No Display on LVDS

[VinithNama]

Hi,

     I'm working on IM8M MINI EVK Linux platform, we are working on integration of panasys LVDS display and we are using SN65DSI83 as an bridge converter.

I 'have applied below patch at the directory kernel-sourcr/.../git/drivers/gpu/drm/bridge.

and i have updated in my device tree file build/tmp/work-shared/imx8qmevk/kernel-source/arch/arm64/boot/dts/freescale/imx8mm-evk.dts as below

&lcdif{

 max-res = <1280>, <1024>;

 status = "okay";

};

&mipi_dsi {

       status = "okay";

        port@1 {

                dsim_to_sn65dsi8: endpoint {

                        remote-endpoint = <&sn65dsi83_in>;

                };

       };

};

&i2c2 {

    clock-frequency = <100000>;

    pinctrl-names = "default";

    status = "okay";

    lvds_bridge: sn65dsi83@2c {

        compatible = "ti,sn65dsi83";

       reg = <0x2c>;

        ti,dsi-lanes = <4>;

        ti,lvds-format = <2>;

        ti,lvds-bpp = <24>;

        ti,width-mm = <376>;

        ti,height-mm = <301>;

        enable-gpios = <&gpio1 14  GPIO_ACTIVE_HIGH>;

        pinctrl-names = "default";

        pinctrl-0 = <&pinctrl_dsi_lvds_bridge>;

        status = "okay";

       display-timings {

            lvds {

/*

                clock-frequency = <90000000>;

               hactive = <1280>;

                hsync-len = <54>;

                hback-porch = <75>;

                hfront-porch = <75>;

                vactive = <1024>;

                vsync-len = <10>;

                vback-porch = <10>;

                vfront-porch = <22>;

                vsync-active = <0>;

                hsync-active =<0>;

                de-active =<0>;

                pixelclk-active =<0>;

*/

                         clock-frequency = <108000000>;

                         hactive = <1280>;

                         hsync-len = <28>;

                         hback-porch = <200>;

                         hfront-porch = <180>;

                         vactive = <1023>;

                         vsync-len = <7>;

                         vback-porch = <30>;

                         vfront-porch = <5>;

                         vsync-active = <0>;

                         hsync-active =<0>;

                         de-active =<0>;

                         pixelclk-active =<0>;

           };

        };

        port {

           sn65dsi83_in: endpoint {

                remote-endpoint = <&dsim_to_sn65dsi8>;

           };

        };

    };

};

after compiling and deploying the kernel using 

bitbake -c compile -f linux-imx and bitbake -c deploy -f linux-imx then I have built entire image using bitbake imx-image-full. I cannot see any display on the LVDS ,can you help me where i was struck.

 

[Zhiming_Liu]

Hi @VinithNama 

PLS share your log

[VinithNama]

Hi Sir,

           Below image shows the log of my uboot.

 

[Zhiming_Liu]

Hi @VinithNama 

Can you confirm that your hardware is working fine?

Try to use Oscilloscope capture the i2c wave.

[VinithNama]

Hi Sir,

 I can able to read the i2c registers and I'm getting the reset value my i2c is working but I'm not able to get any signal in oscilloscope.