Re: [PATCH v2 1/3] dt-bindings: usb: cdns-imx8qm: add imx8qm cdns3 glue bindings

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

On 16/03/2023 22:27, Frank Li wrote:
> NXP imx8qm integrates 1 cdns3 IP. This is glue layer device bindings.
> 

Subject: drop second/last, redundant "bindings". The "dt-bindings"
prefix is already stating that these are bindings.

> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
>  .../bindings/usb/fsl,imx8qm-cdns3.yaml        | 122 ++++++++++++++++++
>  1 file changed, 122 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/usb/fsl,imx8qm-cdns3.yaml
> 
> diff --git a/Documentation/devicetree/bindings/usb/fsl,imx8qm-cdns3.yaml b/Documentation/devicetree/bindings/usb/fsl,imx8qm-cdns3.yaml
> new file mode 100644
> index 000000000000..fc24df1e4483
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/usb/fsl,imx8qm-cdns3.yaml
> @@ -0,0 +1,122 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +# Copyright (c) 2020 NXP
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/usb/fsl,imx8qm-cdns3.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: NXP iMX8QM Soc USB Controller
> +
> +maintainers:
> +  - Frank Li <Frank.Li@nxp.com>
> +
> +properties:
> +  compatible:
> +    const: fsl,imx8qm-usb3
> +
> +  reg:
> +    items:
> +      - description: Address and length of the register set for iMX USB3 Platform Control

Drop "Address and length of the"... or actually just maxItems: 1,
because the description is a bit obvious.

> +
> +  "#address-cells":
> +    enum: [ 1, 2 ]
> +
> +  "#size-cells":
> +    enum: [ 1, 2 ]
> +
> +  ranges: true
> +
> +  clocks:
> +    description:
> +      A list of phandle and clock-specifier pairs for the clocks
> +      listed in clock-names.

Drop description.

> +    items:
> +      - description: Standby clock. Used during ultra low power states.
> +      - description: USB bus clock for usb3 controller.
> +      - description: AXI clock for AXI interface.
> +      - description: ipg clock for register access.
> +      - description: Core clock for usb3 controller.
> +
> +  clock-names:
> +    items:
> +      - const: usb3_lpm_clk
> +      - const: usb3_bus_clk
> +      - const: usb3_aclk
> +      - const: usb3_ipg_clk
> +      - const: usb3_core_pclk
> +
> +  assigned-clocks:
> +    items:
> +      - description: Phandle and clock specifier of IMX_SC_PM_CLK_PER.
> +      - description: Phandle and clock specifoer of IMX_SC_PM_CLK_MISC.
> +      - description: Phandle and clock specifoer of IMX_SC_PM_CLK_MST_BUS.
> +
> +  assigned-clock-rates:
> +    items:
> +      - description: Must be 125 Mhz.
> +      - description: Must be 12 Mhz.
> +      - description: Must be 250 Mhz.

I would argue that both properties above are not needed. If your
hardware requires fixed frequencies, clock provider can fix them, can't it?

> +
> +  power-domains:
> +    maxItems: 1
> +
> +# Required child node:
> +
> +patternProperties:
> +  "^usb@[0-9a-f]+$":
> +    $ref: cdns,usb3.yaml#
> +
> +required:
> +  - compatible
> +  - reg
> +  - "#address-cells"
> +  - "#size-cells"
> +  - ranges
> +  - clocks
> +  - clock-names
> +  - power-domains
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/imx8-lpcg.h>
> +    #include <dt-bindings/firmware/imx/rsrc.h>
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +    usbotg3: usb@5b110000 {

Drop label, unused

> +      compatible = "fsl,imx8qm-usb3";
> +      ranges;
> +      reg = <0x5b110000 0x10000>;

reg is second property

> +      clocks = <&usb3_lpcg IMX_LPCG_CLK_1>,
> +               <&usb3_lpcg IMX_LPCG_CLK_0>,
> +               <&usb3_lpcg IMX_LPCG_CLK_7>,
> +               <&usb3_lpcg IMX_LPCG_CLK_4>,
> +               <&usb3_lpcg IMX_LPCG_CLK_5>;
> +      clock-names = "usb3_lpm_clk", "usb3_bus_clk", "usb3_aclk",
> +                    "usb3_ipg_clk", "usb3_core_pclk";
> +      assigned-clocks = <&clk IMX_SC_R_USB_2 IMX_SC_PM_CLK_PER>,
> +                        <&clk IMX_SC_R_USB_2 IMX_SC_PM_CLK_MISC>,
> +                        <&clk IMX_SC_R_USB_2 IMX_SC_PM_CLK_MST_BUS>;
> +      assigned-clock-rates = <125000000>, <12000000>, <250000000>;
> +      power-domains = <&pd IMX_SC_R_USB_2>;
> +      #address-cells = <1>;
> +      #size-cells = <1>;
> +      status = "disabled";

Drop status

> +
> +      usbotg3_cdns3: usb@5b120000 {

Drop label

> +          compatible = "cdns,usb3";
> +          interrupt-parent = <&gic>;
> +          interrupts = <GIC_SPI 271 IRQ_TYPE_LEVEL_HIGH>,
> +                       <GIC_SPI 271 IRQ_TYPE_LEVEL_HIGH>,
> +                       <GIC_SPI 271 IRQ_TYPE_LEVEL_HIGH>,
> +                       <GIC_SPI 271 IRQ_TYPE_LEVEL_HIGH>;
> +          interrupt-names = "host", "peripheral", "otg", "wakeup";
> +          reg = <0x5b120000 0x10000>,   /* memory area for OTG/DRD registers */
> +                <0x5b130000 0x10000>,   /* memory area for HOST registers */
> +                <0x5b140000 0x10000>;   /* memory area for DEVICE registers */
> +          reg-names = "otg", "xhci", "dev";

reg is second property, reg-names third.

> +          phys = <&usb3_phy>;
> +          phy-names = "cdns3,usb3-phy";
> +      };
> +    };

Best regards,
Krzysztof