[PATCH 2/2] dt-bindings: rng: Add MediaTek MT7981 TRNG

[Daniel Golle]

On Thu, Feb 16, 2023 at 10:14:33AM +0100, Krzysztof Kozlowski wrote:
> On 15/02/2023 14:27, Daniel Golle wrote:
> > Add documentation to describe the MediaTek true random number generator
> > which is provided by ARM TrustedFirmware-A of the MT7981.
> > 
> > Signed-off-by: Daniel Golle <daniel at makrotopia.org>
> > ---
> >  .../bindings/rng/mediatek,mt7981-rng.yaml     | 39 +++++++++++++++++++
> >  MAINTAINERS                                   |  1 +
> >  2 files changed, 40 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/rng/mediatek,mt7981-rng.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/rng/mediatek,mt7981-rng.yaml b/Documentation/devicetree/bindings/rng/mediatek,mt7981-rng.yaml
> > new file mode 100644
> > index 000000000000..d577d60538d8
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/rng/mediatek,mt7981-rng.yaml
> > @@ -0,0 +1,39 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/rng/mediatek,mt7981-rng.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: MediaTek Random number generator (v2/SMC)
> > +
> > +maintainers:
> > +  - Daniel Golle <daniel at makrotopia.org>
> > +
> > +properties:
> > +  $nodename:
> > +    pattern: "^rng$"
> 
> 1. We don't enforce it in device bindings, so drop it.

Ack.

> 2. It's not even correct. You have reg.

No, there isn't any reg, as this driver does not access a MMIO mapped
resource but rather uses Secure Monitor Call interface to access the
TRNG via ARM TrustedFirmware-A.

> 
> 
> > +
> > +  compatible:
> > +    enum:
> > +      - mediatek,mt7981-rng
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  clocks:
> > +    maxItems: 1
> > +
> > +  clock-names:
> > +    items:
> > +      - const: rng
> 
> Drop clock-names and rely on index.

Will drop, reg, clocks and clock-names, that slipped in from the
document I used as template for this one. The driver uses neither of
those.

> 
> > +
> > +required:
> > +  - compatible
> 
> and reg?
> 
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    rng {
> > +      compatible = "mediatek,mt7981-rng";
> > +    };
> 
> Best regards,
> Krzysztof
> 
>