Problem using MIPI DSI Display

[visparon]

Hi i'm creating a custom yocto image to use a mipi dsi display on a Wandboard Dual, i don't know if i'm missing something because i cannot make the image load the drivers or detect the screen. I already did this:

- Modify the mxcfb_hx8369_wvga.c with my display data.
- Modified imx6qdl-wandboard.dtsi and added this:

/ {

mipi_dsi_reset: mipi-dsi-reset {
compatible = "gpio-reset";
reset-gpios = <&gpio1 19 GPIO_ACTIVE_LOW>;
reset-delay-us = <50>;
#reset-cells = <0>;
}; };

&mipi_dsi {
dev_id = <0>;
disp_id = <0>;
lcd_panel = "TRULY-WVGA";
resets = <&mipi_dsi_reset>;
status= "okay";
};

- Compiled my yocto using bitbake core-image-base
- Configure bootloader with this command: 

video=mxcfb0:dev=mipi_dsi,TRULY-WVGA,if=RGB24

But i' still cannot see anything on the display.

My bootloader info is telling me this:  

No panel detected: default to HDMI
Display: HDMI (1024x768)

Hope i can get some help because i already have 1 week with this problem. Thank you in advance.

[igorpadykov]

Hi Hector

one can check suggestions provided on

using mipi dsi for LCD display on imx6dl about android 

in particular: just modify the timing parameters in mxcfb_hx8369_wvga.c

is not enough, the mipi display initialization codes are depends on panel,

it is not common code for all panels.

Best regards
igor
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[visparon]

Hi friend, thanks for your answer.

I already checked my initialization codes and those are okay, in the link you provided where i need to put this line: 
"video=mxcfb0:dev=mipi_dsi,TRULY-WVGA,if=RGB24" because my yocto image using rocko no longer uses uEnv.txt and my uboot is not accepting that line as a parameter.

[visparon]

Is there a way where i can see the steps i need to do after i modified the mxcfb_hx8369_wvga.c to see if i'm doing something wrong?

[igorpadykov]

in general one can debug it using AN4553 Using Open Source

Debugging Tools for Linux on i.MX Processors
https://www.nxp.com/docs/en/application-note/AN4553.pdf

checking mipi lines with data analyzer, check commands/data sent to lcd

and verify with its datasheet.  NXP has Professional Services for

help with developing custom drivers: NXP Professional Services|NXP 

Best regards
igor