tree 425dbd00a766bdfb34101388416402cbeab89df2
parent 97439ecc0178a0935d50a4b3a1774027ae7bebbf
author CoolStar <coolstarorganization@gmail.com> 1687983050 -0700
committer Felix Held <felix-coreboot@felixheld.de> 1689858676 +0000

mb/google/link: rework TP/TS ACPI for new Windows I2C driver

This supports a brand new I2C driver that is designed specifically
for the Pixel 2013 chromebook (LINK). The GMBus interface on the IGPU
is an i2c-compatible interface, but AFAIK only Link has touch devices
attached in this way.

On Windows, the PCIe device for the IGP is owned by the Intel
proprietary driver, hence a separate ACPI device has to be added for
the I2C driver arbitrator to attach to. The MMIO method is used instead
of _CRS so that Windows does not try to assign ownership of the
resource to our device (even though we're using the MMIO registers at
the same time as the IGP driver).

Even though in theory 2 drivers accessing the same MMIO may cause
problems, in testing, there has been no issues with
sleep/wake/hibernate, updating/installing/uninstalling the IGP driver,
or changing display resolutions with the i2c driver attached.

The arbitrator is necessary as well, since even though there are
multiple i2c buses, the MMIO registers are shared. Hence a shared lock
is required for i2c access across the buses.

The original Sleep Button devices are preserved for Linux due to the
completely custom and non-standard implementation of the Windows driver
in order to work around the non-standard nature of Link's hardware.

Change-Id: If7ee05d15bc17d335cf8c1a8e80bea62800de475
Signed-off-by: CoolStar <coolstarorganization@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76159
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>