Documentation/devicetree/bindings/iio/temperature/temperature-bindings.txt

   1 If the temperature sensor device can be configured to use some specific
   2 thermocouple type, you can use the defined types provided in the file
   3 "include/dt-bindings/iio/temperature/thermocouple.h".
   4
   5 Property:
   6 thermocouple-type:      A single cell representing the type of the thermocouple
   7                         used by the device.