On Mon, 17 May 2010 13:02:30 +0300 felipe.balbi@xxxxxxxxx wrote: > From: Felipe Balbi <felipe.balbi@xxxxxxxxx> > > Few architectures, like OMAP, allow you to set > a debouncing time for the gpio before generating > the IRQ. Teach gpiolib about that. > > ... > > --- a/drivers/gpio/gpiolib.c > +++ b/drivers/gpio/gpiolib.c > @@ -1447,6 +1447,49 @@ fail: > } > EXPORT_SYMBOL_GPL(gpio_direction_output); > > +/** > + * gpio_set_debounce - sets @debounce time for a @gpio > + * @gpio: the gpio to set debounce time > + * @debounce: debounce time is microseconds > + */ > +int gpio_set_debounce(unsigned gpio, unsigned debounce) > +{ > + 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 || !chip->set_debounce) > + 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(extra_checks && chip->can_sleep); > + > + return chip->set_debounce(chip, gpio, debounce); > + > +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_debounce); nitlet: I suspect this function is taking gpio_lock sooner than it strictly needs to. Find-tuning that would decrease contention by an insignificant amount ;) -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html