LTC2631

Hi,
we are trying to use the ad5064 driver with latest patch for LTC2631 (one
channel DAC). 
When we try to output some voltage we get: " -sh: echo: write error: No such device or address"
One possibility is that the driver does not seem to read the I2C address from the device tree. I have inserted a few printk statements into " ad5064_i2c_write" function to print out the return value and address value: 
This is the full output: 
root@qcom:/sys/bus/iio/devices/iio:device1# cat uevent
MAJOR=247
MINOR=1
DEVNAME=iio:device1
DEVTYPE=iio_device
OF_NAME=ltc2631-l10
OF_FULLNAME=/soc/i2c@78b8000/ltc2631-l10@20
OF_COMPATIBLE_0=adi,ltc2631-l10
OF_COMPATIBLE_N=1
root@qcom:/sys/bus/iio/devices/iio:device1# echo 200 > out_voltage0_raw
[ 4004.255429]
[ 4004.255429] Attempting to write to LTC2631
[ 4004.255711]
[ 4004.255711] Number of bytes sent over I2C: -6 to I2C address: 0
-sh: echo: write error: No such device or address
are the required device tree entries  for ad5064 driver (for the case of I2C interace) documented somewhere?
This is our device tree entry:
&blsp_i2c4 {
status = "okay";
   ltc2631-l10@20 {
   compatible = "adi,ltc2631-l10";
   eg = <0x20>;
   };
};
Printing diagnostic information from ad5064_i2c_write function indicates
that adrr value is zero while I assume it should be 0x20. Any advice? I tried to force it to be 0x20 in the driver but that did not make any difference, it still reports " write error: No such device or address"
Thank you.
Mirianas