topic Re: Porting LCD driver to uboot on imx8ulp in i.MX Processors

Porting LCD driver to uboot on imx8ulp

wangrucheng — Sat, 13 Jan 2024 11:52:24 GMT

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

Re: Porting LCD driver to uboot on imx8ulp

brian14 — Fri, 12 Jan 2024 18:07:12 GMT

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!

Re: Porting LCD driver to uboot on imx8ulp

wangrucheng — Sat, 13 Jan 2024 11:53:54 GMT

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.

Re: Porting LCD driver to uboot on imx8ulp

wangrucheng — Wed, 17 Jan 2024 06:23:46 GMT

Hi @brian14

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

Thanks!

Re: Porting LCD driver to uboot on imx8ulp

brian14 — Wed, 17 Jan 2024 14:34:13 GMT

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!

Re: Porting LCD driver to uboot on imx8ulp

wangrucheng — Sat, 20 Jan 2024 08:27:59 GMT

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.