Re: [PATCH] i2c: i2c_mxs: Set ACK_MODE bit

[Marek Vasut <marex-ynQEQJNshbs@public.gmane.org>]

Dear Fabio Estevam,

> Hi Uwe,
> 
> On 07/02/2013 03:11 PM, Uwe Kleine-König wrote:
> > On Tue, Jul 02, 2013 at 01:01:00PM -0300, Fabio Estevam wrote:
> >> According to mx23 erratum 2727:
> >> 
> >> "2727 : I2C 9th Clock Pulse (ACK) not generated when RETAIN_CLOCK set.
> >> 
> >> Description:
> >> 
> >> When RETAIN_CLOCK is set, the ninth clock pulse (ACK) is not generated.
> >> However, the SDA line is read at the proper timing interval. If
> >> RETAIN_CLOCK is cleared, the ninth clock pulse is generated.
> >> Also, the HW_I2C_VERSION register incorrectly states the version is 1.2.
> >> It should be 1.3.
> >> 
> >> Workaround:
> >> HW_I2C_CTRL1[ACK_MODE] has default value of 0. It should be set to 1 to
> >> enable the fix for this issue."
> >> 
> >> It has also been noticed that mx28 needs to implement this fix in order
> >> to have SMBus to work properly.
> >> 
> >> Reported-by: Christoph Baumann <cb-/RsSufbtIHM@public.gmane.org>
> >> Signed-off-by: Fabio Estevam <fabio.estevam-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
> > 
> > Did you see this making the driver handle some situations that caused
> > failure before?
> 
> No, I haven't. I saw the report from Christoph in the linux-arm-kernel
> mailing list:
> http://marc.info/?l=linux-arm-kernel&m=137277422127826&w=2
> 
> And thought it could be nice if we could get it fixed for mx23 and mx28.

How/when does this error manifest on the scope/LA?

Best regards,
Marek Vasut