Using AD7999 IIO driver

We've hooked up an ad7999 to the I2C bus of a Zynq 7015 (connected via MIO).

I added the ad7999 from the staging area to the kernel config, and on the devicetree using the following snippet:

               /* AD converter for voltage monitoring */
               monitorvolt: ad799x@29 {
                    compatible = "ad7999";
                    reg = ;
                    adi,reference-voltage-mv = <1500>;

I patched the ad799x driver to accept the vref from devicetree so it no longer requires a platform_data structure. Where can I submit that patch?

This appears to work, the device is probed and sysfs files for IIO appear:

cd /sys/bus/iio/devices/iio\:device0/
# cat in_voltage_scale
# cat in_voltage0_raw 
ad799x 1-0029: I2C read error                                                   
cat: read error: No such device or address 

After poking around a bit, the read error suddenly went away. Is there some sequence of things I have to do first? There are about 5 devices on the I2C bus and they all work just fine.