ath5k: added cfg80211 based rfkill support

This patch introduces initial rfkill support for the ath5k driver
based on rfkill support in the cfg80211 framework.
All rfkill related code is separated into newly created rfkill.c.

Changes to existing code are minimal:

* added a new data structure ath5k_rfkill to the ath5k_softc structure
* inserted calls to HW rfkill init/deinit routines
* ath5k_intr() has been extended to handle AR5K_INT_GPIO interrupts

Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath5k/base.h

@@ -46,6 +46,7 @@
 #include <linux/wireless.h>
 #include <linux/if_ether.h>
 #include <linux/leds.h>
+#include <linux/rfkill.h>
 
 #include "ath5k.h"
 #include "debug.h"
@@ -91,6 +92,15 @@ struct ath5k_led
 	struct led_classdev led_dev;		/* led classdev */
 };
 
+/* Rfkill */
+struct ath5k_rfkill {
+	/* GPIO PIN for rfkill */
+	u16 gpio;
+	/* polarity of rfkill GPIO PIN */
+	bool polarity;
+	/* RFKILL toggle tasklet */
+	struct tasklet_struct toggleq;
+};
 
 #if CHAN_DEBUG
 #define ATH_CHAN_MAX	(26+26+26+200+200)
@@ -167,6 +177,10 @@ struct ath5k_softc {
 	struct tasklet_struct	txtq;		/* tx intr tasklet */
 	struct ath5k_led	tx_led;		/* tx led */
 
+#ifdef CONFIG_ATH5K_RFKILL
+	struct ath5k_rfkill	rf_kill;
+#endif
+
 	spinlock_t		block;		/* protects beacon */
 	struct tasklet_struct	beacontq;	/* beacon intr tasklet */
 	struct ath5k_buf	*bbuf;		/* beacon buffer */