linux-kernel - RE: [PATCH v2 1/2] dt-bindings: can: renesas,rcar-canfd: Document renesas,fd-only property

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Message-ID:
 <TY3PR01MB11346729E8758CFEF18C9E99686D3A@TY3PR01MB11346.jpnprd01.prod.outlook.com>
Date: Sun, 23 Nov 2025 14:17:18 +0000
From: Biju Das <biju.das.jz@...renesas.com>
To: Krzysztof Kozlowski <krzk@...nel.org>, biju.das.au
	<biju.das.au@...il.com>, Marc Kleine-Budde <mkl@...gutronix.de>, Vincent
 Mailhol <mailhol@...nel.org>, Rob Herring <robh@...nel.org>, Krzysztof
 Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, Geert
 Uytterhoeven <geert+renesas@...der.be>, magnus.damm <magnus.damm@...il.com>
CC: Fabrizio Castro <fabrizio.castro.jz@...esas.com>,
	"linux-can@...r.kernel.org" <linux-can@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-renesas-soc@...r.kernel.org" <linux-renesas-soc@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Prabhakar
 Mahadev Lad <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: RE: [PATCH v2 1/2] dt-bindings: can: renesas,rcar-canfd: Document
 renesas,fd-only property

Hi Krzysztof Kozlowski,

> -----Original Message-----
> From: Biju Das
> Sent: 23 November 2025 14:06
> Subject: RE: [PATCH v2 1/2] dt-bindings: can: renesas,rcar-canfd: Document renesas,fd-only property
> 
> 
> 
> > -----Original Message-----
> > From: Krzysztof Kozlowski <krzk@...nel.org>
> > Sent: 23 November 2025 13:26
> > Subject: Re: [PATCH v2 1/2] dt-bindings: can: renesas,rcar-canfd:
> > Document renesas,fd-only property
> >
> > On 23/11/2025 12:23, Biju wrote:
> > > From: Biju Das <biju.das.jz@...renesas.com>
> > >
> > > The CANFD on RZ/{G2L,G3E} and R-Car Gen4 support 3 modes FD-Only
> > > mode, Classical CAN mode and CAN-FD mode. In FD-Only mode,
> > > communication in Classical CAN frame format is disabled. Document
> > > renesas,fd-only to handle this mode. As these SoCs support 3 modes,
> > > update the description of renesas,no-can-fd property and disallow it for R-Car Gen3.
> > >
> > > Signed-off-by: Biju Das <biju.das.jz@...renesas.com>
> > > ---
> > >  v1->v2:
> > >   * Added conditional check to disallow fd-only mode for R-Car Gen3.
> > > ---
> > >  .../bindings/net/can/renesas,rcar-canfd.yaml  | 24
> > > ++++++++++++++++---
> > >  1 file changed, 21 insertions(+), 3 deletions(-)
> > >
> > > diff --git
> > > a/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
> > > b/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
> > > index f4ac21c68427..a52244f0b5d1 100644
> > > ---
> > > a/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
> > > +++ b/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.y
> > > +++ am
> > > +++ l
> > > @@ -125,9 +125,17 @@ properties:
> > >    renesas,no-can-fd:
> > >      $ref: /schemas/types.yaml#/definitions/flag
> > >      description:
> > > -      The controller can operate in either CAN FD only mode (default) or
> > > -      Classical CAN only mode.  The mode is global to all channels.
> > > -      Specify this property to put the controller in Classical CAN only mode.
> > > +      The controller can operate in either CAN-FD mode (default) or FD-Only
> > > +      mode (RZ/{G2L,G3E} and R-Car Gen4) or Classical CAN mode. Specify this
> > > +      property to put the controller in Classical CAN mode.
> > > +
> > > +  renesas,fd-only:
> > > +    $ref: /schemas/types.yaml#/definitions/flag
> > > +    description:
> > > +      The CANFD on RZ/{G2L,G3E} and R-Car Gen4 SoCs support 3 modes FD-Only
> > > +      mode, Classical CAN mode and CAN-FD mode (default). In FD-Only mode,
> > > +      communication in Classical CAN frame format is disabled. Specify this
> > > +      property to put the controller in FD-Only mode.
> > >
> > >    assigned-clocks:
> > >      description:
> > > @@ -267,6 +275,16 @@ allOf:
> > >        patternProperties:
> > >          "^channel[6-7]$": false
> > >
> > > +  - if:
> > > +      properties:
> > > +        compatible:
> > > +          contains:
> > > +            enum:
> > > +              - renesas,rcar-gen3-canfd
> > > +    then:
> > > +      properties:
> > > +        renesas,fd-only: false
> > > +
> >
> > You did not respond to my first paragraph from previous version. As I
> > said, you now need oneOf to restrict these, since you are not using simple enum.
> 
> This is restricting for R-Car Gen3. DT binding check returns error if 'renesas,fd-only"
> is defined for R-Car Gen3.
> 
> Am I missing anything here?

For eg:

--- a/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
+++ b/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
@@ -308,6 +308,7 @@ examples:
             assigned-clock-rates = <40000000>;
             power-domains = <&sysc R8A7795_PD_ALWAYS_ON>;
             resets = <&cpg 914>;
+            renesas,fd-only;
 
             channel0 {
             };


  DTEX    Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.example.dts
  DTC [C] Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.example.dtb
/home/biju/share/linux-work/linux/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.example.dtb: can@...c0000 (renesas,r8a7795-canfd): renesas,fd-only: False schema does not allow True
	from schema $id: http://devicetree.org/schemas/net/can/renesas,rcar-canfd.yaml#

Cheers,
Biju