From 588fc3bceaf81bbd62e18af6f7bd475e01c2b7e8 Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Wed, 15 Nov 2017 16:47:43 +0100 Subject: [PATCH] gpiolib: don't allow OPEN_DRAIN & OPEN_SOURCE flags simultaneously Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If the hardware actually supports enabling both at the same time the electrical result would be disastrous. Suggested-by: Linus Walleij Signed-off-by: Bartosz Golaszewski Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index aad84a6306c4..bdcdcdefdb71 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -459,6 +459,15 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip) if (lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) return -EINVAL; + /* + * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If + * the hardware actually supports enabling both at the same time the + * electrical result would be disastrous. + */ + if ((lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) && + (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) + return -EINVAL; + /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */ if (!(lflags & GPIOHANDLE_REQUEST_OUTPUT) && ((lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||