gpiolib / ACPI: allow passing GPIOF_ACTIVE_LOW for GpioInt resources

The ACPI GpioInt resources contain polarity field that is used to specify
whether the interrupt is active high or low. Since gpiolib supports
GPIOF_ACTIVE_LOW we can pass this information in the flags field in
acpi_find_gpio(), analogous to the DeviceTree version.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index bee93c8..9f3326b 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2264,7 +2264,17 @@
 static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id,
 					unsigned int idx, unsigned long *flags)
 {
-	return acpi_get_gpiod_by_index(dev, idx, NULL);
+	struct acpi_gpio_info info;
+	struct gpio_desc *desc;
+
+	desc = acpi_get_gpiod_by_index(dev, idx, &info);
+	if (IS_ERR(desc))
+		return desc;
+
+	if (info.gpioint && info.active_low)
+		*flags |= GPIOF_ACTIVE_LOW;
+
+	return desc;
 }
 
 static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,