gpio: Add GPIO support for the ACCES 104-IDIO-16

The ACCES 104-IDIO-16 family of PC/104 utility boards feature 16 optically isolated inputs and 16 optically isolated FET solid state outputs. This driver provides GPIO support for these 32 channels of digital I/O. Change-of-State detection interrupts are not supported.

GPIO 0-15 correspond to digital outputs 0-15, while GPIO 16-31 correspond to digital inputs 0-15. The base port address for the device may be set via the a_104_idio_16_base module parameter.

---
Changes in v6:
- Add support for gpio_get_direction functionality
- Add __init attribute to the driver probe function since it is only called at module initialization
- Resolve checkpatch.pl warning about length of return line for the module init function

 drivers/gpio/Kconfig            |  10 ++
 drivers/gpio/Makefile           |   1 +
 drivers/gpio/gpio-104-idio-16.c | 207 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 218 insertions(+)
 create mode 100644 drivers/gpio/gpio-104-idio-16.c

index 8949b3f..dc843e0 100644
@@ -684,6 +684,16 @@ config GPIO_SX150X
 
 endmenu
 
+menu "ISA GPIO drivers"
+
+config GPIO_104_IDIO_16
+	tristate "ACCES 104-IDIO-16 GPIO support"
+	depends on X86
+	help
+	  Enables GPIO support for the ACCES 104-IDIO-16 family.
+
+endmenu
+
 menu "MFD GPIO expanders"
 
 config GPIO_ADP5520

index f79a7c4..6f2fea5 100644
@@ -12,6 +12,7 @@ obj-$(CONFIG_GPIO_ACPI)		+= gpiolib-acpi.o
 # Device drivers. Generally keep list sorted alphabetically
 obj-$(CONFIG_GPIO_GENERIC)	+= gpio-generic.o
 
+obj-$(CONFIG_GPIO_104_IDIO_16)	+= gpio-104-idio-16.o
 obj-$(CONFIG_GPIO_74X164)	+= gpio-74x164.o
 obj-$(CONFIG_GPIO_74XX_MMIO)	+= gpio-74xx-mmio.o
 obj-$(CONFIG_GPIO_ADNP)		+= gpio-adnp.o

2.4.9