Re: [PATCH 2/5] dt-bindings: Amlogic: add the documentation for the SECBUS2 registers

[Rob Herring <robh@kernel.org>]

On Wed, Dec 30, 2020 at 02:27:21AM +0100, Martin Blumenstingl wrote:
> The Meson8/Meson8b/Meson8m2 SoCs have a register bank called SECBUS2 which
> contains registers for various IP blocks such as pin-controller bits for
> the BSD_EN and TEST_N GPIOs as well as some AO ARC core control bits.
> The registers can be accessed directly when not running in "secure mode".
> When "secure mode" is enabled then these registers have to be accessed
> through secure monitor calls.
> 
> So far these SoCs are always known to boot in "non-secure mode".
> Add a binding documentation using syscon (as these registers are shared
> across different IPs) for the SECBUS2 registers.
> 
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> ---
>  .../arm/amlogic/amlogic,meson-mx-secbus2.yaml | 53 +++++++++++++++++++
>  1 file changed, 53 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/arm/amlogic/amlogic,meson-mx-secbus2.yaml
> 
> diff --git a/Documentation/devicetree/bindings/arm/amlogic/amlogic,meson-mx-secbus2.yaml b/Documentation/devicetree/bindings/arm/amlogic/amlogic,meson-mx-secbus2.yaml
> new file mode 100644
> index 000000000000..cfa8e9de6c28
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/amlogic/amlogic,meson-mx-secbus2.yaml
> @@ -0,0 +1,53 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/arm/amlogic/amlogic,meson-mx-secbus2.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: Amlogic Meson8/Meson8b/Meson8m2 SECBUS2 register interface
> +
> +maintainers:
> +  - Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> +
> +description: |
> +  The Meson8/Meson8b/Meson8m2 SoCs have a register bank called SECBUS2 which
> +  contains registers for various IP blocks such as pin-controller bits for
> +  the BSD_EN and TEST_N GPIOs as well as some AO ARC core control bits.
> +  The registers can be accessed directly when not running in "secure mode".
> +  When "secure mode" is enabled then these registers have to be accessed
> +  through secure monitor calls.
> +
> +# We need a select here so we don't match all nodes with 'syscon'

No, you don't. The default 'select' will ignore 'syscon' and 
'simple-mfd'.

> +select:
> +  properties:
> +    compatible:
> +      contains:
> +        enum:
> +          - amlogic,meson8-secbus2
> +          - amlogic,meson8b-secbus2
> +  required:
> +    - compatible
> +
> +properties:
> +  compatible:
> +    items:
> +      - enum:
> +        - amlogic,meson8-secbus2
> +        - amlogic,meson8b-secbus2
> +      - const: syscon
> +
> +  reg:
> +    maxItems: 1
> +
> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    secbus2: system-controller@4000 {
> +      compatible = "amlogic,meson8-secbus2", "syscon";
> +      reg = <0x4000 0x2000>;
> +    };
> -- 
> 2.30.0
>