Re: [PATCH v3] dt-bindings: mfd: Convert ChromeOS EC bindings to json-schema

[Ikjoon Jang <ikjn@chromium.org>]

On Tue, Jan 28, 2020 at 12:05 AM Rob Herring <robh@kernel.org> wrote:
>
> On Tue, Jan 21, 2020 at 03:47:27PM +0800, Ikjoon Jang wrote:
> > Convert the ChromeOS EC bindings to json-schema.
> >
> > Signed-off-by: Ikjoon Jang <ikjn@chromium.org>
> > ---
> > v3: node name changed in rpmsg example
> > v2: cleanup description, fix typos, remove LPC, add add RPMSG example
> > ---
> >  .../devicetree/bindings/mfd/cros-ec.txt       |  76 ------------
> >  .../devicetree/bindings/mfd/cros-ec.yaml      | 111 ++++++++++++++++++
> >  2 files changed, 111 insertions(+), 76 deletions(-)
> >  delete mode 100644 Documentation/devicetree/bindings/mfd/cros-ec.txt
> >  create mode 100644 Documentation/devicetree/bindings/mfd/cros-ec.yaml
>
> > -Required properties (LPC):
> > -- compatible: "google,cros-ec-lpc"
> > -- reg: List of (IO address, size) pairs defining the interface uses
>
> Where did this go?

I'm not sure about the details or future plans on LPC interface,
but I guess LPC has been just a future plan without any usages, so removed it.

>
>
> > diff --git a/Documentation/devicetree/bindings/mfd/cros-ec.yaml b/Documentation/devicetree/bindings/mfd/cros-ec.yaml
> > new file mode 100644
> > index 000000000000..6a5b87cebcfa
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mfd/cros-ec.yaml
> > @@ -0,0 +1,111 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/mfd/cros-ec.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: ChromeOS Embedded Controller
> > +
> > +maintainers:
> > +  - Benson Leung <bleung@chromium.org>
> > +  - Enric Balletbo i Serra <enric.balletbo@collabora.com>
> > +  - Guenter Roeck <groeck@chromium.org>
> > +
> > +description: |
> > +  Google's ChromeOS EC is a microcontroller which talks to the AP and
> > +  implements various functions such as keyboard and battery charging.
> > +  The EC can be connected through various interfaces (I2C, SPI, and others)
> > +  and the compatible string specifies which interface is being used.
> > +

I will drop | here also.

> > +properties:
> > +  compatible:
> > +    oneOf:
> > +      - description:
> > +          For implementations of the EC is connected through I2C.
> > +        const: google,cros-ec-i2c
> > +      - description:
> > +          For implementations of the EC is connected through SPI.
> > +        const: google,cros-ec-spi
> > +      - description:
> > +          For implementations of the EC is connected through RPMSG.
> > +        const: google,cros-ec-rpmsg
> > +
> > +  google,has-vbc-nvram:
> > +    description: |
>
> You can drop '|' if there's no formatting to maintain. And you should
> reflow this.

Okay,

>
> > +      Some implementations of the EC include a small
> > +      nvram space used to store verified boot context data.
> > +      This boolean flag is used to specify whether this nvram is
> > +      present or not.
> > +    type: boolean
> > +
> > +required:
> > +  - compatible
> > +
> > +allOf:
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          const: google,cros-ec-i2c
> > +    then:
> > +      properties:
> > +        reg:
> > +          description: I2C slave address
> > +          maxItems: 1
> > +      required:
> > +        - reg
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          const: google,cros-ec-spi
> > +    then:
> > +      properties:
> > +        reg:
> > +          description: SPI chip select
> > +          maxItems: 1
> > +        google,cros-ec-spi-pre-delay:
> > +          description: |
> > +            This property specifies the delay in usecs between the
> > +            assertion of the CS and the first clock pulse.
>
> Needs a type reference at a minumum and ideally some constraints.

Got it, I will add a type reference here,
and for the constraints, these spi transaction delay cannot be bound.
I will just add default: 0 here.

>
> > +        google,cros-ec-spi-msg-delay:
> > +          description: |
> > +            This property specifies the delay in usecs between messages.
>
> Same here.
>
> > +      required:
> > +        - reg
> > +
>
> Add:
> additionalProperties: false

Ack.

>
> > +examples:
> > +  # Example for I2C
> > +  - |
> > +    i2c0 {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        cros-ec@1e {
> > +            compatible = "google,cros-ec-i2c";
> > +            reg = <0x1e>;
> > +            interrupts = <6 0>;
>
> Not documented.

Sorry but I can't understand this part, can you elaborate on here?
Do you mean adding comments here? or
need more documentation on cros-ec-i2c?

>
> > +            interrupt-parent = <&gpx1>;
> > +        };
> > +    };
> > +  # Example for SPI
> > +  - |
> > +    spi0 {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        cros-ec@0 {
> > +            compatible = "google,cros-ec-spi";
> > +            reg = <0x0>;
> > +            google,cros-ec-spi-msg-delay = <30>;
> > +            interrupts = <99 0>;
> > +            interrupt-parent = <&gpio7>;
> > +            spi-max-frequency = <5000000>;
> > +        };
> > +    };
> > +  # Example for RPMSG
> > +  - |
> > +    scp0 {
> > +        cros-ec@0 {
> > +            compatible = "google,cros-ec-rpmsg";
> > +        };
> > +    };
> > +...
> > --
> > 2.25.0.341.g760bfbb309-goog
> >