Re: [PATCH] mfd: intel-lpss: Fix Intel Cannon Lake LPSS I2C input clock
From: Lee Jones
Date: Mon Jun 04 2018 - 03:40:09 EST
On Fri, 18 May 2018, Jarkko Nikula wrote:
> Intel Cannon Lake PCH has much higher 216 MHz input clock to LPSS I2C
> than Sunrisepoint which uses 120 MHz. Preliminary information was that
> both share the same clock rate but actual silicon implements elevated
> rate for better support for 3.4 MHz high-speed I2C.
> This incorrect input clock rate results too high I2C bus clock in case
> ACPI doesn't provide tuned I2C timing parameters since I2C host
> controller driver calculates them from input clock rate.
> Fix this by using the correct rate. We still share the same 230 ns SDA
> hold time value than Sunrisepoint.
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: b418bbff36dd ("mfd: intel-lpss: Add Intel Cannonlake PCI IDs")
> Reported-by: Jian-Hong Pan <jian-hong@xxxxxxxxxxxx>
> Reported-by: Chris Chiu <chiu@xxxxxxxxxxxx>
> Reported-by: Daniel Drake <drake@xxxxxxxxxxxx>
> Signed-off-by: Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx>
> Hi Jian-Hong, Chris and Daniel. Could you test does this fix your
> touchpad issue?
> drivers/mfd/intel-lpss-pci.c | 25 +++++++++++++++----------
> 1 file changed, 15 insertions(+), 10 deletions(-)
Lee Jones [æçæ]
Linaro Services Technical Lead
Linaro.org â Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog