From a1c781bb20ac1e03280e420abd47a99eb8bbdd3b Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Tue, 13 Aug 2013 12:33:28 +0200
Subject: ath9k: avoid accessing MRC registers on single-chain devices

From: Felix Fietkau <nbd@openwrt.org>

commit a1c781bb20ac1e03280e420abd47a99eb8bbdd3b upstream.

They are not implemented, and accessing them might trigger errors

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/wireless/ath/ath9k/ar9003_phy.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/net/wireless/ath/ath9k/ar9003_phy.c
+++ b/drivers/net/wireless/ath/ath9k/ar9003_phy.c
@@ -1005,6 +1005,10 @@ static bool ar9003_hw_ani_control(struct
 		 * is_on == 0 means MRC CCK is OFF (more noise imm)
 		 */
 		bool is_on = param ? 1 : 0;
+
+		if (ah->caps.rx_chainmask == 1)
+			break;
+
 		REG_RMW_FIELD(ah, AR_PHY_MRC_CCK_CTRL,
 			      AR_PHY_MRC_CCK_ENABLE, is_on);
 		REG_RMW_FIELD(ah, AR_PHY_MRC_CCK_CTRL,