soc/tegra: pmc: Allow optional irq parent callbacks

Make the PMC driver resistent to variable depth interrupt hierarchy,
which we are about to introduce.
Signed-off-by: Marc Zyngier <maz@kernel.org>

drivers/soc/tegra/pmc.c

@@ -2184,6 +2184,34 @@ static int tegra186_pmc_irq_set_type(struct irq_data *data, unsigned int type)
 	return 0;
 }
 
+static void tegra_irq_mask_parent(struct irq_data *data)
+{
+	if (data->parent_data)
+		irq_chip_mask_parent(data);
+}
+
+static void tegra_irq_unmask_parent(struct irq_data *data)
+{
+	if (data->parent_data)
+		irq_chip_unmask_parent(data);
+}
+
+static void tegra_irq_eoi_parent(struct irq_data *data)
+{
+	if (data->parent_data)
+		irq_chip_eoi_parent(data);
+}
+
+static int tegra_irq_set_affinity_parent(struct irq_data *data,
+					 const struct cpumask *dest,
+					 bool force)
+{
+	if (data->parent_data)
+		return irq_chip_set_affinity_parent(data, dest, force);
+
+	return -EINVAL;
+}
+
 static int tegra_pmc_irq_init(struct tegra_pmc *pmc)
 {
 	struct irq_domain *parent = NULL;
@@ -2199,10 +2227,10 @@ static int tegra_pmc_irq_init(struct tegra_pmc *pmc)
 		return 0;
 
 	pmc->irq.name = dev_name(pmc->dev);
-	pmc->irq.irq_mask = irq_chip_mask_parent;
-	pmc->irq.irq_unmask = irq_chip_unmask_parent;
-	pmc->irq.irq_eoi = irq_chip_eoi_parent;
-	pmc->irq.irq_set_affinity = irq_chip_set_affinity_parent;
+	pmc->irq.irq_mask = tegra_irq_mask_parent;
+	pmc->irq.irq_unmask = tegra_irq_unmask_parent;
+	pmc->irq.irq_eoi = tegra_irq_eoi_parent;
+	pmc->irq.irq_set_affinity = tegra_irq_set_affinity_parent;
 	pmc->irq.irq_set_type = pmc->soc->irq_set_type;
 	pmc->irq.irq_set_wake = pmc->soc->irq_set_wake;