Re: [PATCH v2 1/2] dt-bindings: power: Add RPMI device power service bindings

[Krzysztof Kozlowski <krzk@kernel.org>]

On Sun, Aug 30, 2026 at 11:28:11PM +0800, Joshua Yeong wrote:
> diff --git a/Documentation/devicetree/bindings/power/riscv,rpmi-mpxy-device-power.yaml b/Documentation/devicetree/bindings/power/riscv,rpmi-mpxy-device-power.yaml
> new file mode 100644
> index 000000000000..2b7df66ba172

A nit, subject: drop second/last, redundant "bindings". The
"dt-bindings" prefix is already stating that these are bindings.
See also:
https://elixir.bootlin.com/linux/v7.1-rc7/source/Documentation/devicetree/bindings/submitting-patches.rst#L23

> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power/riscv,rpmi-mpxy-device-power.yaml
> @@ -0,0 +1,65 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/power/riscv,rpmi-mpxy-device-power.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: RISC-V RPMI device power service group based message proxy
> +
> +maintainers:
> +  - Joshua Yeong <joshua.yeong@starfivetech.com>
> +
> +description: |
> +  The RISC-V Platform Management Interface (RPMI) [1] defines a
> +  messaging protocol which is modular and extensible. The supervisor
> +  software can send/receive RPMI messages via SBI MPXY extension [2]
> +  or some dedicated supervisor-mode RPMI transport.
> +
> +  The RPMI specification [1] defines device power service group for
> +  accessing and controlling the power state of platform devices managed
> +  by a platform microcontroller. The SBI implementation (machine mode
> +  firmware or hypervisor) can implement an SBI MPXY channel to allow RPMI
> +  device power service group access to the supervisor software.
> +
> +  ===========================================
> +  References
> +  ===========================================
> +
> +  [1] RISC-V Platform Management Interface (RPMI) v1.0 (or higher)
> +      https://github.com/riscv-non-isa/riscv-rpmi/releases
> +
> +  [2] RISC-V Supervisor Binary Interface (SBI) v3.0 (or higher)
> +      https://github.com/riscv-non-isa/riscv-sbi-doc/releases
> +
> +properties:
> +  compatible:
> +    description:
> +      Intended for use by the SBI implementation.
> +    const: riscv,rpmi-mpxy-device-power
> +
> +  mboxes:
> +    maxItems: 1
> +    description:
> +      Mailbox channel of the underlying RPMI transport.
> +
> +  riscv,sbi-mpxy-channel-id:
> +    $ref: /schemas/types.yaml#/definitions/uint32

Why isn't this just phandle to mbox? Or even implied by mbox channel? As
your example shows, having same value in two places points that it is
redundant.

> +    description:
> +      The SBI MPXY channel id to be used for providing RPMI access to
> +      the supervisor software.
> +
> +required:
> +  - compatible
> +  - mboxes
> +  - riscv,sbi-mpxy-channel-id
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    device-power-service {
> +        compatible = "riscv,rpmi-mpxy-device-power";
> +        mboxes = <&rpmi_shmem_mbox 0x9>;
> +        riscv,sbi-mpxy-channel-id = <0x1002>;
> +    };
> +...
> -- 
> 2.43.0
>