Re: [PATCH v2] i3c: dw-i3c-master: Fix IBI count register selection for versalnet

[Jeremy Kerr <jk@codeconstruct.com.au>]

Hi Shubhrajyoti,

> I see three possible approaches here:
> 
>  1. SoC‑specific |compatible|(e.g. VersalNet detection)
>     Use a dedicated compatible string to identify VersalNet and adjust
>     the behavior accordingly.
>  2. Dynamic runtime detection (current approach)
>     The current patch attempts to infer the absence of IBI payload data
>     dynamically, without relying on DT information.
>  3. Explicit DT property (|has-no-ibi-data|)
>     Introduce a boolean device‑tree property to explicitly describe the
>     hardware capability that no IBI payload data is provided, and use
>     that to drive the behavior.
> 
> Could you please advise which approach would be preferred?

Regardless of choice here, you will still need to introduce a
device-specific compatible string.

From there, your three options apply. My thinking is:

 - if you can *guarantee* that the probing method (2) is accurate (and
   there are no other synthesis settings that might invalidate it), then
   use that.

 - otherwise, if you're unsure of the reliability of probing, use a new
   explicit DT property as per your (3). This is more appropriate than
   using the compatible string, as it's an actual configurable property
   of the hardware, rather than a workaround-style thing.

Note that Alexandre has the final say in this though. He's okay with the
probe approach, so it's up to your call on whether that will be solid
enough for all dw-i3c hardware.

Cheers,


Jeremy