designs: ihp-sg13g2: Add I2C GPIO Expander

Simple I2C GPIO expander with 8 GPIO pins.

This design is a full chip layout with IO ring included. It's
missing metal fill and therefore not tape-out ready but a new
example to demonstrate OpenROAD and/or the IHP PDK due it's
short build time.

Signed-off-by: Daniel Schultz <[email protected]>

Author: dnltz

flow/Makefile

@@ -100,6 +100,7 @@
 #DESIGN_CONFIG=./designs/ihp-sg13g2/gcd/config.mk
 #DESIGN_CONFIG=./designs/ihp-sg13g2/spi/config.mk
 #DESIGN_CONFIG=./designs/ihp-sg13g2/riscv32i/config.mk
+#DESIGN_CONFIG=./designs/ihp-sg13g2/i2c-gpio-expander/config.mk
 
 # Default design
 DESIGN_CONFIG ?= ./designs/nangate45/gcd/config.mk