Re: [PATCH 1/4] ARM: dts: exynos5250-snow: add pinctrl for i2c-arbitrator

[Kukjin Kim <kgene.kim@samsung.com>]

On 04/15/14 07:53, Doug Anderson wrote:

+ DT ML

> Tomasz,
>

> On Mon, Apr 14, 2014 at 3:38 PM, Tomasz Figa<tomasz.figa@gmail.com>  wrote:
>> Hi Doug,
>>
>>
>> On 15.04.2014 00:30, Doug Anderson wrote:
>>>
>>> Sachin,
>>>
>>> On Mon, Apr 14, 2014 at 6:16 AM, Sachin Kamat<sachin.kamat@linaro.org>
>>> wrote:
>>>>
>>>> From: Doug Anderson<dianders@chromium.org>
>>>
>>>
>>> I probably wouldn't have bothered giving me authorship since this
>>> isn't exactly a clean patch from the chromium tree (you pulled the
>>> proper pieces yourself, did the commit message yourself, etc).  ...but
>>> I appreciate the thought and as far as I know setting the "author" in
>>> cases like this is a bit of a judgement call...
>>>
>>> The Signed-off-by is certainly correct.  ;)
>>>
>>>>
>>>> Added i2c-arbitrator pinctrl node to Snow board.
>>>>
>>>> Signed-off-by: Doug Anderson<dianders@chromium.org>
>>>> Signed-off-by: Sachin Kamat<sachin.kamat@linaro.org>
>>>> ---
>>>>    arch/arm/boot/dts/exynos5250-snow.dts |   19 +++++++++++++++++++
>>>>    1 file changed, 19 insertions(+)
>>>
>>>
>>> This matches what's in our tree and and is what people are using, so:
>>>
>>> Reviewed-by: Doug Anderson<dianders@chromium.org>
>>>
>>>
>>>> diff --git a/arch/arm/boot/dts/exynos5250-snow.dts
>>>> b/arch/arm/boot/dts/exynos5250-snow.dts
>>>> index 1ce1088..32715b3 100644
>>>> --- a/arch/arm/boot/dts/exynos5250-snow.dts
>>>> +++ b/arch/arm/boot/dts/exynos5250-snow.dts
>>>> @@ -39,6 +39,22 @@
>>>>                   };
>>>>           };
>>>>
>>>> +       pinctrl@13400000 {
>>>> +               arb_their_claim: arb-their-claim {
>>>> +                       samsung,pins = "gpe0-4";
>>>> +                       samsung,pin-function =<0>;
>>>> +                       samsung,pin-pud =<3>;
>>>> +                       samsung,pin-drv =<0>;
>>>> +               };
>>>> +
>>>> +               arb_our_claim: arb-our-claim {
>>>> +                       samsung,pins = "gpf0-3";
>>>> +                       samsung,pin-function =<1>;
>>>> +                       samsung,pin-pud =<0>;
>>>> +                       samsung,pin-drv =<0>;
>>>> +               };
>>>
>>>
>>> It's odd to me that one of these has a pullup but not the other, but I
>>> think that's because the arbitration lines ended up using some other
>>> signals that were originally hooked up for other usage.  Certainly the
>>> pullups / pulldowns match what's in our tree and also match what we
>>> had in the original shipping 3.4 kernel.
>>
>>
>> Just a wild guess, but probably the input needs a pull-up, while obviously
>> the output doesn't. I don't have much idea about the arbitration thing
>> happening on snow, so I can't say much about this series. (Maybe description
>> of patch 1/4 should be saying a bit more about the meaning of this?)
>
> Right, of course.  I'm not sure quite what I was thinking.  I think I
> was getting confused since these go through level converters and my
> brain was in open drain mode.  ...but looking at this again this looks
> reasonable.
>
> I think the whole discussion of arbitration was from a long time ago.
> I think it's fairly well documented in the "i2c-arb-gpio-challenge"
> driver.
>
> Basically it looks like Sachin is getting pinctrl stuff matched up
> properly for the device tree that's upstream.
>
Sounds OK to me.

Tomasz, do you have any concerns still?

Thanks,
Kukjin