task_wdt: Kconfig: Allow to pause the hardware watchdog in sleep

The hardware watchdog optionally used by the Task Watchdog can support
being automatically paused when the system enters a sleep power state.

Add a Kconfig flag to enable such feature.

Signed-off-by: Adrien Ricciardi <aricciardi@baylibre.com>

Author: RICCIARDI-Adrien

subsys/task_wdt/Kconfig

@@ -58,6 +58,16 @@ config TASK_WDT_HW_FALLBACK_DELAY
 	  kernel timer. This is especially important if the hardware watchdog
 	  is clocked by an inaccurate low-speed RC oscillator.
 
+config TASK_WDT_HW_FALLBACK_PAUSE_IN_SLEEP
+	bool "Pause the hardware watchdog in system sleep"
+	depends on TASK_WDT_HW_FALLBACK
+	help
+	  Configure the hardware watchdog to automatically pause when the
+	  system reaches a sleep power state. When the system is resumed, the
+	  watchdog is also automatically resumed.
+	  Note that this feature is supported only by a subset of hardware
+	  watchdogs.
+
 config TASK_WDT_SHELL
 	bool "Task watchdog shell utilities"
 	depends on SHELL

subsys/task_wdt/task_wdt.c

@@ -179,7 +179,11 @@ int task_wdt_add(uint32_t reload_period, task_wdt_callback_t callback,
 			if (!hw_wdt_started && hw_wdt_dev) {
 				/* also start fallback hw wdt */
 				wdt_setup(hw_wdt_dev,
-					WDT_OPT_PAUSE_HALTED_BY_DBG);
+					WDT_OPT_PAUSE_HALTED_BY_DBG
+#ifdef CONFIG_TASK_WDT_HW_FALLBACK_PAUSE_IN_SLEEP
+					| WDT_OPT_PAUSE_IN_SLEEP
+#endif
+				);
 				hw_wdt_started = true;
 			}
 #endif