gpio: xra1403: Add EXAR XRA1403 SPI GPIO expander driver

This driver support basic XRA1403 functionalities:
    - set gpio direction
    - get gpio direction
    - set gpio high/low
    - get gpio status

Signed-off-by: Nandor Han <nandor.han@ge.com>
Signed-off-by: Semi Malinen <semi.malinen@ge.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 23ca51e..dbde3ae 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1225,6 +1225,11 @@
 	  GPIO driver for SPI compatible parallel-in/serial-out shift
 	  registers. These are input only devices.
 
+config GPIO_XRA1403
+	tristate "EXAR XRA1403 16-bit GPIO expander"
+	help
+	  GPIO driver for EXAR XRA1403 16-bit SPI-based GPIO expander.
+
 endmenu
 
 menu "SPI or I2C GPIO expanders"