The Renesas RZ/T2H (R9A09G077) and RZ/N2H (R9A09G087) SoCs do not have
an error interrupt for the DMACs, and the current driver implementation
does not make much use of it.

To prepare for adding support for these SoCs, do not error out if the
error interrupt is missing.

Signed-off-by: Cosmin Tanislav <cosmin-gabriel.tanislav.xa@renesas.com>
---

V2:
 * pick up Fab's Reviewed-by

 drivers/dma/sh/rz-dmac.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
index 38137e8d80b9..20a5c1766a58 100644
--- a/drivers/dma/sh/rz-dmac.c
+++ b/drivers/dma/sh/rz-dmac.c
@@ -954,16 +954,15 @@ static int rz_dmac_probe(struct platform_device *pdev)
 	}
 
 	/* Register interrupt handler for error */
-	irq = platform_get_irq_byname(pdev, irqname);
-	if (irq < 0)
-		return irq;
-
-	ret = devm_request_irq(&pdev->dev, irq, rz_dmac_irq_handler, 0,
-			       irqname, NULL);
-	if (ret) {
-		dev_err(&pdev->dev, "failed to request IRQ %u (%d)\n",
-			irq, ret);
-		return ret;
+	irq = platform_get_irq_byname_optional(pdev, irqname);
+	if (irq > 0) {
+		ret = devm_request_irq(&pdev->dev, irq, rz_dmac_irq_handler, 0,
+				       irqname, NULL);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to request IRQ %u (%d)\n",
+				irq, ret);
+			return ret;
+		}
 	}
 
 	/* Initialize the channels. */
-- 
2.52.0