genirq: introduce irq_chip_mask_ack_parent()

The hierarchical irqchip never before ran into a situation
where the parent is not "simple", i.e. does not implement
.irq_ack() and .irq_mask() like most, but the qcom-pm8xxx.c
happens to implement only .irq_mask_ack().

Since we want to make ssbi-gpio a hierarchical child of this
irqchip, it must *also* only implement .irq_mask_ack()
and call down to the parent, and for this we of course
need irq_chip_mask_ack_parent().

Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

include/linux/irq.h

@@ -605,6 +605,7 @@ extern void irq_chip_disable_parent(struct irq_data *data);
 extern void irq_chip_ack_parent(struct irq_data *data);
 extern int irq_chip_retrigger_hierarchy(struct irq_data *data);
 extern void irq_chip_mask_parent(struct irq_data *data);
+extern void irq_chip_mask_ack_parent(struct irq_data *data);
 extern void irq_chip_unmask_parent(struct irq_data *data);
 extern void irq_chip_eoi_parent(struct irq_data *data);
 extern int irq_chip_set_affinity_parent(struct irq_data *data,

kernel/irq/chip.c

@@ -1277,6 +1277,17 @@ void irq_chip_mask_parent(struct irq_data *data)
 }
 EXPORT_SYMBOL_GPL(irq_chip_mask_parent);
 
+/**
+ * irq_chip_mask_ack_parent - Mask and acknowledge the parent interrupt
+ * @data:	Pointer to interrupt specific data
+ */
+void irq_chip_mask_ack_parent(struct irq_data *data)
+{
+	data = data->parent_data;
+	data->chip->irq_mask_ack(data);
+}
+EXPORT_SYMBOL_GPL(irq_chip_mask_ack_parent);
+
 /**
  * irq_chip_unmask_parent - Unmask the parent interrupt
  * @data:	Pointer to interrupt specific data