Re: [BUG] i2c-hid: ELAN Touchpad does not work on ASUS X580GD

[Chris Chiu <chiu@endlessm.com>]

On Thu, May 17, 2018 at 3:48 PM, Jarkko Nikula
<jarkko.nikula@linux.intel.com> wrote:
> Hi
>
> On 05/15/2018 01:20 PM, Jarkko Nikula wrote:
>>
>> On 05/15/2018 06:22 AM, Chris Chiu wrote:
>>>
>>> What if I change the 120MHz to 180MHz and then make sure that the I2C
>>> operates
>>> in target FS mode frequency 400kHz via scope? Would there be any side
>>> effect?
>>> Maybe some other busses frequency could be also affected and causing some
>>> other
>>> component malfunction?
>>>
>> Should be safe. It is only clock rate information when registering a fixed
>> clock with known rate in intel-lpss.c and i2c-designware uses that info when
>> calculating the timing parameters. I.e. it doesn't change any internal
>> clocks.
>>
>> I'm trying to find a contact who can confirm what is the expected rate of
>> I2C input clock and is it common to all Cannon Lake HW.
>>
> I got confirmation that input clock is actually even higher 216 Mhz.
>
> While checking does it cover all of those CNL CNL-LP and CNL-H PCI IDs may I
> add your Jian-Hong, Chris and Daniel email addresses to Repored-by tags in a
> fix patch?
>
> --
> Jarkko

No problem. Thanks