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>

drivers/gpio/gpiolib-acpi.c

@@ -253,6 +253,8 @@ static int acpi_find_gpio(struct acpi_resource *ares, void *data)
 					      agpio->pin_table[0]);
 		lookup->info.gpioint =
 			agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
+		lookup->info.active_low =
+			agpio->polarity == ACPI_ACTIVE_LOW;
 	}
 
 	return 1;

drivers/gpio/gpiolib.c

@@ -2264,7 +2264,17 @@ static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
 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,

include/linux/acpi_gpio.h

@@ -10,9 +10,11 @@
 /**
  * struct acpi_gpio_info - ACPI GPIO specific information
  * @gpioint: if %true this GPIO is of type GpioInt otherwise type is GpioIo
+ * @active_low: in case of @gpioint, the pin is active low
  */
 struct acpi_gpio_info {
 	bool gpioint;
+	bool active_low;
 };
 
 #ifdef CONFIG_GPIO_ACPI