[12/18] gpio: add support for the sl28cpld GPIO controller

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 3cbf8882a0dd..516e47017ef5 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1211,6 +1211,17 @@  config GPIO_RC5T583
 	  This driver provides the support for driving/reading the gpio pins
 	  of RC5T583 device through standard gpio library.
 
+config GPIO_SL28CPLD
+	tristate "Kontron sl28 GPIO"
+	depends on MFD_SL28CPLD
+	depends on OF_GPIO
+	select GPIOLIB_IRQCHIP
+	help
+	  This enables support for the GPIOs found on the Kontron sl28 CPLD.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called gpio-sl28cpld.
+
 config GPIO_STMPE
 	bool "STMPE GPIOs"
 	depends on MFD_STMPE
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 0b571264ddbc..0ca2d52c78e8 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -127,6 +127,7 @@  obj-$(CONFIG_GPIO_SCH311X)		+= gpio-sch311x.o
 obj-$(CONFIG_GPIO_SCH)			+= gpio-sch.o
 obj-$(CONFIG_GPIO_SIFIVE)		+= gpio-sifive.o
 obj-$(CONFIG_GPIO_SIOX)			+= gpio-siox.o
+obj-$(CONFIG_GPIO_SL28CPLD)		+= gpio-sl28cpld.o
 obj-$(CONFIG_GPIO_SODAVILLE)		+= gpio-sodaville.o
 obj-$(CONFIG_GPIO_SPEAR_SPICS)		+= gpio-spear-spics.o
 obj-$(CONFIG_GPIO_SPRD)			+= gpio-sprd.o
diff --git a/drivers/gpio/gpio-sl28cpld.c b/drivers/gpio/gpio-sl28cpld.c
new file mode 100644
index 000000000000..94f82013882f
--- /dev/null
+++ b/drivers/gpio/gpio-sl28cpld.c
@@ -0,0 +1,332 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SMARC-sAL28 GPIO driver.
+ *
+ * Copyright 2019 Kontron Europe GmbH
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/interrupt.h>
+#include <linux/regmap.h>
+#include <linux/platform_device.h>
+#include <linux/gpio/driver.h>
+
+#define GPIO_REG_DIR	0
+#define GPIO_REG_OUT	1
+#define GPIO_REG_IN	2
+#define GPIO_REG_IE	3
+#define GPIO_REG_IP	4
+
+#define GPI_REG_IN	0
+
+#define GPO_REG_OUT	0
+
+enum sl28cpld_gpio_type {
+	sl28cpld_gpio,
+	sl28cpld_gpi,
+	sl28cpld_gpo,
+};
+
+struct sl28cpld_gpio {
+	struct gpio_chip gpio_chip;
+	struct irq_chip irq_chip;
+	struct regmap *regmap;
+	u32 offset;
+	struct mutex lock;
+	u8 ie;
+};
+
+static void sl28cpld_gpio_set_reg(struct gpio_chip *chip, unsigned int reg,
+				  unsigned int offset, int value)
+{
+	struct sl28cpld_gpio *gpio = gpiochip_get_data(chip);
+	unsigned int mask = 1 << offset;
+	unsigned int val = value << offset;
+
+	regmap_update_bits(gpio->regmap, gpio->offset + reg, mask, val);
+}
+
+static void sl28cpld_gpio_set(struct gpio_chip *chip, unsigned int offset,
+			      int value)
+{
+	sl28cpld_gpio_set_reg(chip, GPIO_REG_OUT, offset, value);
+}
+
+static void sl28cpld_gpo_set(struct gpio_chip *chip, unsigned int offset,
+			     int value)
+{
+	sl28cpld_gpio_set_reg(chip, GPO_REG_OUT, offset, value);
+}
+
+static int sl28cpld_gpio_get_reg(struct gpio_chip *chip, unsigned int reg,
+				 unsigned int offset)
+{
+	struct sl28cpld_gpio *gpio = gpiochip_get_data(chip);
+	unsigned int mask = 1 << offset;
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(gpio->regmap, gpio->offset + reg, &val);
+	if (ret)
+		return ret;
+
+	return (val & mask) ? 1 : 0;
+}
+
+static int sl28cpld_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	return sl28cpld_gpio_get_reg(chip, GPIO_REG_IN, offset);
+}
+
+static int sl28cpld_gpi_get(struct gpio_chip *chip, unsigned int offset)
+{
+	return sl28cpld_gpio_get_reg(chip, GPI_REG_IN, offset);
+}
+
+static int sl28cpld_gpio_get_direction(struct gpio_chip *chip,
+				       unsigned int offset)
+{
+	struct sl28cpld_gpio *gpio = gpiochip_get_data(chip);
+	unsigned int reg;
+	int ret;
+
+	ret = regmap_read(gpio->regmap, gpio->offset + GPIO_REG_DIR, &reg);
+	if (ret)
+		return ret;
+
+	if (reg & (1 << offset))
+		return GPIO_LINE_DIRECTION_OUT;
+	else
+		return GPIO_LINE_DIRECTION_IN;
+}
+
+static int sl28cpld_gpio_set_direction(struct gpio_chip *chip,
+				       unsigned int offset,
+				       bool output)
+{
+	struct sl28cpld_gpio *gpio = gpiochip_get_data(chip);
+	unsigned int mask = 1 << offset;
+	unsigned int val = (output) ? mask : 0;
+
+	return regmap_update_bits(gpio->regmap, gpio->offset + GPIO_REG_DIR,
+				  mask, val);
+
+}
+
+static int sl28cpld_gpio_direction_input(struct gpio_chip *chip,
+					 unsigned int offset)
+{
+	return sl28cpld_gpio_set_direction(chip, offset, false);
+}
+
+static int sl28cpld_gpio_direction_output(struct gpio_chip *chip,
+					  unsigned int offset, int value)
+{
+	sl28cpld_gpio_set_reg(chip, GPIO_REG_OUT, offset, value);
+	return sl28cpld_gpio_set_direction(chip, offset, true);
+}
+
+static void sl28cpld_gpio_irq_lock(struct irq_data *data)
+{
+	struct sl28cpld_gpio *gpio =
+		gpiochip_get_data(irq_data_get_irq_chip_data(data));
+
+	mutex_lock(&gpio->lock);
+}
+
+static void sl28cpld_gpio_irq_sync_unlock(struct irq_data *data)
+{
+	struct sl28cpld_gpio *gpio =
+		gpiochip_get_data(irq_data_get_irq_chip_data(data));
+
+	regmap_write(gpio->regmap, gpio->offset + GPIO_REG_IE, gpio->ie);
+	mutex_unlock(&gpio->lock);
+}
+
+static void sl28cpld_gpio_irq_disable(struct irq_data *data)
+{
+	struct sl28cpld_gpio *gpio =
+		gpiochip_get_data(irq_data_get_irq_chip_data(data));
+
+	if (data->hwirq >= 8)
+		return;
+
+	gpio->ie &= ~(1 << data->hwirq);
+}
+
+static void sl28cpld_gpio_irq_enable(struct irq_data *data)
+{
+	struct sl28cpld_gpio *gpio =
+		gpiochip_get_data(irq_data_get_irq_chip_data(data));
+
+	if (data->hwirq >= 8)
+		return;
+
+	gpio->ie |= (1 << data->hwirq);
+}
+
+static int sl28cpld_gpio_irq_set_type(struct irq_data *data, unsigned int type)
+{
+	/* only edge triggered interrupts on both edges are supported */
+	return (type == IRQ_TYPE_EDGE_BOTH) ? 0 : -EINVAL;
+}
+
+static irqreturn_t sl28cpld_gpio_irq_thread(int irq, void *data)
+{
+	struct sl28cpld_gpio *gpio = data;
+	unsigned int ip;
+	unsigned int virq;
+	int pin;
+	int ret;
+
+	ret = regmap_read(gpio->regmap, gpio->offset + GPIO_REG_IP, &ip);
+	if (ret)
+		return IRQ_NONE;
+
+	/* mask other pending interrupts which are not enabled */
+	ip &= gpio->ie;
+
+	/* ack the interrupts */
+	regmap_write(gpio->regmap, gpio->offset + GPIO_REG_IP, ip);
+
+	/* and handle them */
+	while (ip) {
+		pin = __ffs(ip);
+		ip &= ~BIT(pin);
+
+		virq = irq_find_mapping(gpio->gpio_chip.irq.domain, pin);
+		if (virq)
+			handle_nested_irq(virq);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int sl28_cpld_gpio_irq_init(struct platform_device *pdev, int irq)
+{
+	struct sl28cpld_gpio *gpio = platform_get_drvdata(pdev);
+	struct irq_chip *irq_chip = &gpio->irq_chip;
+	int ret;
+
+	irq_chip->name = "sl28cpld-gpio-irq",
+	irq_chip->irq_bus_lock = sl28cpld_gpio_irq_lock,
+	irq_chip->irq_bus_sync_unlock = sl28cpld_gpio_irq_sync_unlock,
+	irq_chip->irq_disable = sl28cpld_gpio_irq_disable,
+	irq_chip->irq_enable = sl28cpld_gpio_irq_enable,
+	irq_chip->irq_set_type = sl28cpld_gpio_irq_set_type,
+	irq_chip->flags = IRQCHIP_SKIP_SET_WAKE,
+
+	ret = gpiochip_irqchip_add_nested(&gpio->gpio_chip, irq_chip, 0,
+					  handle_simple_irq, IRQ_TYPE_NONE);
+	if (ret)
+		return ret;
+
+	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+					sl28cpld_gpio_irq_thread,
+					IRQF_SHARED | IRQF_ONESHOT,
+					pdev->name, gpio);
+	if (ret)
+		return ret;
+
+	gpiochip_set_nested_irqchip(&gpio->gpio_chip, irq_chip, irq);
+
+	return 0;
+}
+
+static int sl28cpld_gpio_probe(struct platform_device *pdev)
+{
+	enum sl28cpld_gpio_type type =
+		platform_get_device_id(pdev)->driver_data;
+	struct device_node *np = pdev->dev.of_node;
+	struct sl28cpld_gpio *gpio;
+	struct gpio_chip *chip;
+	struct resource *res;
+	bool irq_support = false;
+	int ret;
+	int irq;
+
+	gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
+	if (!gpio)
+		return -ENOMEM;
+
+	if (!pdev->dev.parent)
+		return -ENODEV;
+
+	gpio->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!gpio->regmap)
+		return -ENODEV;
+
+	res = platform_get_resource(pdev, IORESOURCE_REG, 0);
+	if (!res)
+		return -EINVAL;
+	gpio->offset = res->start;
+
+	/* initialize struct gpio_chip */
+	mutex_init(&gpio->lock);
+	chip = &gpio->gpio_chip;
+	chip->parent = &pdev->dev;
+	chip->label = dev_name(&pdev->dev);
+	chip->owner = THIS_MODULE;
+	chip->can_sleep = true;
+	chip->base = -1;
+	chip->ngpio = 8;
+
+	switch (type) {
+	case sl28cpld_gpio:
+		chip->get_direction = sl28cpld_gpio_get_direction;
+		chip->direction_input = sl28cpld_gpio_direction_input;
+		chip->direction_output = sl28cpld_gpio_direction_output;
+		chip->get = sl28cpld_gpio_get;
+		chip->set = sl28cpld_gpio_set;
+		irq_support = true;
+		break;
+	case sl28cpld_gpo:
+		chip->set = sl28cpld_gpo_set;
+		chip->get = sl28cpld_gpi_get;
+		break;
+	case sl28cpld_gpi:
+		chip->get = sl28cpld_gpi_get;
+		break;
+	}
+
+	ret = devm_gpiochip_add_data(&pdev->dev, chip, gpio);
+	if (ret < 0)
+		return ret;
+
+	platform_set_drvdata(pdev, gpio);
+
+	if (irq_support && of_property_read_bool(np, "interrupt-controller")) {
+		irq = platform_get_irq(pdev, 0);
+		if (irq < 0)
+			return ret;
+
+		ret = sl28_cpld_gpio_irq_init(pdev, irq);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static const struct platform_device_id sl28cpld_gpio_id_table[] = {
+	{"sl28cpld-gpio", sl28cpld_gpio},
+	{"sl28cpld-gpi", sl28cpld_gpi},
+	{"sl28cpld-gpo", sl28cpld_gpo},
+};
+MODULE_DEVICE_TABLE(platform, sl28cpld_gpio_id_table);
+
+static struct platform_driver sl28cpld_gpio_driver = {
+	.probe = sl28cpld_gpio_probe,
+	.id_table = sl28cpld_gpio_id_table,
+	.driver = {
+		.name = "sl28cpld-gpio",
+	},
+};
+module_platform_driver(sl28cpld_gpio_driver);
+
+MODULE_DESCRIPTION("sl28cpld GPIO Driver");
+MODULE_LICENSE("GPL");