[PATCH RFC RESEND 0/7] i3c: Support IBI-based system wakeup

[Adrian Hunter]

Hi

[ Re-sent to correct email addresses of linux-pci and linux-pm mailing lists ]

Intel LPSS I3C controllers support up to two I3C busses and can wake the
system from an In-Band Interrupt (IBI) via a PCI PME.  Today that wakeup
capability lives only at the PCI function, with no way to express which
I3C device is actually responsible for waking the system, and no way for
user space to enable or disable wakeup on a per-device basis.

This series pushes the wakeup capability down to the individual I3C
devices and then aggregates the resulting wakeup state back up to the PCI
device.

An IBI-capable I3C device on a bus whose controller can wake the system
is marked as wakeup capable, so it can be managed through the standard
device wakeup framework (e.g. via power/wakeup in sysfs).  When such a
device is enabled for wakeup, a wakeup event is reported each time it
queues an IBI.

At suspend time, the mipi-i3c-hci PCI driver aggregates the wakeup
configuration of the I3C devices across its HCI instances (up to two I3C
busses) and enables PCI wakeup (PME) only when at least one attached I3C
device is enabled as a wakeup source.  This keeps the PCI wakeup state in
sync with the actual requirements of the devices on the busses.

The series is organised as follows:

 - Patches 1-4 add the generic I3C core support: an ibi_wakeup flag for
   controllers, marking IBI-capable devices as wakeup capable, reporting
   wakeup events on IBIs, a helper to query whether any device on a bus
   has wakeup enabled, and a fix to reject IBI requests from devices that
   do not advertise IBI capability.

 - Patches 5-7 wire this up for the mipi-i3c-hci driver: propagate the
   aggregated I3C wakeup requirements to the PCI function, factor out
   i3c_hci_sysdev() for the shared device lookup, and advertise IBI
   wakeup capability when the underlying system device can wake the
   system.

Note, since the PCI wakeup state is now derived from the wakeup
configuration of the attached I3C devices, the PCI device's
power/wakeup sysfs attribute no longer provides independent wakeup
control.


Adrian Hunter (7):
      i3c: master: Support IBI-based wakeup capability
      i3c: master: Report wakeup events for IBIs
      i3c: master: Add helper to query bus wakeup requirements
      i3c: master: Reject IBI requests from non-IBI-capable devices
      i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
      i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
      i3c: mipi-i3c-hci: Advertise IBI wakeup capability

 drivers/i3c/device.c                               |  8 +++--
 drivers/i3c/master.c                               | 41 ++++++++++++++++++++++
 drivers/i3c/master/mipi-i3c-hci/core.c             | 15 ++++++++
 drivers/i3c/master/mipi-i3c-hci/dma.c              | 15 +-------
 drivers/i3c/master/mipi-i3c-hci/hci.h              |  2 ++
 drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c | 23 ++++++++++--
 include/linux/i3c/master.h                         |  3 ++
 7 files changed, 88 insertions(+), 19 deletions(-)


Regards
Adrian