WP7607 UART2 CTS RTS config

IoT Modules
1

I have disabled console function on UART2, and I want to config to 4 wires UART(Tx, Rx ,CTS, RTS) to communicate with other UART device. It’s not work on CTS/RTS pins.
I traced code in msm_serial_hsl driver, and found if the device would be configured to 4 wires UART, the following config need to be described in the device tree.

qcom,config-gpio = <4>;
qcom,tx-gpio = <&msmgpio 41 0x00>;
qcom,rx-gpio = <&msmgpio 42 0x00>;
qcom,cts-gpio = <&msmgpio 43 0x00>;
qcom,rfr-gpio = <&msmgpio 44 0x00>;

Does anyone know how to get the document that describes the pin definition or how to configure CTS/RTS pins of UART2 on WP7607?

current UART node in device tree:
blsp1_uart1: serial@78af000 { /* BLSP1 UART1 */
compatible = “qcom,msm-lsuart-v14”;
reg = <0x78af000 0x200>;
interrupts = <0 107 0>;

clocks = <&clock_gcc clk_gcc_blsp1_uart1_apps_clk>,
	 <&clock_gcc clk_gcc_blsp1_ahb_clk>;
clock-names = "core_clk", "iface_clk";
status = "disabled";

};