devicetree: Add nvmem-consumer

Adds property nvmem-cells for referencing a node that stores some
configuration information. A typical use case is the reading of MAC
address from an EEPROM device.

Signed-off-by: Andriy Gelman <[email protected]>
Signed-off-by: Pieter De Gendt <[email protected]>

Author: talih0

dts/bindings/mtd/nvmem-consumer.yaml

@@ -0,0 +1,13 @@
+# Copyright (c) 2024, Andriy Gelman <[email protected]>
+# SPDX-License-Identifier: Apache-2.0
+
+properties:
+  nvmem-cell-names:
+    type: string-array
+    description:
+      Names for each nvmem-cells specified.
+
+  nvmem-cells:
+    type: phandles
+    description:
+      List of phandles to the nvmem data cells.

include/zephyr/devicetree/nvmem.h

@@ -0,0 +1,266 @@
+/**
+ * @file
+ * @brief NVMEM Devicetree public API header file.
+ */
+
+/*
+ * Copyright (c) 2024, Andriy Gelman
+ * Copyright (c) 2025, Basalte bv
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef INCLUDE_ZEPHYR_DEVICETREE_NVMEM_H_
+#define INCLUDE_ZEPHYR_DEVICETREE_NVMEM_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @defgroup devicetree-nvmem Devicetree NVMEM API
+ * @ingroup devicetree
+ * @{
+ */
+
+/**
+ * @brief Test if a node has an nvmem-cells phandle-array property at a given index
+ *
+ * This expands to 1 if the given index is a valid nvmem-cells property phandle-array index.
+ * Otherwise, it expands to 0.
+ *
+ * Example devicetree fragment:
+ *
+ * @code{.dts}
+ *	eth: ethernet {
+ *		nvmem-cells = <&mac_address>;
+ *		nvmem-cell-names = "mac-address";
+ *	};
+ * @endcode
+ *
+ * Example usage:
+ *
+ *     DT_NVMEM_CELLS_HAS_IDX(DT_NODELABEL(eth), 0) // 1
+ *     DT_NVMEM_CELLS_HAS_IDX(DT_NODELABEL(eth), 1) // 0
+ *
+ * @param node_id node identifier; may or may not have any nvmem-cells property
+ * @param idx index of a nvmem-cells property phandle-array whose existence to check
+ * @return 1 if the index exists, 0 otherwise
+ */
+#define DT_NVMEM_CELLS_HAS_IDX(node_id, idx) DT_PROP_HAS_IDX(node_id, nvmem_cells, idx)
+
+/**
+ * @brief Test if a node has an nvmem-cell-names array property hold a given name.
+ *
+ * This expands to 1 if the name is available as nvmem-cells-name array property cell.
+ * Otherwise, it expands to 0.
+ *
+ * Example devicetree fragment:
+ *
+ * @code{.dts}
+ *	eth: ethernet {
+ *		nvmem-cells = <&mac_address>;
+ *		nvmem-cell-names = "mac-address";
+ *	};
+ * @endcode
+ *
+ * Example usage:
+ *
+ *     DT_NVMEM_CELLS_HAS_NAME(DT_NODELABEL(eth), mac_address) // 1
+ *     DT_NVMEM_CELLS_HAS_NAME(DT_NODELABEL(eth), bogus)       // 0
+ *
+ * @param node_id node identifier; may or may not have any nvmem-cell-names property
+ * @param name lowercase-and-underscores nvmem-cell-names cell value name to check
+ * @return 1 if the index exists, 0 otherwise
+ */
+#define DT_NVMEM_CELLS_HAS_NAME(node_id, name) DT_PROP_HAS_NAME(node_id, nvmem_cells, name)
+
+/**
+ * @brief Get the number of elements in an nvmem-cells property
+ *
+ * Example devicetree fragment:
+ *
+ * @code{.dts}
+ *	eth: ethernet {
+ *		nvmem-cells = <&mac_address>;
+ *		nvmem-cell-names = "mac-address";
+ *	};
+ * @endcode
+ *
+ * Example usage:
+ *
+ *     DT_NUM_NVMEM_CELLS(DT_NODELABEL(eth)) // 1
+ *
+ * @param node_id node identifier with an nvmem-cells property
+ * @return number of elements in the property
+ */
+#define DT_NUM_NVMEM_CELLS(node_id) DT_PROP_LEN(node_id, nvmem_cells)
+
+/**
+ * @brief Get the node identifier for the NVMEM cell from the nvmem-cells property by index.
+ *
+ * Example devicetree fragment:
+ *
+ * @code{.dts}
+ *	mac_eeprom: mac_eeprom@2 {
+ *		#address-cells = <1>;
+ *		#size-cells = <1>;
+ *		mac_address: mac_address@fa {
+ *			reg = <0xfa 0x06>;
+ *		};
+ *	};
+ *
+ *	eth: ethernet {
+ *		nvmem-cells = <&mac_address>;
+ *		nvmem-cell-names = "mac-address";
+ *	};
+ * @endcode
+ *
+ * Example usage:
+ *
+ *	DT_NVMEM_CELL_BY_IDX(DT_NODELABEL(eth), 0) // DT_NODELABEL(mac_address)
+ *
+ * @param node_id node identifier for a node with a nvmem-cells property
+ * @param idx index into the nvmem-cells property
+ *
+ * @return the node identifier for the NVMEM cell at index idx
+ */
+#define DT_NVMEM_CELL_BY_IDX(node_id, idx) DT_PHANDLE_BY_IDX(node_id, nvmem_cells, idx)
+
+/**
+ * @brief Equivalent to DT_NVMEM_CELL_BY_IDX(node_id, 0)
+ * @param node_id node identifier
+ * @return a node identifier for the NVMEM cell at index 0
+ *         in "nvmem-cells"
+ * @see DT_NVMEM_CELL_BY_IDX()
+ */
+#define DT_NVMEM_CELL(node_id) DT_NVMEM_CELL_BY_IDX(node_id, 0)
+
+/**
+ * @brief Get the node identifier for the NVMEM cell from the nvmem-cells property by name.
+ *
+ * Example devicetree fragment:
+ *
+ * @code{.dts}
+ *	mac_eeprom: mac_eeprom@2 {
+ *		#address-cells = <1>;
+ *		#size-cells = <1>;
+ *		mac_address: mac_address@fa {
+ *			reg = <0xfa 0x06>;
+ *		};
+ *	};
+ *
+ *	eth: ethernet {
+ *		nvmem-cells = <&mac_address>;
+ *		nvmem-cell-names = "mac-address";
+ *	};
+ * @endcode
+ *
+ * Example usage:
+ *
+ *	DT_NVMEM_CELL_BY_NAME(DT_NODELABEL(eth), mac_address) // DT_NODELABEL(mac_address)
+ *
+ * @param node_id node identifier for a node with a nvmem-cells property
+ * @param name lowercase-and-underscores name of an nvmem-cells element
+ *             as defined by the node's nvmem-cell-names property
+ *
+ * @return the node identifier for the NVMEM cell by name
+ */
+#define DT_NVMEM_CELL_BY_NAME(node_id, name) DT_PHANDLE_BY_NAME(node_id, nvmem_cells, name)
+
+/**
+ * @brief Equivalent to DT_NVMEM_CELLS_HAS_IDX(DT_DRV_INST(inst), idx)
+ * @param inst DT_DRV_COMPAT instance number; may or may not have any nvmem-cells property
+ * @param idx index of an nvmem-cells property phandle-array whose existence to check
+ * @return 1 if the index exists, 0 otherwise
+ */
+#define DT_INST_NVMEM_CELLS_HAS_IDX(inst, idx) DT_NVMEM_CELLS_HAS_IDX(DT_DRV_INST(inst), idx)
+
+/**
+ * @brief Equivalent to DT_NVMEM_CELLS_HAS_NAME(DT_DRV_INST(inst), name)
+ * @param inst DT_DRV_COMPAT instance number; may or may not have any nvmem-cell-names property.
+ * @param name lowercase-and-underscores nvmem-cell-names cell value name to check
+ * @return 1 if the nvmem cell name exists, 0 otherwise
+ */
+#define DT_INST_NVMEM_CELLS_HAS_NAME(inst, name) DT_NVMEM_CELLS_HAS_NAME(DT_DRV_INST(inst), name)
+
+/**
+ * @brief Equivalent to DT_NUM_NVMEM_CELLS(DT_DRV_INST(inst))
+ * @param inst instance number
+ * @return number of elements in the nvmem-cells property
+ */
+#define DT_INST_NUM_NVMEM_CELLS(inst) DT_NUM_NVMEM_CELLS(DT_DRV_INST(inst))
+
+/**
+ * @brief Get the node identifier for the controller phandle from an
+ *        nvmem-cells phandle-array property at an index
+ *
+ * @param inst instance number
+ * @param idx logical index into nvmem-cells
+ * @return the node identifier for the nvmem cell referenced at
+ *         index "idx"
+ * @see DT_NVMEM_CELL_CTLR_BY_IDX()
+ */
+#define DT_INST_NVMEM_CELL_BY_IDX(inst, idx) DT_NVMEM_CELL_BY_IDX(DT_DRV_INST(inst), idx)
+
+/**
+ * @brief Equivalent to DT_INST_NVMEM_CELL_BY_IDX(inst, 0)
+ * @param inst instance number
+ * @return a node identifier for the nvmem cell at index 0
+ *         in nvmem-cells
+ * @see DT_NVMEM_CELL()
+ */
+#define DT_INST_NVMEM_CELL(inst) DT_INST_NVMEM_CELL_BY_IDX(inst, 0)
+
+/**
+ * @brief Get the node identifier for the controller phandle from an
+ *        nvmem-cells phandle-array property by name
+ *
+ * @param inst instance number
+ * @param name lowercase-and-underscores name of an nvmem-cells element
+ *             as defined by the node's nvmem-cell-names property
+ * @return the node identifier for the nvmem cell referenced by
+ *         the named element
+ * @see DT_NVMEM_CELL_BY_NAME()
+ */
+#define DT_INST_NVMEM_CELL_BY_NAME(inst, name) DT_NVMEM_CELL_BY_NAME(DT_DRV_INST(inst), name)
+
+/**
+ * @brief Get the node identifier of the memory controller for an nvmem cell.
+ *
+ * Example devicetree fragment:
+ *
+ * @code{.dts}
+ *	mac_eeprom: mac_eeprom@2 {
+ *		#address-cells = <1>;
+ *		#size-cells = <1>;
+ *		mac_address: mac_address@fa {
+ *			reg = <0xfa 0x06>;
+ *		};
+ *	};
+ *
+ *	eth: ethernet {
+ *		nvmem-cells = <&mac_address>;
+ *		nvmem-cell-names = "mac-address";
+ *	};
+ * @endcode
+ *
+ * Example usage:
+ *
+ *	DT_MTD_FROM_NVMEM_CELL(DT_NVMEM_CELL(DT_NODELABEL(eth))) // DT_NODELABEL(mac_eeprom)
+ *
+ * @param node_id node identifier for an nvmem cell node
+ * @return the node identifier of the Memory Technology Device (MTD) that
+ * contains the nvmem cell node.
+ */
+#define DT_MTD_FROM_NVMEM_CELL(node_id) DT_PARENT(node_id)
+
+/**
+ * @}
+ */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* INCLUDE_ZEPHYR_DEVICETREE_NVMEM_H_ */