gpio: Add ROHM BD9571MWV-M PMIC GPIO driver

Add driver for the GPIO block in the ROHM BD9571MWV-W MFD PMIC.
This block is pretty trivial and supports setting GPIO direction
as Input/Output and in case of Output, supports setting value.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: linux-gpio@vger.kernel.org
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Linus Walleij <linus.walleij@linaro.org>
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 c0629e6..5662b05 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -844,6 +844,17 @@
 	help
 	  Support for GPIOs on Wolfson Arizona class devices.
 
+config GPIO_BD9571MWV
+	tristate "ROHM BD9571 GPIO support"
+	depends on MFD_BD9571MWV
+	help
+	  Support for GPIOs on ROHM BD9571 PMIC. There are two GPIOs
+	  available on the ROHM PMIC in total, both of which can also
+	  generate interrupts.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called gpio-bd9571mwv.
+
 config GPIO_CRYSTAL_COVE
 	tristate "GPIO support for Crystal Cove PMIC"
 	depends on (X86 || COMPILE_TEST) && INTEL_SOC_PMIC