imx8mp add mipi display (splash screen) to uboot.

[dennis3]

Hello,

I'd like to add support for our mipi display for a splash screen during uboot.  I'm basing dts changes off the imx8mp-evk.dts file in <uboot-dir>/arch/arm/dts/ from the 10_2.6.0 code base.

From the evaluation board dts file, it seems one simply has to 

1) Add your custom panel

2) &lcdif1 { status="okay"; }

3) &mipi_dsi { status="okay"; <add port from dsi to your panel>; }

For me, steps 1 and 3 don't cause any problems but if I simply change lcdif1 from disabled to okay, uboot fails to boot.  The output is normal SPL output:

U-Boot SPL 2020.04-49489-g94eeddb0e5-dirty (Jun 08 2021 - 10:38:08 -0600)
Normal Boot
Trying to boot from BOOTROM
image offset 0x0, pagesize 0x200, ivt offset 0x0

And then the board simply just powers back off.

If I just leave lcdif1 status=disabled, uboot boots normally.  

So it appears I am missing some step to use the lcdif..  Can anyone suggest how to debug or find what is missing to allow proper boot with lcdif1 enabled?

[dennis3]

Would be interested if anyone has a working mipi solution (a splash screen) on their imx8m plus board during uboot.  I'm still unable to boot at all if I enable the lcdif1 driver and have not had any luck debugging why that is.

[AldoG · Accepted solution]

Hello,

You may refer to the following:
https://source.codeaurora.org/external/imx/uboot-imx/commit/?h=imx_v2020.04_5.4.70_2.3.0&id=e14979fc...

Best regards,
Aldo.

[dennis3]

Was able to use jtag to debug uboot and found cause of failure to boot.  Turns it out only happened when the lcdifv3 was enabled in combination with a regulator for usdhc2.  As that is not required for our custom board implementation, I was simply able to remove it.

The original instructions for enabling mipi did indeed work fine, thank you.

[dennis3]

Thank you Aldo for this reference. 

I've gone through the changes in this patch and have verified my code base has all these changes in my board configuration and dts files.  Unfortunately, I haven't made any progress.  Same situation as before.

SPL loads and prints up through the "image offset" message but then there is no more output and the board powers off.  I'm still trying to find how to debug the problem.  

If I simply set status="disabled" in the lcdif1 block I can boot properly without a display.