gpio: pca953x.c: add interrupt handling capability

Most of the GPIO expanders controlled by the pca953x driver are able to
report changes on the input pins through an *INT pin.

This patch implements the irq_chip functionality (edge detection only).

The driver has been tested on an Arcom Zeus.

[akpm@linux-foundation.org: the compiler does inlining for us nowadays]
Signed-off-by: Marc Zyngier <maz@misterjones.org>
Cc: Eric Miao <eric.y.miao@gmail.com>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Nate Case <ncase@xes-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index f3549b8779d..c5cc7d9d88e 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -134,6 +134,13 @@ config GPIO_PCA953X
           This driver can also be built as a module.  If so, the module
           will be called pca953x.
 
+config GPIO_PCA953X_IRQ
+        bool "Interrupt controller support for PCA953x"
+        depends on GPIO_PCA953X=y
+        help
+          Say yes here to enable the pca953x to be used as an interrupt
+          controller. It requires the driver to be built in the kernel.
+
 config GPIO_PCF857X
         tristate "PCF857x, PCA{85,96}7x, and MAX732[89] I2C GPIO expanders"
         depends on I2C