How to enable UART in Android - ROCK5B

#1

Hi!
I am trying to enable UARTs 3,4 and 7 in board Rock5B.

I managed to change dtsi, build image and burn the flash.

But I cannot access UART3 and 4.

The only one I can access is UART7. I made a loopback on the RX-TX pins, but I cannot see any data being transmited.

Here is my changes:
rk3588-radxa-rock5b-imx415.dtsi

&uart3 {
status = “okay”;
pinctrl-0 = &uart3m1_xfer;
};

&uart4 {
status = “okay”;
pinctrl-0 = &uart4m2_xfer;
};

&uart7 {
status = “okay”;
pinctrl-0 = &uart7m1_xfer;
};

image
image.png1390×568 26.6 KB

When I try to access the ttyS4 it gives me:
RadxaRock5B:/dev $ cat /dev/ttyS4
cat: /dev/ttyS4: Permission denied

I guess the change in the dtsi file is not enough to enable the UART.

#2

You need to add permissions to the file device/rockchip/rk3588/init.rk3588.rc

#3

I added, but it is still not working