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

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

On 05/16/14 05:00, Tomasz Figa wrote:
> On 15.05.2014 21:54, Kukjin Kim wrote:
>> 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?
>
> Nope. This series looked quite fine for me from the beginning, just
> wanted to make sure I understand things happening here correctly.
>
> Feel free to add
>
> Reviewed-by: Tomasz Figa<t.figa@samsung.com>
>
> to all four patches if not too late yet.
>
Tomasz,

Thanks for your review.

- Kukjin