gpio: Add gpio driver support for ThunderX and OCTEON-TX

Cavium ThunderX and OCTEON-TX are arm64 based SoCs.  Add driver for
the on-chip GPIO pins.
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -450,6 +450,15 @@ config GPIO_TS4800
 	help
 	  This driver support TS-4800 FPGA GPIO controllers.
 
+config GPIO_THUNDERX
+	tristate "Cavium ThunderX/OCTEON-TX GPIO"
+	depends on ARCH_THUNDER || (64BIT && COMPILE_TEST)
+	depends on PCI_MSI && IRQ_DOMAIN_HIERARCHY
+	select IRQ_FASTEOI_HIERARCHY_HANDLERS
+	help
+	  Say yes here to support the on-chip GPIO lines on the ThunderX
+	  and OCTEON-TX families of SoCs.
+
 config GPIO_TZ1090
 	bool "Toumaz Xenif TZ1090 GPIO support"
 	depends on SOC_TZ1090

drivers/gpio/Makefile

@@ -113,6 +113,7 @@ obj-$(CONFIG_GPIO_SYSCON)	+= gpio-syscon.o
 obj-$(CONFIG_GPIO_TB10X)	+= gpio-tb10x.o
 obj-$(CONFIG_GPIO_TC3589X)	+= gpio-tc3589x.o
 obj-$(CONFIG_GPIO_TEGRA)	+= gpio-tegra.o
+obj-$(CONFIG_GPIO_THUNDERX)	+= gpio-thunderx.o
 obj-$(CONFIG_GPIO_TIMBERDALE)	+= gpio-timberdale.o
 obj-$(CONFIG_GPIO_PALMAS)	+= gpio-palmas.o
 obj-$(CONFIG_GPIO_TPIC2810)	+= gpio-tpic2810.o