diff --git a/arch/arm/mach-ns9xxx/gpio.c b/arch/arm/mach-ns9xxx/gpio.c
index b2230213b983..5286e9fc1d30 100644
--- a/arch/arm/mach-ns9xxx/gpio.c
+++ b/arch/arm/mach-ns9xxx/gpio.c
@@ -31,7 +31,7 @@
 static spinlock_t gpio_lock = __SPIN_LOCK_UNLOCKED(gpio_lock);
 
 /* only access gpiores with atomic ops */
-static DECLARE_BITMAP(gpiores, GPIO_MAX);
+static DECLARE_BITMAP(gpiores, GPIO_MAX + 1);
 
 static inline int ns9xxx_valid_gpio(unsigned gpio)
 {