gpio: xilinx: Convert to immutable irq_chip

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

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

drivers/gpio/gpio-xilinx.c

@@ -68,7 +68,6 @@ struct xgpio_instance {
 	DECLARE_BITMAP(dir, 64);
 	spinlock_t gpio_lock;	/* For serializing operations */
 	int irq;
-	struct irq_chip irqchip;
 	DECLARE_BITMAP(enable, 64);
 	DECLARE_BITMAP(rising_edge, 64);
 	DECLARE_BITMAP(falling_edge, 64);
@@ -416,6 +415,8 @@ static void xgpio_irq_mask(struct irq_data *irq_data)
 		xgpio_writereg(chip->regs + XGPIO_IPIER_OFFSET, temp);
 	}
 	spin_unlock_irqrestore(&chip->gpio_lock, flags);
+
+	gpiochip_disable_irq(&chip->gc, irq_offset);
 }
 
 /**
@@ -431,6 +432,8 @@ static void xgpio_irq_unmask(struct irq_data *irq_data)
 	u32 old_enable = xgpio_get_value32(chip->enable, bit);
 	u32 mask = BIT(bit / 32), val;
 
+	gpiochip_enable_irq(&chip->gc, irq_offset);
+
 	spin_lock_irqsave(&chip->gpio_lock, flags);
 
 	__set_bit(bit, chip->enable);
@@ -544,6 +547,16 @@ static void xgpio_irqhandler(struct irq_desc *desc)
 	chained_irq_exit(irqchip, desc);
 }
 
+static const struct irq_chip xgpio_irq_chip = {
+	.name = "gpio-xilinx",
+	.irq_ack = xgpio_irq_ack,
+	.irq_mask = xgpio_irq_mask,
+	.irq_unmask = xgpio_irq_unmask,
+	.irq_set_type = xgpio_set_irq_type,
+	.flags = IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
 /**
  * xgpio_probe - Probe method for the GPIO device.
  * @pdev: pointer to the platform device
@@ -653,12 +666,6 @@ static int xgpio_probe(struct platform_device *pdev)
 	if (chip->irq <= 0)
 		goto skip_irq;
 
-	chip->irqchip.name = "gpio-xilinx";
-	chip->irqchip.irq_ack = xgpio_irq_ack;
-	chip->irqchip.irq_mask = xgpio_irq_mask;
-	chip->irqchip.irq_unmask = xgpio_irq_unmask;
-	chip->irqchip.irq_set_type = xgpio_set_irq_type;
-
 	/* Disable per-channel interrupts */
 	xgpio_writereg(chip->regs + XGPIO_IPIER_OFFSET, 0);
 	/* Clear any existing per-channel interrupts */
@@ -668,7 +675,7 @@ static int xgpio_probe(struct platform_device *pdev)
 	xgpio_writereg(chip->regs + XGPIO_GIER_OFFSET, XGPIO_GIER_IE);
 
 	girq = &chip->gc.irq;
-	girq->chip = &chip->irqchip;
+	gpio_irq_chip_set_chip(girq, &xgpio_irq_chip);
 	girq->parent_handler = xgpio_irqhandler;
 	girq->num_parents = 1;
 	girq->parents = devm_kcalloc(&pdev->dev, 1,