genirq: Introduce irq_chip_set_type_parent() helper

This helper is required for irq chips which do not implement a
irq_set_type callback and need to call down the irq domain hierarchy
for the actual trigger type change.

This helper is required to fix further wreckage caused by the
conversion of TI OMAP to hierarchical irq domains and therefor tagged
for stable.

[ tglx: Massaged changelog ]

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: <linux@arm.linux.org.uk>
Cc: <nsekhar@ti.com>
Cc: <jason@lakedaemon.net>
Cc: <balbi@ti.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: <tony@atomide.com>
Cc: <marc.zyngier@arm.com>
Cc: stable@vger.kernel.org # 4.1
Link: http://lkml.kernel.org/r/1439554830-19502-3-git-send-email-grygorii.strashko@ti.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

include/linux/irq.h

@@ -484,6 +484,7 @@ extern int irq_chip_set_affinity_parent(struct irq_data *data,
 extern int irq_chip_set_wake_parent(struct irq_data *data, unsigned int on);
 extern int irq_chip_set_vcpu_affinity_parent(struct irq_data *data,
 					     void *vcpu_info);
+extern int irq_chip_set_type_parent(struct irq_data *data, unsigned int type);
 #endif
 
 /* Handling of unhandled and spurious interrupts: */

kernel/irq/chip.c

@@ -984,6 +984,23 @@ int irq_chip_set_affinity_parent(struct irq_data *data,
 	return -ENOSYS;
 }
 
+/**
+ * irq_chip_set_type_parent - Set IRQ type on the parent interrupt
+ * @data:	Pointer to interrupt specific data
+ * @type:	IRQ_TYPE_{LEVEL,EDGE}_* value - see include/linux/irq.h
+ *
+ * Conditional, as the underlying parent chip might not implement it.
+ */
+int irq_chip_set_type_parent(struct irq_data *data, unsigned int type)
+{
+	data = data->parent_data;
+
+	if (data->chip->irq_set_type)
+		return data->chip->irq_set_type(data, type);
+
+	return -ENOSYS;
+}
+
 /**
  * irq_chip_retrigger_hierarchy - Retrigger an interrupt in hardware
  * @data:	Pointer to interrupt specific data