[ARM] 3348/1: Disable GPIO interrupts

Patch from Andrew Victor

disable_irq() lazily disables the interrupt, so the IRQ is only disabled
once the interrupt occurs again.  The GPIO interrupt handler therefore
must first check disable_depth to see if the IRQ needs to be disabled.

Orignal patch by Bill Gatliff.
Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-at91rm9200/gpio.c

@@ -274,8 +274,18 @@ static void gpio_irq_handler(unsigned irq, struct irqdesc *desc, struct pt_regs
 		gpio = &irq_desc[pin];
 
 		while (isr) {
-			if (isr & 1)
-				gpio->handle(pin, gpio, regs);
+			if (isr & 1) {
+				if (unlikely(gpio->disable_depth)) {
+					/*
+					 * The core ARM interrupt handler lazily disables IRQs so
+					 * another IRQ must be generated before it actually gets
+					 * here to be disabled on the GPIO controller.
+					 */
+					gpio_irq_mask(pin);
+				}
+				else
+					gpio->handle(pin, gpio, regs);
+			}
 			pin++;
 			gpio++;
 			isr >>= 1;