How to enable LPUART for ls1028ardb board with mainline kernel(5.9 stable branch)

[hittzt]

Hi experts,

I find that there are new patches for nxp-ls1028ardb lpuart support in mainline kernel, like the following patches:

1. 2607d7246fb2a392091150e1a3ff4371a582d85f("arm64: dts: ls1028a: add missing LPUART nodes")

2. e33253f3b74b5fb2a3436c26c56252a3a8159228("tty: serial: fsl_lpuart: add LS1028A earlycon support")

...

and so on.

How can I test the lpuart function for ls1028 with these new patches?

I build the new kernel image, but the lpuart console did not work.

Would you please help to give full steps to enable lpuart function?

Thanks,

Zhantao

[yipingwang]

LS1028ARDB doesn't support LPUART, LS1028AQDS supports LPUART.

[hittzt]

Hi Yiping,

Thanks for your reply.

That is to say, the patches in mainline kernel is only for LS1028AQDS?

Would you please help to give a full step and log to test lpuart on LS108AQDS?

Is there a plan for LS1028ARDB to support lpuart in future?

And if not, what the reason for LS1028ARDB not support lpuart, hardware not support?

Thanks,

Zhantao

[yipingwang · Accepted solution]

Hello Zhantao,

LS1028ARDB hardware doesn't support LPUART.

In order to use LPUART on ls1028aqds, you need to use LPUART RCW and u-boot.

I uploaded LSDK 20.12 u-boot source code 

https://drive.google.com/file/d/19InOZeR3tVI8PAHGLZ7rbsEe6rc1qAM3/view?usp=sharing

RCW source code in

https://drive.google.com/file/d/1tyJ2hvObSS6Ma6LBC--yEpxrMfY8u7o7/view?usp=sharing

You need to use RCW ./ls1028aqds/R_SQPP_0x85bb/rcw_1500_gpu600_lpuart.rcw

And build u-boot with option configs/ls1028aqds_tfa_lpuart_defconfig.

Build Linux Kernel with the following option enabled.

Device Drivers --->
Character devices --->
Serial drivers --->
<*> Freescale lpuart serial port support
[*] Console on Freescale lpuart serial port

Please boot Linux Kernel with bootargs "console=ttyLP0,1152000".

Thanks,

Yiping

[hittzt]

Hi Yiping,

Got it!

Thanks for your reply.

I will use the steps you give to test ls1028aqds board for lpuart.

And it is a pity for ls1028ardb hardware not support lpuart,

my original aim is to make the ls1028ardb to support lpuart.

Thanks again,

Zhantao