pinctrl: armada-37xx: Add irqchip support

The Armada 37xx SoCs can handle interrupt through GPIO. However it can
only manage the edge ones.

The way the interrupt are managed is classical so we can use the generic
interrupt chip model.

The only unusual "feature" is that many interrupts are connected to the
parent interrupt controller. But we do not take advantage of this and use
the chained irq with all of them.
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/mvebu/pinctrl-armada-37xx.c

@@ -13,7 +13,9 @@
 #include <linux/gpio/driver.h>
 #include <linux/mfd/syscon.h>
 #include <linux/of.h>
+#include <linux/of_address.h>
 #include <linux/of_device.h>
+#include <linux/of_irq.h>
 #include <linux/pinctrl/pinconf-generic.h>
 #include <linux/pinctrl/pinconf.h>
 #include <linux/pinctrl/pinctrl.h>
@@ -30,6 +32,11 @@
 #define OUTPUT_CTL	0x20
 #define SELECTION	0x30
 
+#define IRQ_EN		0x0
+#define IRQ_POL		0x08
+#define IRQ_STATUS	0x10
+#define IRQ_WKUP	0x18
+
 #define NB_FUNCS 2
 #define GPIO_PER_REG	32
 
@@ -75,9 +82,12 @@ struct armada_37xx_pmx_func {
 
 struct armada_37xx_pinctrl {
 	struct regmap			*regmap;
+	void __iomem			*base;
 	const struct armada_37xx_pin_data	*data;
 	struct device			*dev;
 	struct gpio_chip		gpio_chip;
+	struct irq_chip			irq_chip;
+	spinlock_t			irq_lock;
 	struct pinctrl_desc		pctl;
 	struct pinctrl_dev		*pctl_dev;
 	struct armada_37xx_pin_group	*groups;
@@ -346,6 +356,14 @@ static int armada_37xx_pmx_set(struct pinctrl_dev *pctldev,
 	return armada_37xx_pmx_set_by_name(pctldev, name, grp);
 }
 
+static inline void armada_37xx_irq_update_reg(unsigned int *reg,
+					  struct irq_data *d)
+{
+	int offset = irqd_to_hwirq(d);
+
+	armada_37xx_update_reg(reg, offset);
+}
+
 static int armada_37xx_gpio_direction_input(struct gpio_chip *chip,
 					    unsigned int offset)
 {
@@ -468,6 +486,214 @@ static const struct gpio_chip armada_37xx_gpiolib_chip = {
 	.owner = THIS_MODULE,
 };
 
+static void armada_37xx_irq_ack(struct irq_data *d)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
+	struct armada_37xx_pinctrl *info = gpiochip_get_data(chip);
+	u32 reg = IRQ_STATUS;
+	unsigned long flags;
+
+	armada_37xx_irq_update_reg(&reg, d);
+	spin_lock_irqsave(&info->irq_lock, flags);
+	writel(d->mask, info->base + reg);
+	spin_unlock_irqrestore(&info->irq_lock, flags);
+}
+
+static void armada_37xx_irq_mask(struct irq_data *d)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
+	struct armada_37xx_pinctrl *info = gpiochip_get_data(chip);
+	u32 val, reg = IRQ_EN;
+	unsigned long flags;
+
+	armada_37xx_irq_update_reg(&reg, d);
+	spin_lock_irqsave(&info->irq_lock, flags);
+	val = readl(info->base + reg);
+	writel(val & ~d->mask, info->base + reg);
+	spin_unlock_irqrestore(&info->irq_lock, flags);
+}
+
+static void armada_37xx_irq_unmask(struct irq_data *d)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
+	struct armada_37xx_pinctrl *info = gpiochip_get_data(chip);
+	u32 val, reg = IRQ_EN;
+	unsigned long flags;
+
+	armada_37xx_irq_update_reg(&reg, d);
+	spin_lock_irqsave(&info->irq_lock, flags);
+	val = readl(info->base + reg);
+	writel(val | d->mask, info->base + reg);
+	spin_unlock_irqrestore(&info->irq_lock, flags);
+}
+
+static int armada_37xx_irq_set_wake(struct irq_data *d, unsigned int on)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
+	struct armada_37xx_pinctrl *info = gpiochip_get_data(chip);
+	u32 val, reg = IRQ_WKUP;
+	unsigned long flags;
+
+	armada_37xx_irq_update_reg(&reg, d);
+	spin_lock_irqsave(&info->irq_lock, flags);
+	val = readl(info->base + reg);
+	if (on)
+		val |= d->mask;
+	else
+		val &= ~d->mask;
+	writel(val, info->base + reg);
+	spin_unlock_irqrestore(&info->irq_lock, flags);
+
+	return 0;
+}
+
+static int armada_37xx_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
+	struct armada_37xx_pinctrl *info = gpiochip_get_data(chip);
+	u32 val, reg = IRQ_POL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&info->irq_lock, flags);
+	armada_37xx_irq_update_reg(&reg, d);
+	val = readl(info->base + reg);
+	switch (type) {
+	case IRQ_TYPE_EDGE_RISING:
+		val &= ~d->mask;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		val |= d->mask;
+		break;
+	default:
+		spin_unlock_irqrestore(&info->irq_lock, flags);
+		return -EINVAL;
+	}
+	writel(val, info->base + reg);
+	spin_unlock_irqrestore(&info->irq_lock, flags);
+
+	return 0;
+}
+
+
+static void armada_37xx_irq_handler(struct irq_desc *desc)
+{
+	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct armada_37xx_pinctrl *info = gpiochip_get_data(gc);
+	struct irq_domain *d = gc->irqdomain;
+	int i;
+
+	chained_irq_enter(chip, desc);
+	for (i = 0; i <= d->revmap_size / GPIO_PER_REG; i++) {
+		u32 status;
+		unsigned long flags;
+
+		spin_lock_irqsave(&info->irq_lock, flags);
+		status = readl_relaxed(info->base + IRQ_STATUS + 4 * i);
+		/* Manage only the interrupt that was enabled */
+		status &= readl_relaxed(info->base + IRQ_EN + 4 * i);
+		spin_unlock_irqrestore(&info->irq_lock, flags);
+		while (status) {
+			u32 hwirq = ffs(status) - 1;
+			u32 virq = irq_find_mapping(d, hwirq +
+						     i * GPIO_PER_REG);
+
+			generic_handle_irq(virq);
+
+			/* Update status in case a new IRQ appears */
+			spin_lock_irqsave(&info->irq_lock, flags);
+			status = readl_relaxed(info->base +
+					       IRQ_STATUS + 4 * i);
+			/* Manage only the interrupt that was enabled */
+			status &= readl_relaxed(info->base + IRQ_EN + 4 * i);
+			spin_unlock_irqrestore(&info->irq_lock, flags);
+		}
+	}
+	chained_irq_exit(chip, desc);
+}
+
+static int armada_37xx_irqchip_register(struct platform_device *pdev,
+					struct armada_37xx_pinctrl *info)
+{
+	struct device_node *np = info->dev->of_node;
+	int nrirqs = info->data->nr_pins;
+	struct gpio_chip *gc = &info->gpio_chip;
+	struct irq_chip *irqchip = &info->irq_chip;
+	struct resource res;
+	int ret = -ENODEV, i, nr_irq_parent;
+
+	/* Check if we have at least one gpio-controller child node */
+	for_each_child_of_node(info->dev->of_node, np) {
+		if (of_property_read_bool(np, "gpio-controller")) {
+			ret = 0;
+			break;
+		}
+	};
+	if (ret)
+		return ret;
+
+	nr_irq_parent = of_irq_count(np);
+	spin_lock_init(&info->irq_lock);
+
+	if (!nr_irq_parent) {
+		dev_err(&pdev->dev, "Invalid or no IRQ\n");
+		return 0;
+	}
+
+	if (of_address_to_resource(info->dev->of_node, 1, &res)) {
+		dev_err(info->dev, "cannot find IO resource\n");
+		return -ENOENT;
+	}
+
+	info->base = devm_ioremap_resource(info->dev, &res);
+	if (IS_ERR(info->base))
+		return PTR_ERR(info->base);
+
+	irqchip->irq_ack = armada_37xx_irq_ack;
+	irqchip->irq_mask = armada_37xx_irq_mask;
+	irqchip->irq_unmask = armada_37xx_irq_unmask;
+	irqchip->irq_set_wake = armada_37xx_irq_set_wake;
+	irqchip->irq_set_type = armada_37xx_irq_set_type;
+	irqchip->name = info->data->name;
+
+	ret = gpiochip_irqchip_add(gc, irqchip, 0,
+				   handle_edge_irq, IRQ_TYPE_NONE);
+	if (ret) {
+		dev_info(&pdev->dev, "could not add irqchip\n");
+		return ret;
+	}
+
+	/*
+	 * Many interrupts are connected to the parent interrupt
+	 * controller. But we do not take advantage of this and use
+	 * the chained irq with all of them.
+	 */
+	for (i = 0; i < nrirqs; i++) {
+		struct irq_data *d = irq_get_irq_data(gc->irq_base + i);
+
+		/*
+		 * The mask field is a "precomputed bitmask for
+		 * accessing the chip registers" which was introduced
+		 * for the generic irqchip framework. As we don't use
+		 * this framework, we can reuse this field for our own
+		 * usage.
+		 */
+		d->mask = BIT(i % GPIO_PER_REG);
+	}
+
+	for (i = 0; i < nr_irq_parent; i++) {
+		int irq = irq_of_parse_and_map(np, i);
+
+		if (irq < 0)
+			continue;
+
+		gpiochip_set_chained_irqchip(gc, irqchip, irq,
+					     armada_37xx_irq_handler);
+	}
+
+	return 0;
+}
+
 static int armada_37xx_gpiochip_register(struct platform_device *pdev,
 					struct armada_37xx_pinctrl *info)
 {
@@ -494,6 +720,9 @@ static int armada_37xx_gpiochip_register(struct platform_device *pdev,
 	gc->label = info->data->name;
 
 	ret = devm_gpiochip_add_data(&pdev->dev, gc, info);
+	if (ret)
+		return ret;
+	ret = armada_37xx_irqchip_register(pdev, info);
 	if (ret)
 		return ret;