Mini210s and GPIOs

Hi,

I want to us some GPIOs of my Mini210s and have some questions:
1. I see the different gpio-numbers in sys/class/gpio. Does that mean that
the kernel supports gpio access?
2. When I try to get access with a c++ program, I have to use a pin e.g.
160. How do I determine the right number to the pin I need?
3. I want to use the GPIOs from CON9 (SDIO). Is this possible without
kernel modifications?

Thanks and best regards
Ozzy

1. My guess is yes.
2. This document describes the process
http://www.avrfreaks.net/wiki/index.php/Documentation:Linux/GPIO
3. no idea