mfd: intel-lpss: Fix Intel Cannon Lake LPSS I2C input clock
authorJarkko Nikula <jarkko.nikula@linux.intel.com>
Fri, 18 May 2018 08:38:27 +0000 (11:38 +0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 3 Jul 2018 09:25:00 +0000 (11:25 +0200)
commit18be8bd3aceb282c145b74144caaccb51b24bf92
tree02c9ad7e16128a12b91b3c124ced4f6e4c3ad8ad
parentf79c97198b5596fa8052938471bd67ae6ccb4067
mfd: intel-lpss: Fix Intel Cannon Lake LPSS I2C input clock

commit 4e93a658576ab115977225c9d0992b97ff19ba8c upstream.

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@vger.kernel.org
Fixes: b418bbff36dd ("mfd: intel-lpss: Add Intel Cannonlake PCI IDs")
Reported-by: Jian-Hong Pan <jian-hong@endlessm.com>
Reported-by: Chris Chiu <chiu@endlessm.com>
Reported-by: Daniel Drake <drake@endlessm.com>
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Jian-Hong Pan <jian-hong@endlessm.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/mfd/intel-lpss-pci.c