gpio: max732x: Convert to immutable irq_chip

Convert the driver to immutable irq-chip with a bit of
intuition.

Cc: Marc Zyngier <maz@kernel.org>
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

drivers/gpio/gpio-max732x.c

@@ -351,6 +351,7 @@ static void max732x_irq_mask(struct irq_data *d)
 	struct max732x_chip *chip = gpiochip_get_data(gc);
 
 	chip->irq_mask_cur &= ~(1 << d->hwirq);
+	gpiochip_disable_irq(gc, irqd_to_hwirq(d));
 }
 
 static void max732x_irq_unmask(struct irq_data *d)
@@ -358,6 +359,7 @@ static void max732x_irq_unmask(struct irq_data *d)
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct max732x_chip *chip = gpiochip_get_data(gc);
 
+	gpiochip_enable_irq(gc, irqd_to_hwirq(d));
 	chip->irq_mask_cur |= 1 << d->hwirq;
 }
 
@@ -429,7 +431,7 @@ static int max732x_irq_set_wake(struct irq_data *data, unsigned int on)
 	return 0;
 }
 
-static struct irq_chip max732x_irq_chip = {
+static const struct irq_chip max732x_irq_chip = {
 	.name			= "max732x",
 	.irq_mask		= max732x_irq_mask,
 	.irq_unmask		= max732x_irq_unmask,
@@ -437,6 +439,8 @@ static struct irq_chip max732x_irq_chip = {
 	.irq_bus_sync_unlock	= max732x_irq_bus_sync_unlock,
 	.irq_set_type		= max732x_irq_set_type,
 	.irq_set_wake		= max732x_irq_set_wake,
+	.flags			= IRQCHIP_IMMUTABLE,
+	 GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
 static uint8_t max732x_irq_pending(struct max732x_chip *chip)
@@ -517,7 +521,7 @@ static int max732x_irq_setup(struct max732x_chip *chip,
 		}
 
 		girq = &chip->gpio_chip.irq;
-		girq->chip = &max732x_irq_chip;
+		gpio_irq_chip_set_chip(girq, &max732x_irq_chip);
 		/* This will let us handle the parent IRQ in the driver */
 		girq->parent_handler = NULL;
 		girq->num_parents = 0;