LVDS display panel on imx8mp

[Zater]

Hi

I am working on custom imx8mp board in which I have only one LVDS display port//  but there is no activity on the LVDS signal lines.

root@imx8mp-lpddr4-evk:~# cat /etc/os-release
ID=fsl-imx-wayland
NAME="NXP i.MX Release Distro"
VERSION="6.1-mickledore (mickledore)"
VERSION_ID=6.1-mickledore
VERSION_CODENAME="mickledore"
PRETTY_NAME="NXP i.MX Release Distro 6.1-mickledore (mickledore)"

Here is the kernel Messages :

root@imx8mp-lpddr4-evk:~# dmesg | grep drm

[ 1.858448] [drm] Initialized vivante 1.0.0 20170808 for 40000000.mix_gpu_ml on minor 0
[ 5.212383] systemd[1]: Starting Load Kernel Module drm...

root@imx8mp-lpddr4-evk:~# dmesg | grep lvds
[ 0.058502] platform lvds0_panel: Fixed dependency cycle(s) with /soc@0/bus@32c00000/ldb@32ec005c/lvds-channel@0/port@0/endpoint
[ 2.244245] pwm-backlight lvds_backlight: supply power not found, using dummy regulator

here is my dts:

&irqsteer_hdmi {
status = "disabled";
};

&hdmi_blk_ctrl {
status = "disabled";
};

&hdmi_pavi {
status = "disabled";
};

&hdmi {
status = "disabled";
};

&hdmiphy {
status = "disabled";
};

&lcdif1 {
status = "okay";
};

&lcdif2 {
status = "okay";
};

&lcdif3 {
status = "okay";

thres-low = <1 2>; /* (FIFO * 1 / 2) */
thres-high = 4>; /* (FIFO * 3 / 4) */
};

/{
lvds0_panel {
compatible = "panel-lvds";
status = "okay";
backlight = <&lvds_backlight>;
data-mapping = "vesa-24";
width-mm = <216>;
height-mm = <135>;
panel-timing {
clock-frequency = <72400000>;
hactive = <1024>;
vactive = <600>;
hback-porch = <160>;
hfront-porch = <120>;
vback-porch = <23>;
vfront-porch = <10>;
hsync-len = <70>;
vsync-len = <10>;
};

port {
panel0_lvds_in: endpoint {
remote-endpoint = <&lvds0_out>;
};
};
};
};

&ldb {
status = "okay";

lvds-channel@0 {
fsl,data-mapping = "spwg";
fsl,data-width = <24>;
status = "okay";

port@0 {
reg = <0>;

lvds0_out: endpoint {
remote-endpoint = <&panel0_lvds_in>;
};
};
};
};
&ldb_phy {
status = "okay";
};

Would you please advise about this problem

[Zater · Accepted solution]

Solved..
I found that the problem was at defining the ldb channel's connection:

&ldb {
status = "okay";

lvds-channel@0 {
fsl,data-mapping = "spwg";
fsl,data-width = <24>;
status = "okay";

- port@0 {

+ port@1 {
- reg = <0>;

+ reg = <1>;
lvds0_out: endpoint {
remote-endpoint = <&panel0_lvds_in>;
};
};
};
};

[Zater]

I found that the lcdif is deferred

[ 19.191706] platform imx-lcdifv3-crtc.0: deferred probe pending


root@imx8mp-lpddr4-evk:~# cat /sys/kernel/debug/devices_deferred
imx-lcdifv3-crtc.0

how can I fix that