feat(openthread): enable parent search function for MTD

Author: tanyanquan

components/openthread/Kconfig

@@ -327,6 +327,27 @@ menu "OpenThread"
                 commands in the OpenThread command line. These commands allow users to manipulate low-level
                 features of the storage and 15.4 radio.
 
+        config OPENTHREAD_PARENT_SEARCH_MTD
+            bool "Enable Parent Search"
+            depends on OPENTHREAD_MTD
+            default y
+            help
+                Select this option to enable "Periodic Parent Search" function for MTD. This checks the average
+                RSS to its current parent every periodically and starts a parent search process if the average
+                RSS is below OPENTHREAD_PARENT_SEARCH_RSS_THRESHOLD. This feature is always enabled for FTDs.
+        menu "Parent Search Configurations"
+            depends on OPENTHREAD_PARENT_SEARCH_MTD
+            config OPENTHREAD_PARENT_SEARCH_CHECK_INTERVAL_MINS
+                int "The interval in minutes for a child to check the trigger condition to perform a parent search"
+                default 9
+            config OPENTHREAD_PARENT_SEARCH_BACKOFF_INTERVAL_MINS
+                int "The backoff interval in minutes for a child to not perform a parent search after triggering one"
+                default 600
+            config OPENTHREAD_PARENT_SEARCH_RSS_THRESHOLD
+                int "The RSS threshold used to trigger a parent search"
+                default -65
+        endmenu
+
         menu "Thread Memory Allocation"
             depends on (SPIRAM_USE_CAPS_ALLOC || SPIRAM_USE_MALLOC)
             config OPENTHREAD_PLATFORM_MALLOC_CAP_SPIRAM

components/openthread/private_include/openthread-core-esp32x-mtd-config.h

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2021-2024 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2021-2025 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -449,3 +449,47 @@
 #ifndef OPENTHREAD_CONFIG_CSL_RECEIVE_TIME_AHEAD
 #define OPENTHREAD_CONFIG_CSL_RECEIVE_TIME_AHEAD (OPENTHREAD_CONFIG_MAC_CSL_REQUEST_AHEAD_US + 320)
 #endif
+
+/**
+ * @def OPENTHREAD_CONFIG_PARENT_SEARCH_ENABLE
+ *
+ * Enable the periodic parent search feature.
+ *
+ */
+#ifndef OPENTHREAD_CONFIG_PARENT_SEARCH_ENABLE
+#define OPENTHREAD_CONFIG_PARENT_SEARCH_ENABLE CONFIG_OPENTHREAD_PARENT_SEARCH_MTD
+#endif
+
+/**
+ * @def OPENTHREAD_CONFIG_PARENT_SEARCH_CHECK_INTERVAL
+ *
+ * Specifies the interval in seconds for a child to check the trigger condition to perform a parent search.
+ *
+ * Applicable only if periodic parent search feature is enabled (see `OPENTHREAD_CONFIG_PARENT_SEARCH_ENABLE`).
+ */
+#ifndef OPENTHREAD_CONFIG_PARENT_SEARCH_CHECK_INTERVAL
+#define OPENTHREAD_CONFIG_PARENT_SEARCH_CHECK_INTERVAL CONFIG_OPENTHREAD_PARENT_SEARCH_CHECK_INTERVAL_MINS * 60
+#endif
+
+/**
+ * @def OPENTHREAD_CONFIG_PARENT_SEARCH_BACKOFF_INTERVAL
+ *
+ * Specifies the backoff interval in seconds for a child to not perform a parent search after triggering one. This is
+ * used when device is an MTD child.
+ *
+ * Applicable only if periodic parent search feature is enabled (see `OPENTHREAD_CONFIG_PARENT_SEARCH_ENABLE`).
+ */
+#ifndef OPENTHREAD_CONFIG_PARENT_SEARCH_BACKOFF_INTERVAL
+#define OPENTHREAD_CONFIG_PARENT_SEARCH_BACKOFF_INTERVAL CONFIG_OPENTHREAD_PARENT_SEARCH_BACKOFF_INTERVAL_MINS * 60
+#endif
+
+/**
+ * @def OPENTHREAD_CONFIG_PARENT_SEARCH_RSS_THRESHOLD
+ *
+ * Specifies the RSS threshold used to trigger a parent search.
+ *
+ * Applicable only if periodic parent search feature is enabled (see `OPENTHREAD_CONFIG_PARENT_SEARCH_ENABLE`).
+ */
+#ifndef OPENTHREAD_CONFIG_PARENT_SEARCH_RSS_THRESHOLD
+#define OPENTHREAD_CONFIG_PARENT_SEARCH_RSS_THRESHOLD CONFIG_OPENTHREAD_PARENT_SEARCH_RSS_THRESHOLD
+#endif

examples/openthread/ot_sleepy_device/light_sleep/sdkconfig.defaults

@@ -20,6 +20,7 @@ CONFIG_MBEDTLS_ECJPAKE_C=y
 #
 CONFIG_OPENTHREAD_ENABLED=y
 CONFIG_OPENTHREAD_BORDER_ROUTER=n
+CONFIG_OPENTHREAD_MTD=y
 CONFIG_OPENTHREAD_DNS64_CLIENT=y
 CONFIG_OPENTHREAD_CLI=y
 # end of OpenThread