refactor: increase modularity of the firmware (#5)

* refactor: isolate weekday names to ui components

* chore: change tabs to spaces

* refactor: rename display library to userinterface

* chore: remove unused imports

* refactor: expose display in its own subsystem

* refactor: hide lvgl implementation in the subsystem

* refactor: move ui functions to userinterface subsystem

* fix: remove unix_time for all

* feat: use dt aliases for devices

Author: electricalgorithm

boards/esp32.overlay

@@ -1,5 +1,9 @@
-&timer0 {
-    status = "okay";
+/ {
+    aliases {
+        rtccounterdevice = &rtc_timer;
+        lcddisplaydevice = &gc9a01;
+        lcdpwmdevice = &pwm_lcd0;
+    };
 };
 
 &rtc_timer {

src/bluetooth/infrastructure.c

@@ -12,75 +12,75 @@
 LOG_MODULE_REGISTER(ZephyrWatch_BLE, 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)),
+    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),
+    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);
-	}
+    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);
+    LOG_INF("Disconnected (reason 0x%02x).", reason);
 }
 
 BT_CONN_CB_DEFINE(conn_callbacks) = {
-	.connected = m_connected_callback,
-	.disconnected = m_disconnected_callback,
+    .connected = m_connected_callback,
+    .disconnected = m_disconnected_callback,
 };
 
 /* The API function to enable Bluetooth and start advertisement. */
 uint8_t enable_bluetooth_subsystem() {
-	int err;
-	
+    int err;
+    
     err = bt_enable(NULL);
-	if (err) {
-		LOG_ERR("Bluetooth init failed (err %d).", err);
-		return err;
-	}
+    if (err) {
+        LOG_ERR("Bluetooth init failed (err %d).", err);
+        return err;
+    }
 
-	LOG_DBG("Bluetooth initialized.");
+    LOG_DBG("Bluetooth initialized.");
 
-	if (IS_ENABLED(CONFIG_SETTINGS)) {
-		settings_load();
-	}
+    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;
-	}
+    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_DBG("Advertising successfully started.");
+    LOG_DBG("Advertising successfully started.");
     return 0;
 }
 
 uint8_t disable_bluetooth_subsystem() {
-	int err;
+    int err;
 
-	err = bt_le_adv_stop();
-	if (err) {
-		LOG_ERR("Advertising failed to stop (err %d).", err);
-		return err;
-	}
+    err = bt_le_adv_stop();
+    if (err) {
+        LOG_ERR("Advertising failed to stop (err %d).", err);
+        return err;
+    }
 
-	LOG_DBG("Advertising successfully stopped.");
+    LOG_DBG("Advertising successfully stopped.");
 
-	err = bt_disable();
-	if (err) {
-		LOG_ERR("Bluetooth failed to disable (err %d).", err);
-		return err;
-	}
+    err = bt_disable();
+    if (err) {
+        LOG_ERR("Bluetooth failed to disable (err %d).", err);
+        return err;
+    }
 
-	LOG_DBG("Bluetooth disabled.");
-	return 0;
+    LOG_DBG("Bluetooth disabled.");
+    return 0;
 }

src/bluetooth/services/current_time_service.c

@@ -18,51 +18,51 @@ LOG_MODULE_REGISTER(ZephyrWatch_BLE_CTS, LOG_LEVEL_INF);
 
 /* Current Time Service Write Callback */
 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) {
+    struct bt_conn *conn,
+    const struct bt_gatt_attr *attr,
+    const void *buf,
+    uint16_t len,
+    uint16_t offset,
+    uint8_t flags) {
 
-	// Check if we received exactly 4 bytes for UNIX timestamp
-	if (len != 4 || offset != 0) {
-		LOG_ERR("Invalid write length or offset. Expected 4 bytes at offset 0, got %d bytes at offset %d", len, offset);
-		return BT_GATT_ERR(BT_ATT_ERR_INVALID_OFFSET);
-	}
+    // Check if we received exactly 4 bytes for UNIX timestamp
+    if (len != 4 || offset != 0) {
+        LOG_ERR("Invalid write length or offset. Expected 4 bytes at offset 0, got %d bytes at offset %d", len, offset);
+        return BT_GATT_ERR(BT_ATT_ERR_INVALID_OFFSET);
+    }
 
-	// Extract the UNIX timestamp from the buffer (assuming little-endian)
-	uint32_t unix_timestamp = sys_le32_to_cpu(*(uint32_t *)buf);
-	LOG_DBG("Received UNIX timestamp: %u", unix_timestamp);
+    // Extract the UNIX timestamp from the buffer (assuming little-endian)
+    uint32_t unix_timestamp = sys_le32_to_cpu(*(uint32_t *)buf);
+    LOG_DBG("Received UNIX timestamp: %u", unix_timestamp);
 
-	// Get the device twin instance to get the UTC zone
-	device_twin_t *device_twin = get_device_twin_instance();
-	if (device_twin == NULL) {
-		LOG_ERR("Failed to get device twin instance.");
-		return BT_GATT_ERR(BT_ATT_ERR_UNLIKELY);
-	}
+    // Get the device twin instance to get the UTC zone
+    device_twin_t *device_twin = get_device_twin_instance();
+    if (device_twin == NULL) {
+        LOG_ERR("Failed to get device twin instance.");
+        return BT_GATT_ERR(BT_ATT_ERR_UNLIKELY);
+    }
     device_twin->unix_time = unix_timestamp;
     trigger_ui_update();
 
     // Convert UNIX timestamp to local time using the device's UTC zone to print.
-	datetime_t local_time = unix_to_localtime(unix_timestamp, device_twin->utc_zone);
-	LOG_INF("Current time updated to local time: %04d-%02d-%02d %02d:%02d:%02d (UTC%+d)", 
-		local_time.year, local_time.month, local_time.day,
-		local_time.hour, local_time.minute, local_time.second,
-		device_twin->utc_zone);
+    datetime_t local_time = unix_to_localtime(unix_timestamp, device_twin->utc_zone);
+    LOG_INF("Current time updated to local time: %04d-%02d-%02d %02d:%02d:%02d (UTC%+d)", 
+        local_time.year, local_time.month, local_time.day,
+        local_time.hour, local_time.minute, local_time.second,
+        device_twin->utc_zone);
 
-	return len;
+    return len;
 }
 
 /* Dummy data for GATT characteristic - not used for actual data storage */
 static uint8_t dummy_data[4] = {0};
 
 /* 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, dummy_data),
+    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, dummy_data),
 );

src/datetime/datetime.c

@@ -13,16 +13,16 @@
 #include "devicetwin/devicetwin.h"
 #include "datetime/datetime.h"
 
+// Get devices from the device tree.
+#define RTC_COUNTER_DEVICE DT_ALIAS(rtccounterdevice)
+
 // Configuration for counter alarm.
 #define ALARM_INTERVAL_US 1000000
 #define ALARM_CHANNEL_ID 0
 
 /* Register a logger for this library. */
 LOG_MODULE_REGISTER(ZephyrWatch_Datetime, LOG_LEVEL_INF);
 
-/* Global unix_time variable to store datetime. */
-uint32_t unix_time = 1748554674;
-
 /* Disable flag to not set alarm again in ISR.
  * 0: Set alarm again.
  * !: Do not set alarm again.
@@ -57,8 +57,7 @@ void rtc_isr(const struct device *dev, uint8_t channel_id, uint32_t ticks, void
     }
 
     // Update device's current time.
-    device_twin_t *device_twin = get_device_twin_instance();
-    device_twin->unix_time = device_twin->unix_time + 1;
+    set_current_unix_time(get_current_unix_time() + 1);
 }
 
 /* ENABLE_DATETIME_SUBSYSTEM
@@ -69,7 +68,7 @@ int enable_datetime_subsystem() {
     int ret;
 
     // Set the real time counter to trigger an callback every second.
-    const struct device *real_time_counter = DEVICE_DT_GET(DT_NODELABEL(rtc_timer));
+    const struct device *real_time_counter = DEVICE_DT_GET(RTC_COUNTER_DEVICE);
     if (!device_is_ready(real_time_counter)) {
         LOG_ERR("Real time counter device is not ready.");
         return -ENODEV;
@@ -107,7 +106,7 @@ int disable_datetime_subsystem() {
     int ret;
 
     // Set the real time counter to trigger an callback every second.
-    const struct device *real_time_counter = DEVICE_DT_GET(DT_NODELABEL(rtc_timer));
+    const struct device *real_time_counter = DEVICE_DT_GET(RTC_COUNTER_DEVICE);
     if (!device_is_ready(real_time_counter)) {
         LOG_ERR("Real time counter device is not ready.");
         return -ENODEV;
@@ -133,22 +132,24 @@ int disable_datetime_subsystem() {
  * Return the UNIX epochs of the current time.
  */
 uint32_t get_current_unix_time() {
-    return unix_time;
+    device_twin_t *device_twin = get_device_twin_instance();
+    return device_twin->unix_time;
 }
 
 /* SET_CURRENT_UNIX_TIME
  * Set the current time with UNIX epoch.
  */
 int set_current_unix_time(uint32_t new_time) {
-    unix_time = new_time;
+    device_twin_t *device_twin = get_device_twin_instance();
+    device_twin->unix_time = new_time;
     return 0;
 }
 
 /* GET_CURRENT_LOCAL_TIME
  * Return the current time in datetime_t object in local time zone.
  */
 datetime_t get_current_local_time(int8_t utc_offset_hours) {
-    return unix_to_localtime(unix_time, utc_offset_hours);
+    return unix_to_localtime(get_current_unix_time(), utc_offset_hours);
 }
 
 /* UNIX_TO_LOCALTIME

src/display/display.c

@@ -1,24 +1,74 @@
-/** Display initialization implementation for LVGL-based UI setup.
- * Implements display system initialization, theme configuration, and home screen loading for the smartwatch interface.
+/** Display Subsystem for ZephyrWatch.
+ * Provides functions to initialize the display system.
  *
  * @license GNU v3
  * @maintainer electricalgorithm @ github
  */
 
-#include "lvgl.h"
 #include "display/display.h"
+#include <zephyr/drivers/display.h>
+#include <zephyr/drivers/pwm.h>
+#include <zephyr/logging/log.h>
 
+// Get a logger for the display subsystem.
+LOG_MODULE_REGISTER(ZephyrWatch_Display, LOG_LEVEL_INF);
 
-void display_init() {
-    lv_disp_t *display = lv_disp_get_default();
-    lv_theme_t *theme = lv_theme_default_init(
-        display,
-        lv_palette_main(LV_PALETTE_BLUE),
-        lv_palette_main(LV_PALETTE_RED),
-        true,
-        LV_FONT_DEFAULT
-    );
-    lv_disp_set_theme(display, theme);
-    home_screen_init();
-    lv_disp_load_scr(home_screen);
+// Get devices from the device tree.
+#define DISPLAY_DEVICE DT_ALIAS(lcddisplaydevice)
+#define DISPLAY_PWM_DEVICE DT_ALIAS(lcdpwmdevice)
+
+/* ENABLE_DISPLAY_SUBSYSTEM
+ * Set the Zephyr display device and set backlight.
+ */
+int enable_display_subsystem() {
+    int ret;
+
+    const struct device *display_dev = DEVICE_DT_GET(DISPLAY_DEVICE);
+    ret = device_is_ready(display_dev);
+    if (!ret) {
+        LOG_ERR("Display device is not ready, exiting... (RET: %d)", ret);
+        return 1;
+    }
+    LOG_DBG("Display device is ready.");
+
+    const struct pwm_dt_spec backlight = PWM_DT_SPEC_GET_BY_IDX(DISPLAY_PWM_DEVICE, 0);
+    ret = pwm_is_ready_dt(&backlight);
+    if (!ret) {
+        LOG_ERR("PWM device is not ready, exiting... (RET: %d)", ret);
+        return 1;
+    }
+    LOG_DBG("PWM device is ready.");
+
+    ret = pwm_set_dt(&backlight, 500, 250);
+    if (ret) {
+        LOG_ERR("Failed to set PWM pulse, exiting... (RET: %d)", ret);
+        return ret;
+    }
+    LOG_DBG("PWM pulse for LCD backlight set.");
+
+    ret = display_blanking_off(display_dev);
+    if (ret) {
+        LOG_ERR("Failed to set blanking off, exiting... (RET: %d)", ret);
+        return ret;
+    }
+    LOG_DBG("Set the blanking off.");
+
+    return 0;
 }
+
+
+/* ENABLE_DISPLAY_SUBSYSTEM
+ * Disable the Zephyr display device and set backlight to 0.
+ */
+int disable_display_subsystem() {
+    LOG_DBG("Not implemented yet.");
+    return 0;
+}
+
+/* CHANGE_BRIGHTNESS
+ * Change the brightness based on a percentage.
+ */
+int change_brightness(uint8_t perc) {
+    LOG_DBG("Not implemented yet.");
+    return 0;
+}