ath9k: Reintroduce modparam to enable btcoex

It is not ideal to enable btcoex based on subsys id as it is
not unique, they are so random. It is also a pain keeping
all of them in a table to enable btcoex for a particular
hw. Going back to the old idea.

Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath.h b/drivers/net/wireless/ath/ath.h
index 20ea68c..26bdbee 100644
--- a/drivers/net/wireless/ath/ath.h
+++ b/drivers/net/wireless/ath/ath.h
@@ -168,6 +168,8 @@
 	struct ath_regulatory regulatory;
 	const struct ath_ops *ops;
 	const struct ath_bus_ops *bus_ops;
+
+	bool btcoex_enabled;
 };
 
 struct sk_buff *ath_rxbuf_alloc(struct ath_common *common,
diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index ce9e59f..883f6cc 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -1925,8 +1925,7 @@
 	pCap->num_antcfg_2ghz =
 		ah->eep_ops->get_num_ant_config(ah, ATH9K_HAL_FREQ_BAND_2GHZ);
 
-	if (AR_SREV_9280_20_OR_LATER(ah) &&
-	    ath9k_hw_btcoex_supported(ah)) {
+	if (AR_SREV_9280_20_OR_LATER(ah) && common->btcoex_enabled) {
 		btcoex_hw->btactive_gpio = ATH_BTACTIVE_GPIO;
 		btcoex_hw->wlanactive_gpio = ATH_WLANACTIVE_GPIO;
 
diff --git a/drivers/net/wireless/ath/ath9k/init.c b/drivers/net/wireless/ath/ath9k/init.c
index 7eef1fa..d11e6da 100644
--- a/drivers/net/wireless/ath/ath9k/init.c
+++ b/drivers/net/wireless/ath/ath9k/init.c
@@ -38,6 +38,10 @@
 module_param_named(blink, led_blink, int, 0444);
 MODULE_PARM_DESC(blink, "Enable LED blink on activity");
 
+static int ath9k_btcoex_enable;
+module_param_named(btcoex_enable, ath9k_btcoex_enable, int, 0444);
+MODULE_PARM_DESC(btcoex_enable, "Enable wifi-BT coexistence");
+
 /* We use the hw_value as an index into our private channel structure */
 
 #define CHAN2G(_freq, _idx)  { \
@@ -543,6 +547,7 @@
 	common->hw = sc->hw;
 	common->priv = sc;
 	common->debug_mask = ath9k_debug;
+	common->btcoex_enabled = ath9k_btcoex_enable == 1;
 	spin_lock_init(&common->cc_lock);
 
 	spin_lock_init(&sc->wiphy_lock);