From 7ac94f674de0e91e53fe39c462698e9fa79f9734 Mon Sep 17 00:00:00 2001
From: tfrazel <39776922+tfrazel@users.noreply.github.com>
Date: Mon, 4 Jun 2018 11:29:42 -0500
Subject: [PATCH] [kw41z] radio driver fix to allow channel change (#2757)

The NXP KW41Z radio driver prohibited changing channels while in receive
mode; this prevented the leader properly responding to MLE Announces from
orphaned child devices.
---
 examples/platforms/kw41z/radio.c | 33 ++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/examples/platforms/kw41z/radio.c b/examples/platforms/kw41z/radio.c
index 1a9006dce..c503fb3e2 100644
--- a/examples/platforms/kw41z/radio.c
+++ b/examples/platforms/kw41z/radio.c
@@ -234,24 +234,25 @@ otError otPlatRadioReceive(otInstance *aInstance, uint8_t aChannel)
 
     sState = OT_RADIO_STATE_RECEIVE;
 
-    otEXPECT(rf_get_state() != XCVR_RX_c);
+    /* Check if the channel needs to be changed */
+    if ((sChannel != aChannel) || (rf_get_state() != XCVR_RX_c))
+    {
+        rf_abort();
+        /* Set Power level for auto TX */
+        rf_set_tx_power(sAutoTxPwrLevel);
+        rf_set_channel(aChannel);
+        sRxFrame.mChannel = aChannel;
 
-    rf_abort();
+        /* Filter ACK frames during RX sequence */
+        ZLL->RX_FRAME_FILTER &= ~(ZLL_RX_FRAME_FILTER_ACK_FT_MASK);
+        /* Clear all IRQ flags */
+        ZLL->IRQSTS = ZLL->IRQSTS;
+        /* Start the RX sequence */
+        ZLL->PHY_CTRL |= XCVR_RX_c;
 
-    /* Set Power level for auto TX */
-    rf_set_tx_power(sAutoTxPwrLevel);
-    rf_set_channel(aChannel);
-    sRxFrame.mChannel = aChannel;
-
-    /* Filter ACK frames during RX sequence */
-    ZLL->RX_FRAME_FILTER &= ~(ZLL_RX_FRAME_FILTER_ACK_FT_MASK);
-    /* Clear all IRQ flags */
-    ZLL->IRQSTS = ZLL->IRQSTS;
-    /* Start the RX sequence */
-    ZLL->PHY_CTRL |= XCVR_RX_c;
-
-    /* Unmask SEQ interrupt */
-    ZLL->PHY_CTRL &= ~ZLL_PHY_CTRL_SEQMSK_MASK;
+        /* Unmask SEQ interrupt */
+        ZLL->PHY_CTRL &= ~ZLL_PHY_CTRL_SEQMSK_MASK;
+    }
 
 exit:
     return status;