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From: Stefan Eichenberger <eichest@gmail.com>
To: Frank Li <Frank.li@nxp.com>
Cc: o.rempel@pengutronix.de, kernel@pengutronix.de,
	andi.shyti@kernel.org, s.hauer@pengutronix.de,
	festevam@gmail.com, stefan.eichenberger@toradex.com,
	francesco.dolcini@toradex.com, linux-i2c@vger.kernel.org,
	imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v1 2/2] i2c: imx: ensure no clock is generated after last read
Date: Tue, 3 Mar 2026 10:14:08 +0100	[thread overview]
Message-ID: <aaamYByn9dZEIBWb@eichest-laptop> (raw)
In-Reply-To: <aZXq4gn4xhInQQlq@eichest-laptop>

Hi Frank,

On Wed, Feb 18, 2026 at 05:37:54PM +0100, Stefan Eichenberger wrote:
> Hi Frank,
> 
> On Wed, Feb 18, 2026 at 11:26:52AM -0500, Frank Li wrote:
> > On Wed, Feb 18, 2026 at 04:08:50PM +0100, Stefan Eichenberger wrote:
> > > From: Stefan Eichenberger <stefan.eichenberger@toradex.com>
> > >
> > > When reading from the I2DR register, right after releasing the bus by
> > > clearing MSTA and MTX, the I2C controller might still generate an
> > > additional clock cycle which can cause devices to misbehave. Ensure to
> > 
> > Do you means SCL have additional toggle? You capture waveform?
> > 
> 
> Yes exactly. We were able to capture the waveform when the issue
> happens. It doesn't always happen though, it depends on how much time
> passes between clearing MSTA and MTX and reading from I2DR.
> 
> If you want to see the waveform, I uploaded it to our server:
> https://share.toradex.com/dwnhcrl6b9toib6
> You can see the additional clock at the right end, after "0x17 + NAK".

Have you had a chance to look at the waveform? Do you have any concerns
about the proposed solution?

Best regards,
Stefan

  reply	other threads:[~2026-03-03  9:14 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20260218150940.131354-1-eichest@gmail.com>
2026-02-18 15:08 ` [PATCH v1 1/2] i2c: imx: fix i2c issue when reading multiple messages Stefan Eichenberger
2026-02-18 16:22   ` Frank Li
2026-02-18 15:08 ` [PATCH v1 2/2] i2c: imx: ensure no clock is generated after last read Stefan Eichenberger
2026-02-18 16:26   ` Frank Li
2026-02-18 16:37     ` Stefan Eichenberger
2026-03-03  9:14       ` Stefan Eichenberger [this message]
2026-03-03 15:53         ` Frank Li
2026-03-04  3:00           ` Carlos Song
2026-03-19 23:09             ` Andi Shyti
2026-03-20  2:04               ` [EXT] " Carlos Song

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