gpio: Add GPIO support for the ACCES PCI-IDIO-16

The ACCES PCI-IDIO-16 device provides 32 lines of digital I/O (16 lines
of optically-isolated digital inputs for AC and DC control signals, and
16 lines of solid state switch digital outputs). An interrupt is
generated when any of the inputs change state (low to high or high to
low). Input filter control is not supported by this driver, and input
filters are deactivated by this driver.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 28e6219..d4cec61 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1157,6 +1157,15 @@
 	  ML7223/ML7831 is companion chip for Intel Atom E6xx series.
 	  ML7223/ML7831 is completely compatible for Intel EG20T PCH.
 
+config GPIO_PCI_IDIO_16
+	tristate "ACCES PCI-IDIO-16 GPIO support"
+	select GPIOLIB_IRQCHIP
+	help
+	  Enables GPIO support for the ACCES PCI-IDIO-16. An interrupt is
+	  generated when any of the inputs change state (low to high or high to
+	  low). Input filter control is not supported by this driver, and the
+	  input filters are deactivated by this driver.
+
 config GPIO_RDC321X
 	tristate "RDC R-321x GPIO support"
 	select MFD_CORE