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+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/nvmem/mmio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MMIO access based NVMEM
+
+description: |
+ This binding describes simple NVMEM devices with content that can be accessed
+ using MMIO (memory-mapped I/O access).
+
+ More complex devices that support any other access than a simple memory
+ mapping should use a custom binding. In such cases this binding's compatible
+ should NOT be used even as a fallback.
+
+ This binding is designed to describe just an NVMEM content access method. The
+ way of handling actual content should be described independently (on top of
+ this binding).
+
+maintainers:
+ - Rafał Miłecki <rafal@milecki.pl>
+
+allOf:
+ - $ref: nvmem.yaml#
+
+properties:
+ compatible:
+ const: mmio-nvmem
+
+ reg:
+ maxItems: 1
+
+ reg-io-width:
+ description: |
+ The size (in bytes) of the IO accesses that should be performed
+ on the device.
+ enum: [1, 2, 4, 8]
+
+required:
+ - reg
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ nvmem@10000 {
+ compatible = "mmio-nvmem";
+ reg = <0x10000000 0x10000>;
+ };