Re: [RFC PATCH 3/4] dt-bindings: mtd: add OTP bindings

From: Rob Herring
Date: Sat Mar 27 2021 - 13:15:30 EST


On Mon, Mar 22, 2021 at 07:19:48PM +0100, Michael Walle wrote:
> Flash devices can have one-time-programmable regions. Add a nvmem
> binding so they can be used as a nvmem provider.
>
> Signed-off-by: Michael Walle <michael@xxxxxxxx>
> ---
> .../devicetree/bindings/mtd/mtd.yaml | 71 +++++++++++++++++++
> 1 file changed, 71 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/mtd/mtd.yaml b/Documentation/devicetree/bindings/mtd/mtd.yaml
> index 321259aab0f6..2b852f91a6a9 100644
> --- a/Documentation/devicetree/bindings/mtd/mtd.yaml
> +++ b/Documentation/devicetree/bindings/mtd/mtd.yaml
> @@ -21,6 +21,25 @@ properties:
> based name) in order to ease flash device identification and/or
> describe what they are used for.
>
> +patternProperties:
> + "^otp(-[0-9]+)?":

Needs '$' on the end.

> + type: object
> + $ref: ../nvmem/nvmem.yaml#
> +
> + description: |
> + An OTP memory region. Some flashes provide a one-time-programmable
> + memory whose content can either be programmed by a user or is already
> + pre-programmed by the factory. Some flashes might provide both.
> +
> + properties:
> + compatible:
> + enum:
> + - mtd-user-otp
> + - mtd-factory-otp
> +
> + required:
> + - compatible
> +
> additionalProperties: true
>
> examples:
> @@ -36,4 +55,56 @@ examples:
> };
> };
>
> + - |
> + spi {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + flash@0 {
> + reg = <0>;
> + compatible = "some,flash";

Soon (in linux-next, but off by default) this will be a warning for
undocumented compatible string. Use a real device.

> +
> + otp {
> + compatible = "mtd-user-otp";
> + #address-cells = <1>;
> + #size-cells = <1>;
> +
> + serial-number@0 {
> + reg = <0 16>;
> + };
> + };
> + };
> + };
> +
> + - |
> + spi {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + flash@0 {
> + reg = <0>;
> + compatible = "some,flash";
> +
> + otp-1 {
> + compatible = "mtd-factory-otp";
> + #address-cells = <1>;
> + #size-cells = <1>;
> +
> + electronic-serial-number@0 {
> + reg = <0 8>;
> + };
> + };
> +
> + otp-2 {
> + compatible = "mtd-user-otp";
> + #address-cells = <1>;
> + #size-cells = <1>;
> +
> + mac-address@0 {
> + reg = <0 6>;
> + };
> + };
> + };
> + };

The 2nd example is a superset of the 1st, so drop the first one.

Rob