IMX8QXP Mipi clock issue

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IMX8QXP Mipi clock issue

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jakos
Contributor III

Hi,

I am working on a project involving IMX8QXP processor. We are using kernel 4.14 with Yocto project (NXP BSP layers - Sumo). The issue we have encountered is related with mipi clock signals.

In our design mipi1 signals coming from processor are connected to mipi-hdmi bridge (LT9611). It has it's own MCU thus is "transparent" to the system - no initialization is required. Here is our device tree :

 

&mipi_dsi_bridge2 {
    status = "okay";

    panel@0 {
        compatible = "raydium,rm67191";
        power-supply = <&reg_seq3_peri>;
        reg = <0>;
        dsi-lanes = <4>;

        display-timings {
            timing {
                clock-frequency = <132000000>;
                hactive = <1080>;
                vactive = <1920>;
                hfront-porch = <20>;
                hsync-len = <2>;
                hback-porch = <34>;
                vfront-porch = <10>;
                vsync-len = <5>;
                vback-porch = <4>;
                hsync-active = <0>;
                vsync-active = <0>;
                de-active = <0>;
                pixelclk-active = <0>;
            };
        };

        port {
            panel1_in_bendpoint {
                remote-endpoint = <&mipi_dsi_bridge_out>;
            };
        };
    };

    port@2 {
        mipi_dsi_bridge_outendpoint {
            remote-endpoint = <&panel1_in_b>;
        };
    };
};

&mipi_dsi2 {
    pwr-delay = <10>;
    status = "okay";
};

&mipi_dsi_phy2 {
    status = "okay";
};
 
We have received proper binary for the bridge (flashed via i2c with the use of external tools) in accordance to the setting. Unfortunately we do not receive any video on the screen. The bridge has uart configured as a logger, and here is the output:
 
 
Mipi pcr unstable!!!!!!!!!!!!!!!!!!!!!!!!
mipi byteclk = 98991
Set Mipi Settle: 0x06
Input MIPI FMT: RGB888
h_act = 1080
v_act = 1920
v_total = 1939
video_resolution = video_1080x1920_60
pclk_khz = 132162
Htotal_sysclk_num = 201
Frame_sysclk_num = 400524
HDMI 1.4
txpll calibration done
Mipi pcr unstable!!!!!!!!!!!!!!!!!!!!!!!!
mipi byteclk = 98991
Set Mipi Settle: 0x06
Input MIPI FMT: RGB888
h_act = 1080
v_act = 1920
v_total = 1939
video_resolution = video_1080x1920_60
pclk_khz = 132162
Htotal_sysclk_num = 202
Frame_sysclk_num = 400524
HDMI 1.4
txpll calibration done
Mipi pcr unstable!!!!!!!!!!!!!!!!!!!!!!!!
mipi byteclk = 98990
Set Mipi Settle: 0x06
Input MIPI FMT: RGB888
h_act = 1080
v_act = 1920
v_total = 1939
video_resolution = video_1080x1920_60
pclk_khz = 132162
Htotal_sysclk_num = 216
Frame_sysclk_num = 400524
HDMI 1.4
txpll calibration done
 
As You can see "htotal_sysclk_num" differs - this should be stable, hence the bridge won't output any TDMS signals.
 
We have found sort of similar issue here, for different processor: 
 
Most of the patches found in above thread were succesfully applied (except the one related strictly to imx8qmm). No difference.
 
A snippet from dmesg:
 
[ 2.699323] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[ 2.705967] [drm] No driver support for vblank timestamp query.
[ 2.726664] imx-drm display-subsystem: bound imx-drm-dpu-bliteng.2 (ops dpu_bliteng_ops)
[ 2.735370] imx-drm display-subsystem: bound imx-dpu-crtc.0 (ops dpu_crtc_ops)
[ 2.743097] imx-drm display-subsystem: bound imx-dpu-crtc.1 (ops dpu_crtc_ops)
[ 2.750806] nwl-mipi-dsi 56248000.mipi_dsi_bridge: [drm:nwl_dsi_host_attach] lanes=4, format=0x0 flags=0x411
[ 2.760794] imx-drm display-subsystem: bound mipi_dsi@56248000 (ops imx_nwl_dsi_component_ops)
[ 2.962407] imx-drm display-subsystem: fb0: frame buffer device
[ 2.968967] [drm] Initialized imx-drm 1.0.0 20120507 for display-subsystem on minor 0
 
Is there something that we are missing in the devicetree? Or perhaps this is a known problem for which patches exist ? Any help would be much appreciated as this is a crutial element in our desgin.
 
BR
 
 

 

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