gpio: Add Intel WhiskeyCove PMIC GPIO driver

This patch introduces a separate GPIO driver for Intel WhiskeyCove PMIC.
This driver is based on gpio-crystalcove.c.

Changes in v7:
 - Fixed various coding style comments from Andy Shevchenko
Changes in v6:
 - Removed unnecessary wcove_gpio_remove()
 - Used devm_gpiochip_remove() instead of gpiochip_remove()
 - Various coding style changes per Mika's comment
Changes in v5:
 - Revisited the interrupt handler code to iterate until all pending
   interrupts are handled. This change is to avoid missing interrupt
   when we're inside the interrupt handler.
 - Used regmap_bulk_read() to read address adjacent registers.
Changes in v4:
 - Converted CTLI_INTCNT_XX macros to less verbose ones INT_DETECT_XX.
 - Add comments about why there is no .pm for the driver.
 - Header files re-ordered.
 - Various coding style change to address Andy's comments.
Changes in v3:
 - Fixed the year in copyright line(2015-->2016).
 - Removed DRV_NAME macro.
 - Added kernel-doc for regmap_irq_chip of the wcove_gpio structure.
 - Line length fix.
Changes in v2:
 - Typo fix (Whsikey --> Whiskey).
 - Included linux/gpio/driver.h instead of linux/gpio.h
 - Implemented .set_single_ended().
 - Added GPIO register description.
 - Replaced container_of() with gpiochip_get_data().
 - Removed unnecessary "if (gpio > WCOVE_VGPIO_NUM" check.
 - Removed the device id table and added MODULE_ALIAS().

Signed-off-by: Ajay Thomas <ajay.thomas.david.rajamanickam@intel.com>
Signed-off-by: Bin Gao <bin.gao@intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -969,6 +969,19 @@ config GPIO_UCB1400
 	  This enables support for the Philips UCB1400 GPIO pins.
 	  The UCB1400 is an AC97 audio codec.
 
+config GPIO_WHISKEY_COVE
+	tristate "GPIO support for Whiskey Cove PMIC"
+	depends on INTEL_SOC_PMIC
+	select GPIOLIB_IRQCHIP
+	help
+	  Support for GPIO pins on Whiskey Cove PMIC.
+
+	  Say Yes if you have a Intel SoC based tablet with Whiskey Cove PMIC
+	  inside.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called gpio-wcove.
+
 config GPIO_WM831X
 	tristate "WM831x GPIOs"
 	depends on MFD_WM831X

drivers/gpio/Makefile

@@ -121,6 +121,7 @@ obj-$(CONFIG_GPIO_VF610)	+= gpio-vf610.o
 obj-$(CONFIG_GPIO_VIPERBOARD)	+= gpio-viperboard.o
 obj-$(CONFIG_GPIO_VR41XX)	+= gpio-vr41xx.o
 obj-$(CONFIG_GPIO_VX855)	+= gpio-vx855.o
+obj-$(CONFIG_GPIO_WHISKEY_COVE)	+= gpio-wcove.o
 obj-$(CONFIG_GPIO_WM831X)	+= gpio-wm831x.o
 obj-$(CONFIG_GPIO_WM8350)	+= gpio-wm8350.o
 obj-$(CONFIG_GPIO_WM8994)	+= gpio-wm8994.o