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

[Armin Wolf <W_Armin@gmx.de>]

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@gmail.com> 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@gmx.de> 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@gmail.com/
>>>>
>>>> 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