Last edited 7 months ago

VDEC device tree configuration

Applicable for STM32MP25x lines

1. Article purpose[edit source]

This article explains how to configure the VDEC [1] when the peripheral is assigned to the Linux® OS.

The configuration is performed using the device tree mechanism [2].

The Device tree provides a hardware description of the VDEC [1] used by the STM32 VDEC Linux driver.

2. DT bindings documentation[edit source]

The VDEC is represented by the STM32 VDEC device tree bindings [3].

3. DT configuration[edit source]

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.

3.1. DT configuration (STM32/SoC level)[edit source]

The VDEC node is located in the device tree file for the software components, supporting the peripheral and listed in the above DT bindings documentation paragraph.

For STM32MP25x lines More info.png, the VDEC device tree node is declared in stm32mp255.dtsi [4].

	soc@0 {
		rifsc: rifsc@42080000 {
			vdec: vdec@480d0000 {
				compatible = "st,stm32mp25-vdec";
				reg = <0x480d0000 0x3c8>;
				resets = <&rcc VDEC_R>;
				interrupt-names = "vdec";
				interrupts = <GIC_SPI 117 IRQ_TYPE_LEVEL_HIGH>;
				clock-names = "vdec-clk";
				clocks = <&rcc CK_BUS_VDEC>;
				feature-domains = <&rifsc STM32MP25_RIFSC_VDEC_ID>;
				power-domains = <&CLUSTER_PD>;
Warning white.png Warning
This device tree part is related to STM32 microprocessors. It must be kept as is, without being modified by the end-user.

3.2. DT configuration (board level)[edit source]

For STM32MP25x lines More info.png, the STM32 VDEC is already enabled by default in stm32mp255.dtsi [4] so there is no need to enable it at board level.

4. How to configure the DT using STM32CubeMX[edit source]

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.

5. References[edit source]

Please refer to the following links for additional information: