[PATCH v1 2/4] dt-bindings: can: Add bindings for CAST CAN Controller

[William Qiu]

> -----Original Message-----
> From: Conor Dooley <conor at kernel.org>
> Sent: 2024年1月29日 23:37
> To: William Qiu <william.qiu at starfivetech.com>
> Cc: devicetree at vger.kernel.org; linux-kernel at vger.kernel.org;
> linux-riscv at lists.infradead.org; linux-can at vger.kernel.org; Emil Renner
> Berthing <kernel at esmil.dk>; Rob Herring <robh+dt at kernel.org>; Wolfgang
> Grandegger <wg at grandegger.com>; Philipp Zabel <p.zabel at pengutronix.de>;
> Krzysztof Kozlowski <krzysztof.kozlowski+dt at linaro.org>; Conor Dooley
> <conor+dt at kernel.org>; Marc Kleine-Budde <mkl at pengutronix.de>; David S .
> Miller <davem at davemloft.net>; Eric Dumazet <edumazet at google.com>;
> Jakub Kicinski <kuba at kernel.org>; Paolo Abeni <pabeni at redhat.com>; Paul
> Walmsley <paul.walmsley at sifive.com>; Palmer Dabbelt
> <palmer at dabbelt.com>; Albert Ou <aou at eecs.berkeley.edu>
> Subject: Re: [PATCH v1 2/4] dt-bindings: can: Add bindings for CAST CAN
> Controller
> 
> Hey William,
> 
> On Mon, Jan 29, 2024 at 11:12:37AM +0800, William Qiu wrote:
> > Add bindings for CAST CAN Controller
> >
> > Signed-off-by: William Qiu <william.qiu at starfivetech.com>
> > ---
> >  .../devicetree/bindings/net/can/cast,can.yaml | 95
> > +++++++++++++++++++
> >  1 file changed, 95 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/net/can/cast,can.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/net/can/cast,can.yaml
> > b/Documentation/devicetree/bindings/net/can/cast,can.yaml
> > new file mode 100644
> > index 000000000000..ea52132d9b1c
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/net/can/cast,can.yaml
> > @@ -0,0 +1,95 @@
> > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause %YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/net/can/cast,can.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: CAST CAN controller
> > +
> > +maintainers:
> > +  - William Qiu <william.qiu at starfivetech.com>
> > +
> > +allOf:
> > +  - $ref: can-controller.yaml#
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            const: starfive,can
> > +    then:
> > +      required:
> > +        - starfive,syscon
> 
> If you've got property related stuff in the allOf, move it down after the property
> definitions.
> 
Will update
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - cast,can
> > +      - cast,canfd
> 
> I don't like these uber generic compatibles that have no users as a fallback.
> Allowing them in the binding only really discourages people from creating device
> specific compatibles.
> Secondly, this is some purchased IP that I am sure has a versioning scheme and
> the compatibles that you have created do not reflect that.
> If they were being used as a fallback, I would request some versioning.
> That's not going to really work though since the canfd features on the
> jh7110 require setting u0_can_ctrl_can_fd_enable, so neither of these
> compatibles really has a use right now.
> 
I'll add some tag to do versioning.
> > +      - starfive,can
> 
> Just "starfive,can"? Can you please add device specific compatibles for the SoCs
> on which this is used?
> 
Will add.
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +
> > +  clocks:
> > +    minItems: 3
> > +
> > +  clock-names:
> > +    items:
> > +      - const: apb_clk
> > +      - const: timer_clk
> > +      - const: can_clk
> 
> Drop _clk, they're all clocks!
> 
Will drop.
> > +
> > +  resets:
> > +    minItems: 3
> > +
> > +  reset-names:
> > +    items:
> > +      - const: rst_apb
> > +      - const: rst_core
> > +      - const: rst_timer
> 
> Same here, drop rst_
>Will drop.
> > +
> > +  starfive,syscon:
> > +    $ref: /schemas/types.yaml#/definitions/phandle-array
> > +    items:
> > +      - items:
> > +          - description: phandle to System Register Controller syscon node
> > +          - description: offset of SYS_SYSCON_NE__SAIF__SYSCFG
> > + register for CAN controller
> 
> The docs I have call this register "SYS_SYSCONSAIF__SYSCFG". Did the names
> change since the TRM I have was written?
> 
They do change on the 8100 SoC.
Other descriptions may be needed for compatibility. I'll think about it.

Thanks,
William
> > +          - description: shift of SYS_SYSCON_NE__SAIF__SYSCFG register
> for CAN controller
> > +          - description: mask of SYS_SYSCON_NE__SAIF__SYSCFG register
> for CAN controller
> > +    description:
> > +      Should be four parameters, the phandle to System Register Controller
> > +      syscon node and the offset/shift/mask of
> SYS_SYSCON_NE__SAIF__SYSCFG register
> > +      for CAN controller.
> 
> Cheers,
> Conor.