drivers: eeprom: add API for EEPROM devices

Add API for accessing Electrically Erasable Programmable Read-Only
Memory (EEPROM) devices.

EEPROMs have an erase block size of 1 byte, a long lifetime, and allows
overwriting data on byte-by-byte access.

Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>

include/drivers/eeprom.h

@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2019 Vestas Wind Systems A/S
+ *
+ * Heavily based on drivers/flash.h which is:
+ * Copyright (c) 2017 Nordic Semiconductor ASA
+ * Copyright (c) 2016 Intel Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ * @brief Public API for EEPROM drivers
+ */
+
+#ifndef ZEPHYR_INCLUDE_DRIVERS_EEPROM_H_
+#define ZEPHYR_INCLUDE_DRIVERS_EEPROM_H_
+
+/**
+ * @brief EEPROM Interface
+ * @defgroup eeprom_interface EEPROM Interface
+ * @ingroup io_interfaces
+ * @{
+ */
+
+#include <zephyr/types.h>
+#include <stddef.h>
+#include <sys/types.h>
+#include <device.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef int (*eeprom_api_read)(struct device *dev, off_t offset, void *data,
+			       size_t len);
+typedef int (*eeprom_api_write)(struct device *dev, off_t offset,
+				const void *data, size_t len);
+typedef size_t (*eeprom_api_size)(struct device *dev);
+
+struct eeprom_driver_api {
+	eeprom_api_read read;
+	eeprom_api_write write;
+	eeprom_api_size size;
+};
+
+/**
+ *  @brief Read data from EEPROM
+ *
+ *  @param dev EEPROM device
+ *  @param offset Address offset to read from.
+ *  @param data Buffer to store read data.
+ *  @param len Number of bytes to read.
+ *
+ *  @return 0 on success, negative errno code on failure.
+ */
+__syscall int eeprom_read(struct device *dev, off_t offset, void *data,
+			  size_t len);
+
+static inline int z_impl_eeprom_read(struct device *dev, off_t offset,
+				     void *data, size_t len)
+{
+	const struct eeprom_driver_api *api = dev->driver_api;
+
+	return api->read(dev, offset, data, len);
+}
+
+/**
+ *  @brief Write data to EEPROM
+ *
+ *  @param dev EEPROM device
+ *  @param offset Address offset to write data to.
+ *  @param data Buffer with data to write.
+ *  @param len Number of bytes to write.
+ *
+ *  @return 0 on success, negative errno code on failure.
+ */
+__syscall int eeprom_write(struct device *dev, off_t offset, const void *data,
+			   size_t len);
+
+static inline int z_impl_eeprom_write(struct device *dev, off_t offset,
+				      const void *data, size_t len)
+{
+	const struct eeprom_driver_api *api = dev->driver_api;
+
+	return api->write(dev, offset, data, len);
+}
+
+/**
+ *  @brief Get the size of the EEPROM in bytes
+ *
+ *  @param dev EEPROM device.
+ *
+ *  @return EEPROM size in bytes.
+ */
+__syscall size_t eeprom_get_size(struct device *dev);
+
+static inline size_t z_impl_eeprom_get_size(struct device *dev)
+{
+	const struct eeprom_driver_api *api = dev->driver_api;
+
+	return api->size(dev);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+/**
+ * @}
+ */
+
+#include <syscalls/eeprom.h>
+
+#endif /* ZEPHYR_INCLUDE_DRIVERS_EEPROM_H_ */