feat: add bluetooth functionality

Author: electricalgorithm

src/bluetooth/bluetooth_infra.c

@@ -0,0 +1,81 @@
+#include <zephyr/settings/settings.h>
+#include <zephyr/bluetooth/gatt.h>
+#include <zephyr/logging/log.h>
+
+
+LOG_MODULE_REGISTER(ZephyrWatch_BluetoothInfra, LOG_LEVEL_INF);
+
+
+static const struct bt_data m_ad[] = {
+	BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
+	BT_DATA_BYTES(BT_DATA_UUID16_ALL, BT_UUID_16_ENCODE(BT_UUID_CTS_VAL)),
+};
+
+static const struct bt_data m_sd[] = {
+	BT_DATA(BT_DATA_NAME_COMPLETE, CONFIG_BT_DEVICE_NAME, sizeof(CONFIG_BT_DEVICE_NAME) - 1),
+};
+
+static void m_connected_callback(struct bt_conn *conn, uint8_t err) {
+	if (err) LOG_ERR("Connection failed (err %u).", err);
+	else {
+		char addr[BT_ADDR_LE_STR_LEN];
+		bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
+		LOG_INF("Connection established to %s.", addr);
+	}
+}
+
+static void m_disconnected_callback(struct bt_conn *conn, uint8_t reason) {
+	LOG_INF("Disconnected (reason 0x%02x).", reason);
+}
+
+BT_CONN_CB_DEFINE(conn_callbacks) = {
+	.connected = m_connected_callback,
+	.disconnected = m_disconnected_callback,
+};
+
+/* The API function to enable Bluetooth and start advertisement. */
+uint8_t enable_bluetooth_and_start_advertisement() {
+	int err;
+
+    err = bt_enable(NULL);
+	if (err) {
+		LOG_ERR("Bluetooth init failed (err %d).", err);
+		return err;
+	}
+
+	LOG_INF("Bluetooth initialized.");
+
+	if (IS_ENABLED(CONFIG_SETTINGS)) {
+		settings_load();
+	}
+
+	err = bt_le_adv_start(BT_LE_ADV_CONN, m_ad, ARRAY_SIZE(m_ad), m_sd, ARRAY_SIZE(m_sd));
+	if (err) {
+		LOG_ERR("Advertising failed to start (err %d).", err);
+		return err;
+	}
+
+	LOG_INF("Advertising successfully started.");
+    return 0;
+}
+
+uint8_t disable_bluetooth_and_stop_advertisement() {
+	int err;
+
+	err = bt_le_adv_stop();
+	if (err) {
+		LOG_ERR("Advertising failed to stop (err %d).", err);
+		return err;
+	}
+
+	LOG_INF("Advertising successfully stopped.");
+
+	err = bt_disable();
+	if (err) {
+		LOG_ERR("Bluetooth failed to disable (err %d).", err);
+		return err;
+	}
+
+	LOG_INF("Bluetooth disabled.");
+	return 0;
+}

src/bluetooth/bluetooth_infra.h

@@ -0,0 +1,10 @@
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+uint8_t enable_bluetooth_and_start_advertisement();
+uint8_t disable_bluetooth_and_stop_advertisement();
+
+#ifdef __cplusplus
+}
+#endif

src/bluetooth/current_time_service.c

@@ -0,0 +1,83 @@
+#include <zephyr/sys/byteorder.h>
+#include <zephyr/logging/log.h>
+#include <zephyr/bluetooth/gatt.h>
+
+#include "current_time_service.h"
+
+LOG_MODULE_REGISTER(ZephyrWatch_CurrentTimeService, LOG_LEVEL_INF);
+
+
+/* Holds current time data. */
+static uint8_t m_current_time_data[10] = {
+	232U,	// Year (2024) last byte
+	7U,		// Year (2024) first byte
+	5U,		// Month (May)
+	13U,	// Day (13th)
+	23U,	// Hours (23)
+	45U,	// Minutes (45)
+	30U,	// Seconds (30)
+	2U,		// Day of week (Tuesday)
+	0U,		// Fractions 256 part of 'Exact Time 256'
+	0U,		// Adjust reason
+};
+
+/* Current Time Service Declaration */
+static ssize_t m_time_write_callback(
+	struct bt_conn *conn,
+	const struct bt_gatt_attr *attr,
+	const void *buf,
+	uint16_t len,
+	uint16_t offset,
+	uint8_t flags) {
+
+	// Get the value of the attribute.
+	uint8_t *value = attr->user_data;
+
+	// Check if the value written is valid.
+	if (offset + len > sizeof(m_current_time_data)) {
+		LOG_ERR("Write request too long.");
+		return BT_GATT_ERR(BT_ATT_ERR_INVALID_OFFSET);
+	}
+
+	// Copy the new value into the m_current_time_data array (given as buffer).
+	memcpy(value + offset, buf, len);
+	LOG_INF("Current time updated from the Bluetooth client.");
+	return len;
+}
+
+/* Current Time Service Declaration */
+BT_GATT_SERVICE_DEFINE(cts_cvs,
+	BT_GATT_PRIMARY_SERVICE(BT_UUID_CTS),
+	BT_GATT_CHARACTERISTIC(
+		BT_UUID_CTS_CURRENT_TIME,
+		BT_GATT_CHRC_WRITE,
+		BT_GATT_PERM_WRITE,
+		NULL, m_time_write_callback, m_current_time_data),
+);
+
+/* API for the Current Time Service application layer consumers.
+ * - get_current_time: Get the current time. Returns a struct with
+ * proper key-value pairs for year, month, hours, minutes, and seconds.
+ * - set_current_time: Set the current time. Takes a struct with
+ * proper key-value pairs for year, month, hours, minutes, and seconds.
+ */
+
+struct current_time get_current_time(void) {
+	struct current_time time;
+	time.year = sys_le16_to_cpu(*(uint16_t *) &m_current_time_data[0]);
+	time.month = m_current_time_data[2];
+	time.day = m_current_time_data[3];
+	time.hours = m_current_time_data[4];
+	time.minutes = m_current_time_data[5];
+	time.seconds = m_current_time_data[6];
+	return time;
+}
+
+void set_current_time(struct current_time time) {
+	*(uint16_t *) &m_current_time_data[0] = sys_cpu_to_le16(time.year);
+	m_current_time_data[2] = time.month;
+	m_current_time_data[3] = time.day;
+	m_current_time_data[4] = time.hours;
+	m_current_time_data[5] = time.minutes;
+	m_current_time_data[6] = time.seconds;
+}

src/bluetooth/current_time_service.h

@@ -0,0 +1,19 @@
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct current_time {
+	uint16_t year;
+	uint8_t month;
+	uint8_t day;
+	uint8_t hours;
+	uint8_t minutes;
+	uint8_t seconds;
+};
+
+struct current_time get_current_time(void);
+void set_current_time(struct current_time time);
+
+#ifdef __cplusplus
+}
+#endif