Enabling LVDS-to-HDMI bridge (IT6263) on i.MX95

Technical Support
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1

Hi,

We are trying to enable the LVDS-to-HDMI bridge (IT6263) on the i.MX95 EVK. I have added the IT6263 device on I2C4 in my device tree as shown below:

&lpi2c5 {
    status = "okay";
    it6263: lvds-to-hdmi-bridge@4c {
        compatible = "ite,it6263";
        reg = <0x4c>;
        reset-gpios = <&gpio2 4 GPIO_ACTIVE_LOW>;
        status = "okay";

        port {
            it6263_0_in: endpoint {
                remote-endpoint = <&lvds0_out>;
            };
        };
    };
};

/* LVDS Display Bridge (LDB) */
&ldb {
    status = "okay";

    channel@0 {
        reg = <0>;
        fsl,data-mapping = "jeida";
        fsl,data-width = <24>;
        phys = <&ldb0_phy1>;
        phy-names = "lvds_phy";
        status = "okay";

        port@1 {
            reg = <1>;
            lvds0_out: endpoint {
                remote-endpoint = <&it6263_in>;
            };
        };
    };
};

&ldb0_phy {
    status = "okay";
};

When I check the logs, I see multiple “Fixed dependency cycle” messages related to the IT6263 and LDB:

/soc/bus@42000000/i2c@426b0000/lvds-to-hdmi-bridge@4c: Fixed dependency cycle(s) with /soc/syscon@4b0c0000/ldb@4/lvds-channel@0
/hdmi-connector: Fixed dependency cycle(s) with /soc/bus@42000000/i2c@426b0000/lvds-to-hdmi-bridge@4c

Also, dmesg | grep drm shows:

[drm] Initialized imx95-dpu 1.0.0
imx95-dpu 4b400000.display-controller: [drm] Cannot find any crtc or sizes

In /sys/class/drm/, I only see:

card0  
card0-HDMI-1  
renderD128
version

My questions:

1.Is my device tree configuration correct for connecting the IT6263 bridge with the LVDS channel?

2.How can I resolve the dependency cycle warnings reported in the logs?

3.Why is DRM not detecting any CRTC or display sizes from the IT6263 bridge?

4.When I run i2cdetect -y 4, the IT6263 shows up as uu, but dmesg | grep it6263 is empty. Does this mean the IT6263 driver is not binding properly? How can I fix this issue?

5.In /sys/class/drm/card0-HDMI-1/modes, the list is empty. How should I proceed further, and what is the correct way to validate the LVDS-to-HDMI output on a monitor?

2

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(1), (2), and (3):

LVDS-to-HDMI Bridge Configuration on Toradex Modules

Based on the Toradex documentation, I can provide guidance on LVDS configuration for supported modules, though the i.MX95 EVK is not specifically covered in the available sources.

Device Tree Configuration for LVDS

For Toradex modules with LVDS support, the device tree configuration follows specific patterns. According to the documentation, LVDS configuration requires proper color mapping and data width settings (1).

For supported modules, the LVDS configuration includes:

&ldb2 {  
        status = "okay";  
        fsl,dual-channel;  
  
        lvds-channel@0 {  
                fsl,data-mapping = "spwg";  
                fsl,data-width = <18>;  
                status = "okay";  
  
                port@1 {  
                        reg = <1>;

(1)

Color Mapping and Data Width Settings

The documentation specifies valid combinations for LVDS configuration (1):

fsl,data-mapping fsl,data-width data-mapping (panel-lvds node)
spwg 18 jeida-18
spwg 24 vesa-24
jeida 24 jeida-24

DRM Configuration

For supported Toradex modules, display outputs are managed through the DRM/KMS subsystem (1). The X-Server configuration shows how display modes are detected and configured (2).

Troubleshooting Display Issues

When troubleshooting display issues on supported Toradex modules, you can check available modes using xrandr (2):

root@apalis-imx6:~# xrandr  
Screen 0: minimum 240 x 240, current 1920 x 1080, maximum 8192 x 8192  
DISP3 BG connected 1920x1080+0+0 (normal left inverted right x axis y axis) 0mm x 0mm  
   S:1920x1080p-60  60.00*+  
   S:1920x1080p-50  50.00

(2)

Recommendations

Since the i.MX95 EVK is not specifically documented in the available Toradex sources, I recommend:

  1. Check Module Compatibility: Verify that your hardware configuration aligns with supported Toradex modules that have documented LVDS support
  2. Review Device Tree Overlays: For supported modules, overlays are used to enable display outputs (1)
  3. Validate Hardware Connections: Ensure proper hardware setup according to the module’s datasheet specifications

For the specific IT6263 bridge configuration on i.MX95 EVK, you may need to consult additional resources or consider using a supported Toradex module with documented LVDS-to-HDMI bridge support.

Check out these potentially useful sources: Display Output, Resolution and Timings (Linux), X-Server (Linux), Verdin iMX8M Plus V1.0 Datasheet

Would you like me to provide a general answer based on my knowledge instead?

Best regards, Toradex AI Assistant.