The STMicroelectronics STM32MP15 provides a 24-bit RGB LCD-TFT display interface (LTDC). The SOC also provides a MIPI DSI host interface connected internally to the LTDC.

On the ConnectCore MP15:

  • The parallel LCD interface is available on the LGA pads, multiplexed with other functions.

  • The MIPI DSI interface is available on the LGA pads.

On the ConnectCore MP15 Development Kit:

  • The parallel LCD interface is available on the LCD connector.

  • The parallel LCD interface is routed to Rohm BU90T82 parallel-to-LVDS converter.

  • The MIPI DSI interface is routed to the Lontium LT8912 MIPI-to-HDMI bridge.

Kernel configuration

You can manage the video support through the following kernel configuration options:

  • STM LCD controller driver (CONFIG_DRM_STM)

  • STM MIPI DSI DRM driver (CONFIG_DRM_STM_DSI)

These options are enabled as built-in on the default ConnectCore MP15 kernel configuration file.

Kernel driver

The driver for the video interface is located at:

File Description

drivers/gpu/drm/stm/drv.c

Video driver

drivers/gpu/drm/stm/dw_mipi_dsi-stm.c

DRM driver

Device tree bindings and customization

The LCD interface is documented at Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml.

The STM DSI DRM is documented at Documentation/devicetree/bindings/display/st,stm32-dsi.yaml.

The LTDC controller and MIPI-DSI interface are defined in the CPU device tree file.

Definition of the LTDC and MIPI-DSI

ConnectCore MP15 Development Kit device tree
ltdc: display-controller@5a001000 {
	compatible = "st,stm32-ltdc";
	reg = <0x5a001000 0x400>;
	interrupts = <GIC_SPI 88 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 89 IRQ_TYPE_LEVEL_HIGH>;
	clocks = <&rcc LTDC_PX>;
	clock-names = "lcd";
	resets = <&rcc LTDC_R>;
	status = "disabled";

	port {
		#address-cells = <1>;
		#size-cells = <0>;
	};
};

dsi: dsi@5a000000 {
	compatible = "st,stm32-dsi";
	reg = <0x5a000000 0x800>;
	phy-dsi-supply = <&reg18>;
	clocks = <&rcc DSI_K>, <&scmi_clk CK_SCMI_HSE>, <&rcc DSI_PX>;
	clock-names = "pclk", "ref", "px_clk";
	resets = <&rcc DSI_R>;
	reset-names = "apb";
	#address-cells = <1>;
	#size-cells = <0>;
	status = "disabled";

	ports {
		#address-cells = <1>;
		#size-cells = <0>;
	};
};

Display options

You need additional kernel and device tree configurations depending on the video display that you want to use. Find more information on the following sub-topics:

Use the video interface

For Wayland images, a Weston desktop launches after Linux starts.

Play a video

To play a video using Gstreamer:

# gst-launch-1.0 playbin uri=file:///run/media/sda1/big_buck_bunny_480p_h264.mp4
# gst-play-1.0 /run/media/sda1/big_buck_bunny_480p_h264.mp4
The default image does not include a video file.