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>

CODEOWNERS

@@ -120,6 +120,7 @@
 /drivers/display/display_framebuf.c       @andrewboie
 /drivers/dma/*sam0*                       @Sizurka
 /drivers/dma/dma_stm32*                   @cybertale
+/drivers/eeprom/                          @henrikbrixandersen
 /drivers/espi/                            @albertofloyd @franciscomunoz @scottwcpg
 /drivers/ps2/                             @albertofloyd @franciscomunoz @scottwcpg
 /drivers/kscan/                           @albertofloyd @franciscomunoz @scottwcpg

drivers/CMakeLists.txt

@@ -36,6 +36,7 @@ add_subdirectory_if_kconfig(espi)
 add_subdirectory_if_kconfig(ps2)
 add_subdirectory_if_kconfig(kscan)
 add_subdirectory_if_kconfig(video)
+add_subdirectory_if_kconfig(eeprom)
 
 add_subdirectory_ifdef(CONFIG_FLASH_HAS_DRIVER_ENABLED flash)
 add_subdirectory_ifdef(CONFIG_SERIAL_HAS_DRIVER serial)

drivers/Kconfig

@@ -87,4 +87,6 @@ source "drivers/kscan/Kconfig"
 
 source "drivers/video/Kconfig"
 
+source "drivers/eeprom/Kconfig"
+
 endmenu

drivers/eeprom/CMakeLists.txt

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_library()
+
+zephyr_library_sources_ifdef(CONFIG_USERSPACE eeprom_handlers.c)

drivers/eeprom/Kconfig

@@ -0,0 +1,17 @@
+# EEPROM driver configuration options
+
+# Copyright (c) 2019 Vestas Wind Systems A/S
+# SPDX-License-Identifier: Apache-2.0
+
+menuconfig EEPROM
+	bool "EEPROM hardware support"
+	help
+	  Enable support for EEPROM hardware.
+
+if EEPROM
+
+module = EEPROM
+module-str = eeprom
+source "subsys/logging/Kconfig.template.log_config"
+
+endif # EEPROM

drivers/eeprom/eeprom_handlers.c

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2019 Vestas Wind Systems A/S
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <syscall_handler.h>
+#include <drivers/eeprom.h>
+
+static inline int z_vrfy_eeprom_read(struct device *dev, off_t offset,
+				     void *data, size_t len)
+{
+	Z_OOPS(Z_SYSCALL_DRIVER_EEPROM(dev, read));
+	Z_OOPS(Z_SYSCALL_MEMORY_WRITE(data, len));
+	return z_impl_eeprom_read((struct device *)dev, offset, (void *)data,
+				  len);
+}
+#include <syscalls/eeprom_read_mrsh.c>
+
+static inline int z_vrfy_eeprom_write(struct device *dev, off_t offset,
+				      const void *data, size_t len)
+{
+	Z_OOPS(Z_SYSCALL_DRIVER_EEPROM(dev, write));
+	Z_OOPS(Z_SYSCALL_MEMORY_READ(data, len));
+	return z_impl_eeprom_write((struct device *)dev, offset,
+				   (const void *)data, len);
+}
+#include <syscalls/eeprom_write_mrsh.c>
+
+static inline size_t z_vrfy_eeprom_get_size(struct device *dev)
+{
+	Z_OOPS(Z_SYSCALL_DRIVER_EEPROM(dev, size));
+	return z_impl_eeprom_get_size((struct device *)dev);
+}
+#include <syscalls/eeprom_get_size_mrsh.c>

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_ */

scripts/gen_kobject_list.py

@@ -112,6 +112,7 @@ subsystems = [
     "uart_driver_api",
     "can_driver_api",
     "ptp_clock_driver_api",
+    "eeprom_driver_api",
 
     # Fake 'sample driver' subsystem, used by tests/samples
     "sample_driver_api"