STM32F3x power management

[albayenes]

This patch adds full low-power support to STM32F3 in Zephyr, including:

STOP0 & STOP1 modes (with main/LP regulator)
STANDBY (poweroff) mode
Wakeup pin (PA0) support
SoC clock reinitialization on wakeup
Idle timer using RTC
Samples updated to test wakeup pin and poweroff

This is a significant power-management enablement patch for the STM32F3 series.

[github-actions]

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[oflifurkan]

Looks good to me!

[dsseng]

Thank you for your contribution, this is very valuable for other STM32F3 users out there.

Could you please take a look at my comments related to the commit scope and code style?

Also, please sign-off the commits, please find the information in the Contribution Guidelines

[albayenes]

@dsseng I completed your requirements. Thanks for your review. Could you check it?

[dsseng]

Thanks, looks good and ready for review by the maintainers

[etienne-lms]

Thanks for the changes. Some comments for consistency among STM32 SoCs.

Nitpicking on the commit message: could you refine the header line, and remove heading indentation in the message body?

-pm: Add power management for stm32f3x
+soc: st: stm32f3: Add power management
 
-    Adds full low-power support to STM32F3 in Zephyr, including:
+Add full low-power support to STM32F3 in Zephyr, including
 (...)

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[etienne-lms]

I think a prefer way is to not have symbols definitions here but rather

configdefault COUNTER
	y if PM

configdefault COUNTER_RTC_STM32_SUBSECONDS
	y if PM

Or

if PM

configdefault COUNTER
	y

configdefault COUNTER_RTC_STM32_SUBSECONDS
	y

endif # PM

[etienne-lms]

Suggested change

	#include <stm32_ll_cortex.h>
	#include <stm32_ll_pwr.h>
	#include <zephyr/kernel.h>
	#include <zephyr/sys/poweroff.h>
	#include <stm32_common.h>
	#include <stm32_ll_pwr.h>

[etienne-lms]

I think that's a bit too much. I would mean no sleeping unless the system has nothing to do for the next 1sec time window.

From a few stm32f3 datasheets, the SoC wakeup time seems around a dozen on µs. Assuming the exit latency is 400µs (could be refined later if needed), I think 500µs of min residency delay should be far enough.

[etienne-lms]

I find this reference strange. If needing to manually wire to pin PA0, like for nucleo_f103rb, could you add an inline comment to mention it?

[etienne-lms]

Well, I gave it a try. The system powers back when pin A0 (e.g. connector CN7[28]) is connected to 3V3 supply (e.g. CN7[16]). From reference manual, WKUP pins wake the system on rising edge only.

Suggested change

	gpios = <&gpioa 0 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
	/*
	* PA0 is not connected to any button: you must connect it to Vdd (+3.3V)
	* using a jumper wire. For example, wiring PA0 CN7[28] (PA0) to CN7[16]
	*/
	gpios = <&gpioa 0 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>;