gpio: add Technologic I2C-FPGA gpio support

This driver is generic and aims to support all Technologic Systems's
boards embedding FPGA GPIOs with an I2C interface.

This driver supports TS-4900, TS-7970, TS-7990 and TS-4100 series.

Signed-off-by: Lucile Quirion <lucile.quirion@savoirfairelinux.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 825cf3c..5eb7c86 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -777,6 +777,13 @@
 	  To compile this driver as a module, choose M here: the module will
 	  be called gpio-tpic2810.
 
+config GPIO_TS4900
+	tristate "Technologic Systems FPGA I2C GPIO"
+	select REGMAP_I2C
+	help
+	  Say yes here to enabled the GPIO driver for Technologic's FPGA core.
+	  Series supported include TS-4100, TS-4900, TS-7970 and TS-7990.
+
 endmenu
 
 menu "MFD GPIO expanders"