gpio: tegra186: Allow optional irq parent callbacks

Make the tegra186 GPIO driver resistent to variable depth
interrupt hierarchy, which we are about to introduce.

No functionnal change yet.
Signed-off-by: Marc Zyngier <maz@kernel.org>

drivers/gpio/gpio-tegra186.c

@@ -430,7 +430,18 @@ static int tegra186_irq_set_type(struct irq_data *data, unsigned int type)
 	else
 		irq_set_handler_locked(data, handle_edge_irq);
 
-	return irq_chip_set_type_parent(data, type);
+	if (data->parent_data)
+		return irq_chip_set_type_parent(data, type);
+
+	return 0;
+}
+
+static int tegra186_irq_set_wake(struct irq_data *data, unsigned int on)
+{
+	if (data->parent_data)
+		return irq_chip_set_wake_parent(data, on);
+
+	return 0;
 }
 
 static void tegra186_gpio_irq(struct irq_desc *desc)
@@ -678,7 +689,7 @@ static int tegra186_gpio_probe(struct platform_device *pdev)
 	gpio->intc.irq_mask = tegra186_irq_mask;
 	gpio->intc.irq_unmask = tegra186_irq_unmask;
 	gpio->intc.irq_set_type = tegra186_irq_set_type;
-	gpio->intc.irq_set_wake = irq_chip_set_wake_parent;
+	gpio->intc.irq_set_wake = tegra186_irq_set_wake;
 
 	irq = &gpio->gpio.irq;
 	irq->chip = &gpio->intc;