skylake: Support common LPSS I2C driver

Support the common Intel LPSS I2C driver for the 6 I2C bus controllers
that are present on the Skylake-LP PCH with a 120 mHz clock.  The
required lpss_i2c_base_address() method is implemented separately for
verstage/romstage and ramstage environments.

This provides methods to convert to and from "struct device" and the
I2C controller bus number for that device.  These are used to provide
support for the "I2C Bus Operations" that are present in the coreboot
devicetree.

To support the I2C controller before ramstage an early init function
is provided to do minimal initializaiton of the PCI device and assign
a temporary base address for use before memory.  The final base
address is assigned during device enumeration and used during ramstage.

Because it is usually not necessary to enable I2C controllers before
ramstage a config register for the devicetree is provided to perform
early initialization of this controller.  In addition the bus speed
can be set in the devicetree and that speed will be applied when the
device is initialized.  If not provided the default speed is set to
I2C_SPEED_FAST.

This was tested with the google/chell mainboard by reading and writing
from the trackpad and codec devices during both verstage and ramstage.

Change-Id: Ia0270adfaf2843a3be4e00c732c85401a3401ef5
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://review.coreboot.org/15105
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)

0 files changed, 0 insertions, 0 deletions