gpio: Add Intel Granite Rapids-D vGPIO driver

This driver provides a basic GPIO driver for the Intel Granite Rapids-D
virtual GPIOs. On SoCs with limited physical pins on the package, the
physical pins controlled by this driver would be exposed on an external
device such as a BMC or CPLD. The virtual GPIO registers are an
interface to firmware, which communicates with the external device that
implements the GPIO hardware functionality.

Signed-off-by: Aapo Vienamo <aapo.vienamo@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Author: Aapo Vienamo

MAINTAINERS

@@ -10891,6 +10891,7 @@ L:	linux-gpio@vger.kernel.org
 S:	Supported
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/andy/linux-gpio-intel.git
 F:	drivers/gpio/gpio-elkhartlake.c
+F:	drivers/gpio/gpio-graniterapids.c
 F:	drivers/gpio/gpio-ich.c
 F:	drivers/gpio/gpio-merrifield.c
 F:	drivers/gpio/gpio-ml-ioh.c

drivers/gpio/Kconfig

@@ -312,6 +312,24 @@ config GPIO_GENERIC_PLATFORM
 	help
 	  Say yes here to support basic platform_device memory-mapped GPIO controllers.
 
+config GPIO_GRANITERAPIDS
+	tristate "Intel Granite Rapids-D vGPIO support"
+	depends on X86 || COMPILE_TEST
+	select GPIOLIB_IRQCHIP
+	help
+	  Select this to enable virtual GPIO support on platforms with the
+	  following SoCs:
+
+	  - Intel Granite Rapids-D
+
+	  The driver enables basic GPIO functionality and implements interrupt
+	  support. The virtual GPIO driver controls GPIO lines via a firmware
+	  interface. The physical GPIO pins reside on device that is external
+	  from the main SoC package, such as a BMC or a CPLD.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called gpio-graniterapids.
+
 config GPIO_GRGPIO
 	tristate "Aeroflex Gaisler GRGPIO support"
 	depends on OF_GPIO

drivers/gpio/Makefile

@@ -66,6 +66,7 @@ obj-$(CONFIG_GPIO_FTGPIO010)		+= gpio-ftgpio010.o
 obj-$(CONFIG_GPIO_FXL6408)		+= gpio-fxl6408.o
 obj-$(CONFIG_GPIO_GE_FPGA)		+= gpio-ge.o
 obj-$(CONFIG_GPIO_GPIO_MM)		+= gpio-gpio-mm.o
+obj-$(CONFIG_GPIO_GRANITERAPIDS)	+= gpio-graniterapids.o
 obj-$(CONFIG_GPIO_GRGPIO)		+= gpio-grgpio.o
 obj-$(CONFIG_GPIO_GW_PLD)		+= gpio-gw-pld.o
 obj-$(CONFIG_GPIO_HISI)                 += gpio-hisi.o