From the controller number or the controller device path, you can determine the physical device path. In this example the controller number is 4 (the controller device path is /dev/cfg/c4).
# ls -l /dev/cfg/c4 lrwxrwxrwx 1 root root 60 Sep 26 2014 /dev/cfg/c4 -> ../../devices/pci@0,0/pci10de,377@f/pci10df,fc22@0/fp@0,0:fc
Removing ../../devices and :fc from the output, gives you the physical device path.
/pci@0,0/pci10de,377@f/pci10df,fc22@0/fp@0,0