[2/2] gpio: Add GPIO driver for Spreadtrum SC9860 platform

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index d6a8e85..3bece19 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -404,6 +404,13 @@  config GPIO_SPEAR_SPICS
 	help
 	  Say yes here to support ST SPEAr SPI Chip Select as GPIO device
 
+config GPIO_SPRD
+	bool "Spreadtrum GPIO support"
+	depends on ARCH_SPRD || COMPILE_TEST
+	select GPIOLIB_IRQCHIP
+	help
+	  Say yes here to support Spreadtrum GPIO device.
+
 config GPIO_STA2X11
 	bool "STA2x11/ConneXt GPIO support"
 	depends on MFD_STA2X11
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 4bc24fe..5b633a0 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -108,6 +108,7 @@  obj-$(CONFIG_GPIO_SCH)		+= gpio-sch.o
 obj-$(CONFIG_GPIO_SCH311X)	+= gpio-sch311x.o
 obj-$(CONFIG_GPIO_SODAVILLE)	+= gpio-sodaville.o
 obj-$(CONFIG_GPIO_SPEAR_SPICS)	+= gpio-spear-spics.o
+obj-$(CONFIG_GPIO_SPRD)		+= gpio-sprd.o
 obj-$(CONFIG_GPIO_STA2X11)	+= gpio-sta2x11.o
 obj-$(CONFIG_GPIO_STMPE)	+= gpio-stmpe.o
 obj-$(CONFIG_GPIO_STP_XWAY)	+= gpio-stp-xway.o
diff --git a/drivers/gpio/gpio-sprd.c b/drivers/gpio/gpio-sprd.c
new file mode 100644
index 0000000..af59b9f
--- /dev/null
+++ b/drivers/gpio/gpio-sprd.c
@@ -0,0 +1,301 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Spreadtrum Communications Inc.
+ * Copyright (c) 2018 Linaro Ltd.
+ */
+
+#include <linux/bitops.h>
+#include <linux/gpio/driver.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+/* GPIO registers definition */
+#define SPRD_GPIO_DATA		0x0
+#define SPRD_GPIO_DMSK		0x4
+#define SPRD_GPIO_DIR		0x8
+#define SPRD_GPIO_IS		0xc
+#define SPRD_GPIO_IBE		0x10
+#define SPRD_GPIO_IEV		0x14
+#define SPRD_GPIO_IE		0x18
+#define SPRD_GPIO_RIS		0x1c
+#define SPRD_GPIO_MIS		0x20
+#define SPRD_GPIO_IC		0x24
+#define SPRD_GPIO_INEN		0x28
+
+/* We have 16 groups GPIOs and each group contain 16 GPIOs */
+#define SPRD_GPIO_GROUP_NR	16
+#define SPRD_GPIO_NR		256
+#define SPRD_GPIO_GROUP_SIZE	0x80
+#define SPRD_GPIO_GROUP_MASK	GENMASK(15, 0)
+#define SPRD_GPIO_BIT(x)	((x) & (SPRD_GPIO_GROUP_NR - 1))
+
+struct sprd_gpio {
+	struct gpio_chip chip;
+	void __iomem *base;
+	spinlock_t lock;
+	int irq;
+};
+
+static inline void __iomem *sprd_gpio_group_base(struct sprd_gpio *sprd_gpio,
+						 unsigned int group)
+{
+	return sprd_gpio->base + SPRD_GPIO_GROUP_SIZE * group;
+}
+
+static void sprd_gpio_update(struct gpio_chip *chip, unsigned int offset,
+			     unsigned int reg, unsigned int val)
+{
+	struct sprd_gpio *sprd_gpio = gpiochip_get_data(chip);
+	void __iomem *base = sprd_gpio_group_base(sprd_gpio,
+						  offset / SPRD_GPIO_GROUP_NR);
+	u32 shift = SPRD_GPIO_BIT(offset);
+	unsigned long flags;
+	u32 orig, tmp;
+
+	spin_lock_irqsave(&sprd_gpio->lock, flags);
+	orig = readl_relaxed(base + reg);
+
+	tmp = (orig & ~BIT(shift)) | (val << shift);
+	writel_relaxed(tmp, base + reg);
+	spin_unlock_irqrestore(&sprd_gpio->lock, flags);
+}
+
+static int sprd_gpio_read(struct gpio_chip *chip, unsigned int offset,
+			  unsigned int reg)
+{
+	struct sprd_gpio *sprd_gpio = gpiochip_get_data(chip);
+	void __iomem *base = sprd_gpio_group_base(sprd_gpio,
+						  offset / SPRD_GPIO_GROUP_NR);
+	u32 value = readl_relaxed(base + reg) & SPRD_GPIO_GROUP_MASK;
+	u32 shift = SPRD_GPIO_BIT(offset);
+
+	return !!(value & BIT(shift));
+}
+
+static int sprd_gpio_request(struct gpio_chip *chip, unsigned int offset)
+{
+	sprd_gpio_update(chip, offset, SPRD_GPIO_DMSK, 1);
+	return 0;
+}
+
+static void sprd_gpio_free(struct gpio_chip *chip, unsigned int offset)
+{
+	sprd_gpio_update(chip, offset, SPRD_GPIO_DMSK, 0);
+}
+
+static int sprd_gpio_direction_input(struct gpio_chip *chip,
+				     unsigned int offset)
+{
+	sprd_gpio_update(chip, offset, SPRD_GPIO_DIR, 0);
+	sprd_gpio_update(chip, offset, SPRD_GPIO_INEN, 1);
+	return 0;
+}
+
+static int sprd_gpio_direction_output(struct gpio_chip *chip,
+				      unsigned int offset, int value)
+{
+	sprd_gpio_update(chip, offset, SPRD_GPIO_DIR, 1);
+	sprd_gpio_update(chip, offset, SPRD_GPIO_INEN, 0);
+	sprd_gpio_update(chip, offset, SPRD_GPIO_DATA, value);
+	return 0;
+}
+
+static int sprd_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	return sprd_gpio_read(chip, offset, SPRD_GPIO_DATA);
+}
+
+static void sprd_gpio_set(struct gpio_chip *chip, unsigned int offset,
+			  int value)
+{
+	sprd_gpio_update(chip, offset, SPRD_GPIO_DATA, value);
+}
+
+static void sprd_gpio_irq_mask(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	u32 offset = irqd_to_hwirq(data);
+
+	sprd_gpio_update(chip, offset, SPRD_GPIO_IE, 0);
+}
+
+static void sprd_gpio_irq_ack(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	u32 offset = irqd_to_hwirq(data);
+
+	sprd_gpio_update(chip, offset, SPRD_GPIO_IC, 1);
+}
+
+static void sprd_gpio_irq_unmask(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	u32 offset = irqd_to_hwirq(data);
+
+	sprd_gpio_update(chip, offset, SPRD_GPIO_IE, 1);
+}
+
+static int sprd_gpio_irq_set_type(struct irq_data *data,
+				  unsigned int flow_type)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	u32 offset = irqd_to_hwirq(data);
+
+	switch (flow_type) {
+	case IRQ_TYPE_EDGE_RISING:
+		sprd_gpio_update(chip, offset, SPRD_GPIO_IS, 0);
+		sprd_gpio_update(chip, offset, SPRD_GPIO_IBE, 0);
+		sprd_gpio_update(chip, offset, SPRD_GPIO_IEV, 1);
+		irq_set_handler_locked(data, handle_edge_irq);
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		sprd_gpio_update(chip, offset, SPRD_GPIO_IS, 0);
+		sprd_gpio_update(chip, offset, SPRD_GPIO_IBE, 0);
+		sprd_gpio_update(chip, offset, SPRD_GPIO_IEV, 0);
+		irq_set_handler_locked(data, handle_edge_irq);
+		break;
+	case IRQ_TYPE_EDGE_BOTH:
+		sprd_gpio_update(chip, offset, SPRD_GPIO_IS, 0);
+		sprd_gpio_update(chip, offset, SPRD_GPIO_IBE, 1);
+		irq_set_handler_locked(data, handle_edge_irq);
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		sprd_gpio_update(chip, offset, SPRD_GPIO_IS, 1);
+		sprd_gpio_update(chip, offset, SPRD_GPIO_IBE, 0);
+		sprd_gpio_update(chip, offset, SPRD_GPIO_IEV, 1);
+		irq_set_handler_locked(data, handle_level_irq);
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		sprd_gpio_update(chip, offset, SPRD_GPIO_IS, 1);
+		sprd_gpio_update(chip, offset, SPRD_GPIO_IBE, 0);
+		sprd_gpio_update(chip, offset, SPRD_GPIO_IEV, 0);
+		irq_set_handler_locked(data, handle_level_irq);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void sprd_gpio_irq_handler(struct irq_desc *desc)
+{
+	struct gpio_chip *chip = irq_desc_get_handler_data(desc);
+	struct irq_chip *ic = irq_desc_get_chip(desc);
+	struct sprd_gpio *sprd_gpio = gpiochip_get_data(chip);
+	u32 group, n, girq;
+
+	chained_irq_enter(ic, desc);
+
+	for (group = 0; group * SPRD_GPIO_GROUP_NR < chip->ngpio; group++) {
+		void __iomem *base = sprd_gpio_group_base(sprd_gpio, group);
+		unsigned long reg = readl_relaxed(base + SPRD_GPIO_MIS) &
+			SPRD_GPIO_GROUP_MASK;
+
+		for_each_set_bit(n, &reg, SPRD_GPIO_GROUP_NR) {
+			girq = irq_find_mapping(chip->irq.domain,
+						group * SPRD_GPIO_GROUP_NR + n);
+
+			generic_handle_irq(girq);
+		}
+
+	}
+	chained_irq_exit(ic, desc);
+}
+
+static struct irq_chip sprd_gpio_irqchip = {
+	.name = "sprd-gpio",
+	.irq_ack = sprd_gpio_irq_ack,
+	.irq_mask = sprd_gpio_irq_mask,
+	.irq_unmask = sprd_gpio_irq_unmask,
+	.irq_set_type = sprd_gpio_irq_set_type,
+	.flags = IRQCHIP_SKIP_SET_WAKE,
+};
+
+static int sprd_gpio_probe(struct platform_device *pdev)
+{
+	struct gpio_irq_chip *irq;
+	struct sprd_gpio *sprd_gpio;
+	struct resource *res;
+	int ret;
+
+	sprd_gpio = devm_kzalloc(&pdev->dev, sizeof(*sprd_gpio), GFP_KERNEL);
+	if (!sprd_gpio)
+		return -ENOMEM;
+
+	sprd_gpio->irq = platform_get_irq(pdev, 0);
+	if (sprd_gpio->irq < 0) {
+		dev_err(&pdev->dev, "Failed to get GPIO interrupt.\n");
+		return sprd_gpio->irq;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	sprd_gpio->base = devm_ioremap_nocache(&pdev->dev, res->start,
+					       resource_size(res));
+	if (!sprd_gpio->base)
+		return -ENOMEM;
+
+	spin_lock_init(&sprd_gpio->lock);
+
+	sprd_gpio->chip.label = dev_name(&pdev->dev);
+	sprd_gpio->chip.ngpio = SPRD_GPIO_NR;
+	sprd_gpio->chip.base = -1;
+	sprd_gpio->chip.parent = &pdev->dev;
+	sprd_gpio->chip.of_node = pdev->dev.of_node;
+	sprd_gpio->chip.request = sprd_gpio_request;
+	sprd_gpio->chip.free = sprd_gpio_free;
+	sprd_gpio->chip.get = sprd_gpio_get;
+	sprd_gpio->chip.set = sprd_gpio_set;
+	sprd_gpio->chip.direction_input = sprd_gpio_direction_input;
+	sprd_gpio->chip.direction_output = sprd_gpio_direction_output;
+
+	irq = &sprd_gpio->chip.irq;
+	irq->chip = &sprd_gpio_irqchip;
+	irq->handler = handle_simple_irq;
+	irq->default_type = IRQ_TYPE_NONE;
+	irq->parent_handler = sprd_gpio_irq_handler;
+	irq->parent_handler_data = sprd_gpio;
+	irq->num_parents = 1;
+	irq->parents = &sprd_gpio->irq;
+
+	ret = devm_gpiochip_add_data(&pdev->dev, &sprd_gpio->chip, sprd_gpio);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Could not register gpiochip %d\n", ret);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, sprd_gpio);
+	return 0;
+}
+
+static const struct of_device_id sprd_gpio_of_match[] = {
+	{ .compatible = "sprd,sc9860-gpio", },
+	{ /* end of list */ },
+};
+MODULE_DEVICE_TABLE(of, sprd_gpio_of_match);
+
+static struct platform_driver sprd_gpio_driver = {
+	.probe = sprd_gpio_probe,
+	.driver = {
+		.name = "sprd-gpio",
+		.of_match_table	= sprd_gpio_of_match,
+	},
+};
+
+static int __init sprd_gpio_init(void)
+{
+	return platform_driver_register(&sprd_gpio_driver);
+}
+subsys_initcall(sprd_gpio_init);
+
+static void __exit sprd_gpio_exit(void)
+{
+	platform_driver_unregister(&sprd_gpio_driver);
+}
+module_exit(sprd_gpio_exit);
+
+MODULE_DESCRIPTION("Spreadtrum GPIO driver");
+MODULE_LICENSE("GPL v2");