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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 <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Bartosz Golaszewski 2017-11-15 16:47:43 +01:00 committed by Linus Walleij
parent e1c73a9906
commit 588fc3bcea
1 changed files with 9 additions and 0 deletions
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9
drivers/gpio/gpiolib.c
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@ -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) ||