1 /*
2 * Copyright (c) 2021 Thomas Stranger
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #include <zephyr/kernel.h>
8 #include <zephyr/sys/printk.h>
9 #include <zephyr/drivers/eeprom.h>
10 #include <zephyr/device.h>
11
12 #define EEPROM_SAMPLE_OFFSET 0
13 #define EEPROM_SAMPLE_MAGIC 0xEE9703
14
15 struct perisistant_values {
16 uint32_t magic;
17 uint32_t boot_count;
18 };
19
20 /*
21 * Get a device structure from a devicetree node with alias eeprom-0
22 */
get_eeprom_device(void)23 static const struct device *get_eeprom_device(void)
24 {
25 const struct device *const dev = DEVICE_DT_GET(DT_ALIAS(eeprom_0));
26
27 if (!device_is_ready(dev)) {
28 printk("\nError: Device \"%s\" is not ready; "
29 "check the driver initialization logs for errors.\n",
30 dev->name);
31 return NULL;
32 }
33
34 printk("Found EEPROM device \"%s\"\n", dev->name);
35 return dev;
36 }
37
main(void)38 int main(void)
39 {
40 const struct device *eeprom = get_eeprom_device();
41 size_t eeprom_size;
42 struct perisistant_values values;
43 int rc;
44
45 if (eeprom == NULL) {
46 return 0;
47 }
48
49 eeprom_size = eeprom_get_size(eeprom);
50 printk("Using eeprom with size of: %zu.\n", eeprom_size);
51
52 rc = eeprom_read(eeprom, EEPROM_SAMPLE_OFFSET, &values, sizeof(values));
53 if (rc < 0) {
54 printk("Error: Couldn't read eeprom: err: %d.\n", rc);
55 return 0;
56 }
57
58 if (values.magic != EEPROM_SAMPLE_MAGIC) {
59 values.magic = EEPROM_SAMPLE_MAGIC;
60 values.boot_count = 0;
61 }
62
63 values.boot_count++;
64 printk("Device booted %d times.\n", values.boot_count);
65
66 rc = eeprom_write(eeprom, EEPROM_SAMPLE_OFFSET, &values, sizeof(values));
67 if (rc < 0) {
68 printk("Error: Couldn't write eeprom: err:%d.\n", rc);
69 return 0;
70 }
71
72 printk("Reset the MCU to see the increasing boot counter.\n\n");
73 return 0;
74 }
75
