VIM3 uart3 not found

I could not find /dev/ttyS3 device


# Device Tree Overlays
overlays=uart3 pwm_f i2c3 i2s os08a10 watchdog

Please advise

@Jirat_Srisabye Mainline firmware overlays are currently not supported. To open the serial port, you need to modify the source code.

I can compile this kernel by fenix tool, How to modify?

Thank you


You can refer to this, you need to convert the code into a patch

Which file?

All of this ?

Please guide, Thank you :joy:

@Jirat_Srisabye When compiling the mainline kernel, we obtain the corresponding original code from the mainline, and then apply our patch, so if you want to modify the uart, you need to generate a modified patch on the corresponding code of the mainline first, and then put it in the patch file folder, so that your patch will be applied when compiling

For uart not found issue, Do you have patch file?

@Frank I create this patch and recompile but no tty uart device found. :sweat_smile:

diff --git a/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi b/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
index 0b65c6ccf..938634dba 100644
--- a/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
@@ -560,6 +560,12 @@
 	pinctrl-names = "default";
+&uart_C {
+	status = "okay";
+	pinctrl-0 = <&uart_c_pins>;
+	pinctrl-names = "default";
 &usb2_phy0 {
 	phy-supply = <&dc_in>;

@numbqq Do you have patch for this issue? Thank you ^^