[1/6] dt-bindings: nvmem: Add bindings for rmem driver

Firmware/co-processors might use reserved memory areas in order to pass
data stemming from an nvmem device otherwise non accessible to Linux.
For example an EEPROM memory only physically accessible to firmware, or
data only accessible early at boot time.

Introduce the dt-bindings to nvmem's rmem.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
 .../devicetree/bindings/nvmem/rmem.yaml       | 35 +++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/nvmem/rmem.yaml

On Tue, Dec 15, 2020 at 9:56 AM Nicolas Saenz Julienne
<nsaenzjulienne@suse.de> wrote:
>
> Firmware/co-processors might use reserved memory areas in order to pass
> data stemming from an nvmem device otherwise non accessible to Linux.
> For example an EEPROM memory only physically accessible to firmware, or
> data only accessible early at boot time.
>
> Introduce the dt-bindings to nvmem's rmem.
>
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
> ---
>  .../devicetree/bindings/nvmem/rmem.yaml       | 35 +++++++++++++++++++
>  1 file changed, 35 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/nvmem/rmem.yaml
>
> diff --git a/Documentation/devicetree/bindings/nvmem/rmem.yaml b/Documentation/devicetree/bindings/nvmem/rmem.yaml
> new file mode 100644
> index 000000000000..3037ebc4634d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/nvmem/rmem.yaml
> @@ -0,0 +1,35 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/nvmem/rmem.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Reserved Memory Based nvmem Device
> +
> +maintainers:
> +  - Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
> +
> +properties:
> +  compatible:
> +    enum:
> +      - nvmem-rmem
> +
> +  memory-region:
> +    $ref: /schemas/types.yaml#/definitions/phandle
> +    description:
> +      phandle to the reserved memory region

There's no need for this indirection. Just add a compatible to the
reserved-memory node. See ramoops for example.

Please make the compatible specific enough to define what the memory
contains. If you want 'nvmem-rmem' as a fallback that's fine.

> +
> +required:
> +  - compatible
> +  - memory-region
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +        fw-config {
> +                compatible = "nvmem-rmem";
> +                memory-region = <&mem>;
> +        };
> +
> +...
> --
> 2.29.2
>