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SubjectRe: [PATCH 1/2] gpiolib: introduce gpio_set_pullup
On Fri, Nov 25, 2011 at 03:23:05PM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 16:16 Fri 25 Nov , Felipe Balbi wrote:
> > Hi,
> >
> > On Fri, Nov 25, 2011 at 03:08:39PM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > > Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
> > > Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
> > > Cc: Grant Likely <grant.likely@secretlab.ca>
> > > ---
> > > drivers/gpio/gpiolib.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
> > > include/asm-generic/gpio.h | 4 ++++
> > > include/linux/gpio.h | 5 +++++
> > > 3 files changed, 53 insertions(+), 0 deletions(-)
> > >
> > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> > > index a971e3d..b7e5e75 100644
> > > --- a/drivers/gpio/gpiolib.c
> > > +++ b/drivers/gpio/gpiolib.c
> > > @@ -1519,6 +1519,50 @@ fail:
> > > }
> > > EXPORT_SYMBOL_GPL(gpio_set_debounce);
> > >
> > > +/**
> > > + * gpio_set_pullup - sets @pullup for a @gpio
> > > + * @gpio: the gpio to set pullup
> > > + * @pullup: pullup level
> > > + */
> > > +int gpio_set_pullup(unsigned gpio, unsigned pullup)
> > > +{
> > > + unsigned long flags;
> > > + struct gpio_chip *chip;
> > > + struct gpio_desc *desc = &gpio_desc[gpio];
> > > + int status = -EINVAL;
> > > +
> > > + spin_lock_irqsave(&gpio_lock, flags);
> > > +
> > > + if (!gpio_is_valid(gpio))
> > > + goto fail;
> > > + chip = desc->chip;
> > > + if (!chip || !chip->set_pullup)
> > > + goto fail;
> > > + gpio -= chip->base;
> > > + if (gpio >= chip->ngpio)
> > > + goto fail;
> > > + status = gpio_ensure_requested(desc, gpio);
> > > + if (status < 0)
> > > + goto fail;
> > > +
> > > + /* now we know the gpio is valid and chip won't vanish */
> > > +
> > > + spin_unlock_irqrestore(&gpio_lock, flags);
> > > +
> > > + might_sleep_if(chip->can_sleep);
> > > +
> > > + return chip->set_pullup(chip, gpio, pullup);
> > > +
> > > +fail:
> > > + spin_unlock_irqrestore(&gpio_lock, flags);
> > > + if (status)
> > > + pr_debug("%s: gpio-%d status %d\n",
> > > + __func__, gpio, status);
> > > +
> > > + return status;
> > > +}
> > > +EXPORT_SYMBOL_GPL(gpio_set_pullup);
> >
> > Maybe I'm missing something, but isn't it essentially what
> > gpio_set_value() does ? I mean, you set a pullup and you get '1' value
> > and set a pulldown and you get a '0' value ??
> >
> > Without a proper description of the necessity for this change, I can't
> > easily tell them apart :-(
> set_value is for output set_pullup is for input mode
>
> some IP allow you when you configure an gpio as input to enable the
> internal pullup so no need on the board to add an external pull up

I see, that would fit nicely on the changelog :-)

--
balbi
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