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