@User there aren't spice models for GPIOs provided on the pdk... you can try to extract them from the gds file, using magic, if needed... also, there are useful information about the IOs on the pdk's rtd https://skywater-pdk.readthedocs.io/en/latest/contents/libraries/sky130_fd_io/README.html and on the caravel's datasheet... If you are mentioning analog pads the I/Os provided in caravel analog harness version (aka caravan), it is intended to interface high-frequency signals, but need to take care to the ESD sensitivity... for the analog I/O there is an spice here $(PDK_ROOT)/sky130A/libs.ref/sky130_fd_io/spice/... and you can also see chip_io.spice (caravan) and chip_io_alt.spice (caravel)...

"there aren't spice models for GPIOs provided on the pdk" Already found them. They are part of open_pdks, not Google's repositories as I expected. The analog pads are provided in Caravel, in Caravan there is no gpio cells connected as I understand. "need to take care to the ESD sensitivity" That's the hardest part. I am trying to use ready to use cells so I don't have to deal with ESD. I will provide more updates as I progress through. Thanks for helping!

yes... open_pdks is another tool that helps to install, setup and standize the pdks, it generates some useful views from the pdk libs