How to Enable UART on UEXT1

[Nitish]

Please anyone tell me how to configure UART3 on UEXT1.
in #olinuxino-overlay its not showing uart3.

i'm using python library so PB0 and PB1 pins are not working so i'm using UEXT1 uart.
Thanx in advance.

[LubOlimex]

You need to load dtb/dts that enables it. Use the same dtb layout as for the UART2 one:

https://github.com/OLIMEX/olinuxino-overlays/blob/master/sun50i-a64/sun50i-a64-uart2.dts

You can also check the Armbian UART3 dtb/dts:

https://github.com/armbian/sunxi-DT-overlays/blob/master/sun50i-a64/sun50i-a64-uart3.dts

[Nitish]

How to do it?
Is there any source?
Haven't work on kernel level so don't know how to do it.
Thanks.

[LubOlimex]

Your issue is somewhere else. It seems UART3 is already enabled for a64 boards by default, you don't need to enable it via olinuxino-overlay:

https://github.com/OLIMEX/linux-olimex/blob/release-20210821-v5.10.60/arch/arm64/boot/dts/allwinner/sun50i-a64-olinuxino-1G.dts

&uart3 {
        pinctrl-names = "default";
        pinctrl-0 = <&uart3_ph_pins>;
        status = "okay";
};