How to enable /dev/ttyTHS2?

We have a custom board on which we would like to use UART0_RXD and UART0_TXD (module pins 99 and 101) for serial communication to a second device. As far as I understand, these are routed to SOC pins for UART3 (serial@70006200 in the device-tree). A tty device is already created for this uart (/dev/ttyTHS2), but I have not been able to make it work.

The uart on /dev/ttyTHS1 (serial@70006040) is working correctly.

According to lsof, the device is not in use by any other process.

I have modified the dtb as follows:

	serial@70006200 {
		compatible =  "nvidia,tegra114-hsuart";
		reg = <0x0 0x70006200 0x0 0x40>;
		reg-shift = <0x2>;
		interrupts = <0x0 0x2e 0x4>;
		iommus = <0x2b 0xe>;
		dmas = <0x4c 0xa 0x4c 0xa>;
		dma-names = "rx", "tx";
		clocks = <0x21 0x37 0x21 0xf3>;
		clock-names = "serial", "parent";
		resets = <0x21 0x37>;
		reset-names = "serial";
		nvidia,adjust-baud-rates = <0x1c200 0x1c200 0x64>;
		status = "okay";
		linux,phandle = <0x10a>;
		phandle = <0x10a>;

Here is the output from sudo dmesg | grep serial

[    0.460865] iommu: Adding device 70006000.serial to group 3
[    0.460942] platform 70006000.serial: domain=ffffffc0f943ec18 allocates as[0]=ffffffc0f9454178
[    0.461415] iommu: Adding device 70006040.serial to group 4
[    0.461691] iommu: Adding device 70006200.serial to group 5
[    1.059960] No Device Node present for smmu client: serial8250 !!
[    1.059988] platform serial8250: No iommus property found in DT node, got swgids from fixup(101004000)
[    1.060087] iommu: Adding device serial8250 to group 35
[    1.062794] 70006000.serial: ttyS0 at MMIO 0x70006000 (irq = 63, base_baud = 25500000) is a Tegra
[    3.570123] 70006040.serial: ttyTHS1 at MMIO 0x70006040 (irq = 64, base_baud = 0) is a TEGRA_UART
[    3.579410] 70006200.serial: ttyTHS2 at MMIO 0x70006200 (irq = 65, base_baud = 0) is a TEGRA_UART
[    4.140218] usbcore: registered new interface driver usbserial

Thank you!

hello qwertypanda,

are you using Jetson Nano Developer Kit?
this is by default route to M.2 Key E connector on DevKit,

We use a custom carrier board. But never mind my question. I finally was able to solve it. There was problem in our PCB.

Thanks for the quick response.

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