OMAP1: Amstrad Delta: add FIQ handler for serial keyboardport interrupt processing

This patch introduces a Fast Interrupt Request (FIQ) handler for Amstrad Delta
(E3) videophone. The handler's purpose is to process interrupts generated by a
GPIO line that a serial keyboard clock hangs off. It collects consecutive bits
into words, pushing them into a buffer, then requests a higher level interrupt
after one or more words are ready for further processing by a keyboard port
driver.

The handler also processes interrupts generated by two other GPIO lines, used
by other on-board supported devices, by simply requesting a higher level
interrupt, that in turn should invoke those device's specific irq handlers.

IRQ12 line, not used by OMAP1510 hardware (described as reserved), has been
choosen as a higher level interrupt source.

Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/mach-omap1/Kconfig b/arch/arm/mach-omap1/Kconfig
index 27f4897..b18d7c2 100644
--- a/arch/arm/mach-omap1/Kconfig
+++ b/arch/arm/mach-omap1/Kconfig
@@ -152,6 +152,16 @@
 	  Support for the Amstrad E3 (codename Delta) videophone. Say Y here
 	  if you have such a device.
 
+config AMS_DELTA_FIQ
+	bool "Fast Interrupt Request (FIQ) support for the E3"
+	depends on MACH_AMS_DELTA
+	select FIQ
+	help
+	  Provide a FIQ handler for the E3.
+	  This allows for fast handling of interrupts generated
+	  by the clock line of the E3 mailboard (or a PS/2 keyboard)
+	  connected to the GPIO based external keyboard port.
+
 config MACH_OMAP_GENERIC
 	bool "Generic OMAP board"
 	depends on ARCH_OMAP1 && (ARCH_OMAP15XX || ARCH_OMAP16XX)