soc: st: stm32: u5: replace Kconfig power supply configuration with DT

Replace the existing infrastructure to specify power supply configuration
through Kconfig with Devicetree.
Set the LDO as default to reduce out-of-tree breakage - most users were
relying on LDO being the default and it is harmless to use LDO if board
is designed for SMPS. (Existing SMPS users should break anyways since the
Kconfig symbol no longer exists, but this ensures they actively set the
power supply to SMPS in DT)

Signed-off-by: Mathieu Choplain <mathieu.choplain-ext@st.com>

Author: mathieuchopstm

dts/arm/st/u5/stm32u5.dtsi

@@ -888,10 +888,17 @@
 		};
 
 		pwr: power@46020800 {
-			compatible = "st,stm32-pwr";
+			compatible = "st,stm32-dualreg-pwr", "st,stm32-pwr";
 			reg = <0x46020800 0x400>; /* PWR register bank */
 			status = "disabled";
 
+			/*
+			 * After reset, the LDO regulator is selected as
+			 * it works in all hardware configurations; set
+			 * default in SoC DTSI to reduce churn in boards.
+			 */
+			power-supply = "ldo";
+
 			wkup-pins-nb = <8>; /* 8 system wake-up pins */
 			wkup-pin-srcs = <3>; /* 3 gpio sources associated with each wkup pin */
 			wkup-pins-pol;

soc/st/stm32/Kconfig

@@ -78,7 +78,7 @@ config STM32_WKUP_PINS
 choice POWER_SUPPLY_CHOICE
 	prompt "STM32 power supply configuration"
 	default POWER_SUPPLY_LDO
-	depends on SOC_SERIES_STM32U5X || SOC_STM32WBA55XX || SOC_STM32WBA65XX
+	depends on SOC_STM32WBA55XX || SOC_STM32WBA65XX
 
 config POWER_SUPPLY_LDO
 	bool "LDO supply"

soc/st/stm32/stm32u5x/soc.c

@@ -21,6 +21,17 @@
 #define LOG_LEVEL CONFIG_SOC_LOG_LEVEL
 LOG_MODULE_REGISTER(soc);
 
+#define PWR_NODE DT_INST(0, st_stm32_pwr)
+
+/* Helper to simplify following #if chain */
+#define SELECTED_PSU(_x) DT_ENUM_HAS_VALUE(PWR_NODE, power_supply, _x)
+
+#if SELECTED_PSU(ldo)
+#define SELECTED_POWER_SUPPLY LL_PWR_LDO_SUPPLY
+#elif SELECTED_PSU(smps)
+#define SELECTED_POWER_SUPPLY LL_PWR_SMPS_SUPPLY
+#endif
+
 extern void stm32_power_init(void);
 /**
  * @brief Perform basic hardware initialization at boot.
@@ -50,13 +61,7 @@ void soc_early_init_hook(void)
 #endif
 
 	/* Power Configuration */
-#if defined(CONFIG_POWER_SUPPLY_DIRECT_SMPS)
-	LL_PWR_SetRegulatorSupply(LL_PWR_SMPS_SUPPLY);
-#elif defined(CONFIG_POWER_SUPPLY_LDO)
-	LL_PWR_SetRegulatorSupply(LL_PWR_LDO_SUPPLY);
-#else
-#error "Unsupported power configuration"
-#endif
+	LL_PWR_SetRegulatorSupply(SELECTED_POWER_SUPPLY);
 
 #if CONFIG_PM
 	stm32_power_init();