DESK-MX8M-L/Peripherals/LVDS

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History
ID# Issue Date Notes

15725

30/12/2021 First DESK-MX8M-L release

17554

24/02/2023 DESK-MX8M-L-2.0.0 release


Peripheral LVDS[edit | edit source]

Device tree configuration[edit | edit source]

ORCA SOM[edit | edit source]

Here below an example of device tree modification on standard DAVE's kit for the ORCA SOM:

Example of definition aboud LVDS to HDMI convert from imx8mp-mito8mplus-cb1008.dts 

...
...
	reg_lvds_en: regulator_lcd_3V3_en {
		compatible = "regulator-fixed";
		regulator-name = "lvds_enable";
		pinctrl-names = "default";
		pinctrl-0 = <&pinctrl_lcd_3v3_enable>;
		gpio = <&gpio1 6 GPIO_ACTIVE_HIGH>;
		enable-active-high;
		regulator-boot-on;
		regulator-always-on;
	};

        ...
        ...
	reg_vccbkl_en: regulator_lcd_5V_en {
		compatible = "regulator-fixed";
		regulator-name = "vddbkl_enable";
		pinctrl-names = "default";
		pinctrl-0 = <&pinctrl_lcd_5v_enable>;
		gpio = <&gpio1 8 GPIO_ACTIVE_HIGH>;
		enable-active-high;
		regulator-boot-on;
		regulator-always-on;
	};
};
...
...
&i2c6 {
	clock-frequency = <100000>;
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_i2c6>;
	status = "okay";

	lvds_bridge: lvds-to-hdmi-bridge@4c {
		compatible = "ite,it6263";
		reg = <0x4c>;
		reset-gpios = <&gpio1 9 GPIO_ACTIVE_LOW>;
		status = "okay";

		port {
			it6263_in: endpoint {
				remote-endpoint = <&lvds0_out>;
			};
		};
	};
};
...
...

&lcdif2 {
	status = "okay";
};
...
...
&ldb {
	status = "okay";

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

		port@1 {
			reg = <1>;

			lvds0_out: endpoint {
				remote-endpoint = <&it6263_in>;
			};
		};
	};
};
...
...
&ldb_phy {
	status = "okay";
};
...
...
&iomuxc {
	pinctrl_lcd_3v3_enable: lcd_3v3_en {
		fsl,pins = <
			MX8MP_IOMUXC_GPIO1_IO06__GPIO1_IO06		0x19
		>;
	};


	pinctrl_lcd_5v_enable: lcd_5v_en {
		fsl,pins = <
			MX8MP_IOMUXC_GPIO1_IO08__GPIO1_IO08		0x19
		>;
	};
};

Accessing the peripheral[edit | edit source]

Linux messages at boot time[edit | edit source]

...
...
[    1.728512] [drm] Initialized vivante 1.0.0 20170808 for 40000000.mix_gpu_ml on minor 0
[    2.185351] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[    2.197495] [drm] No driver support for vblank timestamp query.
[    2.197563] imx-drm display-subsystem: bound imx-lcdifv3-crtc.0 (ops lcdifv3_crtc_ops)
[    2.209041] imx-drm display-subsystem: bound imx-lcdifv3-crtc.1 (ops lcdifv3_crtc_ops)
[    2.223301] imx-drm display-subsystem: bound 32c00000.bus:ldb@32ec005c (ops imx8mp_ldb_ops)
[    2.589664] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[    2.601954] [drm] No driver support for vblank timestamp query.
[    2.614683] imx-drm display-subsystem: bound imx-lcdifv3-crtc.0 (ops lcdifv3_crtc_ops)
[    2.628695] imx-drm display-subsystem: bound imx-lcdifv3-crtc.1 (ops lcdifv3_crtc_ops)
[    2.636719] imx-drm display-subsystem: bound 32c00000.bus:ldb@32ec005c (ops imx8mp_ldb_ops)
[    2.684571] imx-drm display-subsystem: bound 32fd8000.hdmi (ops dw_hdmi_imx_ops)
[    2.695621] [drm] Initialized imx-drm 1.0.0 20120507 for display-subsystem on minor 1
[    3.315874] imx-drm display-subsystem: fb0: imx-drmdrmfb frame buffer device

...
...

DRM access[edit | edit source]

DRM framework can be accessed using the modetest DRM utility. 

trying to open device 'i915'...failed
trying to open device 'amdgpu'...failed
trying to open device 'radeon'...failed
trying to open device 'nouveau'...failed
trying to open device 'vmwgfx'...failed
trying to open device 'omapdrm'...failed
trying to open device 'exynos'...failed
trying to open device 'tilcdc'...failed
trying to open device 'msm'...failed
trying to open device 'sti'...failed
trying to open device 'tegra'...failed
trying to open device 'imx-drm'...done
Encoders:
id	crtc	type	possible crtcs	possible clones	
37	33	LVDS	0x00000001	0xffffffff
38	0	TMDS	0x00000002	0x00000000

Connectors:
id	encoder	status		name		size (mm)	modes	encoders
39	37	connected	HDMI-A-1       	340x190		2	37
  modes:
	index name refresh (Hz) hdisp hss hse htot vdisp vss vse vtot)
  #0 1280x720 60.00 1280 1390 1430 1650 720 725 730 750 74250 flags: phsync, pvsync; type: driver
  #1 1280x720 50.00 1280 1720 1760 1980 720 725 730 750 74250 flags: phsync, pvsync; type: driver
  props:
	1 EDID:
		flags: immutable blob
		blobs:

		value:
			00ffffffffffff002074560100000000
			141f010380221378fe6435a5544f9e27
			125054bfea0061400101010101010101
			010101010101021900a050d015203020
			780059c21000001e000000fc00543038
			30410a20202020202020000000ff0030
			303030303030300a20202020000000fd
			00304b545413010a20202020202001c9
			020334f1461202030401132309070783
			01000067030c001000384467d85dc401
			448001681a00000109283ce6e50f0000
			0600e200ff0000000000000000000000
			00000000000000000000000000000000
			00000000000000000000000000000000
			00000000000000000000000000000000
			000000000000000000000000000000ca
	2 DPMS:
		flags: enum
		enums: On=0 Standby=1 Suspend=2 Off=3
		value: 0
	5 link-status:
		flags: enum
		enums: Good=0 Bad=1
		value: 0
	6 non-desktop:
		flags: immutable range
		values: 0 1
		value: 0
	4 TILE:
		flags: immutable blob
		blobs:

		value:
40	0	disconnected	HDMI-A-2       	0x0		0	38
  props:
	1 EDID:
		flags: immutable blob
		blobs:

		value:
	2 DPMS:
		flags: enum
		enums: On=0 Standby=1 Suspend=2 Off=3
		value: 0
	5 link-status:
		flags: enum
		enums: Good=0 Bad=1
		value: 0
	6 non-desktop:
		flags: immutable range
		values: 0 1
		value: 0
	4 TILE:
		flags: immutable blob
		blobs:

		value:

CRTCs:
id	fb	pos	size
33	41	(0,0)	(1280x720)
  #0 1280x720 60.00 1280 1390 1430 1650 720 725 730 750 74250 flags: phsync, pvsync; type: driver
  props:
	24 VRR_ENABLED:
		flags: range
		values: 0 1
		value: 0
36	0	(0,0)	(0x0)
  #0  nan 0 0 0 0 0 0 0 0 0 flags: ; type: 
  props:
	24 VRR_ENABLED:
		flags: range
		values: 0 1
		value: 0

Planes:
id	crtc	fb	CRTC x,y	x,y	gamma size	possible crtcs
31	33	41	0,0		0,0	0       	0x00000001
  formats: XR24 AR24 RG16 XB24 AB24 AR15 XR15
  props:
	8 type:
		flags: immutable enum
		enums: Overlay=0 Primary=1 Cursor=2
		value: 1
	32 zpos:
		flags: immutable range
		values: 0 0
		value: 0
34	0	0	0,0		0,0	0       	0x00000002
  formats: XR24 AR24 RG16 XB24 AB24 AR15 XR15
  props:
	8 type:
		flags: immutable enum
		enums: Overlay=0 Primary=1 Cursor=2
		value: 1
	35 zpos:
		flags: immutable range
		values: 0 0
		value: 0

Frame buffers:
id	size	pitch

root@desk-mx8mp:~#

Additional information[edit | edit source]

For some information on DRM/KMS framework, see the STM DRM overview presentation.

HOME SOMs SBCs ToloMEO Embedded Assistant Sale-tag.pngGET A QUOTE Customer-service.pngONLINE HELPDESK
Roadmap IoT Services ML/AI services Embedded Design Services
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