Re: [PATCH 1/5] gpio: Cygnus: define Broadcom Cygnus GPIO binding

Linus Walleij
2015-01-13T07:57:32Z

On Sat, Dec 6, 2014 at 1:40 AM, Ray Jui <rjui@broadcom.com> wrote:

> Document the GPIO device tree binding for Broadcom Cygnus SoC
>
> Signed-off-by: Ray Jui <rjui@broadcom.com>
> Reviewed-by: Scott Branden <sbranden@broadcom.com>
(...)
> +- #gpio-cells:
> + Must be two. The first cell is the GPIO pin number (within the
> +controller's domain) and the second cell is used for the following:
> + bit[0]: polarity (0 for normal and 1 for inverted)
> + bit[18:16]: internal pull up/down: 0 - pull up/down disabled
> + 1 - pull up enabled
> + 2 - pull down enabled
> + bit[22:20]: drive strength: 0 - 2 mA
> + 1 - 4 mA
> + 2 - 6 mA
> + 3 - 8 mA
> + 4 - 10 mA
> + 5 - 12 mA
> + 6 - 14 mA
> + 7 - 16 mA

No. This pull up/down and drive strength is pin controller
business, use a pin control backend behind the GPIO driver
see Documentation/pinctrl.txt.

Initial states for these configurations can be set up using
pin control hogs since pin control and GPIO is orthogonal.

Yours,
Linus Walleij