From b7c4a81702cd48bbb77617eab0817c996325c6db Mon Sep 17 00:00:00 2001
From: Koen Zandberg <koen@bergzand.net>
Date: Sun, 5 Nov 2017 15:05:31 +0100
Subject: [PATCH] drivers/mrf24j40: fix radio ack request enabling

---
 drivers/include/mrf24j40.h         | 1 +
 drivers/mrf24j40/mrf24j40.c        | 2 +-
 drivers/mrf24j40/mrf24j40_netdev.c | 2 ++
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/include/mrf24j40.h b/drivers/include/mrf24j40.h
index cb7fe79e15..8cf6a59ff2 100644
--- a/drivers/include/mrf24j40.h
+++ b/drivers/include/mrf24j40.h
@@ -137,6 +137,7 @@ typedef struct {
     uint8_t idle_state;                     /**< state to return to after sending */
     uint8_t tx_frame_len;                   /**< length of the current TX frame */
     uint8_t header_len;                     /**< length of the header */
+    uint8_t fcf_low;                        /**< Low 8 FCF bits of the current TX frame. */
     uint8_t pending;                        /**< Flags for pending tasks */
     uint8_t irq_flag;                       /**< Flags for IRQs */
     uint8_t tx_retries;                     /**< Number of retries needed for last transmission */
diff --git a/drivers/mrf24j40/mrf24j40.c b/drivers/mrf24j40/mrf24j40.c
index b700f8a0bf..0be7a5033c 100644
--- a/drivers/mrf24j40/mrf24j40.c
+++ b/drivers/mrf24j40/mrf24j40.c
@@ -156,7 +156,7 @@ void mrf24j40_tx_exec(mrf24j40_t *dev)
      */
     mrf24j40_reg_write_long(dev, MRF24J40_TX_NORMAL_FIFO, dev->header_len);
 
-    if (dev->netdev.flags & NETDEV_IEEE802154_ACK_REQ) {
+    if (dev->fcf_low & IEEE802154_FCF_ACK_REQ) {
         mrf24j40_reg_write_short(dev, MRF24J40_REG_TXNCON, MRF24J40_TXNCON_TXNACKREQ | MRF24J40_TXNCON_TXNTRIG);
     }
     else {
diff --git a/drivers/mrf24j40/mrf24j40_netdev.c b/drivers/mrf24j40/mrf24j40_netdev.c
index 262ad61f4c..c0c74a9bb2 100644
--- a/drivers/mrf24j40/mrf24j40_netdev.c
+++ b/drivers/mrf24j40/mrf24j40_netdev.c
@@ -106,6 +106,8 @@ static int _send(netdev_t *netdev, const struct iovec *vector, unsigned count)
         len = mrf24j40_tx_load(dev, ptr->iov_base, ptr->iov_len, len);
         if (i == 0) {
             dev->header_len = len;
+            /* Grab the FCF bits from the frame header */
+            dev->fcf_low = *(uint8_t*)(ptr->iov_base);
         }
 
     }