[v2,3/3] gpio: Add Spreadtrum PMIC EIC driver support

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index c937407..f642314 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -380,6 +380,14 @@  config GPIO_PL061
 	help
 	  Say yes here to support the PrimeCell PL061 GPIO device
 
+config GPIO_PMIC_EIC_SPRD
+	tristate "Spreadtrum PMIC EIC support"
+	depends on MFD_SC27XX_PMIC || COMPILE_TEST
+	depends on OF_GPIO
+	select GPIOLIB_IRQCHIP
+	help
+	  Say yes here to support Spreadtrum PMIC EIC device.
+
 config GPIO_PXA
 	bool "PXA GPIO support"
 	depends on ARCH_PXA || ARCH_MMP
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 66eaa9e..50ba64b 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -99,6 +99,7 @@  obj-$(CONFIG_GPIO_PCI_IDIO_16)	+= gpio-pci-idio-16.o
 obj-$(CONFIG_GPIO_PCIE_IDIO_24)	+= gpio-pcie-idio-24.o
 obj-$(CONFIG_GPIO_PISOSR)	+= gpio-pisosr.o
 obj-$(CONFIG_GPIO_PL061)	+= gpio-pl061.o
+obj-$(CONFIG_GPIO_PMIC_EIC_SPRD)	+= gpio-pmic-eic-sprd.o
 obj-$(CONFIG_GPIO_PXA)		+= gpio-pxa.o
 obj-$(CONFIG_GPIO_RC5T583)	+= gpio-rc5t583.o
 obj-$(CONFIG_GPIO_RDC321X)	+= gpio-rdc321x.o
diff --git a/drivers/gpio/gpio-pmic-eic-sprd.c b/drivers/gpio/gpio-pmic-eic-sprd.c
new file mode 100644
index 0000000..ed5d6b2
--- /dev/null
+++ b/drivers/gpio/gpio-pmic-eic-sprd.c
@@ -0,0 +1,328 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Spreadtrum Communications Inc.
+ * Copyright (C) 2018 Linaro Ltd.
+ */
+
+#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/regmap.h>
+
+/* EIC registers definition */
+#define SPRD_PMIC_EIC_DATA		0x0
+#define SPRD_PMIC_EIC_DMSK		0x4
+#define SPRD_PMIC_EIC_IEV		0x14
+#define SPRD_PMIC_EIC_IE		0x18
+#define SPRD_PMIC_EIC_RIS		0x1c
+#define SPRD_PMIC_EIC_MIS		0x20
+#define SPRD_PMIC_EIC_IC		0x24
+#define SPRD_PMIC_EIC_TRIG		0x28
+#define SPRD_PMIC_EIC_CTRL0		0x40
+
+/*
+ * The PMIC EIC controller only has one bank, and each bank now can contain
+ * 16 EICs.
+ */
+#define SPRD_PMIC_EIC_PER_BANK_NR	16
+#define SPRD_PMIC_EIC_NR		SPRD_PMIC_EIC_PER_BANK_NR
+#define SPRD_PMIC_EIC_DATA_MASK		GENMASK(15, 0)
+#define SPRD_PMIC_EIC_BIT(x)		((x) & (SPRD_PMIC_EIC_PER_BANK_NR - 1))
+#define SPRD_PMIC_EIC_DBNC_MASK		GENMASK(11, 0)
+
+/*
+ * These registers are modified under the irq bus lock and cached to avoid
+ * unnecessary writes in bus_sync_unlock.
+ */
+enum { REG_IEV, REG_IE, REG_TRIG, CACHE_NR_REGS };
+
+/**
+ * struct sprd_pmic_eic - PMIC EIC controller
+ * @chip: the gpio_chip structure.
+ * @intc: the irq_chip structure.
+ * @regmap: the regmap from the parent device.
+ * @offset: the EIC controller's offset address of the PMIC.
+ * @reg: the array to cache the EIC registers.
+ * @buslock: for bus lock/sync and unlock.
+ * @irq: the interrupt number of the PMIC EIC conteroller.
+ */
+struct sprd_pmic_eic {
+	struct gpio_chip chip;
+	struct irq_chip intc;
+	struct regmap *map;
+	u32 offset;
+	u8 reg[CACHE_NR_REGS];
+	struct mutex buslock;
+	int irq;
+};
+
+static void sprd_pmic_eic_update(struct gpio_chip *chip, unsigned int offset,
+				 u16 reg, unsigned int val)
+{
+	struct sprd_pmic_eic *pmic_eic = gpiochip_get_data(chip);
+	u32 shift = SPRD_PMIC_EIC_BIT(offset);
+
+	regmap_update_bits(pmic_eic->map, pmic_eic->offset + reg,
+			   BIT(shift), val << shift);
+}
+
+static int sprd_pmic_eic_read(struct gpio_chip *chip, unsigned int offset,
+			      u16 reg)
+{
+	struct sprd_pmic_eic *pmic_eic = gpiochip_get_data(chip);
+	u32 value;
+	int ret;
+
+	ret = regmap_read(pmic_eic->map, pmic_eic->offset + reg, &value);
+	if (ret)
+		return ret;
+
+	return !!(value & BIT(SPRD_PMIC_EIC_BIT(offset)));
+}
+
+static int sprd_pmic_eic_request(struct gpio_chip *chip, unsigned int offset)
+{
+	sprd_pmic_eic_update(chip, offset, SPRD_PMIC_EIC_DMSK, 1);
+	return 0;
+}
+
+static void sprd_pmic_eic_free(struct gpio_chip *chip, unsigned int offset)
+{
+	sprd_pmic_eic_update(chip, offset, SPRD_PMIC_EIC_DMSK, 0);
+}
+
+static int sprd_pmic_eic_get(struct gpio_chip *chip, unsigned int offset)
+{
+	return sprd_pmic_eic_read(chip, offset, SPRD_PMIC_EIC_DATA);
+}
+
+static int sprd_pmic_eic_direction_input(struct gpio_chip *chip,
+					 unsigned int offset)
+{
+	/* EICs are always input, nothing need to do here. */
+	return 0;
+}
+
+static void sprd_pmic_eic_set(struct gpio_chip *chip, unsigned int offset,
+			      int value)
+{
+	/* EICs are always input, nothing need to do here. */
+}
+
+static int sprd_pmic_eic_set_debounce(struct gpio_chip *chip,
+				      unsigned int offset,
+				      unsigned int debounce)
+{
+	struct sprd_pmic_eic *pmic_eic = gpiochip_get_data(chip);
+	u32 reg, value;
+	int ret;
+
+	reg = SPRD_PMIC_EIC_CTRL0 + SPRD_PMIC_EIC_BIT(offset) * 0x4;
+	ret = regmap_read(pmic_eic->map, pmic_eic->offset + reg, &value);
+	if (ret)
+		return ret;
+
+	value &= ~SPRD_PMIC_EIC_DBNC_MASK;
+	value |= debounce / 1000;
+	return regmap_write(pmic_eic->map, pmic_eic->offset + reg, value);
+}
+
+static int sprd_pmic_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_pmic_eic_set_debounce(chip, offset, arg);
+
+	return -ENOTSUPP;
+}
+
+static void sprd_pmic_eic_irq_mask(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct sprd_pmic_eic *pmic_eic = gpiochip_get_data(chip);
+
+	pmic_eic->reg[REG_IE] = 0;
+	pmic_eic->reg[REG_TRIG] = 0;
+}
+
+static void sprd_pmic_eic_irq_unmask(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct sprd_pmic_eic *pmic_eic = gpiochip_get_data(chip);
+
+	pmic_eic->reg[REG_IE] = 1;
+	pmic_eic->reg[REG_TRIG] = 1;
+}
+
+static int sprd_pmic_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_pmic_eic *pmic_eic = gpiochip_get_data(chip);
+
+	switch (flow_type) {
+	case IRQ_TYPE_LEVEL_HIGH:
+		pmic_eic->reg[REG_IEV] = 1;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		pmic_eic->reg[REG_IEV] = 0;
+		break;
+	default:
+		return -ENOTSUPP;
+	}
+
+	irq_set_handler_locked(data, handle_level_irq);
+	return 0;
+}
+
+static void sprd_pmic_eic_bus_lock(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct sprd_pmic_eic *pmic_eic = gpiochip_get_data(chip);
+
+	mutex_lock(&pmic_eic->buslock);
+}
+
+static void sprd_pmic_eic_bus_sync_unlock(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct sprd_pmic_eic *pmic_eic = gpiochip_get_data(chip);
+	u32 offset = irqd_to_hwirq(data);
+
+	/* Set irq type */
+	sprd_pmic_eic_update(chip, offset, SPRD_PMIC_EIC_IEV,
+			     pmic_eic->reg[REG_IEV]);
+	/* Set irq unmask */
+	sprd_pmic_eic_update(chip, offset, SPRD_PMIC_EIC_IE,
+			     pmic_eic->reg[REG_IE]);
+	/* Generate trigger start pulse for debounce EIC */
+	sprd_pmic_eic_update(chip, offset, SPRD_PMIC_EIC_TRIG,
+			     pmic_eic->reg[REG_TRIG]);
+
+	mutex_unlock(&pmic_eic->buslock);
+}
+
+static irqreturn_t sprd_pmic_eic_irq_handler(int irq, void *data)
+{
+	struct sprd_pmic_eic *pmic_eic = data;
+	struct gpio_chip *chip = &pmic_eic->chip;
+	u32 n, girq, val;
+	int ret;
+
+	ret = regmap_read(pmic_eic->map, pmic_eic->offset + SPRD_PMIC_EIC_MIS,
+			  &val);
+	if (ret)
+		return IRQ_RETVAL(ret);
+
+	val &= SPRD_PMIC_EIC_DATA_MASK;
+
+	for (n = 0; n < chip->ngpio; n++) {
+		if (!(BIT(n) & val))
+			continue;
+
+		/* Clear the interrupt */
+		sprd_pmic_eic_update(chip, n, SPRD_PMIC_EIC_IC, 1);
+
+		girq = irq_find_mapping(chip->irq.domain, n);
+		handle_nested_irq(girq);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int sprd_pmic_eic_probe(struct platform_device *pdev)
+{
+	struct gpio_irq_chip *irq;
+	struct sprd_pmic_eic *pmic_eic;
+	int ret;
+
+	pmic_eic = devm_kzalloc(&pdev->dev, sizeof(*pmic_eic), GFP_KERNEL);
+	if (!pmic_eic)
+		return -ENOMEM;
+
+	mutex_init(&pmic_eic->buslock);
+
+	pmic_eic->irq = platform_get_irq(pdev, 0);
+	if (pmic_eic->irq < 0) {
+		dev_err(&pdev->dev, "Failed to get PMIC EIC interrupt.\n");
+		return pmic_eic->irq;
+	}
+
+	pmic_eic->map = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!pmic_eic->map)
+		return -ENODEV;
+
+	ret = of_property_read_u32(pdev->dev.of_node, "reg", &pmic_eic->offset);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to get PMIC EIC base address.\n");
+		return ret;
+	}
+
+	ret = devm_request_threaded_irq(&pdev->dev, pmic_eic->irq, NULL,
+					sprd_pmic_eic_irq_handler,
+					IRQF_TRIGGER_LOW |
+					IRQF_ONESHOT | IRQF_NO_SUSPEND,
+					dev_name(&pdev->dev), pmic_eic);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to request PMIC EIC IRQ.\n");
+		return ret;
+	}
+
+	pmic_eic->chip.label = dev_name(&pdev->dev);
+	pmic_eic->chip.ngpio = SPRD_PMIC_EIC_NR;
+	pmic_eic->chip.base = -1;
+	pmic_eic->chip.parent = &pdev->dev;
+	pmic_eic->chip.of_node = pdev->dev.of_node;
+	pmic_eic->chip.direction_input = sprd_pmic_eic_direction_input;
+	pmic_eic->chip.request = sprd_pmic_eic_request;
+	pmic_eic->chip.free = sprd_pmic_eic_free;
+	pmic_eic->chip.set_config = sprd_pmic_eic_set_config;
+	pmic_eic->chip.set = sprd_pmic_eic_set;
+	pmic_eic->chip.get = sprd_pmic_eic_get;
+
+	pmic_eic->intc.name = dev_name(&pdev->dev);
+	pmic_eic->intc.irq_mask = sprd_pmic_eic_irq_mask;
+	pmic_eic->intc.irq_unmask = sprd_pmic_eic_irq_unmask;
+	pmic_eic->intc.irq_set_type = sprd_pmic_eic_irq_set_type;
+	pmic_eic->intc.irq_bus_lock = sprd_pmic_eic_bus_lock;
+	pmic_eic->intc.irq_bus_sync_unlock = sprd_pmic_eic_bus_sync_unlock;
+	pmic_eic->intc.flags = IRQCHIP_SKIP_SET_WAKE;
+
+	irq = &pmic_eic->chip.irq;
+	irq->chip = &pmic_eic->intc;
+	irq->threaded = true;
+
+	ret = devm_gpiochip_add_data(&pdev->dev, &pmic_eic->chip, pmic_eic);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Could not register gpiochip %d.\n", ret);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, pmic_eic);
+	return 0;
+}
+
+static const struct of_device_id sprd_pmic_eic_of_match[] = {
+	{ .compatible = "sprd,sc27xx-eic", },
+	{ /* end of list */ }
+};
+MODULE_DEVICE_TABLE(of, sprd_pmic_eic_of_match);
+
+static struct platform_driver sprd_pmic_eic_driver = {
+	.probe = sprd_pmic_eic_probe,
+	.driver = {
+		.name = "sprd-pmic-eic",
+		.of_match_table	= sprd_pmic_eic_of_match,
+	},
+};
+
+module_platform_driver(sprd_pmic_eic_driver);
+
+MODULE_DESCRIPTION("Spreadtrum PMIC EIC driver");
+MODULE_LICENSE("GPL v2");