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Date: Thu, 30 Nov 2017 09:16:38 -0800
From: Guenter Roeck <linux@roeck-us.net>
To: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Peter Rosin <peda@axentia.se>, linux-kernel@vger.kernel.org,
        Rob Herring <robh+dt@kernel.org>, Mark Rutland <mark.rutland@arm.com>,
        Nicolas Ferre <nicolas.ferre@microchip.com>,
        Russell King <linux@armlinux.org.uk>, Jean Delvare <jdelvare@suse.com>,
        Ludovic Desroches <ludovic.desroches@microchip.com>,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-hwmon@vger.kernel.org
Subject: Re: [PATCH v2 2/2] ARM: dts: at91: disable the nxp,se97b SMBUS
 timeout on the TSE-850
Message-ID: <20171130171638.GA17788@roeck-us.net>
References: <20171127163101.27859-1-peda@axentia.se>
 <20171127163101.27859-3-peda@axentia.se>
 <20171129205311.GA20551@roeck-us.net>
 <20171129205629.GO21126@piout.net>
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On Wed, Nov 29, 2017 at 09:56:29PM +0100, Alexandre Belloni wrote:
> On 29/11/2017 at 12:53:11 -0800, Guenter Roeck wrote:
> > On Mon, Nov 27, 2017 at 05:31:01PM +0100, Peter Rosin wrote:
> > > The I2C adapter driver is sometimes slow, causing the SCL line to
> > > be stuck low for more than the stipulated SMBUS timeout of 25-35 ms.
> > > This causes the client device to give up which in turn causes silent
> > > corruption of data. So, disable the SMBUS timeout in the client device.
> > > 
> > > Signed-off-by: Peter Rosin <peda@axentia.se>
> > 
> > Acked-by: Guenter Roeck <linux@roeck-us.net>
> > 
> > I assume this will be sent upstream through an arm tree.
> > 
> 
> Yes, I'm applying it right now.
> 
Are you going to apply the patch for 4.15, or queue it up for 4.16 ?
I have been arguing with myself if this is a feature or a bug fix.
So far I queued the driver change up for 4.16, but I am open to
applying it to 4.15. Any thoughts ?

Guenter

> > Thanks,
> > Guenter
> > 
> > > ---
> > >  arch/arm/boot/dts/at91-tse850-3.dts | 1 +
> > >  1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/arch/arm/boot/dts/at91-tse850-3.dts b/arch/arm/boot/dts/at91-tse850-3.dts
> > > index 5f29010cdbd8..9b82cc8843e1 100644
> > > --- a/arch/arm/boot/dts/at91-tse850-3.dts
> > > +++ b/arch/arm/boot/dts/at91-tse850-3.dts
> > > @@ -221,6 +221,7 @@
> > >  	jc42@18 {
> > >  		compatible = "nxp,se97b", "jedec,jc-42.4-temp";
> > >  		reg = <0x18>;
> > > +		smbus-timeout-disable;
> > >  	};
> > >  
> > >  	dpot: mcp4651-104@28 {
> > > -- 
> > > 2.11.0
> > > 
> 
> -- 
> Alexandre Belloni, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com