Overlay for an LVDS panel on iMX8MP in Torizon

Technical Support
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7

I am still stuck at the same stage.

I tried yet another overlay, using the 10" LVDS overlay recently added for the Mellow carrier board (since our board is similar):

// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
/*
 * Copyright 2020-2022 Toradex
 */

/dts-v1/;
/plugin/;


#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/interrupt-controller/arm-gic.h>
#include <dt-bindings/pwm/pwm.h>


/ {
	compatible = "toradex,verdin-imx8mp";
};

&{/} {
	backlight_lvds_native: backlight-lvds-native {
		compatible = "pwm-backlight";
		pinctrl-names = "default";
		pinctrl-0 = <&pinctrl_i2s_2_d_out_dsi_1_bkl_en>;		
		brightness-levels = <0 45 63 88 119 158 203 255>;
		default-brightness-level = <4>;
		power-supply = <&reg_3p3v>;
		/* Verdin I2S_2_D_OUT as GPIO (SODIMM 46) */
		enable-gpios = <&gpio5 1 GPIO_ACTIVE_HIGH>;	
		/* Verdin PWM_2 (SODIMM 16) */
		pwms = <&pwm2 0 6666667 PWM_POLARITY_INVERTED>;
		status = "okay";
	};

	panel-lvds-native {
		compatible = "panel-lvds";
		backlight = <&backlight_lvds_native>;
		data-width = <24>;
		data-mapping = "vesa-24";
		height-mm = <86>;
		width-mm = <154>;
		status = "okay";

		panel-timing {
			clock-frequency = <44900000 51200000 63000000>;
			de-active = <0>;
			hactive = <1024>;
			hback-porch = <160>;
			hfront-porch = <16 160 216>;
			hsync-len = <1 70 140>;
			pixelclk-active = <1>; /* positive edge */
			vactive = <600>;
			vback-porch = <23>;
			vfront-porch = <1 12 127>;
			vsync-len = <1 10 20>;
		};

		port {
			panel_lvds_native_in: endpoint {
				remote-endpoint = <&lvds_out>;
			};
		};
	};
};

&gpu_2d {
	status = "okay";
};

&gpu_3d {
	status = "okay";
};

&lcdif2 {
	status = "okay";
};

&ldb {
	status = "okay";
};

&ldb_phy {
	status = "okay";
};

&lvds_out{
	remote-endpoint = <&panel_lvds_native_in>;
};

&mix_gpu_ml {
	status = "okay";
};

&ml_vipsi {
	status = "okay";
};

/* Verdin PWM_2 */
&pwm2 {
	status = "okay";
};

I just removed all the touch controller related stuff since I am only looking to make this backlight work. Here is some output from the board:

torizon@verdin-imx8mp-14772918:~$ ls -l /sys/class/backlight/backlight-lvds-native/
total 0
-r--r--r-- 1 root root  4096 Jan 23 12:02 actual_brightness
-rw-rw-r-- 1 root video 4096 Apr 28  2022 bl_power
-rw-rw-r-- 1 root video 4096 Apr 28  2022 brightness
lrwxrwxrwx 1 root root     0 Jan 23 11:59 device -> ../../../backlight-lvds-native
-r--r--r-- 1 root root  4096 Apr 28  2022 max_brightness
drwxr-xr-x 2 root root     0 Jan 23 12:02 power
-r--r--r-- 1 root root  4096 Jan 23 12:02 scale
lrwxrwxrwx 1 root root     0 Apr 28  2022 subsystem -> ../../../../../class/backlight
-r--r--r-- 1 root root  4096 Apr 28  2022 type
-rw-r--r-- 1 root root  4096 Apr 28  2022 uevent
torizon@verdin-imx8mp-14772918:~$ sudo cat /sys/kernel/debug/pwm
platform/30670000.pwm, 1 PWM device
 pwm-0   (backlight-lvds-nativ): requested enabled period: 6666667 ns duty: 3111111 ns polarity: inverse

Also with the gpio container:

gpiochip4 - 32 lines:
        line   0:  "SODIMM_42"       unused   input  active-high
        line   1:  "SODIMM_46"     "enable"  output  active-high [used]

I still have nothing even though it seems like I should.

Maybe this is similar to this issue (My interface board is essentially a simplified version of the Mallow carrier board, same pins, see my first message): Nothing on 10.1" LVDS display with Mallow carrier - Technical Support - Toradex Community