caf: events: Add module_suspend_req_event and module_resume_req_event

Add events used to temporarily suspend an application module. Change
also adds a new module state: MODULE_STATE_SUSPENDED.

Jira: NCSDK-24220

Signed-off-by: Marek Pieta <[email protected]>
Signed-off-by: Aleksander Strzebonski <[email protected]>

Author: MarekPieta

include/caf/events/module_state_event.h

@@ -202,6 +202,11 @@ enum module_state {
 	 */
 	MODULE_STATE_STANDBY,
 
+	/** Module is suspended in reaction to @ref module_suspend_req_event. The module is resumed
+	 *  by @ref module_resume_req_event.
+	 */
+	MODULE_STATE_SUSPENDED,
+
 	/** Module reported fatal error. */
 	MODULE_STATE_ERROR,
 

include/caf/events/module_suspend_event.h

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+#ifndef _MODULE_SUSPEND_EVENT_H_
+#define _MODULE_SUSPEND_EVENT_H_
+
+/**
+ * @file
+ * @defgroup caf_module_suspend_event CAF Module Suspend Event
+ * @{
+ * @brief CAF Module Suspend Event.
+ */
+
+
+#include <app_event_manager.h>
+#include <app_event_manager_profiler_tracer.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct module_suspend_req_event {
+	/** Event header. */
+	struct app_event_header header;
+
+	/** ID of the module to be suspended. */
+	const void *sink_module_id;
+
+	/** ID of the module that requests the suspension. */
+	const void *src_module_id;
+};
+
+APP_EVENT_TYPE_DECLARE(module_suspend_req_event);
+
+struct module_resume_req_event {
+	/** Event header. */
+	struct app_event_header header;
+
+	/** ID of the module to be resumed. */
+	const void *sink_module_id;
+
+	/** ID of the module that requests the resumption. */
+	const void *src_module_id;
+};
+
+APP_EVENT_TYPE_DECLARE(module_resume_req_event);
+
+#ifdef __cplusplus
+}
+#endif
+
+/**
+ * @}
+ */
+
+#endif /* _MODULE_SUSPEND_EVENT_H_ */

subsys/caf/events/CMakeLists.txt

@@ -8,6 +8,10 @@ zephyr_sources_ifdef(CONFIG_CAF_MODULE_STATE_EVENTS
 	module_state_event.c
 )
 
+zephyr_sources_ifdef(CONFIG_CAF_MODULE_SUSPEND_EVENTS
+	module_suspend_event.c
+)
+
 zephyr_sources_ifdef(CONFIG_CAF_PM_EVENTS
 	power_event.c
 )

subsys/caf/events/Kconfig

@@ -137,6 +137,7 @@ rsource "Kconfig.factory_reset_event"
 rsource "Kconfig.force_power_down_event"
 rsource "Kconfig.keep_alive_event"
 rsource "Kconfig.module_state_event"
+rsource "Kconfig.module_suspend_event"
 rsource "Kconfig.power_manager_event"
 rsource "Kconfig.sensor_event"
 

subsys/caf/events/Kconfig.module_suspend_event

@@ -0,0 +1,17 @@
+#
+# Copyright (c) 2025 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+config CAF_MODULE_SUSPEND_EVENTS
+	bool "Module suspend/resume request events"
+	depends on CAF_MODULE_STATE_EVENTS
+	help
+	  Enable support for module suspend/resume request events.
+
+config CAF_INIT_LOG_MODULE_SUSPEND_EVENTS
+	bool "Log module suspend/resume request events"
+	depends on CAF_MODULE_SUSPEND_EVENTS
+	depends on LOG
+	default y

subsys/caf/events/module_state_event.c

@@ -15,6 +15,7 @@ static const char * const state_name[] = {
 	[MODULE_STATE_READY] = "READY",
 	[MODULE_STATE_OFF] = "OFF",
 	[MODULE_STATE_STANDBY] = "STANDBY",
+	[MODULE_STATE_SUSPENDED] = "SUSPENDED",
 	[MODULE_STATE_ERROR] = "ERROR",
 };
 

subsys/caf/events/module_suspend_event.c

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+#include <stdio.h>
+
+#include <caf/events/module_suspend_event.h>
+#include <caf/events/module_state_event.h>
+
+static void log_module_suspend_req_event(const struct app_event_header *aeh)
+{
+	const struct module_suspend_req_event *event = cast_module_suspend_req_event(aeh);
+
+	APP_EVENT_MANAGER_LOG(aeh, "sink module: %s, source module: %s",
+			      module_name_get(event->sink_module_id),
+			      module_name_get(event->src_module_id));
+}
+
+APP_EVENT_TYPE_DEFINE(module_suspend_req_event,
+		      log_module_suspend_req_event,
+		      NULL,
+		      APP_EVENT_FLAGS_CREATE(
+			IF_ENABLED(CONFIG_CAF_INIT_LOG_MODULE_SUSPEND_EVENTS,
+				(APP_EVENT_TYPE_FLAGS_INIT_LOG_ENABLE))));
+
+static void log_module_resume_req_event(const struct app_event_header *aeh)
+{
+	const struct module_resume_req_event *event = cast_module_resume_req_event(aeh);
+
+	APP_EVENT_MANAGER_LOG(aeh, "sink module: %s, source module: %s",
+			      module_name_get(event->sink_module_id),
+			      module_name_get(event->src_module_id));
+}
+
+APP_EVENT_TYPE_DEFINE(module_resume_req_event,
+		      log_module_resume_req_event,
+		      NULL,
+		      APP_EVENT_FLAGS_CREATE(
+			IF_ENABLED(CONFIG_CAF_INIT_LOG_MODULE_SUSPEND_EVENTS,
+				(APP_EVENT_TYPE_FLAGS_INIT_LOG_ENABLE))));