ssb: add locking around gpio register accesses

The GPIOs are access through some registers in the chip common core or
over extif. We need locking around these GPIO accesses, all GPIOs are
accessed through the same registers and parallel writes will cause
problems.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Patchwork: http://patchwork.linux-mips.org/patch/4590
Acked-by: Florian Fainelli <florian@openwrt.org>

drivers/ssb/ssb_private.h

@@ -211,4 +211,12 @@ static inline void b43_pci_ssb_bridge_exit(void)
 extern u32 ssb_pmu_get_cpu_clock(struct ssb_chipcommon *cc);
 extern u32 ssb_pmu_get_controlclock(struct ssb_chipcommon *cc);
 
+#ifdef CONFIG_SSB_DRIVER_EXTIF
+extern void ssb_extif_init(struct ssb_extif *extif);
+#else
+static inline void ssb_extif_init(struct ssb_extif *extif)
+{
+}
+#endif
+
 #endif /* LINUX_SSB_PRIVATE_H_ */