[iMX8QM-MEK] RS232(ttyLP2) setting

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[iMX8QM-MEK] RS232(ttyLP2) setting

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sushi_happy
Contributor III

Hi, all.

I would like to use the imx8qm-mek RS-232 connector (J37).
LPUART2( /dev/ttyLP2 ) is not enabled.
What should I do?

 

I made the following changes.

changes
・init.rc (/device/nxp/imx8q/mek_8q)
  - Added the following code before "on boot".

    chmod 0777 /dev/ttyLP2

・imx8qm-mek.dts (/vendor/nxp-opensource/kernel-imx/arch/arm64/boot/dts/freescale)
  - changed the following code.

    &lpuart2 {
        pinctrl-0 = <&pinctrl_lpuart2>;
        status = "okay";
    };

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sushi_happy
Contributor III
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sushi_happy
Contributor III
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vzeric
Contributor III

Hi, I have exact same problem with my i.MX8 QM MEK board. I am using Base Board to connect PC and Board using RS232. I am using USB-to-serial converter to do that, but I cannot see /dev/ttyLP2. I also tried to change lpuart2 status in dts to "okay" but it didn't help.
Did you manage to solve the problem?
BR,
Vanja

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sushi_happy
Contributor III

Hi, @vzeric .

It's the same situation.
The problem is unresolved.
UART2 is assigned to core M41, and access from core A may be prohibited.
However, UART2 cannot be used even if the SCFW changed.

I was able to use LPUART4 with reference to the following.

Solved: [iMX8QM-MEK] LPUART4 settings - NXP Community

System Controller Firmware 101 - Getting started - NXP Community

Please let us know if there is any progress.

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Rita_Wang
NXP TechSupport
NXP TechSupport

Sorry for miss your thread and late reply.

1. use stty configure the ttyLP2 and test 

stty -F /dev/ttyLP2 115200
echo abc > /dev/ttyLP2

b45499_0-1656589021551.png

 

2. enable ttyLP2 in systemd as another login console for test purpose

systemctl enable serial-getty@ttyLP2

You will have two login consoles. 

b45499_1-1656589022423.png

 

 

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sushi_happy
Contributor III

Thank you @Rita_Wang .
I saw that page, so already it's checked.
How to check rs232 port in imx8-8x baseboard in imx8qxp-mek 

 

Executing that command will fail.

ttyLP2_ss_1.png


There is no ttyLP2 device file in the first place.

ttyLP2_ss_2.png


Executing the command on ttyLP4 does not echo to ttyLP4.

ttyLP2_ss_3.png

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