Hi Krzysztof Kozlowski,
> -----Original Message-----
> From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
> Sent: Saturday, March 9, 2024 1:30 PM
> Subject: Re: [PATCH 4/4] arm64: dts: renesas: r9a07g0{43,44,54}: Update usbhs family compatible
>
> On 09/03/2024 13:32, Biju Das wrote:
> > Hi Krzysztof Kozlowski,
> >
> >> -----Original Message-----
> >> From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
> >> Sent: Saturday, March 9, 2024 12:26 PM
> >> Subject: Re: [PATCH 4/4] arm64: dts: renesas: r9a07g0{43,44,54}:
> >> Update usbhs family compatible
> >>
> >> On 09/03/2024 13:14, Biju Das wrote:
> >>> Hi Krzysztof Kozlowski,
> >>>
> >>> Thanks for the feedback.
> >>>
> >>>> -----Original Message-----
> >>>> From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
> >>>> Sent: Saturday, March 9, 2024 12:08 PM
> >>>> Subject: Re: [PATCH 4/4] arm64: dts: renesas: r9a07g0{43,44,54}:
> >>>> Update usbhs family compatible
> >>>>
> >>>> On 08/03/2024 19:09, Biju Das wrote:
> >>>>> Replace 'renesas,rza2m-usbhs->renesas,rzg2l-usbhs' as family
> >>>>> compatible for RZ/G2L family SOCs as there is a difference in
> >>>>> number of pipe buffers compared to RZ/A2M.
> >>>>>
> >>>>> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> >>>>> ---
> >>>>> arch/arm64/boot/dts/renesas/r9a07g043.dtsi | 2 +-
> >>>>> arch/arm64/boot/dts/renesas/r9a07g044.dtsi | 2 +-
> >>>>> arch/arm64/boot/dts/renesas/r9a07g054.dtsi | 2 +-
> >>>>> 3 files changed, 3 insertions(+), 3 deletions(-)
> >>>>>
> >>>>> diff --git a/arch/arm64/boot/dts/renesas/r9a07g043.dtsi
> >>>>> b/arch/arm64/boot/dts/renesas/r9a07g043.dtsi
> >>>>> index 8721f4c9fa0f..766c54b91acc 100644
> >>>>> --- a/arch/arm64/boot/dts/renesas/r9a07g043.dtsi
> >>>>> +++ b/arch/arm64/boot/dts/renesas/r9a07g043.dtsi
> >>>>> @@ -812,7 +812,7 @@ usb2_phy1: usb-phy@11c70200 {
> >>>>>
> >>>>> hsusb: usb@11c60000 {
> >>>>> compatible = "renesas,usbhs-r9a07g043",
> >>>>> - "renesas,rza2-usbhs";
> >>>>> + "renesas,rzg2l-usbhs";
> >>>>
> >>>> This looks like ABI break and commit msg is quite vague about it.
> >>>
> >>> OK, Will update the commit message as driver is taking care of the
> >>> backward compatibility.
> >>
> >> Ah, I was not precise here, you should consider the impact this is on
> >> DTB used on other kernels. You guys should really stop using
> >> imprecise/incorrect generic fallbacks and, since it is usually tricky to know which fallback is
> correct or not, you should stop using them at all.
> >
> > There will be driver change to handle SoC specific compatible.
> >
> > So ,
> >
> > 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.
Cheers,
Biju
