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>

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

drivers/gpio/gpio-tangier.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Intel Tangier GPIO functions
+ *
+ * Copyright (c) 2016, 2021, 2023 Intel Corporation.
+ *
+ * Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ *          Pandith N <pandith.n@intel.com>
+ *          Raag Jadav <raag.jadav@intel.com>
+ */
+
+#ifndef _GPIO_TANGIER_H_
+#define _GPIO_TANGIER_H_
+
+#include <linux/gpio/driver.h>
+#include <linux/spinlock_types.h>
+#include <linux/types.h>
+
+struct device;
+
+struct tng_gpio_context;
+
+/**
+ * struct tng_wake_regs - Platform specific wake registers
+ * @gwmr: Wake mask
+ * @gwsr: Wake source
+ * @gsir: Secure input
+ */
+struct tng_wake_regs {
+	u32 gwmr;
+	u32 gwsr;
+	u32 gsir;
+};
+
+/**
+ * struct tng_gpio_pinrange - Map pin numbers to gpio numbers
+ * @gpio_base: Starting GPIO number of this range
+ * @pin_base: Starting pin number of this range
+ * @npins: Number of pins in this range
+ */
+struct tng_gpio_pinrange {
+	unsigned int gpio_base;
+	unsigned int pin_base;
+	unsigned int npins;
+};
+
+#define GPIO_PINRANGE(gstart, gend, pstart)		\
+(struct tng_gpio_pinrange) {				\
+		.gpio_base = (gstart),			\
+		.pin_base = (pstart),			\
+		.npins = (gend) - (gstart) + 1,		\
+	}
+
+/**
+ * struct tng_gpio_pin_info - Platform specific pinout information
+ * @pin_ranges: Pin to GPIO mapping
+ * @nranges: Number of pin ranges
+ * @name: Respective pinctrl device name
+ */
+struct tng_gpio_pin_info {
+	const struct tng_gpio_pinrange *pin_ranges;
+	unsigned int nranges;
+	const char *name;
+};
+
+/**
+ * struct tng_gpio_info - Platform specific GPIO and IRQ information
+ * @base: GPIO base to start numbering with
+ * @ngpio: Amount of GPIOs supported by the controller
+ * @first: First IRQ to start numbering with
+ */
+struct tng_gpio_info {
+	int base;
+	u16 ngpio;
+	unsigned int first;
+};
+
+/**
+ * struct tng_gpio - Platform specific private data
+ * @chip: Instance of the struct gpio_chip
+ * @reg_base: Base address of MMIO registers
+ * @irq: Interrupt for the GPIO device
+ * @lock: Synchronization lock to prevent I/O race conditions
+ * @dev: The GPIO device
+ * @ctx: Context to be saved during suspend-resume
+ * @wake_regs: Platform specific wake registers
+ * @pin_info: Platform specific pinout information
+ * @info: Platform specific GPIO and IRQ information
+ */
+struct tng_gpio {
+	struct gpio_chip chip;
+	void __iomem *reg_base;
+	int irq;
+	raw_spinlock_t lock;
+	struct device *dev;
+	struct tng_gpio_context *ctx;
+	struct tng_wake_regs wake_regs;
+	struct tng_gpio_pin_info pin_info;
+	struct tng_gpio_info info;
+};
+
+int devm_tng_gpio_probe(struct device *dev, struct tng_gpio *gpio);
+
+int tng_gpio_suspend(struct device *dev);
+int tng_gpio_resume(struct device *dev);
+
+#endif /* _GPIO_TANGIER_H_ */