linux-kernel - Re: [PATCH v3 1/4] dt-bindings: Add cros-ec Type C port driver

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Date:   Thu, 27 Feb 2020 17:15:47 -0600
From:   Rob Herring <robh@...nel.org>
To:     Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Cc:     Prashant Malani <pmalani@...omium.org>,
        linux-kernel@...r.kernel.org, enric.balletbo@...labora.com,
        bleung@...omium.org,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>, Guenter Roeck <groeck@...omium.org>,
        Mark Rutland <mark.rutland@....com>
Subject: Re: [PATCH v3 1/4] dt-bindings: Add cros-ec Type C port driver

On Thu, Feb 27, 2020 at 05:12:16PM +0200, Heikki Krogerus wrote:
> Hi,
> 
> On Wed, Feb 19, 2020 at 04:30:55PM -0800, Prashant Malani wrote:
> > Some Chrome OS devices with Embedded Controllers (EC) can read and
> > modify Type C port state.
> > 
> > Add an entry in the DT Bindings documentation that lists out the logical
> > device and describes the relevant port information, to be used by the
> > corresponding driver.
> > 
> > Signed-off-by: Prashant Malani <pmalani@...omium.org>
> > ---
> > 
> > Changes in v3:
> > - Fixed license identifier.
> > - Renamed "port" to "connector".
> > - Made "connector" be a "usb-c-connector" compatible property.
> > - Updated port-number description to explain min and max values,
> >   and removed $ref which was causing dt_binding_check errors.
> > - Fixed power-role, data-role and try-power-role details to make
> >   dt_binding_check pass.
> > - Fixed example to include parent EC SPI DT Node.
> > 
> > Changes in v2:
> > - No changes. Patch first introduced in v2 of series.
> > 
> >  .../bindings/chrome/google,cros-ec-typec.yaml | 86 +++++++++++++++++++
> >  1 file changed, 86 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/chrome/google,cros-ec-typec.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/chrome/google,cros-ec-typec.yaml b/Documentation/devicetree/bindings/chrome/google,cros-ec-typec.yaml
> > new file mode 100644
> > index 00000000000000..97fd982612f120
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/chrome/google,cros-ec-typec.yaml
> > @@ -0,0 +1,86 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/chrome/google,cros-ec-typec.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Google Chrome OS EC(Embedded Controller) Type C port driver.
> > +
> > +maintainers:
> > +  - Benson Leung <bleung@...omium.org>
> > +  - Prashant Malani <pmalani@...omium.org>
> > +
> > +description:
> > +  Chrome OS devices have an Embedded Controller(EC) which has access to
> > +  Type C port state. This node is intended to allow the host to read and
> > +  control the Type C ports. The node for this device should be under a
> > +  cros-ec node like google,cros-ec-spi.
> > +
> > +properties:
> > +  compatible:
> > +    const: google,cros-ec-typec
> > +
> > +  connector:
> > +    description: A node that represents a physical Type C connector port
> > +      on the device.
> > +    type: object
> > +    properties:
> > +      compatible:
> > +        const: usb-c-connector
> > +      port-number:
> > +        description: The number used by the Chrome OS EC to identify
> > +          this type C port. Valid values are 0 - (EC_USB_PD_MAX_PORTS - 1).
> > +      power-role:
> > +        description: Determines the power role that the Type C port will
> > +          adopt.
> > +        maxItems: 1
> > +        contains:
> > +          enum:
> > +            - sink
> > +            - source
> > +            - dual
> > +      data-role:
> > +        description: Determines the data role that the Type C port will
> > +          adopt.
> > +        maxItems: 1
> > +        contains:
> > +          enum:
> > +            - host
> > +            - device
> > +            - dual
> > +      try-power-role:
> > +        description: Determines the preferred power role of the Type C port.
> > +        maxItems: 1
> > +        contains:
> > +          enum:
> > +            - sink
> > +            - source
> > +            - dual
> > +
> > +    required:
> > +      - port-number
> > +      - power-role
> > +      - data-role
> > +      - try-power-role
> 
> Do you really need to redefine those?

No.

> 
> I think you just need to mention that there is a required sub-node
> "connector", and the place where it's described. So something
> like this:
> 
>         Required sub-node:
>         - connector : The "usb-c-connector". The bindings of the
>           connector node are specified in:
> 
>                 Documentation/devicetree/bindings/connector/usb-connector.txt

Ideally, we'd convert this to schema first and then here just have:

connector:
  $ref: /schemas/connector/usb-connector.yaml#

> 
> 
> Then you just need to define the Chrome OS EC specific properties, so
> I guess just the "port-number".

'reg' as Stephen suggested.

Rob