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

Ray Jui
2015-01-13T17:07:31Z

On 1/12/2015 11:57 PM, Linus Walleij wrote:
> 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.
>
Yes, I got it! See my reply in the GPIO driver review. Thanks.

> Yours,
> Linus Walleij
>