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From: "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Date: Thu, 7 Mar 2024 10:55:10 +0000
Message-ID: <CA+V-a8vmOv3qZEzz8jAHMmhT2d4kVTQ4ZZ5iOz4Lf3rN4nHbhg@mail.gmail.com>
Subject: Re: [PATCH] dt-bindings: serial: renesas,scif: Document R9A09G057 support
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, 
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Jiri Slaby <jirislaby@kernel.org>, 
	Rob Herring <robh+dt@kernel.org>, Conor Dooley <conor+dt@kernel.org>, 
	Magnus Damm <magnus.damm@gmail.com>, linux-kernel@vger.kernel.org, 
	linux-serial@vger.kernel.org, devicetree@vger.kernel.org, 
	linux-renesas-soc@vger.kernel.org, 
	Fabrizio Castro <fabrizio.castro.jz@renesas.com>, 
	Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
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Hi Geert,

On Thu, Mar 7, 2024 at 10:18=E2=80=AFAM Geert Uytterhoeven <geert@linux-m68=
k.org> wrote:
>
> Hi Prabhakar,
>
> On Thu, Mar 7, 2024 at 11:09=E2=80=AFAM Lad, Prabhakar
> <prabhakar.csengg@gmail.com> wrote:
> > On Wed, Mar 6, 2024 at 10:21=E2=80=AFAM Lad, Prabhakar
> > <prabhakar.csengg@gmail.com> wrote:
> > > On Wed, Mar 6, 2024 at 10:15=E2=80=AFAM Geert Uytterhoeven <geert@lin=
ux-m68k.org> wrote:
> > > > On Wed, Mar 6, 2024 at 11:06=E2=80=AFAM Lad, Prabhakar
> > > > <prabhakar.csengg@gmail.com> wrote:
> > > > > On Wed, Mar 6, 2024 at 9:53=E2=80=AFAM Geert Uytterhoeven <geert@=
linux-m68k.org> wrote:
> > > > > > On Tue, Mar 5, 2024 at 6:16=E2=80=AFPM Prabhakar <prabhakar.cse=
ngg@gmail.com> wrote:
> > > > > > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > > > > >
> > > > > > > Document support for the Serial Communication Interface with =
FIFO (SCIF)
> > > > > > > available in the Renesas RZ/V2H(P) (R9A09G057) SoC. The SCIF =
interface in
> > > > > > > the Renesas RZ/V2H(P) is similar to that available in the RZ/=
G2L
> > > > > > > (R9A07G044) SoC, with the only difference being that the RZ/V=
2H(P) SoC has
> > > > > > > three additional interrupts: one for Tx end/Rx ready and the =
other two for
> > > > > > > Rx and Tx buffer full, which are edge-triggered.
> > > > > > >
> > > > > > > No driver changes are required as generic compatible string
> > > > > > > "renesas,scif-r9a07g044" will be used as a fallback on RZ/V2H=
(P) SoC.
> > > > > >
> > > > > > If you declare SCIF on RZ/V2H compatible with SCIF on RZ/G2L, y=
ou
> > > > > > state that the current driver works fine (but perhaps suboptima=
l),
> > > > > > without adding support for the extra 3 interrupts?
> > > > > >
> > > > > Yes the current driver works without using the extra interrupts o=
n the
> > > > > RZ/V2H. The extra interrupts on the RZ/V2H are just sort of dupli=
cate
> > > > > ie
> > > > > - Transmit End/Data Ready interrupt , for which we we have two
> > > > > seperate interrupts already
> > > > > - Receive buffer full interrupt (EDGE trigger), for which we alre=
ady
> > > > > have a Level triggered interrupt
> > > > > - Transmit buffer empty interrupt (EDGE trigger), for which we al=
ready
> > > > > have a Level triggered interrupt
> > > >
> > > > Thanks for the confirmation!
> > > >
> > > > > Are you suggesting to not fallback on RZ/G2L and instead make RZ/=
V2H
> > > > > an explicit one so that in future we handle these 3 extra interru=
pts?
> > > >
> > > > In light of the confirmation above, I am _not_ suggesting that.
> > > >
> > With the introduction of validation checks for interrupts, falling
> > back to "renesas,scif-r9a07g044" for RZ/V2H will be difficult for
> > validating interrupt count.
> >
> >   - if:
> >       properties:
> >         compatible:
> >           contains:
> >             enum:
> >               - renesas,scif-r7s9210
> >               - renesas,scif-r9a07g044
> >     then:
> >       properties:
> >         interrupts:
> >           minItems: 6
> >
> >         interrupt-names:
> >           minItems: 6
> >
> > With the above check RZ/V2H fall into this if block,
> >
> > Is there any way I can specify to match two compat strings?
>
> if r9a09g057 then ... else if r7s9210 || r9a07g044 then ...?
>
Thanks for the pointer (I was grepping for elif ;)).

Cheers,
Prabhakar