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IMX8MQ EVK: No data on MIPI DSI interface

Question asked by jignesh patel on Feb 26, 2019
Latest reply on Jun 21, 2019 by Liou Harry

We are going to make product based on IMX8MQ (MIMX8MQ6DVAJZAA) processor.  Currently we are doing POC on IMX8MQ processor EVK.

 

  • We have connected kingsfield LCD (800 x 1280). It has driver IC (ILI9881C) and it has MIPI-DSI interface.
  • We have connected  lcd directly using DSI interface provided on IMX8MQ EVK.
  • To verify this setup we are using "fsl-imx8mq-evk-dcss-rm67191.dtb".  We have modified this device tree to support LCD panel we are using.  Following is snippet of device tree modification.

&mipi_dsi_bridge {
        status = "okay";

 

        panel@0 {
                compatible = "bananapi,lhr050h41", "ilitek,ili9881c";
                reg = <0>;
                reset-gpios = <&gpio5 6 GPIO_ACTIVE_HIGH>;
                port {
                        panel1_in: endpoint {
                                remote-endpoint = <&mipi_dsi_bridge_out>;
                        };
                };
        };
        port@1 {
mipi_dsi_bridge_out: endpoint {
                        remote-endpoint = <&panel1_in>;
                };
        };
};

 

Following is snippet of driver change: (drivers/gpu/drm/panel/panel-ilitek-ili9881c.c)

        dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_CLOCK_NON_CONTINUOUS | MIPI_DSI_MODE_VIDEO_HSE;
        dsi->format = MIPI_DSI_FMT_RGB888;
        dsi->lanes = 4;

  • Issue is we are getting clock coming out of IMX8MQ processor or DSI interface of processor but there are no data on data lines. We measured it on EVK itself and we don't see any data on data lines.

 

Are we missing anything? Any suggestion or direction will be appreciated.  As we are in critical phase of our project any help will be appreciated to proceed further.

 

Let me know if any information is required from us.

 

Thanks,

Jignesh

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