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SubjectRE: [EXT] Re: [PATCH v3] i2c: imx-lpi2c: directly return ISR when detect a NACK
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> -----Original Message-----
> From: Andi Shyti <andi.shyti@kernel.org>
> Sent: Wednesday, July 26, 2023 10:52 PM
> To: Carlos Song <carlos.song@nxp.com>
> Cc: Aisheng Dong <aisheng.dong@nxp.com>; shawnguo@kernel.org;
> s.hauer@pengutronix.de; kernel@pengutronix.de; festevam@gmail.com; Clark
> Wang <xiaoning.wang@nxp.com>; Bough Chen <haibo.chen@nxp.com>;
> dl-linux-imx <linux-imx@nxp.com>; linux-i2c@vger.kernel.org;
> linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org
> Subject: [EXT] Re: [PATCH v3] i2c: imx-lpi2c: directly return ISR when detect a
> NACK
>
> Caution: This is an external email. Please take care when clicking links or
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>
> Hi Carlos,
>
> On Wed, Jul 26, 2023 at 05:23:50PM +0800, carlos.song@nxp.com wrote:
> > From: Carlos Song <carlos.song@nxp.com>
> >
> > A NACK flag in ISR means i2c bus error. In such condition, there is no
> > need to do read/write operation.
> >
> > In this patch, i2c will check MSR_NDF, MSR_RDF and MSR_TDF flag in
> > turn, it's making mutually exclusive NACK/read/write.
> > So when a NACK is received(MSR_NDF), i2c will return ISR directly and
> > then stop i2c transfer.
>
> Very good, thank you!
>
> > Fixes: a55fa9d0e42e ("i2c: imx-lpi2c: add low power i2c bus driver")
>
> One last little question here. I want to know if this is actually fixing something or
> cleaning the exit path. What I mean is:
> can the device ever send an NDF along with an RDF or TDF?
>
> If not, this "Fixes:" tag should be removed and this patch can be considered a
> cleanup. Otherwise would be nice to know what failure are you fixing.
>
> I'm just trying to understand here :)
>
> Andi


Hi, Andi,
Yes, no failure to fix just a cleanup. I will remove it and resend v4.

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