Re: [PATCH v3 1/4] i2c: tegra: implement slave mode

From	Andrey Danin <danindrey@mail.ru>
Newsgroups	linux.kernel
Subject	Re: [PATCH v3 1/4] i2c: tegra: implement slave mode
Date	2015-08-20 14:20 +0200
Message-ID	<pZwZ4-4Ab-33@gated-at.bofh.it> (permalink)
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On 24.07.2015 13:52, Wolfram Sang wrote:
>
>> At the begin of my work on this patchset I even denied clock disable call if
>> slave is registered (to minimize code that can affect transfer).
>
> I hacked something like this, but it seems it was not enough.
>
>> If only slave mode is used, then this logic is not needed.
>
> This is not sufficent. We shouldn't break being a master only because we
> also listen to a slave address (as long as the HW supports that of
> course).
>
>> tegra_i2c_init is called on probe and resume. Also it is called in case of
>> xfer fail. If xfer is ok, then I think slave addr must be kept unchanged.
>
> This is fragile. Try scanning the bus with i2cdetect and slave setup
> will be gone.
>
>> As far as I understand it is a loopback mode. Probably it will not work
>> (Stephen Warren already mentioned this).
>
> Just to make clear: I am not saying we should support talking to our own
> slave address. But it should still be possible to communicate with other
> remote devices on the bus.

Sorry for the long delay. I tried to analyze the issue. Attached patch 
works on AC100 (Misha Komarovsky helped me with testing).

Wolfram could you please try the patch with your environment?


Thanks.

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Re: [PATCH v3 1/4] i2c: tegra: implement slave mode Andrey Danin <danindrey@mail.ru> - 2015-08-20 14:20 +0200

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