[nrf fromtree] drivers: power_domain: siwx91x: Add power domain driver for siwx91x SoC

1. Added siwx91x power domain node in siwg917.dtsi
2. Updated UART device nodes to reference the newly added power domain.
3. Implemented power domain driver to manage power domain transitions
   for the SoC.

Signed-off-by: Sai Santhosh Malae <[email protected]>
(cherry picked from commit 295431d)

Author: smalae

drivers/power_domain/CMakeLists.txt

@@ -11,3 +11,4 @@ zephyr_library_sources_ifdef(CONFIG_POWER_DOMAIN_NRFS_GDPWR power_domain_nrfs_gd
 zephyr_library_sources_ifdef(CONFIG_POWER_DOMAIN_NRF_GPIO_PAD_GROUP power_domain_nrf_gpio_pad_group.c)
 zephyr_library_sources_ifdef(CONFIG_POWER_DOMAIN_SOC_PM_STATE power_domain_soc_state_change.c)
 zephyr_library_sources_ifdef(CONFIG_POWER_DOMAIN_TISCI power_domain_tisci.c)
+zephyr_library_sources_ifdef(CONFIG_POWER_DOMAIN_SILABS_SIWX91X power_domain_silabs_siwx91x.c)

drivers/power_domain/Kconfig

@@ -125,5 +125,6 @@ endif #POWER_DOMAIN_TISCI
 
 rsource "Kconfig.nrfs_gdpwr"
 rsource "Kconfig.nrf_gpio_pad_group"
+rsource "Kconfig.silabs_siwx91x"
 
 endif

drivers/power_domain/Kconfig.silabs_siwx91x

@@ -0,0 +1,16 @@
+# Copyright 2025 Silicon Laboratories Inc.
+# SPDX-License-Identifier: Apache-2.0
+
+config POWER_DOMAIN_SILABS_SIWX91X
+	bool "Silabs siwx91x power domain driver"
+	default y
+	select DEVICE_DEPS
+	depends on DT_HAS_SILABS_SIWX91X_POWER_DOMAIN_ENABLED
+	help
+	  Driver for Silabs siwx91x power domain.
+
+config SIWX91X_POWER_DOMAIN_INIT_PRIORITY
+	int "Silabs siwx91x power domain init priority"
+	default 10
+	help
+	  Silabs siwx91x power domain initialization priority.

drivers/power_domain/power_domain_silabs_siwx91x.c

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2025 Silicon Laboratories Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/pm/device.h>
+#include <zephyr/pm/device_runtime.h>
+
+#define DT_DRV_COMPAT silabs_siwx91x_power_domain
+
+static int siwx91x_pd_pm_action(const struct device *dev, enum pm_device_action action)
+{
+	switch (action) {
+	case PM_DEVICE_ACTION_RESUME:
+		pm_device_children_action_run(dev, PM_DEVICE_ACTION_TURN_ON, NULL);
+		break;
+	case PM_DEVICE_ACTION_SUSPEND:
+		pm_device_children_action_run(dev, PM_DEVICE_ACTION_TURN_OFF, NULL);
+		break;
+	case PM_DEVICE_ACTION_TURN_ON:
+		break;
+	case PM_DEVICE_ACTION_TURN_OFF:
+		break;
+	default:
+		return -ENOTSUP;
+	}
+
+	return 0;
+}
+
+static int siwx91x_pd_init(const struct device *dev)
+{
+	return pm_device_driver_init(dev, siwx91x_pd_pm_action);
+}
+
+#define SIWX91X_PD_INIT(inst)                                                                      \
+	PM_DEVICE_DT_INST_DEFINE(inst, siwx91x_pd_pm_action);                                      \
+	DEVICE_DT_INST_DEFINE(inst, siwx91x_pd_init, PM_DEVICE_DT_INST_GET(inst), NULL, NULL,      \
+			      PRE_KERNEL_1, CONFIG_SIWX91X_POWER_DOMAIN_INIT_PRIORITY, NULL);
+
+DT_INST_FOREACH_STATUS_OKAY(SIWX91X_PD_INIT)

dts/arm/silabs/siwg917.dtsi

@@ -124,13 +124,22 @@
 			status = "disabled";
 		};
 
+		siwx91x_soc_pd: siwx91x-soc-pd {
+			compatible = "silabs,siwx91x-power-domain";
+			#power-domain-cells = <0>;
+			zephyr,pm-device-runtime-auto;
+			status = "okay";
+		};
+
 		ulpuart: uart@24041800 {
 			compatible = "ns16550";
 			reg = <0x24041800 0x1000>;
 			interrupts = <12 0>;
 			reg-shift = <2>;
 			clocks = <&clock0 SIWX91X_CLK_ULP_UART>;
 			current-speed = <115200>;
+			power-domains = <&siwx91x_soc_pd>;
+			zephyr,pm-device-runtime-auto;
 			status = "disabled";
 		};
 
@@ -141,6 +150,8 @@
 			reg-shift = <2>;
 			clocks = <&clock0 SIWX91X_CLK_UART0>;
 			current-speed = <115200>;
+			power-domains = <&siwx91x_soc_pd>;
+			zephyr,pm-device-runtime-auto;
 			status = "disabled";
 		};
 
@@ -151,6 +162,8 @@
 			reg-shift = <2>;
 			clocks = <&clock0 SIWX91X_CLK_UART1>;
 			current-speed = <115200>;
+			power-domains = <&siwx91x_soc_pd>;
+			zephyr,pm-device-runtime-auto;
 			status = "disabled";
 		};
 

dts/bindings/power-domain/silabs,siwx91x-power-domain.yaml

@@ -0,0 +1,5 @@
+description: Silabs siwx91x soc power domain
+
+compatible: "silabs,siwx91x-power-domain"
+
+include: power-domain.yaml