From 7b6071671304b5b6bb1fdcd6b8b845f568b6c4f5 Mon Sep 17 00:00:00 2001
From: Abtin Keshavarzian <abtink@google.com>
Date: Tue, 19 Jul 2022 15:55:59 -0700
Subject: [PATCH] [csl] ensure `SubMac`is informed when CSL support changes
 (#7918)

This commit changes `Mac::UpdateCsl()` to ensure we inform `SubMac`
and disable CSL when CSL support changes (e.g., device gets
detached). This ensures that `SubMac` internal variables (CSL period,
channel) are updated on a detach and if the device later attaches
again, we detect the change in CSL configuration and trigger the tx
of MLE Child Update Request.
---
 src/core/mac/mac.cpp | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/src/core/mac/mac.cpp b/src/core/mac/mac.cpp
index dbe3c974a..8ad0518fe 100644
--- a/src/core/mac/mac.cpp
+++ b/src/core/mac/mac.cpp
@@ -2267,27 +2267,24 @@ exit:
 #if OPENTHREAD_CONFIG_MAC_CSL_RECEIVER_ENABLE
 void Mac::UpdateCsl(void)
 {
-    uint16_t period;
-    uint8_t  channel;
-
-    VerifyOrExit(IsCslSupported());
-
-    period  = Get<Mle::Mle>().IsRxOnWhenIdle() ? 0 : GetCslPeriod();
-    channel = GetCslChannel() ? GetCslChannel() : mRadioChannel;
+    uint16_t period  = IsCslEnabled() ? GetCslPeriod() : 0;
+    uint8_t  channel = GetCslChannel() ? GetCslChannel() : mRadioChannel;
 
     if (mLinks.UpdateCsl(period, channel, Get<Mle::Mle>().GetParent().GetRloc16(),
                          &Get<Mle::Mle>().GetParent().GetExtAddress()))
     {
-        Get<DataPollSender>().RecalculatePollPeriod();
-        if (period)
+        if (Get<Mle::Mle>().IsChild())
         {
-            Get<Mle::Mle>().ScheduleChildUpdateRequest();
+            Get<DataPollSender>().RecalculatePollPeriod();
+
+            if (period != 0)
+            {
+                Get<Mle::Mle>().ScheduleChildUpdateRequest();
+            }
         }
+
         UpdateIdleMode();
     }
-
-exit:
-    return;
 }
 
 void Mac::SetCslChannel(uint8_t aChannel)