Messages in this thread | | | Date | Wed, 23 Jul 2014 17:32:42 +0200 | Subject | Re: [PATCH RESEND] gpio: Add support for GPIOF_ACTIVE_LOW to gpio_request_one functions | From | Linus Walleij <> |
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On Mon, Jul 21, 2014 at 8:12 PM, Guenter Roeck <linux@roeck-us.net> wrote:
> 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>
Patch applied after manually rebasing so it hits gpiolib-legacy.c.
Yours, Linus Walleij
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