Re: [PATCH RFC linux] dt-bindings: nvmem: Add binding for U-Boot environment NVMEM provider

[Srinivas Kandagatla <srinivas.kandagatla@linaro.org>]

On 14/10/2021 00:20, Marek Behún wrote:
> Add device tree bindings for U-Boot environment NVMEM provider.
> 
> U-Boot environment can be stored at a specific offset of a MTD device,
> EEPROM, MMC, NAND or SATA device, on an UBI volume, or in a file on a
> filesystem.
> 
> The environment can contain information such as device's MAC address,
> which should be used by the ethernet controller node.
> 

Have you looked at 
./Documentation/devicetree/bindings/mtd/partitions/nvmem-cells.yaml ?


--srini

> Signed-off-by: Marek Behún <kabel@kernel.org>
> ---
>   .../bindings/nvmem/denx,u-boot-env.yaml       | 88 +++++++++++++++++++
>   include/dt-bindings/nvmem/u-boot-env.h        | 18 ++++
>   2 files changed, 106 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/nvmem/denx,u-boot-env.yaml
>   create mode 100644 include/dt-bindings/nvmem/u-boot-env.h
> 
> diff --git a/Documentation/devicetree/bindings/nvmem/denx,u-boot-env.yaml b/Documentation/devicetree/bindings/nvmem/denx,u-boot-env.yaml
> new file mode 100644
> index 000000000000..56505c08e622
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/nvmem/denx,u-boot-env.yaml
> @@ -0,0 +1,88 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/nvmem/denx,u-boot-env.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: U-Boot environment NVMEM Device Tree Bindings
> +
> +maintainers:
> +  - Marek Behún <kabel@kernel.org>
> +
> +description:
> +  This binding represents U-Boot's environment NVMEM settings which can be
> +  stored on a specific offset of an EEPROM, MMC, NAND or SATA device, or
> +  an UBI volume, or in a file on a filesystem.
> +
> +properties:
> +  compatible:
> +    const: denx,u-boot-env
> +
> +  path:
> +    description:
> +      The path to the file containing the environment if on a filesystem.
> +    $ref: /schemas/types.yaml#/definitions/string
> +
> +patternProperties:
> +  "^[^=]+$":
> +    type: object
> +
> +    description:
> +      This node represents one U-Boot environment variable, which is also one
> +      NVMEM data cell.
> +
> +    properties:
> +      name:
> +        description:
> +          If the variable name contains characters not allowed in device tree node
> +          name, use this property to specify the name, otherwise the variable name
> +          is equal to node name.
> +        $ref: /schemas/types.yaml#/definitions/string
> +
> +      type:
> +        description:
> +          Type of the variable. Since variables, even integers and MAC addresses,
> +          are stored as strings in U-Boot environment, for proper conversion the
> +          type needs to be specified. Use one of the U_BOOT_ENV_TYPE_* prefixed
> +          definitions from include/dt-bindings/nvmem/u-boot-env.h.
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        minimum: 0
> +        maximum: 5
> +
> +    required:
> +      - type
> +
> +required:
> +  - compatible
> +
> +additionalProperties: true
> +
> +examples:
> +  - |
> +
> +    #include <dt-bindings/nvmem/u-boot-env.h>
> +
> +    spi-flash {
> +        partitions {
> +            compatible = "fixed-partitions";
> +            #address-cells = <1>;
> +            #size-cells = <1>;
> +
> +            partition@180000 {
> +                compatible = "denx,u-boot-env";
> +                label = "u-boot-env";
> +                reg = <0x180000 0x10000>;
> +
> +                eth0_addr: ethaddr {
> +                    type = <U_BOOT_ENV_TYPE_MAC_ADDRESS>;
> +                };
> +            };
> +        };
> +    };
> +
> +    ethernet-controller {
> +        nvmem-cells = <&eth0_addr>;
> +        nvmem-cell-names = "mac-address";
> +    };
> +
> +...
> diff --git a/include/dt-bindings/nvmem/u-boot-env.h b/include/dt-bindings/nvmem/u-boot-env.h
> new file mode 100644
> index 000000000000..760e5b240619
> --- /dev/null
> +++ b/include/dt-bindings/nvmem/u-boot-env.h
> @@ -0,0 +1,18 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Macros for U-Boot environment NVMEM device tree bindings.
> + *
> + * Copyright (C) 2021 Marek Behún <kabel@kernel.org>
> + */
> +
> +#ifndef __DT_BINDINGS_NVMEM_U_BOOT_ENV_H
> +#define __DT_BINDINGS_NVMEM_U_BOOT_ENV_H
> +
> +#define U_BOOT_ENV_TYPE_STRING		0
> +#define U_BOOT_ENV_TYPE_ULONG		1
> +#define U_BOOT_ENV_TYPE_BOOL		2
> +#define U_BOOT_ENV_TYPE_MAC_ADDRESS	3
> +#define U_BOOT_ENV_TYPE_ULONG_HEX	4
> +#define U_BOOT_ENV_TYPE_ULONG_DEC	5
> +
> +#endif /* __DT_BINDINGS_NVMEM_U_BOOT_ENV_H */
>