[nrf fromlist] modules: openthread: configure router selection jitter

Add CONFIG_OPENTHREAD_ROUTER_SELECTION_JITTER_OVERRIDE
Kconfig option that enables setting the router selection
jitter to CONFIG_OPENTHREAD_ROUTER_SELECTION_JITTER at
startup.

Upstream PR #: 94507

Signed-off-by: Damian Krolik <[email protected]>

Author: Damian-Nordic

modules/openthread/Kconfig.thread

@@ -256,3 +256,12 @@ config OPENTHREAD_RCP_RESTORATION_MAX_COUNT
 	default 2
 	help
 	  The maximum number of attempts to restore the RCP connection.
+
+config OPENTHREAD_ROUTER_SELECTION_JITTER_OVERRIDE
+	bool "Override default router selection jitter"
+	depends on OPENTHREAD_FTD
+
+config OPENTHREAD_ROUTER_SELECTION_JITTER
+	int "OpenThread router selection jitter in seconds"
+	depends on OPENTHREAD_ROUTER_SELECTION_JITTER_OVERRIDE
+	default 120

modules/openthread/openthread.c

@@ -33,6 +33,7 @@ LOG_MODULE_REGISTER(net_openthread_platform, CONFIG_OPENTHREAD_PLATFORM_LOG_LEVE
 #include <openthread/platform/diag.h>
 #include <openthread/tasklet.h>
 #include <openthread/thread.h>
+#include <openthread/thread_ftd.h>
 #include <openthread/dataset.h>
 #include <openthread/joiner.h>
 #include <openthread-system.h>
@@ -98,6 +99,12 @@ LOG_MODULE_REGISTER(net_openthread_platform, CONFIG_OPENTHREAD_PLATFORM_LOG_LEVE
 #define OT_POLL_PERIOD 0
 #endif
 
+#if defined(CONFIG_OPENTHREAD_ROUTER_SELECTION_JITTER)
+#define OT_ROUTER_SELECTION_JITTER CONFIG_OPENTHREAD_ROUTER_SELECTION_JITTER
+#else
+#define OT_ROUTER_SELECTION_JITTER 0
+#endif
+
 #define ZEPHYR_PACKAGE_NAME "Zephyr"
 #define PACKAGE_VERSION     KERNEL_VERSION_STRING
 
@@ -340,6 +347,10 @@ int openthread_init(void)
 		}
 	}
 
+	if (IS_ENABLED(CONFIG_OPENTHREAD_ROUTER_SELECTION_JITTER_OVERRIDE)) {
+		otThreadSetRouterSelectionJitter(openthread_instance, OT_ROUTER_SELECTION_JITTER);
+	}
+
 	openthread_mutex_unlock();
 
 	/* Start work queue for the OpenThread module */