RE: [PATCH V7 3/6] i2c: qup: Transfer each i2c_msg in i2c_msgs without a stop bit

Sricharan
2016-02-05T08:00:39Z

Hi Wolfram,

> -----Original Message-----
> From: linux-arm-kernel [mailto:linux-arm-kernel-
> bounces@lists.infradead.org] On Behalf Of Wolfram Sang
> Sent: Friday, February 05, 2016 1:39 AM
> To: Sricharan
> Cc: devicetree@vger.kernel.org; architt@codeaurora.org; linux-arm-
> msm@vger.kernel.org; ntelkar@codeaurora.org; galak@codeaurora.org;
> linux-kernel@vger.kernel.org; andy.gross@linaro.org; linux-
> i2c@vger.kernel.org; iivanov@mm-sol.com; agross@codeaurora.org;
> dmaengine@vger.kernel.org; linux-arm-kernel@lists.infradead.org
> Subject: Re: [PATCH V7 3/6] i2c: qup: Transfer each i2c_msg in i2c_msgs
> without a stop bit
>
> Hi,
>
> > Ah, so what I meant above is there is no 'STOP' bit between each msg
> > in i2c_msgs, but 'REAPEATED_START' still holds true. We are sending
> > 'START' bit for each msg.
> > So these is how each msg in i2c_msg is sent,
> >
> > |------MSG1--------|-----MSG2---------|------MSG3------------|
> >
> > |START|DATA|------|START|DATA|---|START|DATA|STOP|
> >
> > If my commit text does not make this clear, I can reword that ?
>
> OK, now this looks to me perfectly fine: A number of *messages*
> concatenated into one *transfer* by repeated start. That's the way it
should
> be.
>
> So, I'd simply remove these words:
>
> "The QUP i2c hardware has no way to inform that there should not be a
> 'STOP' at the end of transaction. The only way to implement this is to
> coalesce all the i2c_msg in i2c_msgs in to one transaction and transfer
them."
>
> This sounded like the HW needed a special handling, so I was under the
> impression REP_START was broken. However, unless I misunderstood
> something again, this now sounds like the standard case and we can keep
> the commit message simple. If you are okay with that, I can update it
here,
> no need to resend.
>
Yes the above modified commit text looks perfect to be updated and
thanks
for the update as well.

Regards,
Sricharan