This is the message I got...
root@galileo:~# cat /sys/kernel/debug/gpio
cat: /sys/kernel/debug/gpio: No such file or directory
root@galileo:~# lsmod | grep cy
cy8c9540a 17580 0
i2c_core 27485 3 at24,intel_cln_gip,cy8c9540a
root@galileo:~# modprobe cy8c9540a
root@galileo:~# lsmod | grep cy
cy8c9540a 17580 0
i2c_core 27485 3 at24,intel_cln_gip,cy8c9540a
I think it may be caused by kernel compiling config.
BTW, which firmware version are you using?
I'm using this version: http://downloadmirror.intel.com/23171/eng/LITTLE_LINUX_IMAGE_FirmwareUpdate_Intel_Galileo_v0.7.5.7z