Maximum UART ports in Orange PI PC Plus

Allwinner_H3_Datasheet_V1.2.pdf

up to five UART controllers

In sun8i-h3-orangepi-pc.dts only 4

How do I use all five?

                serial@1c28000 {
                        compatible = "snps,dw-apb-uart";
                        reg = < 0x1c28000 0x400 >;
                        interrupts = < 0x00 0x00 0x04 >;
                        reg-shift = < 0x02 >;
                        reg-io-width = < 0x04 >;
                        clocks = < 0x03 0x3e >;
                        resets = < 0x03 0x31 >;
                        dmas = < 0x15 0x06 0x15 0x06 >;
                        dma-names = "rx\0tx";
                        status = "okay";
                        pinctrl-names = "default";
                        pinctrl-0 = < 0x19 >;
                        phandle = < 0x64 >;
                };

                serial@1c28400 {
                        compatible = "snps,dw-apb-uart";
                        reg = < 0x1c28400 0x400 >;
                        interrupts = < 0x00 0x01 0x04 >;
                        reg-shift = < 0x02 >;
                        reg-io-width = < 0x04 >;
                        clocks = < 0x03 0x3f >;
                        resets = < 0x03 0x32 >;
                        dmas = < 0x15 0x07 0x15 0x07 >;
                        dma-names = "rx\0tx";
                        status = "disabled";
                        pinctrl-names = "default";
                        pinctrl-0 = < 0x1a >;
                        phandle = < 0x65 >;
                };

                serial@1c28800 {
                        compatible = "snps,dw-apb-uart";
                        reg = < 0x1c28800 0x400 >;
                        interrupts = < 0x00 0x02 0x04 >;
                        reg-shift = < 0x02 >;
                        reg-io-width = < 0x04 >;
                        clocks = < 0x03 0x40 >;
                        resets = < 0x03 0x33 >;
                        dmas = < 0x15 0x08 0x15 0x08 >;
                        dma-names = "rx\0tx";
                        status = "disabled";
                        pinctrl-names = "default";
                        pinctrl-0 = < 0x1b >;
                        phandle = < 0x66 >;
                };
                serial@1c28c00 {
                        compatible = "snps,dw-apb-uart";
                        reg = < 0x1c28c00 0x400 >;
                        interrupts = < 0x00 0x03 0x04 >;
                        reg-shift = < 0x02 >;
                        reg-io-width = < 0x04 >;
                        clocks = < 0x03 0x41 >;
                        resets = < 0x03 0x34 >;
                        dmas = < 0x15 0x09 0x15 0x09 >;
                        dma-names = "rx\0tx";
                        status = "disabled";
                        pinctrl-names = "default";
                        pinctrl-0 = < 0x1c >;
                        phandle = < 0x67 >;
                };