Porting LCD driver to uboot on imx8ulp

[wangrucheng]

LCD parameters

static const struct display_timing default_timing = {

    .pixelclock.typ     = 27000000,

    .hactive.typ        = 480,

    .hfront_porch.typ   = 20,

    .hback_porch.typ    = 35,

    .hsync_len.typ      = 4,

    .vactive.typ        = 800,

    .vfront_porch.typ   = 10,

    .vback_porch.typ    = 20,

    .vsync_len.typ      = 4,

};

controller:st7701s

mipi lane:2

format: RGB888

mode:MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_LPM | MIPI_DSI_MODE_VIDEO_BURST

    plat->lanes = priv->lanes;

    plat->format = MIPI_DSI_FMT_RGB888;

    plat->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_LPM | MIPI_DSI_MODE_VIDEO_BURST;

The same logic can run normally in the kernel, but it does not run properly in the uboot stage.

Can you give me some advice？

Thanks

[brian14]

Hi @wangrucheng, 

Thank you for contacting NXP Support.

This problem could be caused due to a difference in device tree used in both stages, U-boot and Kernel.
Please confirm that you are using the same device tree.

Have a great day!

[wangrucheng]

Hi @brian14

Have you ever checked this issue? I am currently stuck here and the deadline is very close.

Thanks!

[wangrucheng]

I am sure there is nothing wrong with the device tree I am using, because hx8394f panel can display the NXP log during the uboot startup phase.but my panel can't.

I uploaded device tree and panel code. 

[brian14]

Hi @wangrucheng, 

Could you please clarify your last reply?
In your first question you are saying that the problem is on uboot stage. However, in your last reply you are saying that your panel is working on uboot stage.

Also, I can't see your device tree or panel code. Could you please reupload your files?

Have a great day!

[wangrucheng]

I used a screen with ST7701S as the controller. Currently, the kernel can display the image normally, but when I porting it to uboot, I found that the NXP logo could not be displayed normally.

What I can confirm is that there is no problem with the device tree and there is no problem with the screen initialization code.

The attachment contains uboot kernel code and panel spec.