gpio: Add Spreadtrum EIC driver support

The Spreadtrum digital-chip EIC controller has 4 sub-modules: debounce EIC,
latch EIC, async EIC and sync EIC, and each sub-module can has multiple
banks and each bank contains 8 EICs.

Each EIC can only be used as input mode, and has the capability to trigger
interrupts when detecting input signals.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

3 files changed, 615 insertions, 0 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 6b1ee11295d5..380aa90501ea 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -170,6 +170,14 @@ config GPIO_DWAPB
 	  Say Y or M here to build support for the Synopsys DesignWare APB
 	  GPIO block.
 
+config GPIO_EIC_SPRD
+	tristate "Spreadtrum EIC support"
+	depends on ARCH_SPRD || COMPILE_TEST
+	depends on OF_GPIO
+	select GPIOLIB_IRQCHIP
+	help
+	  Say yes here to support Spreadtrum EIC device.
+
 config GPIO_EM
 	tristate "Emma Mobile GPIO"
 	depends on (ARCH_EMEV2 || COMPILE_TEST) && OF_GPIO
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 5c1f087c65aa..2437f3596934 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -45,6 +45,7 @@ obj-$(CONFIG_GPIO_DA9055)	+= gpio-da9055.o
 obj-$(CONFIG_GPIO_DAVINCI)	+= gpio-davinci.o
 obj-$(CONFIG_GPIO_DLN2)		+= gpio-dln2.o
 obj-$(CONFIG_GPIO_DWAPB)	+= gpio-dwapb.o
+obj-$(CONFIG_GPIO_EIC_SPRD)	+= gpio-eic-sprd.o
 obj-$(CONFIG_GPIO_EM)		+= gpio-em.o
 obj-$(CONFIG_GPIO_EP93XX)	+= gpio-ep93xx.o
 obj-$(CONFIG_GPIO_ETRAXFS)	+= gpio-etraxfs.o
diff --git a/drivers/gpio/gpio-eic-sprd.c b/drivers/gpio/gpio-eic-sprd.c
new file mode 100644
index 000000000000..de7dd939c043
--- /dev/null
+++ b/drivers/gpio/gpio-eic-sprd.c
@@ -0,0 +1,606 @@
+// 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/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+/* EIC registers definition */
+#define SPRD_EIC_DBNC_DATA		0x0
+#define SPRD_EIC_DBNC_DMSK		0x4
+#define SPRD_EIC_DBNC_IEV		0x14
+#define SPRD_EIC_DBNC_IE		0x18
+#define SPRD_EIC_DBNC_RIS		0x1c
+#define SPRD_EIC_DBNC_MIS		0x20
+#define SPRD_EIC_DBNC_IC		0x24
+#define SPRD_EIC_DBNC_TRIG		0x28
+#define SPRD_EIC_DBNC_CTRL0		0x40
+
+#define SPRD_EIC_LATCH_INTEN		0x0
+#define SPRD_EIC_LATCH_INTRAW		0x4
+#define SPRD_EIC_LATCH_INTMSK		0x8
+#define SPRD_EIC_LATCH_INTCLR		0xc
+#define SPRD_EIC_LATCH_INTPOL		0x10
+#define SPRD_EIC_LATCH_INTMODE		0x14
+
+#define SPRD_EIC_ASYNC_INTIE		0x0
+#define SPRD_EIC_ASYNC_INTRAW		0x4
+#define SPRD_EIC_ASYNC_INTMSK		0x8
+#define SPRD_EIC_ASYNC_INTCLR		0xc
+#define SPRD_EIC_ASYNC_INTMODE		0x10
+#define SPRD_EIC_ASYNC_INTBOTH		0x14
+#define SPRD_EIC_ASYNC_INTPOL		0x18
+#define SPRD_EIC_ASYNC_DATA		0x1c
+
+#define SPRD_EIC_SYNC_INTIE		0x0
+#define SPRD_EIC_SYNC_INTRAW		0x4
+#define SPRD_EIC_SYNC_INTMSK		0x8
+#define SPRD_EIC_SYNC_INTCLR		0xc
+#define SPRD_EIC_SYNC_INTMODE		0x10
+#define SPRD_EIC_SYNC_INTBOTH		0x14
+#define SPRD_EIC_SYNC_INTPOL		0x18
+#define SPRD_EIC_SYNC_DATA		0x1c
+
+/*
+ * The digital-chip EIC controller can support maximum 3 banks, and each bank
+ * contains 8 EICs.
+ */
+#define SPRD_EIC_MAX_BANK		3
+#define SPRD_EIC_PER_BANK_NR		8
+#define SPRD_EIC_DATA_MASK		GENMASK(7, 0)
+#define SPRD_EIC_BIT(x)			((x) & (SPRD_EIC_PER_BANK_NR - 1))
+#define SPRD_EIC_DBNC_MASK		GENMASK(11, 0)
+
+/*
+ * The Spreadtrum EIC (external interrupt controller) can be used only in
+ * input mode to generate interrupts if detecting input signals.
+ *
+ * The Spreadtrum digital-chip EIC controller contains 4 sub-modules:
+ * debounce EIC, latch EIC, async EIC and sync EIC,
+ *
+ * The debounce EIC is used to capture the input signals' stable status
+ * (millisecond resolution) and a single-trigger mechanism is introduced
+ * into this sub-module to enhance the input event detection reliability.
+ * The debounce range is from 1ms to 4s with a step size of 1ms.
+ *
+ * The latch EIC is used to latch some special power down signals and
+ * generate interrupts, since the latch EIC does not depend on the APB clock
+ * to capture signals.
+ *
+ * The async EIC uses a 32k clock to capture the short signals (microsecond
+ * resolution) to generate interrupts by level or edge trigger.
+ *
+ * The EIC-sync is similar with GPIO's input function, which is a synchronized
+ * signal input register.
+ */
+enum sprd_eic_type {
+	SPRD_EIC_DEBOUNCE,
+	SPRD_EIC_LATCH,
+	SPRD_EIC_ASYNC,
+	SPRD_EIC_SYNC,
+	SPRD_EIC_MAX,
+};
+
+struct sprd_eic {
+	struct gpio_chip chip;
+	struct irq_chip intc;
+	void __iomem *base[SPRD_EIC_MAX_BANK];
+	enum sprd_eic_type type;
+	spinlock_t lock;
+	int irq;
+};
+
+struct sprd_eic_variant_data {
+	enum sprd_eic_type type;
+	u32 num_eics;
+};
+
+static const char *sprd_eic_label_name[SPRD_EIC_MAX] = {
+	"eic-debounce", "eic-latch", "eic-async",
+	"eic-sync",
+};
+
+static const struct sprd_eic_variant_data sc9860_eic_dbnc_data = {
+	.type = SPRD_EIC_DEBOUNCE,
+	.num_eics = 8,
+};
+
+static const struct sprd_eic_variant_data sc9860_eic_latch_data = {
+	.type = SPRD_EIC_LATCH,
+	.num_eics = 8,
+};
+
+static const struct sprd_eic_variant_data sc9860_eic_async_data = {
+	.type = SPRD_EIC_ASYNC,
+	.num_eics = 8,
+};
+
+static const struct sprd_eic_variant_data sc9860_eic_sync_data = {
+	.type = SPRD_EIC_SYNC,
+	.num_eics = 8,
+};
+
+static inline void __iomem *sprd_eic_offset_base(struct sprd_eic *sprd_eic,
+						 unsigned int bank)
+{
+	if (bank >= SPRD_EIC_MAX_BANK)
+		return NULL;
+
+	return sprd_eic->base[bank];
+}
+
+static void sprd_eic_update(struct gpio_chip *chip, unsigned int offset,
+			    u16 reg, unsigned int val)
+{
+	struct sprd_eic *sprd_eic = gpiochip_get_data(chip);
+	void __iomem *base =
+		sprd_eic_offset_base(sprd_eic, offset / SPRD_EIC_PER_BANK_NR);
+	unsigned long flags;
+	u32 tmp;
+
+	spin_lock_irqsave(&sprd_eic->lock, flags);
+	tmp = readl_relaxed(base + reg);
+
+	if (val)
+		tmp |= BIT(SPRD_EIC_BIT(offset));
+	else
+		tmp &= ~BIT(SPRD_EIC_BIT(offset));
+
+	writel_relaxed(tmp, base + reg);
+	spin_unlock_irqrestore(&sprd_eic->lock, flags);
+}
+
+static int sprd_eic_read(struct gpio_chip *chip, unsigned int offset, u16 reg)
+{
+	struct sprd_eic *sprd_eic = gpiochip_get_data(chip);
+	void __iomem *base =
+		sprd_eic_offset_base(sprd_eic, offset / SPRD_EIC_PER_BANK_NR);
+
+	return !!(readl_relaxed(base + reg) & BIT(SPRD_EIC_BIT(offset)));
+}
+
+static int sprd_eic_request(struct gpio_chip *chip, unsigned int offset)
+{
+	sprd_eic_update(chip, offset, SPRD_EIC_DBNC_DMSK, 1);
+	return 0;
+}
+
+static void sprd_eic_free(struct gpio_chip *chip, unsigned int offset)
+{
+	sprd_eic_update(chip, offset, SPRD_EIC_DBNC_DMSK, 0);
+}
+
+static int sprd_eic_get(struct gpio_chip *chip, unsigned int offset)
+{
+	return sprd_eic_read(chip, offset, SPRD_EIC_DBNC_DATA);
+}
+
+static int sprd_eic_direction_input(struct gpio_chip *chip, unsigned int offset)
+{
+	/* EICs are always input, nothing need to do here. */
+	return 0;
+}
+
+static void sprd_eic_set(struct gpio_chip *chip, unsigned int offset, int value)
+{
+	/* EICs are always input, nothing need to do here. */
+}
+
+static int sprd_eic_set_debounce(struct gpio_chip *chip, unsigned int offset,
+				 unsigned int debounce)
+{
+	struct sprd_eic *sprd_eic = gpiochip_get_data(chip);
+	void __iomem *base =
+		sprd_eic_offset_base(sprd_eic, offset / SPRD_EIC_PER_BANK_NR);
+	u32 reg = SPRD_EIC_DBNC_CTRL0 + SPRD_EIC_BIT(offset) * 0x4;
+	u32 value = readl_relaxed(base + reg) & ~SPRD_EIC_DBNC_MASK;
+
+	value |= (debounce / 1000) & SPRD_EIC_DBNC_MASK;
+	writel_relaxed(value, base + reg);
+
+	return 0;
+}
+
+static int sprd_eic_set_config(struct gpio_chip *chip, unsigned int offset,
+			       unsigned long config)
+{
+	unsigned long param = pinconf_to_config_param(config);
+	u32 arg = pinconf_to_config_argument(config);
+
+	if (param == PIN_CONFIG_INPUT_DEBOUNCE)
+		return sprd_eic_set_debounce(chip, offset, arg);
+
+	return -ENOTSUPP;
+}
+
+static void sprd_eic_irq_mask(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct sprd_eic *sprd_eic = gpiochip_get_data(chip);
+	u32 offset = irqd_to_hwirq(data);
+
+	switch (sprd_eic->type) {
+	case SPRD_EIC_DEBOUNCE:
+		sprd_eic_update(chip, offset, SPRD_EIC_DBNC_IE, 0);
+		sprd_eic_update(chip, offset, SPRD_EIC_DBNC_TRIG, 0);
+		break;
+	case SPRD_EIC_LATCH:
+		sprd_eic_update(chip, offset, SPRD_EIC_LATCH_INTEN, 0);
+		break;
+	case SPRD_EIC_ASYNC:
+		sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTIE, 0);
+		break;
+	case SPRD_EIC_SYNC:
+		sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTIE, 0);
+		break;
+	default:
+		dev_err(chip->parent, "Unsupported EIC type.\n");
+	}
+}
+
+static void sprd_eic_irq_unmask(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct sprd_eic *sprd_eic = gpiochip_get_data(chip);
+	u32 offset = irqd_to_hwirq(data);
+
+	switch (sprd_eic->type) {
+	case SPRD_EIC_DEBOUNCE:
+		sprd_eic_update(chip, offset, SPRD_EIC_DBNC_IE, 1);
+		sprd_eic_update(chip, offset, SPRD_EIC_DBNC_TRIG, 1);
+		break;
+	case SPRD_EIC_LATCH:
+		sprd_eic_update(chip, offset, SPRD_EIC_LATCH_INTEN, 1);
+		break;
+	case SPRD_EIC_ASYNC:
+		sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTIE, 1);
+		break;
+	case SPRD_EIC_SYNC:
+		sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTIE, 1);
+		break;
+	default:
+		dev_err(chip->parent, "Unsupported EIC type.\n");
+	}
+}
+
+static void sprd_eic_irq_ack(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct sprd_eic *sprd_eic = gpiochip_get_data(chip);
+	u32 offset = irqd_to_hwirq(data);
+
+	switch (sprd_eic->type) {
+	case SPRD_EIC_DEBOUNCE:
+		sprd_eic_update(chip, offset, SPRD_EIC_DBNC_IC, 1);
+		break;
+	case SPRD_EIC_LATCH:
+		sprd_eic_update(chip, offset, SPRD_EIC_LATCH_INTCLR, 1);
+		break;
+	case SPRD_EIC_ASYNC:
+		sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTCLR, 1);
+		break;
+	case SPRD_EIC_SYNC:
+		sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTCLR, 1);
+		break;
+	default:
+		dev_err(chip->parent, "Unsupported EIC type.\n");
+	}
+}
+
+static int sprd_eic_irq_set_type(struct irq_data *data, unsigned int flow_type)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct sprd_eic *sprd_eic = gpiochip_get_data(chip);
+	u32 offset = irqd_to_hwirq(data);
+
+	switch (sprd_eic->type) {
+	case SPRD_EIC_DEBOUNCE:
+		switch (flow_type) {
+		case IRQ_TYPE_LEVEL_HIGH:
+			sprd_eic_update(chip, offset, SPRD_EIC_DBNC_IEV, 1);
+			break;
+		case IRQ_TYPE_LEVEL_LOW:
+			sprd_eic_update(chip, offset, SPRD_EIC_DBNC_IEV, 0);
+			break;
+		default:
+			return -ENOTSUPP;
+		}
+
+		irq_set_handler_locked(data, handle_level_irq);
+		break;
+	case SPRD_EIC_LATCH:
+		switch (flow_type) {
+		case IRQ_TYPE_LEVEL_HIGH:
+			sprd_eic_update(chip, offset, SPRD_EIC_LATCH_INTPOL, 0);
+			break;
+		case IRQ_TYPE_LEVEL_LOW:
+			sprd_eic_update(chip, offset, SPRD_EIC_LATCH_INTPOL, 1);
+			break;
+		default:
+			return -ENOTSUPP;
+		}
+
+		irq_set_handler_locked(data, handle_level_irq);
+		break;
+	case SPRD_EIC_ASYNC:
+		switch (flow_type) {
+		case IRQ_TYPE_EDGE_RISING:
+			sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTBOTH, 0);
+			sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTMODE, 0);
+			sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTPOL, 1);
+			irq_set_handler_locked(data, handle_edge_irq);
+			break;
+		case IRQ_TYPE_EDGE_FALLING:
+			sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTBOTH, 0);
+			sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTMODE, 0);
+			sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTPOL, 0);
+			irq_set_handler_locked(data, handle_edge_irq);
+			break;
+		case IRQ_TYPE_EDGE_BOTH:
+			sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTBOTH, 1);
+			irq_set_handler_locked(data, handle_edge_irq);
+			break;
+		case IRQ_TYPE_LEVEL_HIGH:
+			sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTBOTH, 0);
+			sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTMODE, 1);
+			sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTPOL, 1);
+			irq_set_handler_locked(data, handle_level_irq);
+			break;
+		case IRQ_TYPE_LEVEL_LOW:
+			sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTBOTH, 0);
+			sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTMODE, 1);
+			sprd_eic_update(chip, offset, SPRD_EIC_ASYNC_INTPOL, 0);
+			irq_set_handler_locked(data, handle_level_irq);
+			break;
+		default:
+			return -ENOTSUPP;
+		}
+		break;
+	case SPRD_EIC_SYNC:
+		switch (flow_type) {
+		case IRQ_TYPE_EDGE_RISING:
+			sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTBOTH, 0);
+			sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTMODE, 0);
+			sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTPOL, 1);
+			irq_set_handler_locked(data, handle_edge_irq);
+			break;
+		case IRQ_TYPE_EDGE_FALLING:
+			sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTBOTH, 0);
+			sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTMODE, 0);
+			sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTPOL, 0);
+			irq_set_handler_locked(data, handle_edge_irq);
+			break;
+		case IRQ_TYPE_EDGE_BOTH:
+			sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTBOTH, 1);
+			irq_set_handler_locked(data, handle_edge_irq);
+			break;
+		case IRQ_TYPE_LEVEL_HIGH:
+			sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTBOTH, 0);
+			sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTMODE, 1);
+			sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTPOL, 1);
+			irq_set_handler_locked(data, handle_level_irq);
+			break;
+		case IRQ_TYPE_LEVEL_LOW:
+			sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTBOTH, 0);
+			sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTMODE, 1);
+			sprd_eic_update(chip, offset, SPRD_EIC_SYNC_INTPOL, 0);
+			irq_set_handler_locked(data, handle_level_irq);
+			break;
+		default:
+			return -ENOTSUPP;
+		}
+	default:
+		dev_err(chip->parent, "Unsupported EIC type.\n");
+		return -ENOTSUPP;
+	}
+
+	return 0;
+}
+
+static int sprd_eic_match_chip_by_type(struct gpio_chip *chip, void *data)
+{
+	enum sprd_eic_type type = *(enum sprd_eic_type *)data;
+
+	return !strcmp(chip->label, sprd_eic_label_name[type]);
+}
+
+static void sprd_eic_handle_one_type(struct gpio_chip *chip)
+{
+	struct sprd_eic *sprd_eic = gpiochip_get_data(chip);
+	u32 bank, n, girq;
+
+	for (bank = 0; bank * SPRD_EIC_PER_BANK_NR < chip->ngpio; bank++) {
+		void __iomem *base = sprd_eic_offset_base(sprd_eic, bank);
+		unsigned long reg;
+
+		switch (sprd_eic->type) {
+		case SPRD_EIC_DEBOUNCE:
+			reg = readl_relaxed(base + SPRD_EIC_DBNC_MIS) &
+				SPRD_EIC_DATA_MASK;
+			break;
+		case SPRD_EIC_LATCH:
+			reg = readl_relaxed(base + SPRD_EIC_LATCH_INTMSK) &
+				SPRD_EIC_DATA_MASK;
+			break;
+		case SPRD_EIC_ASYNC:
+			reg = readl_relaxed(base + SPRD_EIC_ASYNC_INTMSK) &
+				SPRD_EIC_DATA_MASK;
+			break;
+		case SPRD_EIC_SYNC:
+			reg = readl_relaxed(base + SPRD_EIC_SYNC_INTMSK) &
+				SPRD_EIC_DATA_MASK;
+			break;
+		default:
+			dev_err(chip->parent, "Unsupported EIC type.\n");
+			return;
+		}
+
+		for_each_set_bit(n, &reg, SPRD_EIC_PER_BANK_NR) {
+			girq = irq_find_mapping(chip->irq.domain,
+					bank * SPRD_EIC_PER_BANK_NR + n);
+
+			generic_handle_irq(girq);
+		}
+	}
+}
+
+static void sprd_eic_irq_handler(struct irq_desc *desc)
+{
+	struct irq_chip *ic = irq_desc_get_chip(desc);
+	struct gpio_chip *chip;
+	enum sprd_eic_type type;
+
+	chained_irq_enter(ic, desc);
+
+	/*
+	 * Since the digital-chip EIC 4 sub-modules (debounce, latch, async
+	 * and sync) share one same interrupt line, we should iterate each
+	 * EIC module to check if there are EIC interrupts were triggered.
+	 */
+	for (type = SPRD_EIC_DEBOUNCE; type < SPRD_EIC_MAX; type++) {
+		chip = gpiochip_find(&type, sprd_eic_match_chip_by_type);
+		if (!chip)
+			continue;
+
+		sprd_eic_handle_one_type(chip);
+	}
+
+	chained_irq_exit(ic, desc);
+}
+
+static int sprd_eic_probe(struct platform_device *pdev)
+{
+	const struct sprd_eic_variant_data *pdata;
+	struct gpio_irq_chip *irq;
+	struct sprd_eic *sprd_eic;
+	struct resource *res;
+	int ret, i;
+
+	pdata = of_device_get_match_data(&pdev->dev);
+	if (!pdata) {
+		dev_err(&pdev->dev, "No matching driver data found.\n");
+		return -EINVAL;
+	}
+
+	sprd_eic = devm_kzalloc(&pdev->dev, sizeof(*sprd_eic), GFP_KERNEL);
+	if (!sprd_eic)
+		return -ENOMEM;
+
+	spin_lock_init(&sprd_eic->lock);
+	sprd_eic->type = pdata->type;
+
+	sprd_eic->irq = platform_get_irq(pdev, 0);
+	if (sprd_eic->irq < 0) {
+		dev_err(&pdev->dev, "Failed to get EIC interrupt.\n");
+		return sprd_eic->irq;
+	}
+
+	for (i = 0; i < SPRD_EIC_MAX_BANK; i++) {
+		/*
+		 * We can have maximum 3 banks EICs, and each EIC has
+		 * its own base address. But some platform maybe only
+		 * have one bank EIC, thus base[1] and base[2] can be
+		 * optional.
+		 */
+		res = platform_get_resource(pdev, IORESOURCE_MEM, i);
+		if (!res)
+			continue;
+
+		sprd_eic->base[i] = devm_ioremap_resource(&pdev->dev, res);
+		if (IS_ERR(sprd_eic->base[i]))
+			return PTR_ERR(sprd_eic->base[i]);
+	}
+
+	sprd_eic->chip.label = sprd_eic_label_name[sprd_eic->type];
+	sprd_eic->chip.ngpio = pdata->num_eics;
+	sprd_eic->chip.base = -1;
+	sprd_eic->chip.parent = &pdev->dev;
+	sprd_eic->chip.of_node = pdev->dev.of_node;
+	sprd_eic->chip.direction_input = sprd_eic_direction_input;
+	switch (sprd_eic->type) {
+	case SPRD_EIC_DEBOUNCE:
+		sprd_eic->chip.request = sprd_eic_request;
+		sprd_eic->chip.free = sprd_eic_free;
+		sprd_eic->chip.set_config = sprd_eic_set_config;
+		sprd_eic->chip.set = sprd_eic_set;
+		/* fall-through */
+	case SPRD_EIC_ASYNC:
+		/* fall-through */
+	case SPRD_EIC_SYNC:
+		sprd_eic->chip.get = sprd_eic_get;
+		break;
+	case SPRD_EIC_LATCH:
+		/* fall-through */
+	default:
+		break;
+	}
+
+	sprd_eic->intc.name = dev_name(&pdev->dev);
+	sprd_eic->intc.irq_ack = sprd_eic_irq_ack;
+	sprd_eic->intc.irq_mask = sprd_eic_irq_mask;
+	sprd_eic->intc.irq_unmask = sprd_eic_irq_unmask;
+	sprd_eic->intc.irq_set_type = sprd_eic_irq_set_type;
+	sprd_eic->intc.flags = IRQCHIP_SKIP_SET_WAKE;
+
+	irq = &sprd_eic->chip.irq;
+	irq->chip = &sprd_eic->intc;
+	irq->handler = handle_bad_irq;
+	irq->default_type = IRQ_TYPE_NONE;
+	irq->parent_handler = sprd_eic_irq_handler;
+	irq->parent_handler_data = sprd_eic;
+	irq->num_parents = 1;
+	irq->parents = &sprd_eic->irq;
+
+	ret = devm_gpiochip_add_data(&pdev->dev, &sprd_eic->chip, sprd_eic);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Could not register gpiochip %d.\n", ret);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, sprd_eic);
+	return 0;
+}
+
+static const struct of_device_id sprd_eic_of_match[] = {
+	{
+		.compatible = "sprd,sc9860-eic-debounce",
+		.data = &sc9860_eic_dbnc_data,
+	},
+	{
+		.compatible = "sprd,sc9860-eic-latch",
+		.data = &sc9860_eic_latch_data,
+	},
+	{
+		.compatible = "sprd,sc9860-eic-async",
+		.data = &sc9860_eic_async_data,
+	},
+	{
+		.compatible = "sprd,sc9860-eic-sync",
+		.data = &sc9860_eic_sync_data,
+	},
+	{
+		/* end of list */
+	}
+};
+MODULE_DEVICE_TABLE(of, sprd_eic_of_match);
+
+static struct platform_driver sprd_eic_driver = {
+	.probe = sprd_eic_probe,
+	.driver = {
+		.name = "sprd-eic",
+		.of_match_table	= sprd_eic_of_match,
+	},
+};
+
+module_platform_driver(sprd_eic_driver);
+
+MODULE_DESCRIPTION("Spreadtrum EIC driver");
+MODULE_LICENSE("GPL v2");