Re: [PATCH v2 0/2] Add UCSI I2C transport driver for ITE885x USB-C controllers

[Armin Wolf]

Am 28.08.26 um 03:04 schrieb Edward Blair:

> Let's try that again.. without gmail's html...
>
> Thanks, that makes sense. I can rework patch 1 to add MSFT8000 to
> ignore_serial_bus_ids[] in acpi_device_enumeration_by_parent(). This
> keeps the ACPI device present while preventing its SerialBus resources
> from being instantiated as bus clients.
>
> If that sounds reasonable, it seems like a good middle ground between
> v1 and v2: it preserves v1's enumeration behaviour while handling the
> device generically in the ACPI core, without the ITE-specific x86
> status override added in v2.
>
> Thanks,
> Edward

Sound reasonable to me, just add a small comment explaining why MSFT8000
had to be added to that list.

Thanks,
Armin Wolf

> On Fri, 28 Aug 2026 at 01:58, Edward Blair <edward.blair@xxxxxxxxx> wrote:
> > Thanks, that makes sense. I can rework patch 1 to add MSFT8000 to ignore_serial_bus_ids[] in acpi_device_enumeration_by_parent(). This keeps the ACPI device present while preventing its SerialBus resources from being instantiated as bus clients.
> >
> > If that sounds reasonable, it seems like a good middle ground between v1 and v2: it preserves v1's enumeration behaviour while handling the device generically in the ACPI core, without the ITE-specific x86 status override added in v2.
> >
> > Thanks,
> > Edward
> >
> > On Thu, 27 Aug 2026 at 23:30, Armin Wolf <W_Armin@xxxxxx> wrote:
> > > Am 25.08.26 um 22:14 schrieb Edward Blair:
> > >
> > > > Some ASUS desktop boards describe the same ITE USB-C controller twice
> > > > in ACPI: as an MSFT8000 Resource Hub Proxy and as an ITE885x device at
> > > > the same I2C address. If the RhProxy node claims the address first, the
> > > > ITE device cannot be registered. Only the ITE node provides the
> > > > interrupt required by this transport.
> > > >
> > > > Patch 1 marks the RhProxy node absent only when its I2C resource exactly
> > > > matches a supported ITE node which also has an interrupt.
> > > AFAIK the MSFT8000 device is used to grant userspace applications under Windows
> > > access to I2C, SPI, UART and GPIO resources. Since we already provide those functions
> > > natively i suggest that we generally ignore MSFT8000 devices when checking for resource
> > > conflicts.
> > >
> > > Thanks,
> > > Armin Wolf
> > >
> > > > Patch 2 adds the ITE885x UCSI transport. These controllers use
> > > > ITE-specific offsets for CCI, MESSAGE_IN, CONTROL and interrupt
> > > > handling. They do not expose a VERSION register or accept PPM_RESET
> > > > over I2C.
> > > >
> > > > The register layout and reset behaviour were checked against the ITE
> > > > Windows driver supplied for this board.
> > > >
> > > > Tested on an ASUS ROG Strix Z790-E Gaming WiFi with ITE8853:
> > > >
> > > > - Built and booted on x86_64.
> > > > - ucsi_ite bound to ITE8853:00 without the previous -EBUSY failure.
> > > > - /sys/class/typec/port0 was registered.
> > > > - USB-C attachment detection worked.
> > > > - No UCSI, ITE or Type-C initialization errors were logged.
> > > >
> > > > Suspend/resume and the ITE8800 through ITE8805 IDs have not been tested.
> > > >
> > > > Changes since v1:
> > > >
> > > > - Move the duplicate-device quirk from the I2C core to the ACPI x86
> > > >     status-override code, as suggested by Mika and Heikki.
> > > > - Correctly identify MSFT8000 as a Resource Hub Proxy.
> > > > - Restrict the quirk to exact matching I2C resources.
> > > > - Use devm_request_threaded_irq(), as suggested by Heikki.
> > > > - Rebase onto Linux 7.2 and update for the current UCSI API.
> > > > - Read and cache complete UCSI events before acknowledging them.
> > > > - Match the vendor transport's MESSAGE_IN and PPM_RESET behaviour.
> > > >
> > > > Link: https://lore.kernel.org/all/20260314013157.7181-1-edward.blair@xxxxxxxxx/
> > > >
> > > > Edward Blair (2):
> > > >     ACPI: x86: hide duplicate RhProxy node for ITE UCSI controllers
> > > >     usb: typec: ucsi: add ITE885x I2C transport driver
> > > >
> > > >    drivers/acpi/x86/utils.c          | 151 ++++++++++++
> > > >    drivers/usb/typec/ucsi/Kconfig    |  11 +
> > > >    drivers/usb/typec/ucsi/Makefile   |   1 +
> > > >    drivers/usb/typec/ucsi/ucsi_ite.c | 395 ++++++++++++++++++++++++++++++
> > > >    4 files changed, 558 insertions(+)
> > > >    create mode 100644 drivers/usb/typec/ucsi/ucsi_ite.c
> > > >
> > > >
> > > > base-commit: 66498c75b4f8017f62d720d9b59675bdf3abce91