VENC device tree configuration

Applicable for

STM32MP25x lines

---

1. Article purpose

This article explains how to configure the VENC when the peripheral is assigned to the Linux^® OS.

The configuration is performed using the device tree mechanism .

The Device tree provides a hardware description of the VENC used by the STM32 VENC Linux driver.

2. DT bindings documentation

The VENC is represented by the STM32 VDEC device tree bindings file: st,stm32mp25-video-codec.yaml .

3. 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.

3.1. DT configuration (STM32/SoC level)

The VENC 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 , the VENC device tree node is declared in arch/arm64/boot/dts/st/stm32mp255.dtsi :

...
&rifsc {
...
	venc: venc@480e0000 {
		compatible = "st,stm32mp25-venc";
		reg = <0x480e0000 0x800>;
		resets = <&rcc VENC_R>;
		interrupts = <GIC_SPI 167 IRQ_TYPE_LEVEL_HIGH>;
		clocks = <&rcc CK_BUS_VENC>;
		access-controllers = <&rifsc 90>;
		power-domains = <&CLUSTER_PD>;
	};
...

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)

For STM32MP25x lines , the STM32 VENC is already enabled by default in stm32mp255.dtsi , so there is no need to enable it at board level.

4. 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.

5. References

Please refer to the following links for additional information: