applications: nrf_desktop: failsafe: migrate to Zephyr hwinfo driver

Updated the nRF Desktop Failsafe module to use the Zephyr HWinfo
driver as its dependency instead of relying on the nrfx reset reason
helper.

Ref: NCSDK-25090

Signed-off-by: Kamil Piszczek <[email protected]>

Author: kapi-no

applications/nrf_desktop/doc/failsafe.rst

@@ -33,3 +33,9 @@ Additionally, make sure that the following options are set as follows:
 This is to ensure that the device will be blocked after a fatal error and then the watchdog will trigger the reboot.
 
 After the reboot caused either by the watchdog or by the CPU lockup, the failsafe module erases the settings partition and clears the non-volatile settings data.
+
+Implementation details
+**********************
+
+The failsafe module uses the Zephyr :ref:`zephyr:hwinfo_api` driver.
+The module gets the reset reason information with the :c:func:`hwinfo_get_reset_cause` function and clears it with the :c:func:`hwinfo_clear_reset_cause` function.

applications/nrf_desktop/src/modules/Kconfig.failsafe

@@ -10,6 +10,7 @@ config DESKTOP_FAILSAFE_ENABLE
 	bool "Enable failsafe"
 	depends on WATCHDOG
 	depends on !RESET_ON_FATAL_ERROR
+	select HWINFO
 	help
 	  When a device is rebooted by watchdog or due to the CPU lockup,
 	  the settings partition will be erased.

applications/nrf_desktop/src/modules/failsafe.c

@@ -5,7 +5,7 @@
  */
 
 #include <zephyr/kernel.h>
-#include <helpers/nrfx_reset_reason.h>
+#include <zephyr/drivers/hwinfo.h>
 #include <zephyr/storage/flash_map.h>
 
 #define MODULE failsafe
@@ -15,17 +15,27 @@
 LOG_MODULE_REGISTER(MODULE, CONFIG_DESKTOP_FAILSAFE_LOG_LEVEL);
 
 
-static bool failsafe_check(void)
+static int failsafe_check(bool *failure_detected)
 {
-	uint32_t mask = NRFX_RESET_REASON_DOG_MASK |
-			NRFX_RESET_REASON_LOCKUP_MASK;
+	int err;
+	uint32_t reas = 0;
+	static const uint32_t mask = RESET_WATCHDOG | RESET_CPU_LOCKUP;
 
-	uint32_t reas = nrfx_reset_reason_get();
+	err = hwinfo_get_reset_cause(&reas);
+	if (err) {
+		LOG_ERR("Failed to fetch reset cause: %d", err);
+		return err;
+	}
+
+	*failure_detected = ((reas & mask) != 0);
 
-	return (reas & mask) != 0;
+	LOG_INF("Reset reason (0x%08X) trigger %s", reas,
+		*failure_detected ? "active" : "inactive");
+
+	return err;
 }
 
-static void failsafe_erase(void)
+static int failsafe_erase(void)
 {
 	const struct flash_area *flash_area;
 	int err = flash_area_open(FIXED_PARTITION_ID(storage_partition),
@@ -37,15 +47,24 @@ static void failsafe_erase(void)
 	}
 
 	if (err) {
-		LOG_ERR("Failsafe cannot erase settings");
+		LOG_ERR("Failsafe cannot erase settings: %d", err);
 	} else {
 		LOG_WRN("Failsafe erased settings");
 	}
+
+	return err;
 }
 
-static void failsafe_clear(void)
+static int failsafe_clear(void)
 {
-	nrfx_reset_reason_clear(nrfx_reset_reason_get());
+	int err;
+
+	err = hwinfo_clear_reset_cause();
+	if (err) {
+		LOG_ERR("Failed to clear reset cause: %d", err);
+	}
+
+	return err;
 }
 
 static bool app_event_handler(const struct app_event_header *aeh)
@@ -55,17 +74,27 @@ static bool app_event_handler(const struct app_event_header *aeh)
 				cast_module_state_event(aeh);
 
 		if (check_state(event, MODULE_ID(main), MODULE_STATE_READY)) {
+			int err;
+			bool failure_detected;
 			static bool initialized;
 
 			__ASSERT_NO_MSG(!initialized);
 			initialized = true;
 
-			if (failsafe_check()) {
-				failsafe_erase();
+			err = failsafe_check(&failure_detected);
+			if (!err && failure_detected) {
+				err = failsafe_erase();
 			}
-			failsafe_clear();
 
-			module_set_state(MODULE_STATE_READY);
+			if (!err) {
+				err = failsafe_clear();
+			}
+
+			if (!err) {
+				module_set_state(MODULE_STATE_READY);
+			} else {
+				module_set_state(MODULE_STATE_ERROR);
+			}
 		}
 
 		return false;

doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst

@@ -198,7 +198,10 @@ nRF5340 Audio
 nRF Desktop
 -----------
 
-|no_changes_yet_note|
+* Updated:
+
+  * The :ref:`nrf_desktop_failsafe` to use the Zephyr :ref:`zephyr:hwinfo_api` driver for getting and clearing the reset reason information (see the :c:func:`hwinfo_get_reset_cause` and :c:func:`hwinfo_clear_reset_cause` functions).
+    The Zephyr :ref:`zephyr:hwinfo_api` driver replaces the nrfx reset reason helper dependency (see the :c:func:`nrfx_reset_reason_get` and :c:func:`nrfx_reset_reason_clear` functions).
 
 nRF Machine Learning (Edge Impulse)
 -----------------------------------