Re: [PATCH V5 1/6] dt-bindings: usb: Add NVIDIA Tegra234 XUSB host controller binding

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 06/01/2023 16:28, Jon Hunter wrote:
> From: Wayne Chang <waynec@nvidia.com>
> 
> Add device-tree binding documentation for the XUSB host controller present
> on Tegra234 SoC. This controller supports the USB 3.1 specification.
> 
> Signed-off-by: Wayne Chang <waynec@nvidia.com>
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
> ---
> V4 -> V5: No changes
> V3 -> V4: minor update to the power-domain description
> V2 -> V3: nothing has changed
> V1 -> V2: address the issue on phy-names property
> 
>  .../bindings/usb/nvidia,tegra234-xusb.yaml    | 158 ++++++++++++++++++
>  1 file changed, 158 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/usb/nvidia,tegra234-xusb.yaml
> 
> diff --git a/Documentation/devicetree/bindings/usb/nvidia,tegra234-xusb.yaml b/Documentation/devicetree/bindings/usb/nvidia,tegra234-xusb.yaml
> new file mode 100644
> index 000000000000..190a23c72963
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/usb/nvidia,tegra234-xusb.yaml
> @@ -0,0 +1,158 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/usb/nvidia,tegra234-xusb.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: NVIDIA Tegra234 xHCI controller
> +
> +maintainers:
> +  - Thierry Reding <thierry.reding@gmail.com>
> +  - Jon Hunter <jonathanh@nvidia.com>
> +
> +description: The Tegra xHCI controller supports both USB2 and USB3 interfaces

Line ends after "description:"

> +  exposed by the Tegra XUSB pad controller.
> +
> +properties:
> +  compatible:
> +    const: nvidia,tegra234-xusb
> +
> +  reg:
> +    items:
> +      - description: base and length of the xHCI host registers

Just "xHCI host registers". Same in other places.

> +      - description: base and length of the XUSB FPCI registers
> +      - description: base and length of the XUSB bar2 registers
> +
> +  reg-names:
> +    items:
> +      - const: hcd
> +      - const: fpci
> +      - const: bar2
> +
> +  interrupts:
> +    items:
> +      - description: xHCI host interrupt
> +      - description: mailbox interrupt
> +
> +  clocks:
> +    items:
> +      - description: XUSB host clock
> +      - description: XUSB Falcon source clock
> +      - description: XUSB SuperSpeed clock
> +      - description: XUSB SuperSpeed source clock
> +      - description: XUSB HighSpeed clock source
> +      - description: XUSB FullSpeed clock source
> +      - description: USB PLL
> +      - description: reference clock
> +      - description: I/O PLL
> +
> +  clock-names:
> +    items:
> +      - const: xusb_host
> +      - const: xusb_falcon_src
> +      - const: xusb_ss
> +      - const: xusb_ss_src
> +      - const: xusb_hs_src
> +      - const: xusb_fs_src
> +      - const: pll_u_480m
> +      - const: clk_m
> +      - const: pll_e
> +
> +  interconnects:
> +    items:
> +      - description: read client
> +      - description: write client
> +
> +  interconnect-names:
> +    items:
> +      - const: dma-mem # read
> +      - const: write
> +
> +  iommus:
> +    maxItems: 1
> +
> +  nvidia,xusb-padctl:
> +    $ref: /schemas/types.yaml#/definitions/phandle
> +    description: phandle to the XUSB pad controller that is used to configure
> +      the USB pads used by the XHCI controller
> +
> +  phys:
> +    minItems: 1
> +    maxItems: 8
> +
> +  phy-names:
> +    minItems: 1
> +    maxItems: 8
> +    items:
> +      enum:
> +        - usb2-0
> +        - usb2-1
> +        - usb2-2
> +        - usb2-3
> +        - usb3-0
> +        - usb3-1
> +        - usb3-2
> +        - usb3-3

Why do you have so many optional phys? In what case you would put there
usb2-0 and usb3-3 together? Or even 8 phys at the same time? IOW, what
are the differences between them and why one controller would be
connected once to usb3-2 and once to usb3-3 phy? And once to both?

> +
> +  power-domains:
> +    items:
> +      - description: XUSBC power domain (for Host and USB 2.0)
> +      - description: XUSBA power domain (for SuperSpeed)
> +
> +  power-domain-names:
> +    items:
> +      - const: xusb_host
> +      - const: xusb_ss
> +
> +  dma-coherent:

Just: true

> +    type: boolean

Drop

> +
> +allOf:
> +  - $ref: usb-xhci.yaml
> +
> +unevaluatedProperties: false
> +

Best regards,
Krzysztof