1. Article purpose[edit | edit source]
This article explains how to configure the IWDG internal peripheral when it is assigned to the Linux® OS. In that case, it is controlled by the IWDG Framework (see watchdog overview).
The configuration is performed using the device tree mechanism that provides a hardware description of the IWDG peripheral.
2. DT bindings documentation[edit | edit source]
The IWDG internal peripheral is a watchdog device. Refer to arm-smc-wdt.yaml [1] or to st,stm32-iwdg.yaml [2] for the corresponding binding document.
3. DT configuration[edit | 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 level)[edit | edit source]
The STM32MP1 IWDG node is located
- for STM32MP13x lines
in stm32mp131.dtsi [3] - for STM32MP15x lines in stm32mp151.dtsi [4]
- for STM32MP25x lines in stm32mp251.dtsi [5]
see Device tree for further explanation.
For example, for using SMC driver in U-Boot and Linux:
arm_wdt: watchdog {
compatible = "arm,smc-wdt";
arm,smc-id = <0xb200005a>;
status = "disabled";
};
For using the native driver:
iwdg2: iwdg@5a002000 {
compatible = "st,stm32mp1-iwdg";
reg = <0x5a002000 0x400>;
clocks = <&rcc IWDG2>, <&rcc CK_LSI>;
clock-names = "pclk", "lsi";
status = "disabled";
};
3.2. DT configuration (board level)[edit | edit source]
This part is used to enable the IWDG hardware on a board, and define a custom timeout (timeout-sec) in seconds:
&iwdg2 {
timeout-sec = <32>; /* Watchdog timeout value in seconds */
status = "okay";
};
3.3. DT configuration examples[edit | edit source]
Only the timeout-sec parameter can be modified, as illustrated above.
4. How to configure the DT using STM32CubeMX[edit | 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 | edit source]