Device Tree Customization for SSI and GPIOs

Yes. This would be the safest way.

Ok. I’ll check it.
For enabling the SPI peripheral I followed this link for the device tree customization.
I couldn’t find any resource for enabling the GPIOs. Since I am completely new to Linux and Device Tree Customization, any example for enabling and disabling GPIOs inside device trees would be highly helpful.

Thank You.

You should have a look here.