[PATCH] spi: dw: Set default value if reg-io-width isn't specified

[Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>]

According to the dt-bindings, the default value of reg-io-width is 4.
However, the value becomes zero when reg-io-width isn't specified.

Should set the actual value to dws->reg_io_width, considering it
referenced.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>
---
 drivers/spi/spi-dw-mmio.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
index a963bc96c223..7eafc07ef7aa 100644
--- a/drivers/spi/spi-dw-mmio.c
+++ b/drivers/spi/spi-dw-mmio.c
@@ -369,7 +369,9 @@ static int dw_spi_mmio_probe(struct platform_device *pdev)
 
 	dws->max_freq = clk_get_rate(dwsmmio->clk);
 
-	device_property_read_u32(&pdev->dev, "reg-io-width", &dws->reg_io_width);
+	if (device_property_read_u32(&pdev->dev, "reg-io-width",
+				     &dws->reg_io_width))
+		dws->reg_io_width = 4;
 
 	num_cs = 4;
 
-- 
2.25.1