Thread (26 messages) 26 messages, 4 authors, 2016-03-28

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

From: Sricharan <hidden>
Date: 2016-02-05 08:00:39
Also in: linux-arm-msm, linux-devicetree, linux-i2c, lkml

Hi Wolfram,
-----Original Message-----
From: linux-arm-kernel [mailto:linux-arm-kernel-
bounces at lists.infradead.org] On Behalf Of Wolfram Sang
Sent: Friday, February 05, 2016 1:39 AM
To: Sricharan
Cc: devicetree at vger.kernel.org; architt at codeaurora.org; linux-arm-
msm at vger.kernel.org; ntelkar at codeaurora.org; galak at codeaurora.org;
linux-kernel at vger.kernel.org; andy.gross at linaro.org; linux-
i2c at vger.kernel.org; iivanov at mm-sol.com; agross at codeaurora.org;
dmaengine at vger.kernel.org; linux-arm-kernel at lists.infradead.org
Subject: Re: [PATCH V7 3/6] i2c: qup: Transfer each i2c_msg in i2c_msgs
without a stop bit

Hi,
quoted
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
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