drivers: eeprom: add fake EEPROM driver

Add a FFF-based fake EEPROM driver which can be used either as a stub or a
mock for testing.

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

drivers/eeprom/CMakeLists.txt

@@ -12,3 +12,4 @@ zephyr_library_sources_ifdef(CONFIG_EEPROM_SIMULATOR eeprom_simulator.c)
 zephyr_library_sources_ifdef(CONFIG_EEPROM_EMULATOR eeprom_emulator.c)
 zephyr_library_sources_ifdef(CONFIG_EEPROM_TMP116 eeprom_tmp116.c)
 zephyr_library_sources_ifdef(CONFIG_EEPROM_XEC eeprom_mchp_xec.c)
+zephyr_library_sources_ifdef(CONFIG_EEPROM_FAKE eeprom_fake.c)

drivers/eeprom/Kconfig

@@ -96,4 +96,11 @@ config EEPROM_SIMULATOR_MIN_WRITE_TIME_US
 
 endif # EEPROM_SIMULATOR_SIMULATE_TIMING
 
+config EEPROM_FAKE
+	bool "Fake EEPROM driver"
+	default y
+	depends on DT_HAS_ZEPHYR_FAKE_EEPROM_ENABLED
+	help
+	  Enable support for the FFF-based fake EEPROM driver.
+
 endif # EEPROM

drivers/eeprom/eeprom_fake.c

@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2022 Vestas Wind Systems A/S
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/device.h>
+#include <zephyr/drivers/eeprom.h>
+#include <zephyr/drivers/eeprom/eeprom_fake.h>
+#include <zephyr/fff.h>
+
+#ifdef CONFIG_ZTEST_NEW_API
+#include <zephyr/ztest.h>
+#endif /* CONFIG_ZTEST_NEW_API */
+
+#define DT_DRV_COMPAT zephyr_fake_eeprom
+
+struct fake_eeprom_config {
+	size_t size;
+};
+
+DEFINE_FAKE_VALUE_FUNC(int, fake_eeprom_read, const struct device *, off_t, void *, size_t);
+
+DEFINE_FAKE_VALUE_FUNC(int, fake_eeprom_write, const struct device *, off_t, const void *, size_t);
+
+DEFINE_FAKE_VALUE_FUNC(size_t, fake_eeprom_size, const struct device *);
+
+size_t fake_eeprom_size_delegate(const struct device *dev)
+{
+	const struct fake_eeprom_config *config = dev->config;
+
+	return config->size;
+}
+
+#ifdef CONFIG_ZTEST_NEW_API
+static void fake_eeprom_reset_rule_before(const struct ztest_unit_test *test, void *fixture)
+{
+	ARG_UNUSED(test);
+	ARG_UNUSED(fixture);
+
+	RESET_FAKE(fake_eeprom_read);
+	RESET_FAKE(fake_eeprom_write);
+	RESET_FAKE(fake_eeprom_size);
+
+	/* Re-install default delegate for reporting the EEPROM size */
+	fake_eeprom_size_fake.custom_fake = fake_eeprom_size_delegate;
+}
+
+ZTEST_RULE(fake_eeprom_reset_rule, fake_eeprom_reset_rule_before, NULL);
+#endif /* CONFIG_ZTEST_NEW_API */
+
+static const struct eeprom_driver_api fake_eeprom_driver_api = {
+	.read = fake_eeprom_read,
+	.write = fake_eeprom_write,
+	.size = fake_eeprom_size,
+};
+
+static int fake_eeprom_init(const struct device *dev)
+{
+	ARG_UNUSED(dev);
+
+	/* Install default delegate for reporting the EEPROM size */
+	fake_eeprom_size_fake.custom_fake = fake_eeprom_size_delegate;
+
+	return 0;
+}
+
+#define FAKE_EEPROM_INIT(inst)							\
+	static const struct fake_eeprom_config fake_eeprom_config_##inst = {	\
+		.size = DT_INST_PROP(inst, size),				\
+	};									\
+										\
+	DEVICE_DT_INST_DEFINE(inst, &fake_eeprom_init, NULL, NULL,		\
+			      &fake_eeprom_config_##inst,			\
+			      POST_KERNEL, CONFIG_EEPROM_INIT_PRIORITY,		\
+			      &fake_eeprom_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(FAKE_EEPROM_INIT)

dts/bindings/mtd/zephyr,fake-eeprom.yaml

@@ -0,0 +1,13 @@
+# Copyright (c) 2022 Vestas Wind Systems A/S
+# SPDX-License-Identifier: Apache-2.0
+
+description: |
+    This binding provides a fake EEPROM for use as either a stub or a mock in Zephyr testing.
+
+compatible: "zephyr,fake-eeprom"
+
+include: eeprom-base.yaml
+
+properties:
+    size:
+      required: true

include/zephyr/drivers/eeprom/eeprom_fake.h

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2022 Vestas Wind Systems A/S
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_DRIVERS_EEPROM_FAKE_EEPROM_H_
+#define ZEPHYR_INCLUDE_DRIVERS_EEPROM_FAKE_EEPROM_H_
+
+#include <zephyr/drivers/eeprom.h>
+#include <zephyr/fff.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+DECLARE_FAKE_VALUE_FUNC(int, fake_eeprom_read, const struct device *, off_t, void *, size_t);
+
+DECLARE_FAKE_VALUE_FUNC(int, fake_eeprom_write, const struct device *, off_t, const void *, size_t);
+
+DECLARE_FAKE_VALUE_FUNC(size_t, fake_eeprom_size, const struct device *);
+
+size_t fake_eeprom_size_delegate(const struct device *dev);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ZEPHYR_INCLUDE_DRIVERS_EEPROM_FAKE_EEPROM_H_ */