i.mx8 UART0_RX and UART0_TX swapped

[sergey_tarassen]

Hello,

we want to use serial ports UART0 and UART2 of the i.MX8 on the following pins:

AB32 UART0_RX
AA29 UART0_TX
AD34 UART2_RX
AC35 UART2_TX

UART2 works correctly, however it looks like TX and RX pins of UART0 are swapped. 

after executing "echo some text > /dev/ttyLP0" in linux data is coming on UART0_RX (AB32) pin. What could be causing RX/TX swap?

We use following UART configuration in device tree:

&lpuart0 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_lpuart0>;
	power-domain-names = "uart";
	dma-names = "tx", "rx";
	dmas = <&edma2 9 0 0>,
		<&edma2 8 0 0>;
	status = "okay";
};

&lpuart2 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_lpuart2>;
	status = "okay";
	/delete-property/ power-domain-names;
	/delete-property/ dma-names;
	/delete-property/ dmas;
};

pinctrl_lpuart0: lpuart0grp {
	fsl,pins = <
		IMX8QXP_UART0_RX_ADMA_UART0_RX		0x06000020
		IMX8QXP_UART0_TX_ADMA_UART0_TX		0x06000020
	>;
};

pinctrl_lpuart2: lpuart2grp {
	fsl,pins = <
		IMX8QXP_UART2_TX_ADMA_UART2_TX		0x06000020
		IMX8QXP_UART2_RX_ADMA_UART2_RX		0x06000020
	>;
};

Thank you in advance!

[sergey_tarassen · Accepted solution]

Problem was caused due to missmatch between layout and schematics. Actually UART works as expected.