Re: [PATCH 3/4] devicetree: bindings: Add defeature-repeated-start property for Cadence I2C

[Harini Katakam]

Hi,

On Tue, Dec 2, 2014 at 6:46 PM, Wolfram Sang <wsa@xxxxxxxxxxxxx> wrote:
>
>> But given the bugs, it will be useful to just disable it if the system doesn't
>> require repeated start.
>
> What do you do when disable repeated start? Sending STOP and START? If
> so, this is really something different than repeated start. By using
> I2C_FUNC_I2C a user expects repeated start, so if the HW does not
> support it, we should say so and don't try to emulate it with something
> different.
>

Yes, we send stop.
Using repeated start, when number of messages passed > 1, HOLD bit is set
by the driver. This is an indication to the controller not to send a STOP.
If we disable repeated start, the driver will not set HOLD bit.
All the messages are sent but with START and a STOP for each of them.

Regards,
Harini
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/