I see that there is a ready sht15 driver in linux. I can see it on Overo by "locate sht15":
Linux documentation (http://www.mjmwired.net/kernel/Documentation/hwmon/sysfs-interface) says that after modprobing the driver, there will be an entry at " /sys/class/hwmon/hwmon* ".
Then the reading would be done by the file " /sys/class/hwmon/hwmon*/humidity1_input ".
But after modprobing I couldn't find that entry. Does this works on Gumstix?