gpio: make gpiod_to_irq() return negative for NO_IRQ

If a translation returns zero, that means NO_IRQ, so we
should return an error since the function is documented to
return a negative code on error.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 340b021a37821a072619bde709bbf4b7e10cc5e9..a68c6d7328189a94444829fda5760c891920d248 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1999,13 +1999,22 @@ EXPORT_SYMBOL_GPL(gpiod_cansleep);
  */
 int gpiod_to_irq(const struct gpio_desc *desc)
 {
-       struct gpio_chip        *chip;
-       int                     offset;
+       struct gpio_chip *chip;
+       int offset;
 
        VALIDATE_DESC(desc);
        chip = desc->gdev->chip;
        offset = gpio_chip_hwgpio(desc);
-       return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
+       if (chip->to_irq) {
+               int retirq = chip->to_irq(chip, offset);
+
+               /* Zero means NO_IRQ */
+               if (!retirq)
+                       return -ENXIO;
+
+               return retirq;
+       }
+       return -ENXIO;
 }
 EXPORT_SYMBOL_GPL(gpiod_to_irq);