i2c: brcmstb: Fix handling of optional interrupt

If there is no interrupt defined then an error is logged due
to the use of platform_get_irq. The driver handles not having
the interrupt by falling back to polling, therefore make
the appropriate call when claiming it.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-brcmstb.c

@@ -647,20 +647,22 @@ static int brcmstb_i2c_probe(struct platform_device *pdev)
 		int_name = NULL;
 
 	/* Get the interrupt number */
-	dev->irq = platform_get_irq(pdev, 0);
+	dev->irq = platform_get_irq_optional(pdev, 0);
 
 	/* disable the bsc interrupt line */
 	brcmstb_i2c_enable_disable_irq(dev, INT_DISABLE);
 
 	/* register the ISR handler */
-	rc = devm_request_irq(&pdev->dev, dev->irq, brcmstb_i2c_isr,
-			      IRQF_SHARED,
-			      int_name ? int_name : pdev->name,
-			      dev);
-
-	if (rc) {
-		dev_dbg(dev->device, "falling back to polling mode");
-		dev->irq = -1;
+	if (dev->irq >= 0) {
+		rc = devm_request_irq(&pdev->dev, dev->irq, brcmstb_i2c_isr,
+				      IRQF_SHARED,
+				      int_name ? int_name : pdev->name,
+				      dev);
+
+		if (rc) {
+			dev_dbg(dev->device, "falling back to polling mode");
+			dev->irq = -1;
+		}
 	}
 
 	if (of_property_read_u32(dev->device->of_node,