The wrong test was used, gpio is unsigned and it had an off-by-one.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Alek Du <alek.du@intel.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/gpio/langwell_gpio.c

@@ -123,7 +123,7 @@ static int lnw_irq_type(unsigned irq, unsigned type)
 	void __iomem *grer = (void __iomem *)(&lnw->reg_base->GRER[reg]);
 	void __iomem *gfer = (void __iomem *)(&lnw->reg_base->GFER[reg]);
 
-	if (gpio < 0 || gpio > lnw->chip.ngpio)
+	if (gpio >= lnw->chip.ngpio)
 		return -EINVAL;
 	spin_lock_irqsave(&lnw->lock, flags);
 	if (type & IRQ_TYPE_EDGE_RISING)