From mboxrd@z Thu Jan 1 00:00:00 1970 From: sricharan@codeaurora.org (Sricharan) Date: Fri, 5 Feb 2016 13:30:25 +0530 Subject: [PATCH V7 3/6] i2c: qup: Transfer each i2c_msg in i2c_msgs without a stop bit In-Reply-To: <20160204200903.GE1958@tetsubishi> References: <1453197766-18976-1-git-send-email-sricharan@codeaurora.org> <1453197766-18976-4-git-send-email-sricharan@codeaurora.org> <20160124112915.GA1775@katana> <001401d15988$59f6dcf0$0de496d0$@codeaurora.org> <20160204200903.GE1958@tetsubishi> Message-ID: <006e01d15feb$4a08d0a0$de1a71e0$@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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, > > > 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