diff options
| author | Guenter Roeck <linux@roeck-us.net> | 2014-07-21 22:12:16 +0400 |
|---|---|---|
| committer | Linus Walleij <linus.walleij@linaro.org> | 2014-07-23 19:31:57 +0400 |
| commit | 2be001739242fac1083f3b21898158492844699d (patch) | |
| tree | f9f3564e20cd82eea5c0b27b0155dff51f24b365 | |
| parent | 190dc2e6844ad8a47838207cbe739c94d88d94cd (diff) | |
| download | linux-2be001739242fac1083f3b21898158492844699d.tar.xz | |
gpio: Add support for GPIOF_ACTIVE_LOW to gpio_request_one functions
The gpio include file and the gpio documentation declare and document
GPIOF_ACTIVE_LOW as one of the flags to be passed to gpio_request_one
and related functions. However, the flag is not evaluated or used.
This can cause problems in at least two areas: First, the same API can
be used to auto-export pins to user space. The missing support for
GPIOF_ACTIVE_LOW results in unexpected behavior for such auto-exported
pins. Second, the requested gpio pin can be convered for use by
gpiod functions with gpio_to_desc(). While gpio API functions do not
support GPIOF_ACTIVE_LOW, gpiod functions do, which again results in
unexpected behavior.
Check the flag in gpio_request_one and set the gpio internal flag
FLAG_ACTIVE_LOW if it is set to address those problems.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
| -rw-r--r-- | drivers/gpio/gpiolib-legacy.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-legacy.c b/drivers/gpio/gpiolib-legacy.c index eb5a4e2cee85..c684d94cdbb4 100644 --- a/drivers/gpio/gpiolib-legacy.c +++ b/drivers/gpio/gpiolib-legacy.c @@ -34,6 +34,9 @@ int gpio_request_one(unsigned gpio, unsigned long flags, const char *label) if (flags & GPIOF_OPEN_SOURCE) set_bit(FLAG_OPEN_SOURCE, &desc->flags); + if (flags & GPIOF_ACTIVE_LOW) + set_bit(FLAG_ACTIVE_LOW, &desc->flags); + if (flags & GPIOF_DIR_IN) err = gpiod_direction_input(desc); else |