[PATCH] gpio: langwell_gpio: ack the correct bit for langwell gpio interrupts

[Alan Cox <alan@lxorguk.ukuu.org.uk>]

From: Mathias Nyman <mathias.nyman@linux.intel.com>

The wrong bit was masked when acking langwell gpio interrupts.

Reason for maskig the wrong bit was probably because__ffs() and ffs() functions
return bit indexes differently (0..31 vs 1..32)

This fixes langwell based devices from hanging when a gpio interrupt is
triggered and undoes the breakage which occurred in change set
732063b92bb727b27e61580ce278dddefe31c6ad

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
---

 drivers/gpio/langwell_gpio.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)


diff --git a/drivers/gpio/langwell_gpio.c b/drivers/gpio/langwell_gpio.c
index bd6571e..644ba12 100644
--- a/drivers/gpio/langwell_gpio.c
+++ b/drivers/gpio/langwell_gpio.c
@@ -223,7 +223,7 @@ static void lnw_irq_handler(unsigned irq, struct irq_desc *desc)
 		gedr = gpio_reg(&lnw->chip, base, GEDR);
 		pending = readl(gedr);
 		while (pending) {
-			gpio = __ffs(pending) - 1;
+			gpio = __ffs(pending);
 			mask = BIT(gpio);
 			pending &= ~mask;
 			/* Clear before handling so we can't lose an edge */