[PATCH v6 9/9] gpio: gpio-aspeed-sgpio: Return error if ngpios is not multiple of 8.

[Steven Lee]

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 <steven_lee at aspeedtech.com>
Reviewed-by: Andrew Jeffery <andrew at aj.id.au>
---
 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 b3d05fc724f0..191b82a2560c 100644
--- a/drivers/gpio/gpio-aspeed-sgpio.c
+++ b/drivers/gpio/gpio-aspeed-sgpio.c
@@ -537,6 +537,10 @@ static int __init aspeed_sgpio_probe(struct platform_device *pdev)
 	if (rc < 0) {
 		dev_err(&pdev->dev, "Could not read ngpios property\n");
 		return -EINVAL;
+	} else if (nr_gpios % 8) {
+		dev_err(&pdev->dev, "Number of GPIOs not multiple of 8: %d\n",
+			nr_gpios);
+		return -EINVAL;
 	}
 
 	rc = device_property_read_u32(&pdev->dev, "bus-frequency", &sgpio_freq);
-- 
2.17.1