[PATCH 2/3] i2c: sh_mobile: Use platform_get_irq_optional() to get the interrupt

[Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>]

platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.

In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq_optional() for DT users only.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
---
 drivers/i2c/busses/i2c-sh_mobile.c | 39 +++++++++++++++++++++++-------
 1 file changed, 30 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index 7b8caf172851..d887f351f53c 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -830,20 +830,41 @@ static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd)
 
 static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, struct sh_mobile_i2c_data *pd)
 {
-	struct resource *res;
-	resource_size_t n;
+	struct device_node *np = dev_of_node(&dev->dev);
 	int k = 0, ret;
 
-	while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
-		for (n = res->start; n <= res->end; n++) {
-			ret = devm_request_irq(&dev->dev, n, sh_mobile_i2c_isr,
-					  0, dev_name(&dev->dev), pd);
+	if (!np) {
+		struct resource *res;
+		resource_size_t n;
+
+		while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
+			for (n = res->start; n <= res->end; n++) {
+				ret = devm_request_irq(&dev->dev, n, sh_mobile_i2c_isr,
+						       0, dev_name(&dev->dev), pd);
+				if (ret) {
+					dev_err(&dev->dev, "cannot request IRQ %pa\n", &n);
+					return ret;
+				}
+			}
+			k++;
+		}
+	} else {
+		int irq;
+
+		do {
+			irq = platform_get_irq_optional(dev, k);
+			if (irq <= 0 && irq != -ENXIO)
+				return irq ? irq : -ENXIO;
+			if (irq == -ENXIO)
+				break;
+			ret = devm_request_irq(&dev->dev, irq, sh_mobile_i2c_isr,
+					       0, dev_name(&dev->dev), pd);
 			if (ret) {
-				dev_err(&dev->dev, "cannot request IRQ %pa\n", &n);
+				dev_err(&dev->dev, "cannot request IRQ %d\n", irq);
 				return ret;
 			}
-		}
-		k++;
+			k++;
+		} while (irq);
 	}
 
 	return k > 0 ? 0 : -ENOENT;
-- 
2.17.1