Re: [PATCH] of/gpio: Define OF_GPIO_OPEN_DRAIN flag for Open Drain outputs.

[David Daney]

On 02/10/2014 08:31 PM, Alexandre Courbot wrote:
> On Tue, Feb 11, 2014 at 7:05 AM, David Daney <ddaney.cavm@xxxxxxxxx> wrote:
> > From: David Daney <david.daney@xxxxxxxxxx>
> >
> > When we have a GPIO pin connected to an open-drain network, we want a
> > standard way of specifying this in the device tree.  So we choose bit
> > 1 of the flag field to indicate open drain.
> >
> > A typical use case would be something like:
> >
> >          enum of_gpio_flags f;
> >          .
> >          .
> >          .
> >          reset_gpio = of_get_named_gpio_flags(node, "reset", 0, &f);
> >          .
> >          .
> >          .
> >          ret = gpio_request_one(reset_gpio,
> >                  (f & OF_GPIO_OPEN_DRAIN) ? GPIOF_OPEN_DRAIN : 0,
> >                   "reset");
> >          .
> >          .
> >          .
> >          gpio_direction_output(reset_gpio, 1);
> >          gpio_set_value(reset_gpio, 0);
> >          msleep(20);
> >          gpio_set_value(reset_gpio, 1);
>
> This is also useful for gpiod_get(). However, while you are at it,
> could you also add a flag for the OF_GPIO_OPEN_SOURCE property? My joy
> would be complete if you could also take the time to update
> of_find_gpio() to pass these new flags back to the caller as it
> already does for OF_GPIO_ACTIVE_LOW.
>
> Then you could even switch your use-case to the gpiod interface and
> not bother with passing these flags by yourself anymore. Just sayin'.
> ;)

Thanks for the suggestion.  I will send a revised patch set for your 
consideration.

David Daney

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/