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Subject: Re: [RFC PATCH i2c-next 1/2] dt-bindings: i2c: aspeed: Add
 'idle-wait-timeout-ms' setting
To:     Wolfram Sang <wsa@the-dreams.de>
Cc:     linux-aspeed@lists.ozlabs.org,
        James Feist <james.feist@linux.intel.com>,
        Andrew Jeffery <andrew@aj.id.au>, openbmc@lists.ozlabs.org,
        Brendan Higgins <brendanhiggins@google.com>,
        linux-kernel@vger.kernel.org,
        Jarkko Nikula <jarkko.nikula@linux.intel.com>,
        Vernon Mauery <vernon.mauery@linux.intel.com>,
        linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org
References: <20180910214519.14126-1-jae.hyun.yoo@linux.intel.com>
 <20180910214519.14126-2-jae.hyun.yoo@linux.intel.com>
 <a81a6092-a9d0-78d5-3596-cddc5d6a0713@linux.intel.com>
 <20180924215850.GD18592@kunai>
 <2c8563fd-0641-5237-0026-f559c480ad91@linux.intel.com>
 <20180925082717.GB2270@kunai>
From:   Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
Message-ID: <7b4e5715-3a87-8f77-8d0d-4647f02c87a8@linux.intel.com>
Date:   Tue, 25 Sep 2018 09:20:02 -0700
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On 9/25/2018 1:27 AM, Wolfram Sang wrote:
> On Mon, Sep 24, 2018 at 03:15:46PM -0700, Jae Hyun Yoo wrote:
>> Hi Wolfram,
>>
>> On 9/24/2018 2:58 PM, Wolfram Sang wrote:
>>> On Tue, Sep 18, 2018 at 11:02:54AM -0700, Jae Hyun Yoo wrote:
>>>> On 9/10/2018 2:45 PM, Jae Hyun Yoo wrote:
>>>>> +- idle-wait-timeout-ms	: bus idle waiting timeout in milliseconds when
>>>>> +			  multi-master is set, defaults to 100 ms when not
>>>>> +			  specified.
>>>>
>>>> Will change it to 'aspeed,idle-wait-timeout-ms' as it's a non standard
>>>> property.
>>>
>>> No need. This binding is not a HW description, so not a DT property in
>>> my book. I still don't understand: Your IP core in master mode does not
>>> have a BUSY bit or similar which detects when a START was detected and
>>> clears after a STOP?
>>>
>>
>> Okay, I'll keep this property as it is then.
> 
> Sorry for the misunderstanding. I don't think this a property, at all.
> It doesn't describe the hardware, it is more of a configuration thing,
> or?
> 

You are right. It doesn't describe the hardware but it needs to be
configurable because it very depends on the peer master's behavior.
If peer master sends a long packet usually, it should have a long
timeout value since a slave receiving operation takes long time,
and it should be adjusted with an optimal value with taking some
experiments to make it not too long. Any suggestion?

Thanks,
Jae