kernel/Documentation/devicetree/bindings/serial/sprd-uart.txt

   1 * Spreadtrum serial UART
   2
   3 Required properties:
   4 - compatible: must be "sprd,sc9836-uart"
   5 - reg: offset and length of the register set for the device
   6 - interrupts: exactly one interrupt specifier
   7 - clocks: phandles to input clocks.