Message-ID: <20200305220558.GC142502@google.com>
Date:   Thu, 5 Mar 2020 14:05:58 -0800
From:   Prashant Malani <pmalani@...omium.org>
To:     Stephen Boyd <swboyd@...omium.org>
Cc:     devicetree@...r.kernel.org, bleung@...omium.org,
        heikki.krogerus@...ux.intel.com, enric.balletbo@...labora.com,
        Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
        Chunfeng Yun <chunfeng.yun@...iatek.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-mediatek@...ts.infradead.org, linux-usb@...r.kernel.org,
        Mark Rutland <mark.rutland@....com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Rob Herring <robh+dt@...nel.org>
Subject: Re: [PATCH v2] dt-bindings: Convert usb-connector to YAML format.

Hi Stephen,

Thanks for reviewing the patch. Kindly see my responses inline.

Best regards,

-Prashant

On Thu, Mar 05, 2020 at 01:20:04PM -0800, Stephen Boyd wrote:
> Quoting Prashant Malani (2020-03-04 19:01:30)
> > diff --git a/Documentation/devicetree/bindings/connector/usb-connector.yaml b/Documentation/devicetree/bindings/connector/usb-connector.yaml
> > new file mode 100644
> > index 0000000000000..b386e2880405c
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/connector/usb-connector.yaml
> > @@ -0,0 +1,203 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/connector/usb-connector.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: USB Connector
> > +
> > +maintainers:
> > +  - linux-usb@...r.kernel.org
> > +
> > +description:
> > +  A USB connector node represents a physical USB connector. It should be a child
> > +  of a USB interface controller.
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - usb-a-connector
> > +      - usb-b-connector
> > +      - usb-c-connector
> > +
> > +  label:
> > +    description: Symbolic name for the connector.
> > +
> > +  type:
> > +    description: Size of the connector, should be specified in case of USB-A,
> > +      USB-B non-fullsize connectors.
> 
> Maybe "should be specified in case of non-fullsize 'usb-a-connector' or
> 'usb-b-connector' compatible connectors"?
> 
Done.

> > +    $ref: /schemas/types.yaml#definitions/string
> > +    enum:
> > +      - mini
> > +      - micro
> > +
> > +  self-powered:
> > +    description: Set this property if the USB device has its own power source.
> > +    type: boolean
> > +
> > +  # The following are optional properties for "usb-b-connector".
> > +  id-gpios:
> > +    description: An input gpio for USB ID pin.
> > +    maxItems: 1
> > +
> > +  vbus-gpios:
> > +    description: An input gpio for USB VBus pin, used to detect presence of
> > +      VBUS 5V. See gpio/gpio.txt.
> 
> Can this be written as bindings/gpio/gpio.txt?

Dropping it based on Rob's later comment.
> 
> > +    maxItems: 1
> > +
> > +  vbus-supply:
> > +    description: A phandle to the regulator for USB VBUS if needed when host
> > +      mode or dual role mode is supported.
> > +      Particularly, if use an output GPIO to control a VBUS regulator, should
> > +      model it as a regulator. See regulator/fixed-regulator.yaml
> 
> And bindings/regulator/fixed-regulator.yaml? The idea is to
> disambiguate from kernel Documentation/ directory.

Done.
> 
> > +
> > +  # The following are optional properties for "usb-c-connector".
> 
> Is there a way to constrain the binding so that this can't be put in a
> connector that doesn't have the usb-c-connector compatible string?
> 
> > +  power-role:
> > +    description: Determines the power role that the Type C connector will
> > +      support. "dual" refers to Dual Role Port (DRP).
> > +    allOf:
> > +      - $ref: /schemas/types.yaml#definitions/string
> > +    enum:
> > +      - source
> > +      - sink
> > +      - dual
> > +
> > +  try-power-role:
> > +    description: Preferred power role.
> > +    allOf:
> > +      - $ref: /schemas/types.yaml#definitions/string
> > +    enum:
> > +     - source
> > +     - sink
> > +     - dual
> > +
> > +  data-role:
> > +    description: Data role if Type C connector supports USB data. "dual" refers
> > +      Dual Role Device (DRD).
> > +    allOf:
> > +      - $ref: /schemas/types.yaml#definitions/string
> > +    enum:
> > +      - host
> > +      - device
> > +      - dual
> 
> Is there a way to maintain a description for each possible string
> property? Then we could move the last sentence in the description above
> to be attached to '- dual' here.
> 
I'm not sure of a way to do this, so leaving this as is for now.
> > +
> > +  # The following are optional properties for "usb-c-connector" with power
> > +  # delivery support.
> > +  source-pdos:
> > +    description: An array of u32 with each entry providing supported power
> > +      source data object(PDO), the detailed bit definitions of PDO can be found
> > +      in "Universal Serial Bus Power Delivery Specification" chapter 6.4.1.2
> > +      Source_Capabilities Message, the order of each entry(PDO) should follow
> > +      the PD spec chapter 6.4.1. Required for power source and power dual role.
> > +      User can specify the source PDO array via PDO_FIXED/BATT/VAR/PPS_APDO()
> > +      defined in dt-bindings/usb/pd.h.
> > +    minItems: 1
> > +    maxItems: 7
> > +    allOf:
> > +      - $ref: /schemas/types.yaml#/definitions/uint32-array
> > +
> > +  sink-pdos:
> > +    description: An array of u32 with each entry providing supported power sink
> > +      data object(PDO), the detailed bit definitions of PDO can be found in
> > +      "Universal Serial Bus Power Delivery Specification" chapter 6.4.1.3
> > +      Sink Capabilities Message, the order of each entry(PDO) should follow the
> > +      PD spec chapter 6.4.1. Required for power sink and power dual role. User
> > +      can specify the sink PDO array via PDO_FIXED/BATT/VAR/PPS_APDO() defined
> > +      in dt-bindings/usb/pd.h.
> > +    minItems: 1
> > +    maxItems: 7
> > +    allOf:
> > +      - $ref: /schemas/types.yaml#/definitions/uint32-array
> > +
> > +  op-sink-microwatt:
> > +    description: Sink required operating power in microwatt, if source can't
> > +      offer the power, Capability Mismatch is set. Required for power sink and
> > +      power dual role.
> > +
> > +  ports:
> > +    description: OF graph bindings (specified in bindings/graph.txt) that model
> > +      any data bus to the connector unless the bus is between parent node and
> > +      the connector. Since a single connector can have multiple data buses every
> > +      bus has assigned OF graph port number as described below.
> 
> has an assigned?

Done.
> 
> > +    type: object
> > +    properties:
> > +      port@0:
> > +        type: object
> > +        description: High Speed (HS), present in all connectors.
> > +
> > +      port@1:
> > +        type: object
> > +        description: Super Speed (SS), present in SS capable connectors.
> > +
> > +      port@2:
> > +        type: object
> > +        description: Sideband Use (SBU), present in USB-C.
> 
> Likewise, is it possible to constrain this to only usb-c-connector
> compatible string based bindings? And if so, does it become required for
> that compatible string?
> 
> > +
> > +    required:
> > +      - port@0
> > +
> > +required:
> > +  - compatible
> > +
> > +examples:
> > +  # Micro-USB connector with HS lines routed via controller (MUIC).
> > +  - |+
> > +    muic-max77843@66 {
> 
> Add a reg = <0x66>; here? Or drop the unit address above.

Dropped the unit address.
> 
> > +      usb_con1: connector {
> > +        compatible = "usb-b-connector";
> > +        label = "micro-USB";
> > +        type = "micro";
> > +      };
> > +    };
> > +
> > +  # USB-C connector attached to CC controller (s2mm005), HS lines routed
> > +  # to companion PMIC (max77865), SS lines to USB3 PHY and SBU to DisplayPort.
> > +  # DisplayPort video lines are routed to the connector via SS mux in USB3 PHY.
> > +  - |+
> > +    ccic: s2mm005@33 {
> 
> Same unit address comment.
Dropped the unit address.
> 
> > +      usb_con2: connector {
> > +        compatible = "usb-c-connector";
> > +        label = "USB-C";
> > +
> > +        ports {
> > +          #address-cells = <1>;
> > +          #size-cells = <0>;
> > +
> > +          port@0 {
> > +            reg = <0>;
> > +            usb_con_hs: endpoint {
> > +              remote-endpoint = <&max77865_usbc_hs>;
> > +            };
> > +          };
> > +          port@1 {
> > +            reg = <1>;
> > +            usb_con_ss: endpoint {
> > +            remote-endpoint = <&usbdrd_phy_ss>;
> > +            };
> > +          };
> > +          port@2 {
> > +            reg = <2>;
> > +            usb_con_sbu: endpoint {
> > +            remote-endpoint = <&dp_aux>;
> > +            };
> 
> Tabs should be replaced with spaces.

Fixed the spacing here.
> 
> > +          };
> > +        };
> > +      };
> > +    };
> > +
> > +  # USB-C connector attached to a typec port controller(ptn5110), which has
> > +  # power delivery support and enables drp.
> > +  - |+
> > +    #include <dt-bindings/usb/pd.h>
> > +    typec: ptn5110@50 {
> 
> Same unit address comment.

Dropped the unit address.
> 
> > +      usb_con3: connector {
> > +        compatible = "usb-c-connector";
> > +        label = "USB-C";
> > +        power-role = "dual";
> > +        try-power-role = "sink";
> > +        source-pdos = <PDO_FIXED(5000, 2000, PDO_FIXED_USB_COMM)>;
> > +        sink-pdos = <PDO_FIXED(5000, 2000, PDO_FIXED_USB_COMM)
> > +                     PDO_VAR(5000, 12000, 2000)>;
> > +        op-sink-microwatt = <10000000>;
> > +      };
> > +    };

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