gpio: dln2: Fix interrupts when replugging the device

When replugging the device the following message shows up:

gpio gpiochip2: (dln2): detected irqchip that is shared with multiple gpiochips: please fix the driver.

This also has the effect that interrupts won't work.
The same problem would also show up if multiple devices where plugged in.

Fix this by allocating the irq_chip data structure per instance like other
drivers do.

I don't know when this problem appeared, but it is present in 5.10.

Cc: <stable@vger.kernel.org> # 5.10+
Cc: Daniel Baluta <daniel.baluta@gmail.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

drivers/gpio/gpio-dln2.c

@@ -46,6 +46,7 @@
 struct dln2_gpio {
 	struct platform_device *pdev;
 	struct gpio_chip gpio;
+	struct irq_chip irqchip;
 
 	/*
 	 * Cache pin direction to save us one transfer, since the hardware has
@@ -383,15 +384,6 @@ static void dln2_irq_bus_unlock(struct irq_data *irqd)
 	mutex_unlock(&dln2->irq_lock);
 }
 
-static struct irq_chip dln2_gpio_irqchip = {
-	.name = "dln2-irq",
-	.irq_mask = dln2_irq_mask,
-	.irq_unmask = dln2_irq_unmask,
-	.irq_set_type = dln2_irq_set_type,
-	.irq_bus_lock = dln2_irq_bus_lock,
-	.irq_bus_sync_unlock = dln2_irq_bus_unlock,
-};
-
 static void dln2_gpio_event(struct platform_device *pdev, u16 echo,
 			    const void *data, int len)
 {
@@ -473,8 +465,15 @@ static int dln2_gpio_probe(struct platform_device *pdev)
 	dln2->gpio.direction_output = dln2_gpio_direction_output;
 	dln2->gpio.set_config = dln2_gpio_set_config;
 
+	dln2->irqchip.name = "dln2-irq",
+	dln2->irqchip.irq_mask = dln2_irq_mask,
+	dln2->irqchip.irq_unmask = dln2_irq_unmask,
+	dln2->irqchip.irq_set_type = dln2_irq_set_type,
+	dln2->irqchip.irq_bus_lock = dln2_irq_bus_lock,
+	dln2->irqchip.irq_bus_sync_unlock = dln2_irq_bus_unlock,
+
 	girq = &dln2->gpio.irq;
-	girq->chip = &dln2_gpio_irqchip;
+	girq->chip = &dln2->irqchip;
 	/* The event comes from the outside so no parent handler */
 	girq->parent_handler = NULL;
 	girq->num_parents = 0;