gpio: mb86s70: Return error if requesting an already assigned gpio

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-mb86s7x.c b/drivers/gpio/gpio-mb86s7x.c
index 21b1ce5abdfe..ee93c0ab0a59 100644
--- a/drivers/gpio/gpio-mb86s7x.c
+++ b/drivers/gpio/gpio-mb86s7x.c
@@ -58,6 +58,11 @@ static int mb86s70_gpio_request(struct gpio_chip *gc, unsigned gpio)
         spin_lock_irqsave(&gchip->lock, flags);
 
         val = readl(gchip->base + PFR(gpio));
+        if (!(val & OFFSET(gpio))) {
+                spin_unlock_irqrestore(&gchip->lock, flags);
+                return -EINVAL;
+        }
+
         val &= ~OFFSET(gpio);
         writel(val, gchip->base + PFR(gpio));