Re: [RFC 1/2] dt-bindings: usb: dwc3: Add support for multiport related properties

From: Rob Herring <robh@kernel.org>
To: Harsh Agarwal <quic_harshq@quicinc.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Felipe Balbi <balbi@kernel.org>,
	linux-usb@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, quic_pkondeti@quicinc.com,
	quic_ppratap@quicinc.com
Subject: Re: [RFC 1/2] dt-bindings: usb: dwc3: Add support for multiport related properties
Date: Mon, 23 May 2022 07:25:54 -0500	[thread overview]
Message-ID: <20220523122554.GA416176-robh@kernel.org> (raw)
In-Reply-To: <1652963695-10109-2-git-send-email-quic_harshq@quicinc.com>

On Thu, May 19, 2022 at 06:04:54PM +0530, Harsh Agarwal wrote:
> Added support for multiport, mport, num-ssphy and num-hsphy
> properties. These properties are used to support devices having
> a multiport controller.
> 
> Signed-off-by: Harsh Agarwal <quic_harshq@quicinc.com>
> ---
>  .../devicetree/bindings/usb/snps,dwc3.yaml         | 55 ++++++++++++++++++++++
>  1 file changed, 55 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> index f4471f8..39c61483 100644
> --- a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> +++ b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> @@ -341,6 +341,35 @@ properties:
>        This port is used with the 'usb-role-switch' property  to connect the
>        dwc3 to type C connector.
>  
> +  multiport:
> +    description:
> +      If a single USB controller supports multiple ports, then it's referred to as
> +      a multiport controller. Each port of the multiport controller can support
> +      either High Speed or Super Speed or both and have their own PHY phandles. Each
> +      port is represented by "mport" node and all the "mport" nodes are grouped
> +      together inside the "multiport" node where individual "mport" node defines the
> +      PHYs supported by that port.
> +    required:
> +      - mport
> +
> +  num-hsphy:
> +    description: Total number of HS-PHYs defined by the multiport controller.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +
> +  num-ssphy:
> +    description: Total number of SS-PHYs defined by the multiport controller.
> +    $ref: /schemas/types.yaml#/definitions/uint32

These seem redundant. Can't you count ports/phys?

> +
> +  mport:
> +    description: Each mport node represents one port of the multiport controller.
> +    patternProperties: "^mport@[0-9a-f]+$"

Think about how the USB device binding fits into this. A hub vs. 
multiple root ports doesn't seem much different.

Rob