[PATCH 2/2] gpiolib: don't allow OPEN_DRAIN & OPEN_SOURCE flags for input

Bartosz Golaszewski
2017-10-16T09:33:04Z

OPEN_DRAIN and OPEN_SOURCE flags only affect the way we drive a GPIO
line, so they only make sense for output mode. Just as we only allow
input mode for event handle requests, don't allow passing open-drain
and open-source flags for any other mode than explicit output.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
---
drivers/gpio/gpiolib.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 5d98345c9dc8..eac86ead6cfa 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -457,6 +457,12 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
if (lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
return -EINVAL;

+ /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
+ if (!(lflags & GPIOHANDLE_REQUEST_OUTPUT) &&
+ ((lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
+ (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
+ return -EINVAL;
+
lh = kzalloc(sizeof(*lh), GFP_KERNEL);
if (!lh)
return -ENOMEM;
--
2.13.2