Hi for your information,
I implemented a driver that make instance of the i2c-gpio adapter for the A20.
You can find it here
https://github.com/lephiloux/sunxi-gpio-i2c
Hi,
i added another more generic one that give the possibility to create any number of i2c gpio based busses
with differents gpio couple
see here https://github.com/lephiloux/gpio-i2c-busses