Add a struct gpio_chip and define some methods so that this device's
I/O can be accessed via /sys/class/gpio.
Signed-off-by: NChristopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: NAndrew Jeffery <andrew@aj.id.au>
Signed-off-by: NEddie James <eajames@linux.vnet.ibm.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>