DSI device tree configuration

Italic text== Article purpose == 本文介绍了将外围设备分配给 Linux^® 操作系统时，如何配置DSI 的方法。 使用设备树机制 执行配置。

The Device tree 提供了STM32“ DSI Linux驱动程序”使用的DSI 的硬件描述。

DT bindings documentation

DSI由STM32 DSI设备树绑定表示 .

DT configuration

This hardware description is a combination of the STM32 microprocessor device tree files (.dtsi extension) and board device tree files (.dts extension). See the Device tree for an explanation of the device tree file split.

STM32CubeMX can be used to generate the board device tree. Refer to How to configure the DT using STM32CubeMX for more details.

DT configuration (STM32 level)

The DSI device tree node is declared in stm32mp157c.dtsi . The declaration (shown below) defines the hardware registers base address, the clocks and the reset.

		dsi: dsi@5a000000 {
			compatible = "st,stm32-dsi";
			reg = <0x5a000000 0x800>;
			clocks = <&rcc DSI_K>, <&clk_hse>, <&rcc DSI_PX>;
			clock-names = "pclk", "ref", "px_clk";
			resets = <&rcc DSI_R>;
			reset-names = "apb";
			status = "disabled";
		};

This device tree part is related to STM32 microprocessors. It must be kept as is, without being modified by the end-user.

DT configuration (board level)

The DSI device tree related to a particular board may have the following nodes, depending on the board hardware:

• dsi node: containing the in/out port descriptions and a panel sub-node.
• ltdc node: containing the in/out port description related to the dsi node.
• panel_backlight node: related to the panel node.

A full example of the STM32MP157 Evaluation board device tree is available in stm32mp157c-ev1.dts .

&dsi {
	#address-cells = <1>;
	#size-cells = <0>;
	status = "okay";

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

		port@0 {
			reg = <0>;
			dsi_in: endpoint {
				remote-endpoint = <&ltdc_ep0_out>;
			};
		};

		port@1 {
			reg = <1>;
			dsi_out: endpoint {
				remote-endpoint = <&panel_in>;
			};
		};
	};

	panel@0 {
		compatible = "raydium,rm68200";
		reg = <0>;
		reset-gpios = <&gpiof 15 GPIO_ACTIVE_LOW>;
		backlight = <&panel_backlight>;
		status = "okay";

		port {
			panel_in: endpoint {
				remote-endpoint = <&dsi_out>;
			};
		};
	};
};

&ltdc {
	status = "okay";

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

		ltdc_ep0_out: endpoint@0 {
			reg = <0>;
			remote-endpoint = <&dsi_in>;
		};
	};
};

...
	panel_backlight: panel-backlight {
		compatible = "gpio-backlight";
		gpios = <&gpiod 13 GPIO_ACTIVE_LOW>;
		default-on;
		status = "okay";
	};
};

How to configure the DT using STM32CubeMX

The STM32CubeMX tool can be used to configure the STM32MPU device and get the corresponding platform configuration device tree files.
The STM32CubeMX may not support all the properties described in the above DT bindings documentation paragraph. If so, the tool inserts user sections in the generated device tree. These sections can then be edited to add some properties and they are preserved from one generation to another. Refer to STM32CubeMX user manual for further information.

References

Please refer to the following links for additional information:

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