Hi Krzysztof Kozlowski,
> -----Original Message-----
> From: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> Sent: Saturday, March 9, 2024 3:43 PM
> Subject: RE: [PATCH 4/4] arm64: dts: renesas: r9a07g0{43,44,54}: Update usbhs family compatible
>
> 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.
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.
Cheers,
Biju
