misc: microchip: pci1xxxx: Convert to immutable irqchip

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

Cc: linux-gpio@vger.kernel.org
Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230223133252.2257276-1-linus.walleij@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mchp_pci1xxxx/mchp_pci1xxxx_gpio.c

@@ -175,9 +175,13 @@ static void pci1xxxx_gpio_irq_set_mask(struct irq_data *data, bool set)
 	unsigned int gpio = irqd_to_hwirq(data);
 	unsigned long flags;
 
+	if (!set)
+		gpiochip_enable_irq(chip, gpio);
 	spin_lock_irqsave(&priv->lock, flags);
 	pci1xxx_assign_bit(priv->reg_base, INTR_MASK_OFFSET(gpio), (gpio % 32), set);
 	spin_unlock_irqrestore(&priv->lock, flags);
+	if (set)
+		gpiochip_disable_irq(chip, gpio);
 }
 
 static void pci1xxxx_gpio_irq_mask(struct irq_data *data)
@@ -283,12 +287,14 @@ static irqreturn_t pci1xxxx_gpio_irq_handler(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static struct irq_chip pci1xxxx_gpio_irqchip = {
+static const struct irq_chip pci1xxxx_gpio_irqchip = {
 	.name = "pci1xxxx_gpio",
 	.irq_ack = pci1xxxx_gpio_irq_ack,
 	.irq_mask = pci1xxxx_gpio_irq_mask,
 	.irq_unmask = pci1xxxx_gpio_irq_unmask,
 	.irq_set_type = pci1xxxx_gpio_set_type,
+	.flags = IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
 static int pci1xxxx_gpio_suspend(struct device *dev)
@@ -351,7 +357,7 @@ static int pci1xxxx_gpio_setup(struct pci1xxxx_gpio *priv, int irq)
 		return retval;
 
 	girq = &priv->gpio.irq;
-	girq->chip = &pci1xxxx_gpio_irqchip;
+	gpio_irq_chip_set_chip(girq, &pci1xxxx_gpio_irqchip);
 	girq->parent_handler = NULL;
 	girq->num_parents = 0;
 	girq->parents = NULL;