Questions about mipi dsi at imx8qm

[sjkim]

Hello,

Currently I am using imx8qm custom board.

The development environment is yocto 4.9.51.

The purpose is to operate the LCD of the mipi-dsi interface, but nothing comes out.

The driver IC of the LCD is ICNL9707.

The boot sequence is correct and I am modifying the "drivers \ gpu \ drm \ panel \ panel-raydium-rm67191.c" file.

OTP Flow is as above. But "MIPI Interface ready" does not seem to work.

It is stated that LP11 signal should be maintained before hardware reset.

If you know how to run LP11 in the kernel, please share it.

I have attached the dts file and driver code.

Please answer.
Thank you.

[igorpadykov]

Hi sujin

except correct power-up sequence, it is also necessary to perform lcd

initialization (specific for each lcd), please check function cmd_set_entry manufacturer_cmd_set[]

in driver code: panel-raydium-rm67191.c\panel\drm\gpu\drivers - linux-imx - i.MX Linux kernel 

Also L4.9.51 is very old, recommended to use latest nxp linux: Linux 4.19.35_1.1.0 Documentation

Best regards
igor
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[sjkim]

Thank you for answer.

But I have already confirmed what you said.(initialization code)

We also checked with LCD companies.

LCD companies say that mipi data should maintain LP11 before h / w reset.

LP11 doesn't seem to work with imx8 at this time.

So I have a question about LP11.

Will it work if I use Linux 4.19.35?

Please answer.

Thank you.

[igorpadykov]

Hi sujin

LP mode can be set in the register DSI_HOST_PKT_CONTROL as shown below:

Best regards
igor

[sjkim]

Thank you for answer.

Oh!

Where can I set this?

I can't check it in my documentation.

Can you link to the relevant source code or documentation?

Please answer.

Thank you.

[igorpadykov]

one can try to set in driver code: panel-raydium-rm67191.c\panel\drm\gpu\drivers - linux-imx - i.MX Linux kernel 

Best regards
igor