Re: [PATCH v6 1/7] dt-bindings: i2c: xiic: make clocks optional

[Michal Simek <michal.simek@amd.com>]

On 1/28/26 15:45, Andy Shevchenko wrote:
> On Wed, Jan 28, 2026 at 03:34:02PM +0100, Andrew Lunn wrote:
>> On Wed, Jan 28, 2026 at 12:21:41PM +0100, Michal Simek wrote:
>>> On 1/28/26 11:37, Krzysztof Kozlowski wrote:
>>>> On Tue, Jan 27, 2026 at 09:03:55PM +0000, Abdurrahman Hussain wrote:
>>>>> The xiic driver is designed to operate without explicit clock configuration
>>>>
>>>> And if you change this in the driver, then you change bindings?
>>>>
>>>> You miss here explanation based on hardware - how does the hardware work
>>>> if nothing ticks it clocks?
>>>
>>> Hardware obviously have clock input which needs to be connected. Without it
>>> it won't work.
>>
>> Should ACPI potential limitations be making the DT description less
>> accurate?
>>
>> Would it not be better that the driver has an DT binding and an ACPI
>> binding? Where there are common properties, common functions can be
>> used to retrieve them. However, if ACPI lacks usable clocks, use the
>> of_ method to get the clock from DT, and skip it for ACPI.
> 
> Why should we use of_ methods? If this is required we can check the type of
> fwnode and act accordingly, but I think this should go deeper into some
> treewide available helpers, because now some drivers repeat the mantra.
> 
> But how do the driver get the clock frequency (if needed for some register
> settings and/or calculations)? DT seems to have well established property
> 'clock-frequency' for that. Can we consider it as "ACPI binding" as well?

"clock-frequency" property in i2c is used for selecting i2c speed 100/400kHz.

Clock frequency in this driver is about describing clock coming to IP itself.
Documentation/devicetree/bindings/i2c/xlnx,xps-iic-2.00.a.yaml

Thanks,
Michal