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

Marek Behún
2021-10-13T23:21:12Z

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.

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 */
--
2.32.0