gpio: pca953x: fix irq_stat not updated when irq is disabled (irq_mask not set)

commit dba7857985 upstream.

When one port's input state get inverted (eg. from low to hight) after
pca953x_irq_setup but before setting irq_mask (by some other driver such as
"gpio-keys"), the next inversion of this port (eg. from hight to low) will not
be triggered any more (because irq_stat is not updated at the first time). Issue
should be fixed after this commit.

Fixes: 89ea8bbe9c ("gpio: pca953x.c: add interrupt handling capability")
Signed-off-by: Puyou Lu <puyou.lu@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/gpio/gpio-pca953x.c

@@ -762,11 +762,11 @@ static bool pca953x_irq_pending(struct pca953x_chip *chip, unsigned long *pendin
 	bitmap_xor(cur_stat, new_stat, old_stat, gc->ngpio);
 	bitmap_and(trigger, cur_stat, chip->irq_mask, gc->ngpio);
 
+	bitmap_copy(chip->irq_stat, new_stat, gc->ngpio);
+
 	if (bitmap_empty(trigger, gc->ngpio))
 		return false;
 
-	bitmap_copy(chip->irq_stat, new_stat, gc->ngpio);
-
 	bitmap_and(cur_stat, chip->irq_trig_fall, old_stat, gc->ngpio);
 	bitmap_and(old_stat, chip->irq_trig_raise, new_stat, gc->ngpio);
 	bitmap_or(new_stat, old_stat, cur_stat, gc->ngpio);