Need guidance: How to start LVDS display integration (dual-channel) on Verdin AM62 + Mallow Carrier Board using Yocto?

Technical Support
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1

Hi Toradex Team,

I’m working on a Verdin AM62 + Mallow Carrier Board project and have successfully built a custom Yocto image.

Now, I’m trying to interface a dual-channel LVDS display (connection details from datasheet attached). The display works through Channel A (Odd Pixels) and Channel B (Even Pixels) LVDS lines, and includes backlight control via separate signals.

:package: Current Setup:

  • Verdin AM62 SOM
  • Mallow Carrier Board
  • Custom Yocto image
  • LVDS display with capacitive touch
    (Display connection diagram attached — includes LVDS_A/B signals, backlight control, and I2C touch)

:question: My Questions:

I’m quite new to display bring-up and device tree modifications, so I need help from step 1. I’m not sure what exactly to modify or create.

  1. Where should I start the integration process?
  • Do I need to modify existing .dts/.dtsi files?
  • Or should I create a device tree overlay (.dto) for this?
  1. What changes are required in the device tree to enable dual-channel LVDS output?
  2. How can I configure and control the backlight signals (LVDS_BKL_EN_CON, LVDS_PWM_CON)?
  3. How do I bring up the capacitive touch (I2C interface on Mallow X13)?
  4. Are there any recommended Yocto layer additions, kernel configs, or overlays for this setup?

:paperclip: Notes:

  • I have mapped the LVDS_A/B signals and power connections as per the display datasheet.
  • Control signals like RESETB and STBYB are mentioned to be tied high — should these be handled in the device tree or externally via hardware?
  • Pins 35 & 37 are mentioned as connected to LED driver for backlight control.

Would greatly appreciate a beginner-friendly direction — even high-level steps would help me get started properly.

Thanks so much in advance!
Raju

Interface between Mallow board and display.pdf (632.3 KB)

blank_compressed.pdf (1.2 MB)

2

Hi, I’m the Toradex AI Assistant. The Toradex Support team will follow up with you shortly!

Did you like my answer?

:+1: :-1:

Hello!

To integrate your LVDS display with the Verdin AM62, you can follow these steps:

  1. Device Tree Overlay: Use the device tree overlay approach. The pre-built overlay for LVDS displays is verdin-am62_panel-cap-touch-10inch-lvds_overlay.dtbo. You can find more details in the Toradex documentation.

  2. Dual-Channel LVDS Configuration: For dual-channel LVDS, consider the following:

    • It supports resolutions up to 1920x1080 @60fps with a maximum pixel clock of 160MHz. More information is available here.
    • Configure the interface to handle odd pixels in the first channel and even pixels in the second channel.

  3. Display Control Signals:

    • Use PWM_3_DSI for controlling display brightness.
    • Use I2S_2_D_OUT for enabling the display backlight. Further details can be found in the Verdin product family specification.

  4. Capacitive Touch Integration:

    • The touch interface requires a separate cable connection. Ensure the cable is properly oriented, with the blue part facing down on the connector. You can refer to this community discussion for more insights.

  5. Enabling the Display:

    • Add the required overlay to your /boot/overlays.txt file and reboot the system after making changes. Detailed instructions are available in the Toradex documentation.

If you have any specific questions or need further clarification on any of these points, feel free to ask!

Best regards,
Toradex AI Assistant.

4

Hi,

Thanks for the support

I wanted to ask a follow-up regarding the Winstar WF123BSRAYLNBO LVDS display I’m using.

According to the display’s datasheet (screenshot attached), there’s a specific power ON/OFF sequence involving:

Screenshot from 2025-04-22 11-27-07
Screenshot from 2025-04-22 11-27-07588×588 54 KB

VCC

RESETB

STBYB

LVDS signals

Backlight enable

Power ON requires:

VCC first

RESETB ≥10us later

STBYB ≥0s after that

LVDS signals on

Backlight after ≥350ms

Power OFF needs:

Backlight off first

Then LVDS off

Then STBYB pulled low (≥150ms)

Then RESETB low

Then VCC off

My questions are:

Where should I implement this power sequencing in the Verdin AM62 + Mallow setup?

Can this be handled purely via the device tree (e.g. using reset-gpios, delays, etc)?

Or should I handle the sequence in a panel driver or via userspace (e.g. systemd service/script)?

For GPIOs like RESETB and STBYB, can I define them in the device tree and associate delays or sequences there?

Is there a recommended approach from Toradex for safely handling such display power sequences?

Would love some direction on this so I can ensure I’m powering the panel safely and correctly.

Thanks again!
Raju

5

Hi @raju3003!

As far as I understand, the driver should take care of this power sequence. The driver should be specified in the compatible variable of the display node in the device tree or overlay, for example, on line 34 of this overlay.

If you are interested in the driver code, you can find it here.

Best regards.
Lucas Azeituno