IMX8M Mini working with UART3

[shai_b]

Dear team,

My customer is trying to use UART3 with our IMX8MM-EVK, as I know such changes need to be done within the device tree.

but since the customer needs to change such a small parameter he would like to know if there is an option to change the UART3 of imx8mm (based on Yocto 5.15x Multimedia image) via U-Boot?

looking for your kind support, thanks in advance 

KR,

Shai

[Rita_Wang]

https://community.nxp.com/t5/i-MX-Community-Articles/How-to-Change-i-MX8MM-evk-Linux-Debug-UART/ba-p... You can refer to this.

[shai_b]

Hi @Rita_Wang ,

The customer does not want to change the debug port, but only to add the option to enable the UART3 so he can work use it on the user space?

can you please send me an example of how to change the correct device tree file and enable the UART3 to be 'active'?

Wating for your kind feedback, Many thanks.

Shai

[Rita_Wang]

Like this, you can ask customer to try

imx8mn-evk.dtsi
1. Remove UART2

pinctrl_uart3: uart3grp {
    fsl,pins = <
    MX8MN_IOMUXC_UART3_RXD_UART3_DCE_RX 0x140
    MX8MN_IOMUXC_UART3_TXD_UART3_DCE_TX 0x140
    >;
};

/*
&uart2 { 
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_uart2>;
    status = "okay";
};
*/

&uart3 { /*Console*/
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_uart3>;
    assigned-clocks = <&clk IMX8MN_CLK_UART3>;
    assigned-clock-parents = <&clk IMX8MN_SYS_PLL1_80M>;
    /*fsl,uart-has-rtscts;*/  
    status = "okay";
};

2. changing uart2 to uart3
#include <dt-bindings/usb/pd.h>
#include "imx8mn.dtsi"

/ {
    chosen {
        stdout-path = &uart3;
    };

[shai_b]

There is any update?

KR,

Shai