RE: [PATCH 4/4] arm64: dts: renesas: r9a07g0{43,44,54}: Update usbhs family compatible

From: Biju Das <biju.das.jz@bp.renesas.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>,
	Magnus Damm <magnus.damm@gmail.com>,
	"linux-renesas-soc@vger.kernel.org"
	<linux-renesas-soc@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>,
	biju.das.au <biju.das.au@gmail.com>
Subject: RE: [PATCH 4/4] arm64: dts: renesas: r9a07g0{43,44,54}: Update usbhs family compatible
Date: Sat, 9 Mar 2024 12:32:00 +0000	[thread overview]
Message-ID: <OSAPR01MB15874A9DB0CE13AB0440242186262@OSAPR01MB1587.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <ff569d52-f68f-410d-9897-9e1102171a1b@linaro.org>

Hi Krzysztof Kozlowski,

> -----Original Message-----
> From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> 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@linaro.org>
> >> 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@bp.renesas.com>
> >>> ---
> >>>  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.

Cheer,
Biju