[RFC PATCH 0/2] x86/usb: Add Yoga Book XMM7260 modem power sequencing

[Maurizio Casciano]

The Lenovo Yoga Book YB1-X91L connects an Intel XMM7260 modem through a
Cherry Trail xHCI SSIC port.  Firmware exposes an INT34D0 ACPI device,
but the modem requires both SSIC controller restoration and an ACPI/PMIC
power sequence before its USB boot function can transition to MBIM.

Add a DMI-scoped xHCI quirk which restores the SSIC vendor state across
setup and resume, followed by a platform driver which performs the
firmware power sequence and coordinates xHCI runtime PM while waiting
for the runtime function.

This is an RFC because live XMM7260-to-MBIM enumeration and suspend/resume
acceptance are not yet complete.  Feedback is particularly requested on
the xHCI/platform-driver split and the ownership of the SSIC sequencing.

Maurizio Casciano (2):
  xhci: Restore SSIC state on the Lenovo Yoga Book
  platform/x86: Add Cherry Trail XMM7260 power driver

 MAINTAINERS                            |   1 +
 drivers/platform/x86/intel/Kconfig     |  16 +
 drivers/platform/x86/intel/Makefile    |   1 +
 drivers/platform/x86/intel/cht_modem.c | 418 +++++++++++++++++++++++++
 drivers/usb/host/xhci-pci.c            | 114 ++++++-
 drivers/usb/host/xhci-ring.c           |  31 ++
 drivers/usb/host/xhci.h                |   1 +
 7 files changed, 581 insertions(+), 1 deletion(-)
 create mode 100644 drivers/platform/x86/intel/cht_modem.c


base-commit: 45c13f3f9e3bb15fd89ff2864c6f627a3b4b4229
-- 
2.53.0