gpio: Add support for Intel Crystal Cove PMIC

Devices based on Intel SoC products such as Baytrail have a Power
Management IC. In the PMIC there are subsystems for voltage regulation,
A/D conversion, GPIO and PWMs. The PMIC in Baytrail-T platform is
called Crystal Cove.

This patch adds support for the GPIO function in Crystal Cove.

Signed-off-by: Yang, Bin <bin.yang@intel.com>
Signed-off-by: Zhu, Lejun <lejun.zhu@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 4a1b511..4a065b4 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -450,6 +450,19 @@
 	help
 	  Support for GPIOs on Wolfson Arizona class devices.
 
+config GPIO_CRYSTAL_COVE
+	tristate "GPIO support for Crystal Cove PMIC"
+	depends on INTEL_SOC_PMIC
+	select GPIOLIB_IRQCHIP
+	help
+	  Support for GPIO pins on Crystal Cove PMIC.
+
+	  Say Yes if you have a Intel SoC based tablet with Crystal Cove PMIC
+	  inside.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called gpio-crystalcove.
+
 config GPIO_LP3943
 	tristate "TI/National Semiconductor LP3943 GPIO expander"
 	depends on MFD_LP3943