Re: [PATCH 1/2] i2c: usbio: Add ACPI device-id for MTL-CVF devices

[Hans de Goede <hansg@kernel.org>]

Hi,

First of all I messed up the git format-patch command,
there is no second patch in this series.

(at least not for the i2c subsystem. There is a similar GPIO
patch but I send that out separately)

On 1-Oct-25 11:58 PM, Sakari Ailus wrote:
> Hi Hans,
> 
> On Wed, Oct 01, 2025 at 11:23:10PM +0200, Hans de Goede wrote:
>> Add "INTC10D2" ACPI device-id for MTL-CVF devices, like the Dell Latitude
>> 7450.
>>
>> Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2368506
>> Signed-off-by: Hans de Goede <hansg@kernel.org>
>> ---
>> Note this applies on top of the addition of the new i2c-usbio driver which
>> is being merged through gregkh/usb.git usb-next
>> ---
>>  drivers/i2c/busses/i2c-usbio.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/i2c/busses/i2c-usbio.c b/drivers/i2c/busses/i2c-usbio.c
>> index d42f9ab6e9a5..e7799abf6787 100644
>> --- a/drivers/i2c/busses/i2c-usbio.c
>> +++ b/drivers/i2c/busses/i2c-usbio.c
>> @@ -27,6 +27,7 @@ static const struct acpi_device_id usbio_i2c_acpi_hids[] = {
>>  	{ "INTC1008" }, /* MTL */
>>  	{ "INTC10B3" }, /* ARL */
>>  	{ "INTC10B6" }, /* LNL */
>> +	{ "INTC10D2" }, /* MTL-CVF */
> 
> INTC10D2 is apparently already claimed by the LJCA I²C driver. Do you have
> an actual system that uses USBIO and this HID?

Yes, see the Closes: tag which points to a bug-report which such a system:

https://bugzilla.redhat.com/show_bug.cgi?id=2368506

Let me also reply to your other comment here:

>> INTC10D2 is apparently already claimed by the LJCA I²C driver. Do you have
>> an actual system that uses USBIO and this HID?
> 
> Actually it looks like i2c-ljca.c shouldn't list this HID. The same
> probably goes for all 10CF--10D3.

I would not be so sure of this, there are at least some Dell systems
which use a combination of ljca and Meteor Lake and I believe these
do use the "INTC10D2" HID with LJCA for the I2C part and the same
goes for the GPIO / SPI parts.. One example of such a system is
the Dell Precision 5490.

The way these Intel uses these HIDs is really weird they seem to
simply mean "I2C" on *a* USBIO expander with this generation CPU.

Where there really seems no reason to change the HID for CPU
generations, where as it would be a good reason to change the HID
if the actual USBIO expander is different ...

Regards,

Hans