Re: [PATCH v2 0/2] i2c:dw: Add APM X-Gene ACPI I2C device support

Ben Dooks
2016-01-04T09:09:37Z

On 23/12/15 09:34, Ken Xue wrote:
> On Tue, 2015-12-15 at 16:59 +0200, Mika Westerberg wrote:
>> On Tue, Dec 15, 2015 at 08:52:19AM -0600, Suravee Suthikulpanit wrote:

> During test, I2C bus should run in different "ConnectionSpeed" of
> device.
>
> That means windows driver can modify I2C bus speed to match the
> "ConnectionSpeed" of device on-the-fly. Static value from SSCN and FMCN
> can not work for WITT test cases.
>
> It sounds like odd that multi-speed can be applied over one I2C bus, But
> everything goes well.
> Does this behavior(multi-speed) violate the I2C spec?

I can't remember if the spec says it, but I would say the bus should
run at the speed of the slowest attached peripheral as they all have
to listen for the address-byte being sent at the start of each i2c
transaction.

--
Ben Dooks http://www.codethink.co.uk/
Senior Engineer Codethink - Providing Genius