net: openthread: Allow to configure SED

Allow to select Sleepy End Device, and configure it during OpenThread
initialization.

According to Thread Specification, Sleepy End Devices should always
attach to the network as SED, to indicate increased buffer requirement
to a parent. Therefore, we reconfigure the Link Mode on each boot.

Note, that Poll Period value is not stored in the persistent storage,
hence we also need to initialize it on each boot.

Signed-off-by: Robert Lubos <[email protected]>

Author: rlubos

subsys/net/l2/openthread/Kconfig

@@ -145,6 +145,15 @@ config OPENTHREAD_MTD
 	bool "MTD - Minimal Thread Device"
 endchoice
 
+config OPENTHREAD_MTD_SED
+	bool "SED - Sleepy End Device"
+	depends on OPENTHREAD_MTD
+
+config OPENTHREAD_POLL_PERIOD
+	int "Poll period for sleepy end devices [ms]"
+	default 236000
+	depends on OPENTHREAD_MTD_SED
+
 config OPENTHREAD_SHELL
 	bool "Enable OpenThread shell"
 	select SHELL

subsys/net/l2/openthread/openthread.c

@@ -53,6 +53,12 @@ LOG_MODULE_REGISTER(net_l2_openthread, CONFIG_OPENTHREAD_L2_LOG_LEVEL);
 #define OT_PLATFORM_INFO ""
 #endif
 
+#if defined(CONFIG_OPENTHREAD_POLL_PERIOD)
+#define OT_POLL_PERIOD CONFIG_OPENTHREAD_POLL_PERIOD
+#else
+#define OT_POLL_PERIOD 0
+#endif
+
 extern void platformShellInit(otInstance *aInstance);
 
 K_SEM_DEFINE(ot_sem, 0, 1);
@@ -318,6 +324,19 @@ static void openthread_start(struct openthread_context *ot_context)
 	otInstance *ot_instance = ot_context->instance;
 	otError error;
 
+	/* Sleepy End Device specific configuration. */
+	if (IS_ENABLED(CONFIG_OPENTHREAD_MTD_SED)) {
+		otLinkModeConfig ot_mode = otThreadGetLinkMode(ot_instance);
+
+		/* A SED should always attach the network as a SED to indicate
+		 * increased buffer requirement to a parent.
+		 */
+		ot_mode.mRxOnWhenIdle = false;
+
+		otThreadSetLinkMode(ot_context->instance, ot_mode);
+		otLinkSetPollPeriod(ot_context->instance, OT_POLL_PERIOD);
+	}
+
 	if (otDatasetIsCommissioned(ot_instance)) {
 		/* OpenThread already has dataset stored - skip the
 		 * configuration.