From 33475911186d0cde85a8a0d6f5721cf62f43121d Mon Sep 17 00:00:00 2001
From: Linus Walleij <linus.walleij@linaro.org>
Date: Wed, 15 Jun 2016 22:57:38 +0200
Subject: [PATCH] gpio: make sure gpiod_to_irq() returns negative on NULL desc
commit 2e30dd33e6414b5dd7cc3f00192d925ba481cdd8
("gpio: bail out silently on NULL descriptors")
doesn't work for gpiod_to_irq(): drivers assume that NULL
descriptors will give negative IRQ numbers in return.
It has been pointed out that returning 0 is NO_IRQ and that
drivers should be amended to treat this as an error, but that
is for the longer term: now let us repair the semantics.
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Reported-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
drivers/gpio/gpiolib.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 58d822d7e8da1..f39bf05993e7f 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2056,7 +2056,14 @@ int gpiod_to_irq(const struct gpio_desc *desc)
struct gpio_chip *chip;
int offset;
- VALIDATE_DESC(desc);
+ /*
+ * Cannot VALIDATE_DESC() here as gpiod_to_irq() consumer semantics
+ * requires this function to not return zero on an invalid descriptor
+ * but rather a negative error number.
+ */
+ if (!desc || !desc->gdev || !desc->gdev->chip)
+ return -EINVAL;
+
chip = desc->gdev->chip;
offset = gpio_chip_hwgpio(desc);
if (chip->to_irq) {
--
2.39.5