[RFC v7 5/6] gpio: mpfs: pass gpio line number as irq data

[Conor Dooley <conor.dooley@microchip.com>]

Since the interrupt mux is going to provide us a 1:1 mapping for
interrupts, and it is no longer correct to hit all of the set bits in
the interrupt handler, store the GPIO that "owns" an interrupt in its
data pointer, so that we can determine which bit to clear.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
This patch will need to be squashed, I've kept it apart for illustrative
purposes.
---
 drivers/gpio/gpio-mpfs.c | 85 +++++++++++++++++++++++++++-------------
 1 file changed, 57 insertions(+), 28 deletions(-)

diff --git a/drivers/gpio/gpio-mpfs.c b/drivers/gpio/gpio-mpfs.c
index 1ac0526ba1029..b92f094964822 100644
--- a/drivers/gpio/gpio-mpfs.c
+++ b/drivers/gpio/gpio-mpfs.c
@@ -43,6 +43,7 @@ struct mpfs_gpio_chip {
 	struct clk *clk;
 	raw_spinlock_t	lock;
 	struct gpio_chip gc;
+	u8 irq_data[MAX_NUM_GPIO];
 };
 
 static void mpfs_gpio_assign_bit(void __iomem *addr, unsigned int bit_offset, bool value)
@@ -129,7 +130,7 @@ static int mpfs_gpio_irq_set_type(struct irq_data *data, unsigned int type)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
 	struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
-	int gpio_index = irqd_to_hwirq(data);
+	int gpio_index = irqd_to_hwirq(data) % 32;
 	u32 interrupt_type;
 	u32 gpio_cfg;
 	unsigned long flags;
@@ -168,11 +169,10 @@ static void mpfs_gpio_irq_unmask(struct irq_data *data)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
 	struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
-	int gpio_index = irqd_to_hwirq(data);
+	int gpio_index = irqd_to_hwirq(data) % 32;
 
 	gpiochip_enable_irq(gc, gpio_index);
 	mpfs_gpio_direction_input(gc, gpio_index);
-	mpfs_gpio_assign_bit(mpfs_gpio->base + MPFS_IRQ_REG, gpio_index, 1);
 	mpfs_gpio_assign_bit(mpfs_gpio->base + MPFS_GPIO_CTRL(gpio_index),
 			     MPFS_GPIO_EN_INT, 1);
 }
@@ -181,19 +181,18 @@ static void mpfs_gpio_irq_mask(struct irq_data *data)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
 	struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
-	int gpio_index = irqd_to_hwirq(data);
+	int gpio_index = irqd_to_hwirq(data) % 32;
 
-	mpfs_gpio_assign_bit(mpfs_gpio->base + MPFS_IRQ_REG, gpio_index, 1);
 	mpfs_gpio_assign_bit(mpfs_gpio->base + MPFS_GPIO_CTRL(gpio_index),
 			     MPFS_GPIO_EN_INT, 0);
 	gpiochip_disable_irq(gc, gpio_index);
 }
 
 static const struct irq_chip mpfs_gpio_irqchip = {
-	.name = "mpfs",
+	.name = "MPFS GPIO",
 	.irq_set_type = mpfs_gpio_irq_set_type,
-	.irq_mask	= mpfs_gpio_irq_mask,
-	.irq_unmask	= mpfs_gpio_irq_unmask,
+	.irq_mask = mpfs_gpio_irq_mask,
+	.irq_unmask = mpfs_gpio_irq_unmask,
 	.flags = IRQCHIP_IMMUTABLE | IRQCHIP_MASK_ON_SUSPEND,
 	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
@@ -201,18 +200,24 @@ static const struct irq_chip mpfs_gpio_irqchip = {
 static void mpfs_gpio_irq_handler(struct irq_desc *desc)
 {
 	struct irq_chip *irqchip = irq_desc_get_chip(desc);
-	struct mpfs_gpio_chip *mpfs_gpio =
-		gpiochip_get_data(irq_desc_get_handler_data(desc));
+	void *handler_data = irq_desc_get_handler_data(desc);
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(&desc->irq_data);
+	struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
+	u8 gpio_index = *((u8 *)handler_data);
 	unsigned long status;
-	int offset;
+
+	/*
+	 * Since the parent may be a muxed/"non-direct" interrupt, this
+	 * interrupt may not be for us.
+	 */
+	status = readl(mpfs_gpio->base + MPFS_IRQ_REG);
+	if (!(status & BIT(gpio_index)))
+		return;
 
 	chained_irq_enter(irqchip, desc);
 
-	status = readl(mpfs_gpio->base + MPFS_IRQ_REG);
-	for_each_set_bit(offset, &status, mpfs_gpio->gc.ngpio) {
-		mpfs_gpio_assign_bit(mpfs_gpio->base + MPFS_IRQ_REG, offset, 1);
-		generic_handle_irq(irq_find_mapping(mpfs_gpio->gc.irq.domain, offset));
-	}
+	generic_handle_irq(irq_find_mapping(mpfs_gpio->gc.irq.domain, gpio_index));
+	mpfs_gpio_assign_bit(mpfs_gpio->base + MPFS_IRQ_REG, gpio_index, 1);
 
 	chained_irq_exit(irqchip, desc);
 }
@@ -222,6 +227,7 @@ static int mpfs_gpio_probe(struct platform_device *pdev)
 	struct clk *clk;
 	struct device *dev = &pdev->dev;
 	struct device_node *node = pdev->dev.of_node;
+	void **irq_data = NULL;
 	struct mpfs_gpio_chip *mpfs_gpio;
 	struct gpio_irq_chip *girq;
 	int i, ret, ngpios, nirqs;
@@ -232,7 +238,8 @@ static int mpfs_gpio_probe(struct platform_device *pdev)
 
 	mpfs_gpio->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(mpfs_gpio->base))
-		return dev_err_probe(dev, PTR_ERR(mpfs_gpio->base), "failed to ioremap memory resource\n");
+		return dev_err_probe(dev, PTR_ERR(mpfs_gpio->base),
+				     "failed to ioremap memory resource\n");
 
 	clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(clk))
@@ -266,20 +273,42 @@ static int mpfs_gpio_probe(struct platform_device *pdev)
 		ret = -ENXIO;
 		goto cleanup_clock;
 	}
+
 	girq = &mpfs_gpio->gc.irq;
-	gpio_irq_chip_set_chip(girq, &mpfs_gpio_irqchip);
-	girq->handler = handle_simple_irq;
-	girq->parent_handler = mpfs_gpio_irq_handler;
-	girq->default_type = IRQ_TYPE_NONE;
 	girq->num_parents = nirqs;
-	girq->parents = devm_kcalloc(&pdev->dev, nirqs,
-				     sizeof(*girq->parents), GFP_KERNEL);
-	if (!girq->parents) {
-		ret = -ENOMEM;
-		goto cleanup_clock;
+
+	if (girq->num_parents) {
+		gpio_irq_chip_set_chip(girq, &mpfs_gpio_irqchip);
+		girq->parent_handler = mpfs_gpio_irq_handler;
+
+		girq->parents = devm_kcalloc(&pdev->dev, girq->num_parents,
+					     sizeof(*girq->parents), GFP_KERNEL);
+		irq_data = devm_kmalloc_array(&pdev->dev, girq->num_parents,
+					      sizeof(*irq_data), GFP_KERNEL);
+
+		if (!girq->parents || !irq_data) {
+			ret = -ENOMEM;
+			goto cleanup_clock;
+		}
+
+		for (i = 0; i < girq->num_parents; i++) {
+			ret = platform_get_irq(pdev, i);
+			if (ret < 0)
+				goto cleanup_clock;
+
+			girq->parents[i] = ret;
+			mpfs_gpio->irq_data[i] = i;
+			irq_data[i] = &mpfs_gpio->irq_data[i];
+
+			irq_set_chip_data(ret, &mpfs_gpio->gc);
+			irq_set_handler(ret, handle_simple_irq);
+		}
+
+		girq->parent_handler_data_array = irq_data;
+		girq->per_parent_data = true;
+		girq->handler = handle_simple_irq;
+		girq->default_type = IRQ_TYPE_NONE;
 	}
-	for (i = 0; i < nirqs; i++)
-		girq->parents[i] = platform_get_irq(pdev, i);
 
 	ret = gpiochip_add_data(&mpfs_gpio->gc, mpfs_gpio);
 	if (ret)
-- 
2.43.2