Messages in this thread Patch in this message | | | From | Bartosz Golaszewski <> | Subject | [PATCH] gpiolib: don't allow OPEN_DRAIN & OPEN_SOURCE flags simultaneously | Date | Wed, 15 Nov 2017 16:47:43 +0100 |
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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 <linus.walleij@linaro.org> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl> --- There was a misunderstanding as to what the goal of my previous commit 609aaf6a6029 ("gpiolib: don't allow OPEN_DRAIN & OPEN_SOURCE flags for input") was, which resulted in discovering another thing that needs fixing. This change was suggested to me by Linus earlier today.
drivers/gpio/gpiolib.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 641a5eb552cb..ec80e0146fd5 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) || -- 2.13.2
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