genirq: Add irqchip_set_wake_parent

This proves to be useful with stacked domains, when the current
domain doesn't implement wake-up, but expect the parent to do so.

Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/1426088629-15377-2-git-send-email-marc.zyngier@arm.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

include/linux/irq.h

@@ -460,6 +460,7 @@ extern void irq_chip_eoi_parent(struct irq_data *data);
 extern int irq_chip_set_affinity_parent(struct irq_data *data,
 					const struct cpumask *dest,
 					bool force);
+extern int irq_chip_set_wake_parent(struct irq_data *data, unsigned int on);
 #endif
 
 /* Handling of unhandled and spurious interrupts: */

kernel/irq/chip.c

@@ -948,6 +948,22 @@ int irq_chip_retrigger_hierarchy(struct irq_data *data)
 
 	return -ENOSYS;
 }
+
+/**
+ * irq_chip_set_wake_parent - Set/reset wake-up on the parent interrupt
+ * @data:	Pointer to interrupt specific data
+ * @on:		Whether to set or reset the wake-up capability of this irq
+ *
+ * Conditional, as the underlying parent chip might not implement it.
+ */
+int irq_chip_set_wake_parent(struct irq_data *data, unsigned int on)
+{
+	data = data->parent_data;
+	if (data->chip->irq_set_wake)
+		return data->chip->irq_set_wake(data, on);
+
+	return -ENOSYS;
+}
 #endif
 
 /**