html?highlight=nrf52832