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

Bjorn Andersson
2022-05-21T03:03:28Z

On Thu 19 May 05:34 PDT 2022, 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>

Please do run dt_binding_check on your bindings, even though they are
RFCs.

> ---
> .../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:

Why are you inventing an of_graph lookalike here?

> + 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

I'm expecting that you wont' have any superspeed-only ports. As such
this number would imply be the number of ports listed under the node.

> +
> + num-ssphy:
> + description: Total number of SS-PHYs defined by the multiport controller.
> + $ref: /schemas/types.yaml#/definitions/uint32

Can you please explain why it's necessary to specify usb_nop_phy?
Wouldn't it be possible to omit the phy in the case of a HS-only port?
In which case this could just be calculated as well.

Regards,
Bjorn

> +
> + mport:
> + description: Each mport node represents one port of the multiport controller.
> + patternProperties: "^mport@[0-9a-f]+$"
> + oneOf:
> + - required:
> + - usb-phy
> + - required:
> + - phys
> + - phy-names
> +
> unevaluatedProperties: false
>
> required:
> @@ -369,4 +398,30 @@ examples:
> snps,dis_u2_susphy_quirk;
> snps,dis_enblslpm_quirk;
> };
> + - |
> + usb@4a000000 {
> + compatible = "snps,dwc3";
> + reg = <0x4a000000 0xcfff>;
> + interrupts = <0 92 4>;
> +
> + multiport {
> +
> + MP_1: mport@1 {
> + usb-phy = <&usb2_phy0>, <&usb3_phy0>;
> + };
> +
> + MP_2: mport@2 {
> + usb-phy = <&usb2_phy1>, <&usb3_phy1>;
> + };
> +
> + MP_3: mport@3 {
> + usb-phy = <&usb2_phy2>, <&usb_nop_phy>;
> + };
> +
> + MP_4: mport@4 {
> + usb-phy = <&usb2_phy3>, <&usb_nop_phy>;
> + };
> +
> + };
> + };
> ...
> --
> 2.7.4
>