Add an else-if condition in the probe function to check whether ngpios is
multiple of 8.
Per AST datasheet, numbers of available serial GPIO pins in Serial GPIO
Configuration Register must be n bytes. For instance, if n = 1, it means
AST SoC supports 8 GPIO pins.

Signed-off-by: Steven Lee <redacted>
---
 drivers/gpio/gpio-aspeed-sgpio.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpio/gpio-aspeed-sgpio.c b/drivers/gpio/gpio-aspeed-sgpio.c
index f1e40486d401..1a3fcc721664 100644
--- a/drivers/gpio/gpio-aspeed-sgpio.c
+++ b/drivers/gpio/gpio-aspeed-sgpio.c

@@ -572,6 +572,10 @@ static int __init aspeed_sgpio_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "Number of GPIOs exceeds the maximum of %d: %d\n",
 			gpio->max_ngpios, nr_gpios);
 		return -EINVAL;
+	} else if (nr_gpios % 8) {
+		dev_err(&pdev->dev, "Number of GPIOs not multiple of 8: %d\n",
+			nr_gpios);
+		return -EINVAL;
 	}
 	gpio->n_sgpio = nr_gpios;
 

-- 
2.17.1