gpio: visconti: Convert to immutable irq_chip

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

The driver is for a hierarchical chip so some extra care
needs to be taken to introduce two new callbacks.

Cc: Marc Zyngier <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>
Reviewed-by: Marc Zyngier <[e-mail]>
Signed-off-by: Bartosz Golaszewski <[e-mail]>

drivers/gpio/gpio-visconti.c

···
 #include <linux/io.h>
 #include <linux/of_irq.h>
 #include <linux/platform_device.h>
+#include <linux/seq_file.h>
 #include <linux/bitops.h>
 
 /* register offset */
···
 	void __iomem *base;
 	spinlock_t lock; /* protect gpio register */
 	struct gpio_chip gpio_chip;
-	struct irq_chip irq_chip;
+	struct device *dev;
 };
 
 static int visconti_gpio_irq_set_type(struct irq_data *d, unsigned int type)
···
 	return 0;
 }
 
+static void visconti_gpio_mask_irq(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+
+	irq_chip_mask_parent(d);
+	gpiochip_disable_irq(gc, irqd_to_hwirq(d));
+}
+
+static void visconti_gpio_unmask_irq(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+
+	gpiochip_enable_irq(gc, irqd_to_hwirq(d));
+	irq_chip_unmask_parent(d);
+}
+
+static void visconti_gpio_irq_print_chip(struct irq_data *d, struct seq_file *p)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct visconti_gpio *priv = gpiochip_get_data(gc);
+
+	seq_printf(p, dev_name(priv->dev));
+}
+
+static const struct irq_chip visconti_gpio_irq_chip = {
+	.irq_mask = visconti_gpio_mask_irq,
+	.irq_unmask = visconti_gpio_unmask_irq,
+	.irq_eoi = irq_chip_eoi_parent,
+	.irq_set_type = visconti_gpio_irq_set_type,
+	.irq_print_chip = visconti_gpio_irq_print_chip,
+	.flags = IRQCHIP_SET_TYPE_MASKED | IRQCHIP_MASK_ON_SUSPEND |
+		 IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
 static int visconti_gpio_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct visconti_gpio *priv;
-	struct irq_chip *irq_chip;
 	struct gpio_irq_chip *girq;
 	struct irq_domain *parent;
 	struct device_node *irq_parent;
···
 		return -ENOMEM;
 
 	spin_lock_init(&priv->lock);
+	priv->dev = dev;
 
 	priv->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(priv->base))
···
 		return ret;
 	}
 
-	irq_chip = &priv->irq_chip;
-	irq_chip->name = dev_name(dev);
-	irq_chip->irq_mask = irq_chip_mask_parent;
-	irq_chip->irq_unmask = irq_chip_unmask_parent;
-	irq_chip->irq_eoi = irq_chip_eoi_parent;
-	irq_chip->irq_set_type = visconti_gpio_irq_set_type;
-	irq_chip->flags = IRQCHIP_SET_TYPE_MASKED | IRQCHIP_MASK_ON_SUSPEND;
-
 	girq = &priv->gpio_chip.irq;
-	girq->chip = irq_chip;
+	gpio_irq_chip_set_chip(girq, &visconti_gpio_irq_chip);
 	girq->fwnode = of_node_to_fwnode(dev->of_node);
 	girq->parent_domain = parent;
 	girq->child_to_parent_hwirq = visconti_gpio_child_to_parent_hwirq;