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

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

Dear Wolfram Sang,

> 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>
> 
> What's with this one? Bogus? Needed? Still needed after PIO rework?

I dont think this is needed on MX28 as this is set by default. On MX23, I dont 
see any difference with this enabled/disabled.

Best regards,
Marek Vasut