gpio: tqmx86: Add GPIO from for this IO controller

Some TQ-Systems ComExpress modules contain an IO controller with 8
GPIO lines.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 333 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-tqmx86.c b/drivers/gpio/gpio-tqmx86.c
new file mode 100644
index 000000000000..6f7250c6f597
--- /dev/null
+++ b/drivers/gpio/gpio-tqmx86.c
@@ -0,0 +1,333 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * TQ-Systems TQMx86 PLD GPIO driver
+ *
+ * Based on vendor driver by:
+ *   Vadim V.Vlasov <vvlasov@dev.rtsoft.ru>
+ */
+
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/gpio/driver.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+
+#define TQMX86_NGPIO	8
+#define TQMX86_NGPO	4	/* 0-3 - output */
+#define TQMX86_NGPI	4	/* 4-7 - input */
+#define TQMX86_DIR_INPUT_MASK	0xf0	/* 0-3 - output, 4-7 - input */
+
+#define TQMX86_GPIODD	0	/* GPIO Data Direction Register */
+#define TQMX86_GPIOD	1	/* GPIO Data Register */
+#define TQMX86_GPIIC	3	/* GPI Interrupt Configuration Register */
+#define TQMX86_GPIIS	4	/* GPI Interrupt Status Register */
+
+#define TQMX86_GPII_FALLING	BIT(0)
+#define TQMX86_GPII_RISING	BIT(1)
+#define TQMX86_GPII_MASK	(BIT(0) | BIT(1))
+#define TQMX86_GPII_BITS	2
+
+struct tqmx86_gpio_data {
+	struct gpio_chip	chip;
+	struct irq_chip		irq_chip;
+	void __iomem		*io_base;
+	int			irq;
+	raw_spinlock_t		spinlock;
+	u8			irq_type[TQMX86_NGPI];
+};
+
+static u8 tqmx86_gpio_read(struct tqmx86_gpio_data *gd, unsigned int reg)
+{
+	return ioread8(gd->io_base + reg);
+}
+
+static void tqmx86_gpio_write(struct tqmx86_gpio_data *gd, u8 val,
+			      unsigned int reg)
+{
+	iowrite8(val, gd->io_base + reg);
+}
+
+static int tqmx86_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
+
+	return !!(tqmx86_gpio_read(gpio, TQMX86_GPIOD) & BIT(offset));
+}
+
+static void tqmx86_gpio_set(struct gpio_chip *chip, unsigned int offset,
+			    int value)
+{
+	struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
+	unsigned long flags;
+	u8 val;
+
+	raw_spin_lock_irqsave(&gpio->spinlock, flags);
+	val = tqmx86_gpio_read(gpio, TQMX86_GPIOD);
+	if (value)
+		val |= BIT(offset);
+	else
+		val &= ~BIT(offset);
+	tqmx86_gpio_write(gpio, val, TQMX86_GPIOD);
+	raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
+}
+
+static int tqmx86_gpio_direction_input(struct gpio_chip *chip,
+				       unsigned int offset)
+{
+	/* Direction cannot be changed. Validate is an input. */
+	if (BIT(offset) & TQMX86_DIR_INPUT_MASK)
+		return 0;
+	else
+		return -EINVAL;
+}
+
+static int tqmx86_gpio_direction_output(struct gpio_chip *chip,
+					unsigned int offset,
+					int value)
+{
+	/* Direction cannot be changed, validate is an output */
+	if (BIT(offset) & TQMX86_DIR_INPUT_MASK)
+		return -EINVAL;
+	else
+		return 0;
+}
+
+static int tqmx86_gpio_get_direction(struct gpio_chip *chip,
+				     unsigned int offset)
+{
+	return !!(TQMX86_DIR_INPUT_MASK & BIT(offset));
+}
+
+static void tqmx86_gpio_irq_mask(struct irq_data *data)
+{
+	unsigned int offset = (data->hwirq - TQMX86_NGPO);
+	struct tqmx86_gpio_data *gpio = gpiochip_get_data(
+		irq_data_get_irq_chip_data(data));
+	unsigned long flags;
+	u8 gpiic, mask;
+
+	mask = TQMX86_GPII_MASK << (offset * TQMX86_GPII_BITS);
+
+	raw_spin_lock_irqsave(&gpio->spinlock, flags);
+	gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
+	gpiic &= ~mask;
+	tqmx86_gpio_write(gpio, gpiic, TQMX86_GPIIC);
+	raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
+}
+
+static void tqmx86_gpio_irq_unmask(struct irq_data *data)
+{
+	unsigned int offset = (data->hwirq - TQMX86_NGPO);
+	struct tqmx86_gpio_data *gpio = gpiochip_get_data(
+		irq_data_get_irq_chip_data(data));
+	unsigned long flags;
+	u8 gpiic, mask;
+
+	mask = TQMX86_GPII_MASK << (offset * TQMX86_GPII_BITS);
+
+	raw_spin_lock_irqsave(&gpio->spinlock, flags);
+	gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
+	gpiic &= ~mask;
+	gpiic |= gpio->irq_type[offset] << (offset * TQMX86_GPII_BITS);
+	tqmx86_gpio_write(gpio, gpiic, TQMX86_GPIIC);
+	raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
+}
+
+static int tqmx86_gpio_irq_set_type(struct irq_data *data, unsigned int type)
+{
+	struct tqmx86_gpio_data *gpio = gpiochip_get_data(
+		irq_data_get_irq_chip_data(data));
+	unsigned int offset = (data->hwirq - TQMX86_NGPO);
+	unsigned int edge_type = type & IRQF_TRIGGER_MASK;
+	unsigned long flags;
+	u8 new_type, gpiic;
+
+	switch (edge_type) {
+	case IRQ_TYPE_EDGE_RISING:
+		new_type = TQMX86_GPII_RISING;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		new_type = TQMX86_GPII_FALLING;
+		break;
+	case IRQ_TYPE_EDGE_BOTH:
+		new_type = TQMX86_GPII_FALLING | TQMX86_GPII_RISING;
+		break;
+	default:
+		return -EINVAL; /* not supported */
+	}
+
+	gpio->irq_type[offset] = new_type;
+
+	raw_spin_lock_irqsave(&gpio->spinlock, flags);
+	gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
+	gpiic &= ~((TQMX86_GPII_MASK) << (offset * TQMX86_GPII_BITS));
+	gpiic |= new_type << (offset * TQMX86_GPII_BITS);
+	tqmx86_gpio_write(gpio, gpiic, TQMX86_GPIIC);
+	raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
+
+	return 0;
+}
+
+static void tqmx86_gpio_irq_handler(struct irq_desc *desc)
+{
+	struct gpio_chip *chip = irq_desc_get_handler_data(desc);
+	struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
+	struct irq_chip *irq_chip = irq_desc_get_chip(desc);
+	unsigned long irq_bits;
+	int i = 0, child_irq;
+	u8 irq_status;
+
+	chained_irq_enter(irq_chip, desc);
+
+	irq_status = tqmx86_gpio_read(gpio, TQMX86_GPIIS);
+	tqmx86_gpio_write(gpio, irq_status, TQMX86_GPIIS);
+
+	irq_bits = irq_status;
+	for_each_set_bit(i, &irq_bits, TQMX86_NGPI) {
+		child_irq = irq_find_mapping(gpio->chip.irq.domain,
+					     i + TQMX86_NGPO);
+		generic_handle_irq(child_irq);
+	}
+
+	chained_irq_exit(irq_chip, desc);
+}
+
+/* Minimal runtime PM is needed by the IRQ subsystem */
+static int __maybe_unused tqmx86_gpio_runtime_suspend(struct device *dev)
+{
+	return 0;
+}
+
+static int __maybe_unused tqmx86_gpio_runtime_resume(struct device *dev)
+{
+	return 0;
+}
+
+static const struct dev_pm_ops tqmx86_gpio_dev_pm_ops = {
+	SET_RUNTIME_PM_OPS(tqmx86_gpio_runtime_suspend,
+			   tqmx86_gpio_runtime_resume, NULL)
+};
+
+static int tqmx86_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct tqmx86_gpio_data *gpio;
+	struct gpio_chip *chip;
+	void __iomem *io_base;
+	struct resource *res;
+	int ret, irq;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "Cannot get I/O\n");
+		return -ENODEV;
+	}
+
+	io_base = devm_ioport_map(&pdev->dev, res->start, resource_size(res));
+	if (!io_base)
+		return -ENOMEM;
+
+	gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
+	if (!gpio)
+		return -ENOMEM;
+
+	raw_spin_lock_init(&gpio->spinlock);
+	gpio->io_base = io_base;
+
+	tqmx86_gpio_write(gpio, (u8)~TQMX86_DIR_INPUT_MASK, TQMX86_GPIODD);
+
+	platform_set_drvdata(pdev, gpio);
+
+	chip = &gpio->chip;
+	chip->label = "gpio-tqmx86";
+	chip->owner = THIS_MODULE;
+	chip->can_sleep = false;
+	chip->base = -1;
+	chip->direction_input = tqmx86_gpio_direction_input;
+	chip->direction_output = tqmx86_gpio_direction_output;
+	chip->get_direction = tqmx86_gpio_get_direction;
+	chip->get = tqmx86_gpio_get;
+	chip->set = tqmx86_gpio_set;
+	chip->ngpio = TQMX86_NGPIO;
+	chip->irq.need_valid_mask = true;
+	chip->parent = pdev->dev.parent;
+
+	pm_runtime_enable(&pdev->dev);
+
+	ret = devm_gpiochip_add_data(dev, chip, gpio);
+	if (ret) {
+		dev_err(dev, "Could not register GPIO chip\n");
+		goto out_pm_dis;
+	}
+
+	if (irq) {
+		struct irq_chip *irq_chip = &gpio->irq_chip;
+		u8 irq_status;
+
+		irq_chip->name = chip->label;
+		irq_chip->parent_device = &pdev->dev;
+		irq_chip->irq_mask = tqmx86_gpio_irq_mask;
+		irq_chip->irq_unmask = tqmx86_gpio_irq_unmask;
+		irq_chip->irq_set_type = tqmx86_gpio_irq_set_type;
+
+		/* Mask all interrupts */
+		tqmx86_gpio_write(gpio, 0, TQMX86_GPIIC);
+
+		/* Clear all pending interrupts */
+		irq_status = tqmx86_gpio_read(gpio, TQMX86_GPIIS);
+		tqmx86_gpio_write(gpio, irq_status, TQMX86_GPIIS);
+
+		ret = gpiochip_irqchip_add(chip, irq_chip,
+					   0, handle_simple_irq,
+					   IRQ_TYPE_EDGE_BOTH);
+		if (ret) {
+			dev_err(dev, "Could not add irq chip\n");
+			goto out_remove;
+		}
+
+		gpiochip_set_chained_irqchip(chip, irq_chip,
+					     irq, tqmx86_gpio_irq_handler);
+	}
+
+	/* Only GPIOs 4-7 are valid for interrupts. Clear the others */
+	clear_bit(0, chip->irq.valid_mask);
+	clear_bit(1, chip->irq.valid_mask);
+	clear_bit(2, chip->irq.valid_mask);
+	clear_bit(3, chip->irq.valid_mask);
+
+	dev_info(dev, "GPIO functionality initialized with %d pins\n",
+		 chip->ngpio);
+
+	return 0;
+
+out_remove:
+	gpiochip_remove(&gpio->chip);
+out_pm_dis:
+	pm_runtime_disable(&pdev->dev);
+
+	return ret;
+}
+
+static struct platform_driver tqmx86_gpio_driver = {
+	.driver = {
+		.name = "tqmx86-gpio",
+		.pm = &tqmx86_gpio_dev_pm_ops,
+	},
+	.probe		= tqmx86_gpio_probe,
+};
+
+module_platform_driver(tqmx86_gpio_driver);
+
+MODULE_DESCRIPTION("TQMx86 PLD GPIO Driver");
+MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:tqmx86-gpio");