Re: [PATCH/RFC 1/1] recover from davinci i2c time out conditions

[Craig Matsuura <cmatsuura-/SMLdF/PHsZWk0Htik3J/w@public.gmane.org>]

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Philby,

Sorry, I forgot to mention, I did correct a problem with accessing a regs, it 
is where yo usend a NACK.  I changed the read from DAVINCI_I2C_IMR_REG to 
DAVINCI_I2C_MDR_REG.  

 +            flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
 +            flag |=  DAVINCI_I2C_MDR_NACK;
 +            /* write the data into mode register */
 +            davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);


Craig

On Monday 21 September 2009 12:31:00 am Philby John wrote:
> Hello Craig,
>
> 	Good to know. With out any modifications on a DM6443?
>
> Regards,
> Philby
>
> On Fri, 2009-09-18 at 23:12 -0600, Craig Matsuura wrote:
> > The patch submitted appears specific to the dm355. The changes are
> > very similar to the 2.6.10 kernel from mv. If the correct gpio's and
> > pinmux are disabled/enabled it should work for the dm644x.
> >
> >
> >
> > I took the patch from Philby and tried it on our dm6443 platform (on a
> > 2.6.28 kernel) and it appears to work for the problem we have when the
> > i2c appears to lock up.
> >
> >
> >
> > Craig
> >
> > On Wednesday 22 July 2009 5:14:35 am Philby John wrote:
> > > On Wed, 2009-07-22 at 04:03 -0700, Nitin Mahajan wrote:
> > > > Hello,
> > > >
> > > > ----- Original Message ----
> > > >
> > > > > From: Philby John <pjohn-k0rHJ+Hhz/SB+jHODAdFcQ@public.gmane.org>
> > > > > To: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> > > > > Cc: khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org;
> >
> > davinci-linux-open-source-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org
> >
> > > > > Sent: Wednesday, July 15, 2009 13:04:27
> > > > > Subject: [PATCH/RFC 1/1] recover from davinci i2c time out
> >
> > conditions
> >
> > > > > >From dbe7e824d576636bb15b82a20fd2557fddc9a8f7 Mon Sep 17
> >
> > 00:00:00 2001
> >
> > > > > From: Philby John
> > > > > Date: Tue, 14 Jul 2009 21:46:47 +0530
> > > > > Subject: [PATCH] Reset i2c bus to come out of time out
> >
> > conditions
> >
> > > > > Get out of i2c time out condition by resetting
> > > > > the i2c bus. The kernel must be robust enough to
> > > > > gracefully recover from i2c bus failure without having
> > > > > to reset the machine. This is done by first NACKing the slave
> > > > > and then resetting the i2c bus after a certain timeout.
> > > > >
> > > > > Signed-off-by: Philby John
> > > >
> > > > I tried this on DM6443 based board with 2.6.18 kernel. The result
> >
> > I am
> >
> > > > posting below. It gives controller time out again and again.
> > > >
> > > > dhcppc9 login: i2c_davinci i2c_davinci.1: controller timed out
> > > > i2c_davinci i2c_davinci.1: initiating i2c bus recovery
> > > > i2c_davinci i2c_davinci.1: controller timed out
> > > > i2c_davinci i2c_davinci.1: initiating i2c bus recovery
> > >
> > > There is something gravely wrong about this patch and I would submit
> >
> > a
> >
> > > fix shortly incorporating the review comments. But please be aware
> >
> > that
> >
> > > I do not guarantee a definitive time line for a fix cause I have
> >
> > much at
> >
> > > hand at the moment.
> > >
> > >
> > > Regards,
> > > Philby
> > >
> > >
> > > _______________________________________________
> > > Davinci-linux-open-source mailing list
> > > Davinci-linux-open-source-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org
> >
> > http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
> >
> > --
> >
> >
> >
> >
> >
> > ______________________________________________________________________
> >
> >
> > Craig Matsuura - Principal Engineer
> > Control4
> > 11734 South Election Road - Suite 200
> > Salt Lake City, UT 84020-6432
> > PH: 801-523-3161
> > FX: 801-523-3199

-- 




Craig Matsuura - Principal Engineer
Control4
11734 South Election Road - Suite 200
Salt Lake City, UT 84020-6432
PH: 801-523-3161
FX: 801-523-3199

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