linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "Jonas Mark (BT-FIR/ENG1-Grb)" <Mark.Jonas@de.bosch.com>
To: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>,
	Support Opensource <Support.Opensource@diasemi.com>,
	Lee Jones <lee.jones@linaro.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>,
	Steve Twiss <stwiss.opensource@diasemi.com>,
	"marek.vasut@gmail.com" <marek.vasut@gmail.com>,
	"RUAN Tingquan (BT-FIR/ENG1-Zhu)" <Tingquan.Ruan@cn.bosch.com>,
	"Streidl Hubert (BT-FIR/ENG1-Grb)" <Hubert.Streidl@de.bosch.com>,
	Wolfram Sang <wsa@kernel.org>,
	"Jonas Mark (BT-FIR/ENG1-Grb)" <Mark.Jonas@de.bosch.com>
Subject: AW: [PATCH v4] mfd: da9063: Support SMBus and I2C mode
Date: Fri, 19 Feb 2021 16:39:01 +0000	[thread overview]
Message-ID: <90bd35fa8c6f420fb1656c678c016509@de.bosch.com> (raw)
In-Reply-To: <PR3PR10MB41422B90076115ACCE07D2A5808E9@PR3PR10MB4142.EURPRD10.PROD.OUTLOOK.COM>

Hi,

> > From: Hubert Streidl <hubert.streidl@de.bosch.com>
> >
> > By default the PMIC DA9063 2-wire interface is SMBus compliant. This
> > means the PMIC will automatically reset the interface when the clock
> > signal ceases for more than the SMBus timeout of 35 ms.
> >
> > If the I2C driver / device is not capable of creating atomic I2C
> > transactions, a context change can cause a ceasing of the clock signal.
> > This can happen if for example a real-time thread is scheduled. Then
> > the DA9063 in SMBus mode will reset the 2-wire interface. Subsequently
> > a write message could end up in the wrong register. This could cause
> > unpredictable system behavior.
> >
> > The DA9063 PMIC also supports an I2C compliant mode for the 2-wire
> > interface. This mode does not reset the interface when the clock
> > signal ceases. Thus the problem depicted above does not occur.
> >
> > This patch tests for the bus functionality "I2C_FUNC_I2C". It can
> > reasonably be assumed that the bus cannot obey SMBus timings if this
> > functionality is set. SMBus commands most probably are emulated in
> > this case which is prone to the latency issue described above.
> >
> > This patch enables the I2C bus mode if I2C_FUNC_I2C is set or
> > otherwise enables the SMBus mode for a native SMBus controller which
> > doesn't have I2C_FUNC_I2C set.
> >
> > Signed-off-by: Hubert Streidl <hubert.streidl@de.bosch.com>
> > Signed-off-by: Mark Jonas <mark.jonas@de.bosch.com>
> 
> Thanks for your efforts. Looks sensible to me, so:
> 
> Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>

Is the patch already on the way upstream?

Is https://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git/log/?h=for-mfd-next the right place to watch for mainlining progress?

Thanks,
Mark

  reply	other threads:[~2021-02-19 16:39 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-08 15:27 [PATCH v4] mfd: da9063: Support SMBus and I2C mode Mark Jonas
2021-02-09 10:40 ` Wolfram Sang
2021-02-09 13:18 ` Adam Thomson
2021-02-19 16:39   ` Jonas Mark (BT-FIR/ENG1-Grb) [this message]
2021-02-20 11:07     ` Wolfram Sang
2021-02-22  9:10       ` Lee Jones
2021-03-08 14:42 ` Lee Jones
2021-03-09  8:19   ` Mark Jonas
2021-03-09  9:42     ` Lee Jones
2021-03-09 22:42       ` Adam Ward
2021-03-10  8:58         ` Lee Jones

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=90bd35fa8c6f420fb1656c678c016509@de.bosch.com \
    --to=mark.jonas@de.bosch.com \
    --cc=Adam.Thomson.Opensource@diasemi.com \
    --cc=Hubert.Streidl@de.bosch.com \
    --cc=Support.Opensource@diasemi.com \
    --cc=Tingquan.Ruan@cn.bosch.com \
    --cc=lee.jones@linaro.org \
    --cc=linux-i2c@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=marek.vasut@gmail.com \
    --cc=stwiss.opensource@diasemi.com \
    --cc=wsa@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).