arm: silabs: Enable DCDC before setting up clk

This enables DCDC for Silabs devices before initializing the
clock.

Signed-off-by: Endre Karlson <endre.karslon@gmail.com>

boards/arm/efr32mg_sltb004a/efr32mg_sltb004a_defconfig

@@ -11,3 +11,5 @@ CONFIG_CORTEX_M_SYSTICK=y
 CONFIG_GPIO=y
 CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC=38400000
 CONFIG_CMU_HFCLK_HFRCO=y
+CONFIG_SOC_GECKO_EMU_DCDC=y
+CONFIG_SOC_GECKO_EMU_DCDC_MODE_ON=y

ext/hal/silabs/gecko/CMakeLists.txt

@@ -24,7 +24,7 @@ zephyr_compile_definitions(
 
 zephyr_sources(                                    emlib/src/em_system.c)
 zephyr_sources_ifdef(CONFIG_HAS_CMU                emlib/src/em_cmu.c)
-zephyr_sources_ifdef(CONFIG_HAS_EMU                emlib/src/em_emu.c)
+zephyr_sources_ifdef(CONFIG_SOC_GECKO_EMU          emlib/src/em_emu.c)
 zephyr_sources_ifdef(CONFIG_GPIO_GECKO             emlib/src/em_gpio.c)
 zephyr_sources_ifdef(CONFIG_UART_GECKO             emlib/src/em_usart.c)
 zephyr_sources_ifdef(CONFIG_LEUART_GECKO           emlib/src/em_leuart.c)

soc/arm/silabs_exx32/Kconfig

@@ -29,10 +29,35 @@ config SOC_PART_NUMBER
 	  that you should not set directly. The part number selection choice defines
 	  the default value for this string.
 
-config HAS_EMU
+config SOC_GECKO_EMU
 	bool
 	help
-	  Set if the energy management unit (EMU) is present in the SoC.
+	  Set if the energy management unit (EMU) is used.
+
+config SOC_GECKO_EMU_DCDC
+	bool "Enable SoC DC/DC regulator"
+	select SOC_GECKO_EMU
+	help
+	  Enable the on chip DC/DC regulator
+
+choice SOC_GECKO_EMU_DCDC_MODE
+	prompt "DC/DC mode"
+	depends on SOC_GECKO_EMU_DCDC
+	help
+	  Select power configuration mode of the on chip DC/DC converter.
+
+	config SOC_GECKO_EMU_DCDC_MODE_UNCONFIGURED
+		bool "Initial / Unconfigured"
+
+	config SOC_GECKO_EMU_DCDC_MODE_ON
+		bool "DC/DC On"
+
+	config SOC_GECKO_EMU_DCDC_MODE_OFF
+		bool "DC/DC Off"
+
+	config SOC_GECKO_EMU_DCDC_MODE_BYPASS
+		bool "Bypass"
+endchoice
 
 config HAS_CMU
 	bool

soc/arm/silabs_exx32/common/soc.c

@@ -13,6 +13,7 @@
 #include <init.h>
 #include <soc.h>
 #include <em_cmu.h>
+#include <em_emu.h>
 #include <em_chip.h>
 #include <arch/cpu.h>
 #include <cortex_m/exc.h>
@@ -70,6 +71,25 @@ static ALWAYS_INLINE void clkInit(void)
 #endif
 }
 
+#ifdef CONFIG_SOC_GECKO_EMU_DCDC
+static ALWAYS_INLINE void dcdc_init(void)
+{
+#if defined(CONFIG_SOC_GECKO_EMU_DCDC_MODE_UNCONFIGURED)
+	/* Nothing to do, leave DC/DC converter in unconfigured, safe state. */
+#elif defined(CONFIG_SOC_GECKO_EMU_DCDC_MODE_ON) || defined(CONFIG_SOC_GECKO_EMU_DCDC_MODE_BYPASS)
+	EMU_DCDCInit_TypeDef init_cfg = EMU_DCDCINIT_DEFAULT;
+#if defined(CONFIG_SOC_GECKO_EMU_DCDC_MODE_BYPASS)
+	init_cfg.dcdcMode = emuDcdcMode_Bypass;
+#endif
+	EMU_DCDCInit(&init_cfg);
+#elif defined(CONFIG_SOC_GECKO_EMU_DCDC_MODE_OFF)
+	EMU_DCDCPowerOff();
+#else
+#error "Unsupported power configuration mode of the on chip DC/DC converter."
+#endif
+}
+#endif
+
 /**
  * @brief Perform basic hardware initialization
  *
@@ -92,6 +112,10 @@ static int silabs_exx32_init(struct device *arg)
 
 	_ClearFaults();
 
+#ifdef CONFIG_SOC_GECKO_EMU_DCDC
+	dcdc_init();
+#endif
+
 	/* Initialize system clock according to CONFIG_CMU settings */
 	clkInit();
 

soc/arm/silabs_exx32/efm32pg12b/Kconfig.soc

@@ -12,7 +12,7 @@ depends on SOC_SERIES_EFM32PG12B
 config SOC_EFM32PG12B
 	bool "SOC_EFM32PG12B"
 	select HAS_CMU
-	select HAS_EMU
+	select SOC_GECKO_EMU
 
 endchoice
 

soc/arm/silabs_exx32/efr32mg12p/Kconfig.soc

@@ -13,7 +13,7 @@ config SOC_EFR32MG12P
 	bool "SOC_EFR32MG12P"
 	select HAS_SILABS_GECKO
 	select HAS_CMU
-	select HAS_EMU
+	select SOC_GECKO_EMU
 
 endchoice