pinctrl: sunxi: Add external interrupts support

The port controller IP found in the Allwinner A10 and A13 can use few of
the pins it manage as an interrupt source, called external interrupts in
the datasheet.

The number of these external interrupts are SoCs specific, but the
current upper limit is 32. In order to work, the external interrupts'
pins have to be muxed to a specific function to generate an interrupt.

This patch adds the irqchip and the needed logic to use the PIO
controller as an interrupt controller.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 155 insertions, 0 deletions

diff --git a/drivers/pinctrl/pinctrl-sunxi.c b/drivers/pinctrl/pinctrl-sunxi.c
index f4a74f1c0bfd..e2bab0f75fc5 100644
--- a/drivers/pinctrl/pinctrl-sunxi.c
+++ b/drivers/pinctrl/pinctrl-sunxi.c
@@ -13,10 +13,12 @@
 #include <linux/io.h>
 #include <linux/clk.h>
 #include <linux/gpio.h>
+#include <linux/irqdomain.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
+#include <linux/of_irq.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/pinctrl/machine.h>
 #include <linux/pinctrl/pinctrl.h>
@@ -1796,6 +1798,26 @@ static int sunxi_pinctrl_gpio_of_xlate(struct gpio_chip *gc,
 	return pin;
 }
 
+static int sunxi_pinctrl_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+	struct sunxi_pinctrl *pctl = dev_get_drvdata(chip->dev);
+	struct sunxi_desc_function *desc;
+
+	if (offset > chip->ngpio)
+		return -ENXIO;
+
+	desc = sunxi_pinctrl_desc_find_function_by_pin(pctl, offset, "irq");
+	if (!desc)
+		return -EINVAL;
+
+	pctl->irq_array[desc->irqnum] = offset;
+
+	dev_dbg(chip->dev, "%s: request IRQ for GPIO %d, return %d\n",
+		chip->label, offset + chip->base, desc->irqnum);
+
+	return irq_find_mapping(pctl->domain, desc->irqnum);
+}
+
 static struct gpio_chip sunxi_pinctrl_gpio_chip = {
 	.owner			= THIS_MODULE,
 	.request		= sunxi_pinctrl_gpio_request,
@@ -1805,10 +1827,118 @@ static struct gpio_chip sunxi_pinctrl_gpio_chip = {
 	.get			= sunxi_pinctrl_gpio_get,
 	.set			= sunxi_pinctrl_gpio_set,
 	.of_xlate		= sunxi_pinctrl_gpio_of_xlate,
+	.to_irq			= sunxi_pinctrl_gpio_to_irq,
 	.of_gpio_n_cells	= 3,
 	.can_sleep		= 0,
 };
 
+static int sunxi_pinctrl_irq_set_type(struct irq_data *d,
+				      unsigned int type)
+{
+	struct sunxi_pinctrl *pctl = irq_data_get_irq_chip_data(d);
+	u32 reg = sunxi_irq_cfg_reg(d->hwirq);
+	u8 index = sunxi_irq_cfg_offset(d->hwirq);
+	u8 mode;
+
+	switch (type) {
+	case IRQ_TYPE_EDGE_RISING:
+		mode = IRQ_EDGE_RISING;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		mode = IRQ_EDGE_FALLING;
+		break;
+	case IRQ_TYPE_EDGE_BOTH:
+		mode = IRQ_EDGE_BOTH;
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		mode = IRQ_LEVEL_HIGH;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		mode = IRQ_LEVEL_LOW;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	writel((mode & IRQ_CFG_IRQ_MASK) << index, pctl->membase + reg);
+
+	return 0;
+}
+
+static void sunxi_pinctrl_irq_mask_ack(struct irq_data *d)
+{
+	struct sunxi_pinctrl *pctl = irq_data_get_irq_chip_data(d);
+	u32 ctrl_reg = sunxi_irq_ctrl_reg(d->hwirq);
+	u8 ctrl_idx = sunxi_irq_ctrl_offset(d->hwirq);
+	u32 status_reg = sunxi_irq_status_reg(d->hwirq);
+	u8 status_idx = sunxi_irq_status_offset(d->hwirq);
+	u32 val;
+
+	/* Mask the IRQ */
+	val = readl(pctl->membase + ctrl_reg);
+	writel(val & ~(1 << ctrl_idx), pctl->membase + ctrl_reg);
+
+	/* Clear the IRQ */
+	writel(1 << status_idx, pctl->membase + status_reg);
+}
+
+static void sunxi_pinctrl_irq_mask(struct irq_data *d)
+{
+	struct sunxi_pinctrl *pctl = irq_data_get_irq_chip_data(d);
+	u32 reg = sunxi_irq_ctrl_reg(d->hwirq);
+	u8 idx = sunxi_irq_ctrl_offset(d->hwirq);
+	u32 val;
+
+	/* Mask the IRQ */
+	val = readl(pctl->membase + reg);
+	writel(val & ~(1 << idx), pctl->membase + reg);
+}
+
+static void sunxi_pinctrl_irq_unmask(struct irq_data *d)
+{
+	struct sunxi_pinctrl *pctl = irq_data_get_irq_chip_data(d);
+	struct sunxi_desc_function *func;
+	u32 reg = sunxi_irq_ctrl_reg(d->hwirq);
+	u8 idx = sunxi_irq_ctrl_offset(d->hwirq);
+	u32 val;
+
+	func = sunxi_pinctrl_desc_find_function_by_pin(pctl,
+						       pctl->irq_array[d->hwirq],
+						       "irq");
+
+	/* Change muxing to INT mode */
+	sunxi_pmx_set(pctl->pctl_dev, pctl->irq_array[d->hwirq], func->muxval);
+
+	/* Unmask the IRQ */
+	val = readl(pctl->membase + reg);
+	writel(val | (1 << idx), pctl->membase + reg);
+}
+
+static struct irq_chip sunxi_pinctrl_irq_chip = {
+	.irq_mask	= sunxi_pinctrl_irq_mask,
+	.irq_mask_ack	= sunxi_pinctrl_irq_mask_ack,
+	.irq_unmask	= sunxi_pinctrl_irq_unmask,
+	.irq_set_type	= sunxi_pinctrl_irq_set_type,
+};
+
+static void sunxi_pinctrl_irq_handler(unsigned irq, struct irq_desc *desc)
+{
+	struct sunxi_pinctrl *pctl = irq_get_handler_data(irq);
+	const unsigned long reg = readl(pctl->membase + IRQ_STATUS_REG);
+
+	/* Clear all interrupts */
+	writel(reg, pctl->membase + IRQ_STATUS_REG);
+
+	if (reg) {
+		int irqoffset;
+
+		for_each_set_bit(irqoffset, &reg, SUNXI_IRQ_NUMBER) {
+			int pin_irq = irq_find_mapping(pctl->domain, irqoffset);
+			generic_handle_irq(pin_irq);
+		}
+	}
+}
+
 static struct of_device_id sunxi_pinctrl_match[] = {
 	{ .compatible = "allwinner,sun4i-a10-pinctrl", .data = (void *)&sun4i_a10_pinctrl_data },
 	{ .compatible = "allwinner,sun5i-a13-pinctrl", .data = (void *)&sun5i_a13_pinctrl_data },
@@ -2005,6 +2135,31 @@ static int sunxi_pinctrl_probe(struct platform_device *pdev)
 
 	clk_prepare_enable(clk);
 
+	pctl->irq = irq_of_parse_and_map(node, 0);
+	if (!pctl->irq) {
+		ret = -EINVAL;
+		goto gpiochip_error;
+	}
+
+	pctl->domain = irq_domain_add_linear(node, SUNXI_IRQ_NUMBER,
+					     &irq_domain_simple_ops, NULL);
+	if (!pctl->domain) {
+		dev_err(&pdev->dev, "Couldn't register IRQ domain\n");
+		ret = -ENOMEM;
+		goto gpiochip_error;
+	}
+
+	for (i = 0; i < SUNXI_IRQ_NUMBER; i++) {
+		int irqno = irq_create_mapping(pctl->domain, i);
+
+		irq_set_chip_and_handler(irqno, &sunxi_pinctrl_irq_chip,
+					 handle_simple_irq);
+		irq_set_chip_data(irqno, pctl);
+	};
+
+	irq_set_chained_handler(pctl->irq, sunxi_pinctrl_irq_handler);
+	irq_set_handler_data(pctl->irq, pctl);
+
 	dev_info(&pdev->dev, "initialized sunXi PIO driver\n");
 
 	return 0;