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From: Wolfram Sang <wsa@the-dreams.de>
To: Sricharan <sricharan@codeaurora.org>
Cc: devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	agross@codeaurora.org, linux-kernel@vger.kernel.org,
	linux-i2c@vger.kernel.org, iivanov@mm-sol.com,
	galak@codeaurora.org, dmaengine@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, andy.gross@linaro.org,
	ntelkar@codeaurora.org, architt@codeaurora.org
Subject: Re: [PATCH V7 3/6] i2c: qup: Transfer each i2c_msg in i2c_msgs without a stop bit
Date: Thu, 4 Feb 2016 21:09:03 +0100	[thread overview]
Message-ID: <20160204200903.GE1958@tetsubishi> (raw)
In-Reply-To: <001401d15988$59f6dcf0$0de496d0$@codeaurora.org>

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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.

Thanks,

   Wolfram

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  reply	other threads:[~2016-02-04 20:09 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-19 10:02 [PATCH V7 0/6] i2c: qup: Add support for v2 tags and bam dma Sricharan R
2016-01-19 10:02 ` [PATCH V7 1/6] i2c: qup: Change qup_wait_writeready function to use for all timeouts Sricharan R
2016-02-12 18:37   ` Wolfram Sang
2016-01-19 10:02 ` [PATCH V7 2/6] i2c: qup: Add V2 tags support Sricharan R
2016-02-12 18:37   ` Wolfram Sang
2016-01-19 10:02 ` [PATCH V7 3/6] i2c: qup: Transfer each i2c_msg in i2c_msgs without a stop bit Sricharan R
2016-01-24 11:29   ` Wolfram Sang
2016-01-28  4:57     ` Sricharan
2016-02-04 20:09       ` Wolfram Sang [this message]
2016-02-05  8:00         ` Sricharan
2016-02-12 18:38   ` Wolfram Sang
2016-01-19 10:02 ` [PATCH V7 4/6] i2c: qup: Add bam dma capabilities Sricharan R
2016-02-12 18:37   ` Wolfram Sang
2016-02-12 18:42     ` Wolfram Sang
2016-02-13  6:58     ` Sricharan
2016-02-22 12:24     ` Sricharan
2016-02-22 12:32       ` Wolfram Sang
2016-02-22 13:41         ` Sricharan
2016-01-19 10:02 ` [PATCH V7 5/6] dts: msm8974: Add blsp2_bam dma node Sricharan R
2016-03-25 23:17   ` Bjorn Andersson
2016-03-26  2:26     ` Andy Gross
2016-03-28 12:59       ` Sricharan
2016-01-19 10:02 ` [PATCH V7 6/6] dts: msm8974: Add dma channels for blsp2_i2c1 node Sricharan R
2016-01-19 10:14 ` [PATCH V7 0/6] i2c: qup: Add support for v2 tags and bam dma Sricharan
2016-01-24 11:33   ` Wolfram Sang
2016-01-28  5:27     ` Sricharan

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