device property: Introduce fwnode_irq_get()

Until now there were two very similar functions allowing
to get Linux IRQ number from ACPI handle (acpi_irq_get())
and OF node (of_irq_get()). The first one appeared to be used
only as a subroutine of platform_irq_get(), which (in the generic
code) limited IRQ obtaining from _CRS method only to nodes
associated to kernel's struct platform_device.

This patch introduces a new helper routine - fwnode_irq_get(),
which allows to get the IRQ number directly from the fwnode
to be used as common for OF/ACPI worlds. It is usable not
only for the parents fwnodes, but also for the child nodes
comprising their own _CRS methods with interrupts description.

In order to be able o satisfy compilation with !CONFIG_ACPI
and also simplify the new code, introduce a helper macro
(ACPI_HANDLE_FWNODE), with which it is possible to reach
an ACPI handle directly from its fwnode.

Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index dc1ebfe..f05b9b6 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -56,6 +56,8 @@
 #define ACPI_COMPANION_SET(dev, adev)	set_primary_fwnode(dev, (adev) ? \
 	acpi_fwnode_handle(adev) : NULL)
 #define ACPI_HANDLE(dev)		acpi_device_handle(ACPI_COMPANION(dev))
+#define ACPI_HANDLE_FWNODE(fwnode)	\
+				acpi_device_handle(to_acpi_device_node(fwnode))
 
 static inline struct fwnode_handle *acpi_alloc_fwnode_static(void)
 {
@@ -626,6 +628,7 @@
 #define ACPI_COMPANION(dev)		(NULL)
 #define ACPI_COMPANION_SET(dev, adev)	do { } while (0)
 #define ACPI_HANDLE(dev)		(NULL)
+#define ACPI_HANDLE_FWNODE(fwnode)	(NULL)
 #define ACPI_DEVICE_CLASS(_cls, _msk)	.cls = (0), .cls_msk = (0),
 
 struct fwnode_handle;