I can't seem to get UART to work on Radxa Zero 3W

System info https://paste.next.armbian.com/savaleceqe

The usual enable UART options (that I see with other boards) do not show up under armbian-config->System->Kernel->Manage Device Tree Overlays.  (In fact very little shows up there, all the usual SPI / i2c / w1 / usbhost etc are all missing).

 

I did decompile /boot/dtb/rockchip/rk3566-radxa-zero3.dtb to take a look at what in their, and UART1,2,3,4,5,6,7 along with other missing options armbian-config are their, but the references to other files look to be missing IF (and that's a big IF) I am understanding the dtb / dts correctly. 

Within /boot/dtb/rockchip/rk3566-radxa-zero3.dtb with the symbols stanza I see the following 

 __symbols__ {
    uart1 = "/serial@fe650000";
    uart2 = "/serial@fe660000";
    uart3 = "/serial@fe670000";
}

 

I'm assuming uart1 is referancing this section within the same file

 

serial@fe650000 { 
                compatible = "rockchip,rk3568-uart\0snps,dw-apb-uart";
                reg = <0x00 0xfe650000 0x00 0x100>;
                interrupts = <0x00 0x75 0x04>;
                clocks = <0x24 0x11f 0x24 0x11c>;
                clock-names = "baudclk\0apb_pclk";
                dmas = <0x44 0x02 0x44 0x03>;
                pinctrl-0 = <0xe7 0xe8>;
                pinctrl-names = "default";
                reg-io-width = <0x04>;
                reg-shift = <0x02>;
                status = "okay";
                phandle = <0x1a1>;
        };      

 

What I can't find are any file named rk3568-uart on my system, but I can find files like rk3576-uart*

Same goes for all the other missing items like i2c, spi, etc.

 

I have no idea if this is the reason.  But would love some help on this as I don;t want to move to a different distribution.

 

Thanks.

Just in case you're still looking for an answer...

 

In order to enable a uart you have to grab the relevant dts file from:

https://github.com/radxa-pkg/radxa-overlays/tree/main/arch/arm64/boot/dts/rockchip/overlays

They're all in rk3568-* for some reason.

 

For example if you wanted to enable uart4 on pins 16/18 you'd grab

https://github.com/radxa-pkg/radxa-overlays/blob/main/arch/arm64/boot/dts/rockchip/overlays/rk3568-uart4-m1.dts

 

Then load it with armbian-add-overlay.

amrbian-add-overlay rk3568-uart4-m1.dts

and reboot.

On 3/11/2025 at 3:44 AM, alansrobotlab said:

Just in case you're still looking for an answer...

 

In order to enable a uart you have to grab the relevant dts file from:

 

Is this not done by default, yet?  Even on the latest images? @twwn Would you be kind enough to test / comment as well?

Outdated kernel. overlays were probably added later 

https://github.com/armbian/linux-rockchip/tree/rk-6.1-rkr5.1/arch/arm64/boot/dts/rockchip/overlay