This issue randomly happen after several system reset then the downstream reading (GBIC transceivers) return all zero.
I check the I2C bus and there is no other device holding the bus as both SCL and SDA are high when the issue happen.
The issue only resolve if I reset the port accordingly (register 0x00 bit 0-3).
My question: what probably causing the FPC402 go into stuck mode and only port reset can help.
Thanks
Minh