pinctrl: amd: Make the irqchip immutable

Prevent gpiolib from messing with the irqchip by advertising
the irq_chip structure as immutable, making it const, and adding
the various calls that gpiolib relies upon.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220419141846.598305-9-maz@kernel.org

drivers/pinctrl/pinctrl-amd.c

@@ -387,6 +387,8 @@ static void amd_gpio_irq_enable(struct irq_data *d)
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct amd_gpio *gpio_dev = gpiochip_get_data(gc);
 
+	gpiochip_enable_irq(gc, d->hwirq);
+
 	raw_spin_lock_irqsave(&gpio_dev->lock, flags);
 	pin_reg = readl(gpio_dev->base + (d->hwirq)*4);
 	pin_reg |= BIT(INTERRUPT_ENABLE_OFF);
@@ -408,6 +410,8 @@ static void amd_gpio_irq_disable(struct irq_data *d)
 	pin_reg &= ~BIT(INTERRUPT_MASK_OFF);
 	writel(pin_reg, gpio_dev->base + (d->hwirq)*4);
 	raw_spin_unlock_irqrestore(&gpio_dev->lock, flags);
+
+	gpiochip_disable_irq(gc, d->hwirq);
 }
 
 static void amd_gpio_irq_mask(struct irq_data *d)
@@ -577,7 +581,7 @@ static void amd_irq_ack(struct irq_data *d)
 	*/
 }
 
-static struct irq_chip amd_gpio_irqchip = {
+static const struct irq_chip amd_gpio_irqchip = {
 	.name         = "amd_gpio",
 	.irq_ack      = amd_irq_ack,
 	.irq_enable   = amd_gpio_irq_enable,
@@ -593,7 +597,8 @@ static struct irq_chip amd_gpio_irqchip = {
 	 * the wake event. Otherwise the wake event will never clear and
 	 * prevent the system from suspending.
 	 */
-	.flags        = IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND,
+	.flags        = IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND | IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
 #define PIN_IRQ_PENDING	(BIT(INTERRUPT_STS_OFF) | BIT(WAKE_STS_OFF))
@@ -1026,7 +1031,7 @@ static int amd_gpio_probe(struct platform_device *pdev)
 	amd_gpio_irq_init(gpio_dev);
 
 	girq = &gpio_dev->gc.irq;
-	girq->chip = &amd_gpio_irqchip;
+	gpio_irq_chip_set_chip(girq, &amd_gpio_irqchip);
 	/* This will let us handle the parent IRQ in the driver */
 	girq->parent_handler = NULL;
 	girq->num_parents = 0;