Assistance Required for LVDS Display Issue on Custom i.MX 93 Board

[Embedded-world]

Dear Experts,

I am working on a custom i.MX 93 board with an LVDS display.

But, the LVDS device does not seem to be functioning correctly, as indicated by the following message:

Moreover, the brightness node cannot be found in the lvds_backlight node:

Below is the LVDS device tree configuration for our board:

----------------------------------------------------------------------------------------

lvds_backlight: lvds_backlight {

compatible = "pwm-backlight";

// pwms = <&adp5585pwm 0 100000 0>;

pwms = <&tpm3 0 100000 0>;

enable-gpios = <&gpio2 24 GPIO_ACTIVE_HIGH>;

power-supply = <&reg_vdd_12v>;

status = "okay";

brightness-levels = < 0  1  2  3  4  5  6  7  8  9

     10 11 12 13 14 15 16 17 18 19

     20 21 22 23 24 25 26 27 28 29

     30 31 32 33 34 35 36 37 38 39

     40 41 42 43 44 45 46 47 48 49

     50 51 52 53 54 55 56 57 58 59

     60 61 62 63 64 65 66 67 68 69

     70 71 72 73 74 75 76 77 78 79

     80 81 82 83 84 85 86 87 88 89

     90 91 92 93 94 95 96 97 98 99

    100>;

default-brightness-level = <80>;

};

lvds_panel  {

status = "okay";

backlight = <&lvds_backlight>;

//compatible = "boe,ev121wxm-n10-1850";

compatible = "panel-lvds"; 

data-mapping = "jeida-24";

width-mm = <124>;

height-mm = <80>;

panel-timing {

clock-frequency = <25000000>;

hactive = <800>;

vactive = <480>;

hfront-porch = <8>;

hback-porch = <8>;

hsync-len = <1>;

vback-porch = <8>;

vfront-porch = <8>;

vsync-len = <1>;

hsync-active = <0>;

vsync-active = <0>;

pixelclk-active = <0>;

};

port {

panel_lvds_in: endpoint {

remote-endpoint = <&lvds_out>;

};

};

};

&tpm3 {

pinctrl-names = "default";

pinctrl-0 = <&pinctrl_tpm3>;

status = "okay";

};

&ldb {

status = "okay";

lvds-channel@0 {

status = "okay";

port@1 {

reg = <1>;

lvds_out: endpoint {

remote-endpoint = <&panel_lvds_in>;

};

};

};

};

&ldb_phy {

status = "okay";

};

&lcdif {

status = "okay";

        /* assigned-clock-rates = <484000000>, <121000000>, <400000000>, <133333333>; */

assigned-clock-rates = <498000000>, <71142857>, <400000000>, <133333333>; 

};

&dphy {

status = "disabled";

};

&dsi {

status = "disabled";

};

&iomuxc {

pinctrl_tpm3: tpm3grp {

fsl,pins = <

        MX93_PAD_GPIO_IO24__TPM3_CH3                    0x19e

>;

};

-----------------------------------------------------------------------------------

Could you please help resolve this issue? Your assistance would be greatly appreciated.

Thanks in advance.

Best Regards,

Ravikumar

[Embedded-world]

Hi Alejandro_Salas,

I'm currently using Kernel Version 6.6.52-2.2.0 and compiling all images using the Yocto Project resources [ https://github.com/nxp-imx/meta-imx/tree/scarthgap-6.6.52-2.2.0 ] from this repository.

This is my first time working on LVDS display integration with a custom IMX93 board. already resolved almost all the previous errors mentioned in earlier posts. but I am still facing the following errors:

I've referred to multiple documents related to LVDS display integration and analyzed the IMX8M Plus reference .dts file. I have made changes according to the LVDS display datasheet, but I am still facing DRM and LCD controller errors.

Can someone guide me on the necessary Device Tree (DTS) modifications or any additional kernel configurations I might be missing?

Our board’s DTS file: https://drive.google.com/file/d/11fOvV4iwWO78he2PFxgs7VBPVcuA6JqJ/view?usp=drive_link

Any suggestions or guidance would be greatly appreciated.

Thanks & Regards,
Ravikumar 

[Manuel_Salas]

Hello, 

I am not sure about your LVDS panel, maybe it is a generic panel, but if possible, please share schematic related to the connections to LVDS panel.

I could see you referred to imx93-11x11-boe-wxga-lvds-panel.dts. 

In your device tree, I could see you have the back-light node as simple GPIO, why not TPM or an external PWM module? 

Please clarify.

Best regards,

Salas. 

[Embedded-world]

Hi Alejandro_Salas,

We're using a generic LVDS panel display & have referred to the imx93-11x11-boe-wxga-lvds-panel.dts file also for configuration. moreover we're not using an any of the external PWM module. We've attempted both methods—configuring the TPM & utilizing the internal PWM—yet we continue to encounter the same LCD control error:

"Failed to create device link <0x180> with 4ae30000.lcd controller. & lcd controller"

For reference, please find attached the LVDS display schematic section.

We would appreciate any insights or guidance in resolving this issue. Looking forward to a positive response.

Thanks & Regards,
Ravikumar

[Manuel_Salas]

Hello @Embedded-world 

I hope you are doing very well.

Could you please clarify the kernel version and how you compiled your custom image?

Thank you.

Best regards,

Salas.