Hi Krzysztof Kozlowski,
> -----Original Message-----
> From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
> Sent: Sunday, March 10, 2024 8:40 AM
> Subject: Re: [PATCH 4/4] arm64: dts: renesas: r9a07g0{43,44,54}: Update usbhs family compatible
>
> On 10/03/2024 09:16, Biju Das wrote:
> > Hi Krzysztof Kozlowski,
> >
> >> -----Original Message-----
> >> From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
> >> Sent: Sunday, March 10, 2024 8:06 AM
> >> Subject: Re: [PATCH 4/4] arm64: dts: renesas: r9a07g0{43,44,54}:
> >> Update usbhs family compatible
> >>
> >> On 10/03/2024 08:57, Biju Das wrote:
> >>>>>>> old DTB + old kernel will have 16 pipe buffers old DTB + newer
> >>>>>>> kernel will have 9 pipe buffers.
> >>>>>>> New DTB + new kernel will have 9 pipe buffer.
> >>>>>>
> >>>>>> You missed new DTB and old kernel. This breaks all users of DTS.
> >>>>>> That's the entire point of your broken generic compatibles which you did not address.
> >>>>>
> >>>>> As per my knowledge, there is no user in RZ/G2L is using new DTB and old kernel.
> >>>>> So, it is safe.
> >>>>
> >>>> If there is a user for such change, we could use
> >>>>
> >>>> compatible = "renesas,usbhs-r9a07g043",
> >>>> "renesas,rzg2l-usbhs",
> >>>> "renesas,rza2-usbhs";
> >>>>
> >>>> Or
> >>>>
> >>>> compatible = "renesas,usbhs-r9a07g043",
> >>>> "renesas,rza2-usbhs";
> >>>>
> >>>>
> >>>> The former consumes less memory compared to the later.
> >>>>
> >>>> As later requires, 3 platform structures for rz/g2l, rz/v2l and
> >>>> rz/gul whereas the former requires just 1.
> >>>
> >>> Another way is using RZ/G2L SoC fallback compatible for both RZ/V2L
> >>> and RZ/Five varients
> >>>
> >>> compatible = "renesas,usbhs-r9a07g043",
> >>> "renesas, usbhs-r9a07g044",
> >>
> >> How does it solve anything? Nothing binds to this.
> >
> > This will solve all the issues.
>
> That's not really the answer, but I see you plan to keep old fallback.
Yes, To avoid the ABI breakage as per the use case you mentioned for new dtb + old kernel
> So this means old fallback is correct and entire patchset does not make sense.
>
> This is confusing.
I need to correct the binding/driver code as per the below for avoiding all possible ABI breakage
and at the same time optimize the memory usage in driver as all(r9a07g0{43,44,54} belong
to the same RZ/G2L family SoCs.
compatible = "renesas,usbhs-r9a07g043",
"renesas,usbhs-r9a07g044",
"renesas,rza2-usbhs";
Or
compatible = "renesas,usbhs-r9a07g043",
"renesas,rzg2l-usbhs",
"renesas,rza2-usbhs";
Cheers,
Biju
