This adds support for the htu21 humidity and temperature sensor.
To get it to work you have to do something like this:
echo "htu21 0x40" >/sys/class/i2c-dev/i2c-1/device/new_device
for example by adding it to rc.local
Compile tested on brcm2708 and I have used an earlier version of this
patch for more than a year.
Signed-off-by: Torbjörn Jansson <torbjorn.jansson@mbox200.swipnet.se>