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AM62L: Assistance Required for MIPI-DSI Display Bring-Up Without Bridge (Using panel-simple-dsi)

Dheeraj K
Intellectual 750 points
Part Number: AM62L

Tool/software:

Hello,

I am currently working on bringing up a MIPI-DSI display on our custom hardware. Unfortunately, the display initialization has failed so far.

During investigation, I referred to the device tree used for the Raspberry Pi display on the EVM, and I noticed that it includes a bridge component that converts DSI signals to DPI. However, my display panel accepts native DSI input directly and does not require any such bridge.

I plan to use the panel-simple-dsi compatible with the simple-panel driver, and intend to configure the necessary display timing parameters directly within the device tree.

Could someone please provide guidance or an example on how to correctly structure the device tree so that the panel-simple-dsi driver probes successfully for a native MIPI-DSI panel without using any bridge?

Any help on configuring the ports, endpoints, and timing parameters correctly would be greatly appreciated.

Thank you.

  • 0
    TI__Expert 7990 points

    Hi Dheeraj,
    Unfortunately we haven't used/tested panel-simple-dsi with any of our panels and do not have any reference for the same. We directly use the panel driver along with panel-simple for panels tested by us.

  • 0 in reply to Divyansh Mittal
    Intellectual 750 points

    Hi Divyansh, 

    Just to confirm — since the device tree uses a bridge that converts DSI signals to DPI, does that mean the Raspberry Pi display being validated is not a native MIPI-DSI display? Is it a display which uses dpi signals for sending data signals

  • 0 in reply to Dheeraj K
    TI__Expert 7990 points

    Hi Dheeraj,
    Can you please explain what a "native MIPI-DSI display" is?

    As far as I know, using DSI means serializing data on processor side, communicating it to panel with lesser number of lines and again deserialize DSI data received into DSI panel to DPI/LVDS; which can actually be consumed by pixels on the panel.

    I have not seen a panel that takes in DSI data and displays it without deserializing to other format internally. If you have seen such a panel, would request you to share the datasheet of the same.

  • 0 in reply to Divyansh Mittal
    Intellectual 750 points

    I have validated the display currently in use, and it appears to operate solely using DSI signals for rendering pixels. At the moment, I do not have access to the panel's datasheet. Once I obtain the datasheet, I will share the relevant details to confirm this behavior.

    native MIPI-DSI display: A Mipi display which directly uses DSI Signals to render GUI 

  • 0 in reply to Dheeraj K
    Intellectual 750 points

    WF70A8TYAHMNGB (1) 1 1.pdf

    1. Attached is the datasheet,kindly check this and verify weather this can be validated on AM62L3 platform 
  • 0 in reply to Dheeraj K
    Intellectual 750 points

    Hi , 

    Any updates ? I was facing issue with bringing up the gui in this display ? kindly check this and verify weather this can be validated on AM62L3 platform?

  • 0 in reply to Dheeraj K
    TI__Expert 7990 points

    We cannot validate custom displays on our end. Since your question was about the presence of the bridge, can you share what the following IC are doing?

    From brief read of the datasheet, looks like this is TFT LCD panel?

  • 0 in reply to Divyansh Mittal
    Intellectual 750 points

    Hi,

    I dont want to you to validate the display . I just want to know that this display falls under supported MIPI-DSI panels for this particular processor.
     this is TFT LCD panel? Yes.
    And that driver is hw mounted on the display (nothing of importance)

  • 0 in reply to Dheeraj K
    TI__Expert 7990 points
    Dheeraj K said:
    I just want to know that this display falls under supported MIPI-DSI panels for this particular processor.

    In general, any MIPI-DSI panel is supported.

    Dheeraj K said:
    And that driver is hw mounted on the display (nothing of importance)

    What is the driver IC doing? Is it not consuming DSI data and yielding DPI or something similar?

  • 0 in reply to Divyansh Mittal
    Intellectual 750 points

    Is it not consuming DSI data and yielding DPI or something similar? - No 

    In general, any MIPI-DSI panel is supported. -Okay .Thank you for the update

     

  • 0 in reply to Dheeraj K
    TI__Expert 7990 points

    I checked the datasheet for the driver ICs mentioned in the datasheets, and there are some registers associated with it. Is there any driver that is configuring those registers?

  • 0 in reply to Divyansh Mittal
    Intellectual 750 points

    Alll the register writing is being handled by the panel-winstar driver (shared by the vendor).

  • 0 in reply to Dheeraj K
    Intellectual 750 points

    Hi, 

    As you have asked the detail of the driver IC -EK79007AD3 : The EK79007AD is a highly integrated solution for small size to middle size a-Si TFT-LCD panels. This chip integrates 1536ch source driver with MIPI input interface.

    Single Chip 1536 Channel Source Driver
    with Timing Controller for 1024(RGB) × 600 TFT LCD
    1. GENERAL DESCRIPTION
    The EK79007AD is a highly integrated solution for small size to middle size a-Si TFT-LCD panels. This chip
    integrates 1536ch source driver with MIPI input interface.
    2. FEATURES
    Special design for middle size TFT LCD Panel with MIPI interface
    Integrate 1536 channel source driver and timing controller with dual gate function
    Support panel resolution (HxV):1024(RGB)x768, 1024(RGB)x600,
    800(RGB)x600,800(RGB)x480
    8-bit resolution 256 gray-scale with dithering(6-bits DAC +2 bits FRC or HFRC)
    Power for MIPI circuit(VDD_IF): 1.8V
    Power for digital circuit(VDD): 1.8V
    Power for analog circuit(AVDD): 8.0V ~ 13.5V
    Support interface: MIPI (4lane/3lane/2lane)
    Embedded Gamma Table for special customer request
    V1~V14 for adjusting Gamma correction
    1+2 dot inversion architecture
    Built-In VCOM buffer
    Built-In AUTO pattern
    Built-In SDRRS function
    Support no_clock detection
    COG package
    Chip size = 24975um * 695um
    bump height=9um
    Output bump pitch = 15um

  • 0 in reply to Dheeraj K
    Intellectual 750 points

    Hi, 

    Any updates Regarding this?

  • 0 in reply to Dheeraj K
    TI__Expert 7990 points

    Not sure if there was an open question here?

    Dheeraj K said:
    Alll the register writing is being handled by the panel-winstar driver (shared by the vendor).

    As you said this is the case, I would recommend you to wait for few upcoming DSI based patches in couple of weeks.

  • 0 in reply to Divyansh Mittal
    Intellectual 750 points

    Hi ,

    Thank you for the updates.