gpio: tangier: Introduce Intel Tangier GPIO driver

Intel Elkhart Lake and Merrifield platforms have same GPIO IP.
Intel Tangier implements the common GPIO functionalities for both
Elkhart Lake and Merrifield platforms.

Signed-off-by: Pandith N <pandith.n@intel.com>
Co-developed-by: Raag Jadav <raag.jadav@intel.com>
Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Author: pandithn

MAINTAINERS

@@ -10287,6 +10287,7 @@ F:	drivers/gpio/gpio-ml-ioh.c
 F:	drivers/gpio/gpio-pch.c
 F:	drivers/gpio/gpio-sch.c
 F:	drivers/gpio/gpio-sodaville.c
+F:	drivers/gpio/gpio-tangier.c
 
 INTEL GVT-g DRIVERS (Intel GPU Virtualization)
 M:	Zhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpio/Kconfig

@@ -619,6 +619,14 @@ config GPIO_SYSCON
 	help
 	  Say yes here to support GPIO functionality though SYSCON driver.
 
+config GPIO_TANGIER
+	tristate
+	select GPIOLIB_IRQCHIP
+	help
+	  GPIO support for Intel Tangier and compatible platforms.
+
+	  If built as a module its name will be gpio-tangier.
+
 config GPIO_TB10X
 	bool
 	select GPIO_GENERIC

drivers/gpio/Makefile

@@ -145,6 +145,7 @@ obj-$(CONFIG_GPIO_SPRD)			+= gpio-sprd.o
 obj-$(CONFIG_GPIO_STMPE)		+= gpio-stmpe.o
 obj-$(CONFIG_GPIO_STP_XWAY)		+= gpio-stp-xway.o
 obj-$(CONFIG_GPIO_SYSCON)		+= gpio-syscon.o
+obj-$(CONFIG_GPIO_TANGIER)		+= gpio-tangier.o
 obj-$(CONFIG_GPIO_TB10X)		+= gpio-tb10x.o
 obj-$(CONFIG_GPIO_TC3589X)		+= gpio-tc3589x.o
 obj-$(CONFIG_GPIO_TEGRA186)		+= gpio-tegra186.o