gpio: max77620: add gpio driver for MAX77620/MAX20024

MAXIM Semiconductor's PMIC, MAX77620/MAX20024 has 8 GPIO
pins. It also supports interrupts from these pins.

Add GPIO driver for these pins to control via GPIO APIs.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 48da857..9244381 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -870,6 +870,15 @@
 	  LP3943 can be used as a GPIO expander which provides up to 16 GPIOs.
 	  Open drain outputs are required for this usage.
 
+config GPIO_MAX77620
+	tristate "GPIO support for PMIC MAX77620 and MAX20024"
+	depends on MFD_MAX77620
+	help
+	  GPIO driver for MAX77620 and MAX20024 PMIC from Maxim Semiconductor.
+	  MAX77620 PMIC has 8 pins that can be configured as GPIOs. The
+	  driver also provides interrupt support for each of the gpios.
+	  Say yes here to enable the max77620 to be used as gpio controller.
+
 config GPIO_MSIC
 	bool "Intel MSIC mixed signal gpio support"
 	depends on MFD_INTEL_MSIC