gpio: Add GPIO support for the ACCES PCIe-IDIO-24 family

The ACCES PCIe-IDIO-24 device provides 56 lines of digital I/O (24 lines
of optically-isolated non-polarized digital inputs for AC and DC control
signals, 24 lines of isolated solid state FET digital outputs, and 8
non-isolated TTL/CMOS compatible programmable I/O). 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. These devices are capable of
get_multiple and set_multiple functionality, but these functions have
not yet been implemented for this driver. Change-Of-State (COS)
detection functionality may be configured to fire interrupts on
exclusively rising/falling edges, but this driver currently only
implements COS detection for either both edges or none.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

MAINTAINERS

@@ -270,6 +270,12 @@ L:	linux-gpio@vger.kernel.org
 S:	Maintained
 F:	drivers/gpio/gpio-pci-idio-16.c
 
+ACCES PCIe-IDIO-24 GPIO DRIVER
+M:	William Breathitt Gray <vilhelm.gray@gmail.com>
+L:	linux-gpio@vger.kernel.org
+S:	Maintained
+F:	drivers/gpio/gpio-pcie-idio-24.c
+
 ACENIC DRIVER
 M:	Jes Sorensen <jes@trained-monkey.org>
 L:	linux-acenic@sunsite.dk

drivers/gpio/Kconfig

@@ -1244,6 +1244,16 @@ config GPIO_PCI_IDIO_16
 	  low). Input filter control is not supported by this driver, and the
 	  input filters are deactivated by this driver.
 
+config GPIO_PCIE_IDIO_24
+	tristate "ACCES PCIe-IDIO-24 GPIO support"
+	select GPIOLIB_IRQCHIP
+	help
+	  Enables GPIO support for the ACCES PCIe-IDIO-24 family (PCIe-IDIO-24,
+	  PCIe-IDI-24, PCIe-IDO-24, PCIe-IDIO-12). 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

drivers/gpio/Makefile

@@ -95,6 +95,7 @@ obj-$(CONFIG_GPIO_PCA953X)	+= gpio-pca953x.o
 obj-$(CONFIG_GPIO_PCF857X)	+= gpio-pcf857x.o
 obj-$(CONFIG_GPIO_PCH)		+= gpio-pch.o
 obj-$(CONFIG_GPIO_PCI_IDIO_16)	+= gpio-pci-idio-16.o
+obj-$(CONFIG_GPIO_PCIE_IDIO_24)	+= gpio-pcie-idio-24.o
 obj-$(CONFIG_GPIO_PISOSR)	+= gpio-pisosr.o
 obj-$(CONFIG_GPIO_PL061)	+= gpio-pl061.o
 obj-$(CONFIG_GPIO_PXA)		+= gpio-pxa.o