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

[Jarkko Nikula]

On 05/10/2018 03:03 PM, Chris Chiu wrote:
> Report from guys who can access scope. If i2c-sda-falling-time-ns=400ns
> , HCNT increase to 117, the SCL high duration is 576ns as follows
> https://pasteboard.co/HkwERvP.png
>
> The original SCL high duration (HCNT = 105, 120MHz) is as follows
> https://pasteboard.co/HkwFxgY.png
>
> So the HCNT does affect but per this HCNT/LCNT value, just not 400kHz
> as expected. Any suggestion?
Thanks for measurements. I was sidetracked last week so I don't have yet 
explanation why signals run faster than expected :-(

Using 120 MHz SPT I2C clocks in commit b418bbff36dd ("mfd: intel-lpss: 
Add Intel Cannonlake PCI IDs") is clearly wrong but before going to 133 
MHz (which work for you but still runs too fast) I would like to find 
explanation why it appears to be much higher.

--
Jarkko