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Date: Mon, 29 Jan 2024 15:37:08 +0000
From: Conor Dooley <conor@kernel.org>
To: William Qiu <william.qiu@starfivetech.com>
Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-riscv@lists.infradead.org, linux-can@vger.kernel.org,
	Emil Renner Berthing <kernel@esmil.dk>,
	Rob Herring <robh+dt@kernel.org>,
	Wolfgang Grandegger <wg@grandegger.com>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Marc Kleine-Budde <mkl@pengutronix.de>,
	"David S . Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>
Subject: Re: [PATCH v1 2/4] dt-bindings: can: Add bindings for CAST CAN
 Controller
Message-ID: <20240129-garnet-polar-65afd461a1c6@spud>
References: <20240129031239.17037-1-william.qiu@starfivetech.com>
 <20240129031239.17037-3-william.qiu@starfivetech.com>
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Hey William,

On Mon, Jan 29, 2024 at 11:12:37AM +0800, William Qiu wrote:
> Add bindings for CAST CAN Controller
>=20
> Signed-off-by: William Qiu <william.qiu@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.ya=
ml
>=20
> diff --git a/Documentation/devicetree/bindings/net/can/cast,can.yaml b/Do=
cumentation/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@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.

> +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
=66rom 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.

> +      - starfive,can

Just "starfive,can"? Can you please add device specific compatibles for
the SoCs on which this is used?

> +
> +  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!

> +
> +  resets:
> +    minItems: 3
> +
> +  reset-names:
> +    items:
> +      - const: rst_apb
> +      - const: rst_core
> +      - const: rst_timer

Same here, drop rst_

> +
> +  starfive,syscon:
> +    $ref: /schemas/types.yaml#/definitions/phandle-array
> +    items:
> +      - items:
> +          - description: phandle to System Register Controller syscon no=
de
> +          - 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?

> +          - description: shift of SYS_SYSCON_NE__SAIF__SYSCFG register f=
or CAN controller
> +          - description: mask of SYS_SYSCON_NE__SAIF__SYSCFG register fo=
r CAN controller
> +    description:
> +      Should be four parameters, the phandle to System Register Controll=
er
> +      syscon node and the offset/shift/mask of SYS_SYSCON_NE__SAIF__SYSC=
FG register
> +      for CAN controller.

Cheers,
Conor.

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