[PATCH] dt-bindings: nvmem: layouts: add fixed-layout

[PATCH] dt-bindings: nvmem: layouts: add fixed-layout

[Rafał Miłecki]

From: Rafał Miłecki <rafal@milecki.pl>

With the introduction of NVMEM layouts I believe we should prefer and
support describing all NVMEM devices content in the "nvmem-layout" node.
Inluding fixed NVMEM cells (those with hardcoded offset & size).

This seems to be cleaner design and more explicit.

Introduce a binding allowing fixed NVMEM cells as a type of layout.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
 .../bindings/nvmem/layouts/fixed-layout.yaml  | 52 +++++++++++++++++++
 .../bindings/nvmem/layouts/nvmem-layout.yaml  |  1 +
 2 files changed, 53 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/nvmem/layouts/fixed-layout.yaml

diff --git a/Documentation/devicetree/bindings/nvmem/layouts/fixed-layout.yaml b/Documentation/devicetree/bindings/nvmem/layouts/fixed-layout.yaml
new file mode 100644
index 000000000000..7eb86c999a5e
--- /dev/null
+++ b/Documentation/devicetree/bindings/nvmem/layouts/fixed-layout.yaml
@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/nvmem/layouts/fixed-layout.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NVMEM layout for fixed NVMEM cells
+
+description:
+  Many NVMEM devices have hardcoded cells layout (offset and size of specific
+  NVMEM content doesn't change).
+
+  This binding allows defining such cells using NVMEM layout. It can be used on
+  top of any NVMEM device.
+
+maintainers:
+  - Rafał Miłecki <rafal@milecki.pl>
+
+properties:
+  compatible:
+    const: fixed-layout
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 1
+
+patternProperties:
+  "@[a-f0-9]+$":
+    type: object
+    description: NVMEM cell
+    properties:
+      reg:
+        maxItems: 1
+
+required:
+  - compatible
+
+additionalProperties: false
+
+examples:
+  - |
+    nvmem-layout {
+        compatible = "fixed-layout";
+        #address-cells = <1>;
+        #size-cells = <1>;
+
+        calibration@4000 {
+            reg = <0x4000 0x100>;
+        };
+    };
diff --git a/Documentation/devicetree/bindings/nvmem/layouts/nvmem-layout.yaml b/Documentation/devicetree/bindings/nvmem/layouts/nvmem-layout.yaml
index 8512ee538c4c..03da7848c713 100644
--- a/Documentation/devicetree/bindings/nvmem/layouts/nvmem-layout.yaml
+++ b/Documentation/devicetree/bindings/nvmem/layouts/nvmem-layout.yaml
@@ -18,6 +18,7 @@ description: |
   perform their parsing. The nvmem-layout container is here to describe these.
 
 oneOf:
+  - $ref: fixed-layout.yaml
   - $ref: kontron,sl28-vpd.yaml
   - $ref: onie,tlv-layout.yaml
 
-- 
2.34.1

Re: [PATCH] dt-bindings: nvmem: layouts: add fixed-layout

[Rafał Miłecki]

On 9.03.2023 10:34, Rafał Miłecki wrote:
> With the introduction of NVMEM layouts I believe we should prefer and
> support describing all NVMEM devices content in the "nvmem-layout" node.
> Inluding fixed NVMEM cells (those with hardcoded offset & size).
> 
> This seems to be cleaner design and more explicit.
> 
> Introduce a binding allowing fixed NVMEM cells as a type of layout.

While this is obvious to me I should make it clear anyway:

We must not break backward compatibility. Old binding should remain
supported. We may want to deprecate old binding but we have to support
existing DT files.

Re: [PATCH] dt-bindings: nvmem: layouts: add fixed-layout

[Michael Walle]

Hi,

Am 2023-03-09 10:34, schrieb Rafał Miłecki:
> From: Rafał Miłecki <rafal@milecki.pl>
> 
> With the introduction of NVMEM layouts I believe we should prefer and
> support describing all NVMEM devices content in the "nvmem-layout" 
> node.
> Inluding fixed NVMEM cells (those with hardcoded offset & size).
> 
> This seems to be cleaner design and more explicit.
> 
> Introduce a binding allowing fixed NVMEM cells as a type of layout.
> 
> Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
> ---
>  .../bindings/nvmem/layouts/fixed-layout.yaml  | 52 +++++++++++++++++++
>  .../bindings/nvmem/layouts/nvmem-layout.yaml  |  1 +
>  2 files changed, 53 insertions(+)
>  create mode 100644
> Documentation/devicetree/bindings/nvmem/layouts/fixed-layout.yaml
> 
> diff --git
> a/Documentation/devicetree/bindings/nvmem/layouts/fixed-layout.yaml
> b/Documentation/devicetree/bindings/nvmem/layouts/fixed-layout.yaml
> new file mode 100644
> index 000000000000..7eb86c999a5e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/nvmem/layouts/fixed-layout.yaml
> @@ -0,0 +1,52 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/nvmem/layouts/fixed-layout.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: NVMEM layout for fixed NVMEM cells
> +
> +description:
> +  Many NVMEM devices have hardcoded cells layout (offset and size of 
> specific
> +  NVMEM content doesn't change).
> +
> +  This binding allows defining such cells using NVMEM layout. It can 
> be used on
> +  top of any NVMEM device.
> +
> +maintainers:
> +  - Rafał Miłecki <rafal@milecki.pl>
> +
> +properties:
> +  compatible:
> +    const: fixed-layout
> +
> +  "#address-cells":
> +    const: 1
> +
> +  "#size-cells":
> +    const: 1
> +
> +patternProperties:
> +  "@[a-f0-9]+$":
> +    type: object
> +    description: NVMEM cell
> +    properties:
> +      reg:
> +        maxItems: 1

Looking at Documentation/devicetree/bindings/nvmem/nvmem.yaml this
is missing the bits property. Also, can we share that information
between the old style and the new style somehow so we don't
duplicate that here?

-michael

> +
> +required:
> +  - compatible
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    nvmem-layout {
> +        compatible = "fixed-layout";
> +        #address-cells = <1>;
> +        #size-cells = <1>;
> +
> +        calibration@4000 {
> +            reg = <0x4000 0x100>;
> +        };
> +    };
> diff --git
> a/Documentation/devicetree/bindings/nvmem/layouts/nvmem-layout.yaml
> b/Documentation/devicetree/bindings/nvmem/layouts/nvmem-layout.yaml
> index 8512ee538c4c..03da7848c713 100644
> --- a/Documentation/devicetree/bindings/nvmem/layouts/nvmem-layout.yaml
> +++ b/Documentation/devicetree/bindings/nvmem/layouts/nvmem-layout.yaml
> @@ -18,6 +18,7 @@ description: |
>    perform their parsing. The nvmem-layout container is here to 
> describe these.
> 
>  oneOf:
> +  - $ref: fixed-layout.yaml
>    - $ref: kontron,sl28-vpd.yaml
>    - $ref: onie,tlv-layout.yaml