Trackball kernel driver

Devices/lilygo-tdeck/Source/Trackball/Trackball.cpp

@@ -1,129 +1,67 @@
 #include "Trackball.h"
 
 #include <Tactility/Assets.h>
-#include <atomic>
+#include <tactility/device.h>
 #include <tactility/log.h>
 
+#include <drivers/tdeck_trackball.h>
+
 constexpr auto* TAG = "Trackball";
 
 namespace trackball {
 
-static TrackballConfig g_config;
 static lv_indev_t* g_indev = nullptr;
-static std::atomic<bool> g_initialized{false};
+static Device* g_device = nullptr;
-static std::atomic<bool> g_enabled{true};
+static bool g_enabled = true;
-static std::atomic<Mode> g_mode{Mode::Encoder};
+static Mode g_mode = Mode::Encoder;
+static uint8_t g_encoderSensitivity = 1;
+static uint8_t g_pointerSensitivity = 10;
 
-// Interrupt-driven position tracking (atomic for ISR safety)
+// Pointer mode cursor position (screen-relative)
-static std::atomic<int32_t> g_cursorX{160};
+static int32_t g_cursorX = 160;
-static std::atomic<int32_t> g_cursorY{120};
+static int32_t g_cursorY = 120;
-static std::atomic<bool> g_buttonPressed{false};
 
-// Encoder mode: accumulated diff since last read
-static std::atomic<int32_t> g_encoderDiff{0};
-
-// Sensitivity cached for ISR access (atomic for thread safety)
-static std::atomic<int32_t> g_encoderSensitivity{1};   // Steps per tick for encoder
-static std::atomic<int32_t> g_pointerSensitivity{10};  // Pixels per tick for pointer
-
-// Cursor object for pointer mode
 static lv_obj_t* g_cursor = nullptr;
 
 // Screen dimensions (T-Deck: 320x240)
 static constexpr int32_t SCREEN_WIDTH = 320;
 static constexpr int32_t SCREEN_HEIGHT = 240;
-
 static constexpr int32_t CURSOR_SIZE = 16;
 
-// ISR handler for trackball directions
-static void IRAM_ATTR trackball_isr_handler(void* arg) {
-    // Skip accumulating movement when disabled
-    if (!g_enabled.load(std::memory_order_relaxed)) {
-        return;
-    }
-
-    gpio_num_t pin = static_cast<gpio_num_t>(reinterpret_cast<intptr_t>(arg));
-
-    if (g_mode.load(std::memory_order_relaxed) == Mode::Pointer) {
-        // Pointer mode: update absolute position using atomic fetch_add/sub
-        // Clamping is done in read_cb to avoid race conditions
-        int32_t step = g_pointerSensitivity.load(std::memory_order_relaxed);
-        if (pin == g_config.pinRight) {
-            g_cursorX.fetch_add(step, std::memory_order_relaxed);
-        } else if (pin == g_config.pinLeft) {
-            g_cursorX.fetch_sub(step, std::memory_order_relaxed);
-        } else if (pin == g_config.pinUp) {
-            g_cursorY.fetch_sub(step, std::memory_order_relaxed);
-        } else if (pin == g_config.pinDown) {
-            g_cursorY.fetch_add(step, std::memory_order_relaxed);
-        }
-    } else {
-        // Encoder mode: accumulate diff
-        int32_t step = g_encoderSensitivity.load(std::memory_order_relaxed);
-        if (pin == g_config.pinRight || pin == g_config.pinDown) {
-            g_encoderDiff.fetch_add(step, std::memory_order_relaxed);
-        } else if (pin == g_config.pinLeft || pin == g_config.pinUp) {
-            g_encoderDiff.fetch_sub(step, std::memory_order_relaxed);
-        }
-    }
-}
-
-// ISR handler for button (any edge)
-static void IRAM_ATTR button_isr_handler(void* arg) {
-    // Read current button state (active low)
-    bool pressed = gpio_get_level(g_config.pinClick) == 0;
-    g_buttonPressed.store(pressed, std::memory_order_relaxed);
-}
-
-// Helper to clamp value to range
 static inline int32_t clamp(int32_t val, int32_t minVal, int32_t maxVal) {
     if (val < minVal) return minVal;
     if (val > maxVal) return maxVal;
     return val;
 }
 
-static void read_cb(lv_indev_t* indev, lv_indev_data_t* data) {
+// Note: must be called from the LVGL thread (main thread), same as the setters below.
-    Mode currentMode = g_mode.load(std::memory_order_relaxed);
+static void read_cb(lv_indev_t* /*indev*/, lv_indev_data_t* data) {
-
+    // Always drain accumulated movement so it doesn't jump on re-enable, but discard it while disabled.
-    if (!g_initialized.load(std::memory_order_relaxed) || !g_enabled.load(std::memory_order_relaxed)) {
+    int32_t dx = 0;
-        data->state = LV_INDEV_STATE_RELEASED;
+    int32_t dy = 0;
-        if (currentMode == Mode::Encoder) {
+    tdeck_trackball_read_delta(g_device, &dx, &dy);
-            data->enc_diff = 0;
+    if (!g_enabled) {
-        } else {
+        dx = 0;
-            // Clamp cursor position to screen bounds
+        dy = 0;
-            int32_t x = clamp(g_cursorX.load(std::memory_order_relaxed), 0, SCREEN_WIDTH - CURSOR_SIZE - 1);
-            int32_t y = clamp(g_cursorY.load(std::memory_order_relaxed), 0, SCREEN_HEIGHT - CURSOR_SIZE - 1);
-            g_cursorX.store(x, std::memory_order_relaxed);
-            g_cursorY.store(y, std::memory_order_relaxed);
-            data->point.x = static_cast<int16_t>(x);
-            data->point.y = static_cast<int16_t>(y);
-        }
-        return;
     }
 
-    if (currentMode == Mode::Encoder) {
+    if (g_mode == Mode::Encoder) {
-        // Read and reset accumulated encoder diff
+        int32_t ticks = (dx + dy) * static_cast<int32_t>(g_encoderSensitivity);
-        int32_t diff = g_encoderDiff.exchange(0);
+        data->enc_diff = static_cast<int16_t>(clamp(ticks, INT16_MIN, INT16_MAX));
-        data->enc_diff = static_cast<int16_t>(clamp(diff, INT16_MIN, INT16_MAX));
+        if (ticks != 0) {
-
-        if (diff != 0) {
             lv_display_trigger_activity(nullptr);
         }
     } else {
-        // Pointer mode: read and clamp cursor position
+        g_cursorX = clamp(g_cursorX + dx * static_cast<int32_t>(g_pointerSensitivity), 0, SCREEN_WIDTH - CURSOR_SIZE - 1);
-        int32_t x = clamp(g_cursorX.load(std::memory_order_relaxed), 0, SCREEN_WIDTH - CURSOR_SIZE - 1);
+        g_cursorY = clamp(g_cursorY + dy * static_cast<int32_t>(g_pointerSensitivity), 0, SCREEN_HEIGHT - CURSOR_SIZE - 1);
-        int32_t y = clamp(g_cursorY.load(std::memory_order_relaxed), 0, SCREEN_HEIGHT - CURSOR_SIZE - 1);
+        data->point.x = static_cast<int16_t>(g_cursorX);
-
+        data->point.y = static_cast<int16_t>(g_cursorY);
-        // Store clamped values back to prevent unbounded growth
-        g_cursorX.store(x, std::memory_order_relaxed);
-        g_cursorY.store(y, std::memory_order_relaxed);
-
-        data->point.x = static_cast<int16_t>(x);
-        data->point.y = static_cast<int16_t>(y);
     }
 
-    // Button state (same for both modes)
+    bool pressed = false;
-    bool pressed = g_buttonPressed.load(std::memory_order_relaxed);
+    if (g_enabled) {
+        tdeck_trackball_get_button_pressed(g_device, &pressed);
+    }
     data->state = pressed ? LV_INDEV_STATE_PRESSED : LV_INDEV_STATE_RELEASED;
 
     if (pressed) {
@@ -131,136 +69,31 @@ static void read_cb(lv_indev_t* indev, lv_indev_data_t* data) {
     }
 }
 
-lv_indev_t* init(const TrackballConfig& config) {
+lv_indev_t* init() {
-    if (g_initialized.load(std::memory_order_relaxed)) {
+    if (g_indev != nullptr) {
         LOG_W(TAG, "Already initialized");
         return g_indev;
     }
 
-    g_config = config;
+    g_device = device_find_first_active_by_type(&TDECK_TRACKBALL_TYPE);
-
+    if (g_device == nullptr) {
-    // Set default sensitivities if not specified
+        LOG_E(TAG, "tdeck_trackball kernel device not found or not started");
-    if (g_config.encoderSensitivity == 0) {
-        g_config.encoderSensitivity = 1;
-    }
-    if (g_config.pointerSensitivity == 0) {
-        g_config.pointerSensitivity = 10;
-    }
-    g_encoderSensitivity.store(g_config.encoderSensitivity, std::memory_order_relaxed);
-    g_pointerSensitivity.store(g_config.pointerSensitivity, std::memory_order_relaxed);
-
-    // Initialize cursor position to center
-    g_cursorX.store(SCREEN_WIDTH / 2, std::memory_order_relaxed);
-    g_cursorY.store(SCREEN_HEIGHT / 2, std::memory_order_relaxed);
-    g_encoderDiff.store(0, std::memory_order_relaxed);
-    g_buttonPressed.store(false, std::memory_order_relaxed);
-
-    // Configure direction pins as interrupt inputs (falling edge)
-    const gpio_num_t dirPins[4] = {
-        config.pinRight,
-        config.pinUp,
-        config.pinLeft,
-        config.pinDown
-    };
-
-    gpio_config_t io_conf = {};
-    io_conf.intr_type = GPIO_INTR_NEGEDGE;  // Falling edge (active low)
-    io_conf.mode = GPIO_MODE_INPUT;
-    io_conf.pull_up_en = GPIO_PULLUP_ENABLE;
-    io_conf.pull_down_en = GPIO_PULLDOWN_DISABLE;
-
-    // Install GPIO ISR service (if not already installed)
-    static bool isr_service_installed = false;
-    if (!isr_service_installed) {
-        esp_err_t err = gpio_install_isr_service(ESP_INTR_FLAG_IRAM);
-        if (err == ESP_OK || err == ESP_ERR_INVALID_STATE) {
-            // ESP_ERR_INVALID_STATE means already installed, which is fine
-            isr_service_installed = true;
-        } else {
-            LOG_E(TAG, "Failed to install GPIO ISR service: %s", esp_err_to_name(err));
-            return nullptr;
-        }
-    }
-
-    // Track added handlers for cleanup on failure
-    int handlersAdded = 0;
-
-    // Configure and attach ISR for direction pins
-    for (int i = 0; i < 4; i++) {
-        io_conf.pin_bit_mask = (1ULL << dirPins[i]);
-        esp_err_t err = gpio_config(&io_conf);
-        if (err != ESP_OK) {
-            LOG_E(TAG, "Failed to configure GPIO %d: %s", static_cast<int>(dirPins[i]), esp_err_to_name(err));
-            // Cleanup previously added handlers
-            for (int j = 0; j < handlersAdded; j++) {
-                gpio_isr_handler_remove(dirPins[j]);
-            }
         return nullptr;
     }
 
-        err = gpio_isr_handler_add(dirPins[i], trackball_isr_handler, reinterpret_cast<void*>(static_cast<intptr_t>(dirPins[i])));
+    g_cursorX = SCREEN_WIDTH / 2;
-        if (err != ESP_OK) {
+    g_cursorY = SCREEN_HEIGHT / 2;
-            LOG_E(TAG, "Failed to add ISR for GPIO %d: %s", static_cast<int>(dirPins[i]), esp_err_to_name(err));
-            // Cleanup previously added handlers
-            for (int j = 0; j < handlersAdded; j++) {
-                gpio_isr_handler_remove(dirPins[j]);
-            }
-            return nullptr;
-        }
-        handlersAdded++;
-    }
 
-    // Configure button pin (any edge for press/release detection)
-    io_conf.intr_type = GPIO_INTR_ANYEDGE;
-    io_conf.pin_bit_mask = (1ULL << config.pinClick);
-    esp_err_t err = gpio_config(&io_conf);
-    if (err != ESP_OK) {
-        LOG_E(TAG, "Failed to configure button GPIO %d: %s", static_cast<int>(config.pinClick), esp_err_to_name(err));
-        // Cleanup direction handlers
-        for (int i = 0; i < 4; i++) {
-            gpio_isr_handler_remove(dirPins[i]);
-        }
-        return nullptr;
-    }
-
-    err = gpio_isr_handler_add(config.pinClick, button_isr_handler, nullptr);
-    if (err != ESP_OK) {
-        LOG_E(TAG, "Failed to add button ISR: %s", esp_err_to_name(err));
-        // Cleanup direction handlers
-        for (int i = 0; i < 4; i++) {
-            gpio_isr_handler_remove(dirPins[i]);
-        }
-        return nullptr;
-    }
-
-    // Read initial button state
-    g_buttonPressed.store(gpio_get_level(config.pinClick) == 0);
-
-    // Register as LVGL encoder input device for group navigation (default mode)
     g_indev = lv_indev_create();
     if (g_indev == nullptr) {
         LOG_E(TAG, "Failed to register LVGL input device");
-        // Cleanup ISR handlers on failure
+        g_device = nullptr;
-        const gpio_num_t pins[5] = {
-            config.pinRight, config.pinUp, config.pinLeft,
-            config.pinDown, config.pinClick
-        };
-        for (int i = 0; i < 5; i++) {
-            gpio_intr_disable(pins[i]);
-            gpio_isr_handler_remove(pins[i]);
-        }
         return nullptr;
     }
 
     lv_indev_set_type(g_indev, LV_INDEV_TYPE_ENCODER);
     lv_indev_set_read_cb(g_indev, read_cb);
-    g_initialized.store(true, std::memory_order_relaxed);
+    LOG_I(TAG, "Initialized");
-    LOG_I(TAG, "Initialized with interrupts (R:%d U:%d L:%d D:%d Click:%d)",
-             static_cast<int>(config.pinRight),
-             static_cast<int>(config.pinUp),
-             static_cast<int>(config.pinLeft),
-             static_cast<int>(config.pinDown),
-             static_cast<int>(config.pinClick));
 
     return g_indev;
 }
@@ -272,8 +105,6 @@ static void createCursor() {
     g_cursor = lv_image_create(lv_layer_sys());
     if (g_cursor != nullptr) {
         lv_obj_remove_flag(g_cursor, LV_OBJ_FLAG_CLICKABLE);
-
-        // Set cursor image
         lv_image_set_src(g_cursor, TT_ASSETS_UI_CURSOR);
         lv_indev_set_cursor(g_indev, g_cursor);
         LOG_D(TAG, "Cursor created");
@@ -291,67 +122,41 @@ static void destroyCursor() {
 }
 
 void deinit() {
-    if (!g_initialized.load(std::memory_order_relaxed)) return;
+    if (g_indev == nullptr) return;
 
     destroyCursor();
 
-    // Disable interrupts and remove ISR handlers
-    const gpio_num_t pins[5] = {
-        g_config.pinRight,
-        g_config.pinUp,
-        g_config.pinLeft,
-        g_config.pinDown,
-        g_config.pinClick
-    };
-
-    for (int i = 0; i < 5; i++) {
-        gpio_intr_disable(pins[i]);
-        gpio_isr_handler_remove(pins[i]);
-    }
-
-    if (g_indev) {
     lv_indev_delete(g_indev);
     g_indev = nullptr;
-    }
+    g_device = nullptr;
 
-    g_initialized.store(false, std::memory_order_relaxed);
+    g_mode = Mode::Encoder;
-    g_mode.store(Mode::Encoder, std::memory_order_relaxed);
+    g_enabled = true;
-    g_enabled.store(true, std::memory_order_relaxed);
     LOG_I(TAG, "Deinitialized");
 }
 
 void setEncoderSensitivity(uint8_t sensitivity) {
     if (sensitivity > 0) {
-        // Only update the atomic - ISR reads from atomic, not g_config
+        g_encoderSensitivity = sensitivity;
-        g_encoderSensitivity.store(sensitivity, std::memory_order_relaxed);
         LOG_D(TAG, "Encoder sensitivity set to %d", sensitivity);
     }
 }
 
 void setPointerSensitivity(uint8_t sensitivity) {
     if (sensitivity > 0) {
-        // Only update the atomic - ISR reads from atomic, not g_config
+        g_pointerSensitivity = sensitivity;
-        g_pointerSensitivity.store(sensitivity, std::memory_order_relaxed);
         LOG_D(TAG, "Pointer sensitivity set to %d", sensitivity);
     }
 }
 
 void setEnabled(bool enabled) {
-    g_enabled.store(enabled, std::memory_order_relaxed);
+    g_enabled = enabled;
 
-    if (!enabled) {
+    if (g_cursor != nullptr) {
-        // Clear accumulated state to prevent jumps on re-enable
-        g_encoderDiff.store(0, std::memory_order_relaxed);
-    }
-
-    // Hide/show cursor based on enabled state when in pointer mode
-    // Note: Must be called from LVGL thread (main thread) for thread safety
-    lv_obj_t* cursor = g_cursor;  // Local copy to avoid race with setMode
-    if (cursor != nullptr) {
         if (enabled) {
-            lv_obj_clear_flag(cursor, LV_OBJ_FLAG_HIDDEN);
+            lv_obj_clear_flag(g_cursor, LV_OBJ_FLAG_HIDDEN);
         } else {
-            lv_obj_add_flag(cursor, LV_OBJ_FLAG_HIDDEN);
+            lv_obj_add_flag(g_cursor, LV_OBJ_FLAG_HIDDEN);
         }
     }
 
@@ -359,40 +164,35 @@ void setEnabled(bool enabled) {
 }
 
 void setMode(Mode mode) {
-    // Note: Must be called from LVGL thread (main thread) for thread safety
+    if (g_indev == nullptr) {
-    if (!g_initialized.load(std::memory_order_relaxed) || g_indev == nullptr) {
         LOG_W(TAG, "Cannot set mode - not initialized");
         return;
     }
 
-    if (g_mode.load(std::memory_order_relaxed) == mode) {
+    if (g_mode == mode) {
         return;
     }
 
-    g_mode.store(mode, std::memory_order_relaxed);
+    g_mode = mode;
 
     if (mode == Mode::Pointer) {
-        // Switch to pointer mode
         lv_indev_set_type(g_indev, LV_INDEV_TYPE_POINTER);
         createCursor();
-        if (!g_enabled.load(std::memory_order_relaxed) && g_cursor != nullptr) {
+        if (!g_enabled && g_cursor != nullptr) {
             lv_obj_add_flag(g_cursor, LV_OBJ_FLAG_HIDDEN);
         }
-        // Reset cursor to center when switching modes
+        g_cursorX = SCREEN_WIDTH / 2;
-        g_cursorX.store(SCREEN_WIDTH / 2, std::memory_order_relaxed);
+        g_cursorY = SCREEN_HEIGHT / 2;
-        g_cursorY.store(SCREEN_HEIGHT / 2, std::memory_order_relaxed);
         LOG_I(TAG, "Switched to Pointer mode");
     } else {
-        // Switch to encoder mode
         destroyCursor();
         lv_indev_set_type(g_indev, LV_INDEV_TYPE_ENCODER);
-        g_encoderDiff.store(0, std::memory_order_relaxed);  // Reset encoder diff
         LOG_I(TAG, "Switched to Encoder mode");
     }
 }
 
 Mode getMode() {
-    return g_mode.load(std::memory_order_relaxed);
+    return g_mode;
 }
 
 }

Devices/lilygo-tdeck/Source/Trackball/Trackball.h

@@ -1,6 +1,5 @@
 #pragma once
 
-#include <driver/gpio.h>
 #include <lvgl.h>
 
 namespace trackball {
@@ -14,24 +13,10 @@ enum class Mode {
 };
 
 /**
- * @brief Trackball configuration structure
+ * @brief Initialize trackball as an LVGL input device, backed by the kernel tdeck_trackball driver.
+ * @return LVGL input device pointer, or nullptr if the kernel device isn't found/started
  */
-struct TrackballConfig {
+lv_indev_t* init();
-    gpio_num_t pinRight;          // Right direction GPIO
-    gpio_num_t pinUp;             // Up direction GPIO
-    gpio_num_t pinLeft;           // Left direction GPIO
-    gpio_num_t pinDown;           // Down direction GPIO
-    gpio_num_t pinClick;          // Click/select button GPIO
-    uint8_t encoderSensitivity = 1;   // Encoder mode: steps per tick
-    uint8_t pointerSensitivity = 10;   // Pointer mode: pixels per tick
-};
-
-/**
- * @brief Initialize trackball as LVGL input device
- * @param config Trackball GPIO configuration
- * @return LVGL input device pointer, or nullptr on failure
- */
-lv_indev_t* init(const TrackballConfig& config);
 
 /**
  * @brief Deinitialize trackball

Devices/lilygo-tdeck/Source/bindings/tdeck_trackball.h

@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+#include <tactility/bindings/bindings.h>
+#include <drivers/tdeck_trackball.h>
+
+DEFINE_DEVICETREE(tdeck_trackball, struct TdeckTrackballConfig)

Devices/lilygo-tdeck/Source/devices/TrackballDevice.cpp

@@ -1,57 +0,0 @@
-#include "TrackballDevice.h"
-#include <Trackball/Trackball.h>  // Driver
-#include <Tactility/lvgl/LvglSync.h>
-#include <Tactility/settings/TrackballSettings.h>
-#include <tactility/log.h>
-
-constexpr auto* TAG = "TrackballDevice";
-
-bool TrackballDevice::start() {
-    if (initialized) {
-        return true;
-    }
-
-    // T-Deck trackball GPIO configuration from LilyGo reference
-    trackball::TrackballConfig config = {
-        .pinRight = GPIO_NUM_2,       // BOARD_TBOX_G02
-        .pinUp = GPIO_NUM_3,          // BOARD_TBOX_G01
-        .pinLeft = GPIO_NUM_1,        // BOARD_TBOX_G04
-        .pinDown = GPIO_NUM_15,       // BOARD_TBOX_G03
-        .pinClick = GPIO_NUM_0,       // BOARD_BOOT_PIN
-        .encoderSensitivity = 1,      // 1 step per tick for menu navigation
-        .pointerSensitivity = 10      // 10 pixels per tick for cursor movement
-    };
-
-    indev = trackball::init(config);
-    if (indev == nullptr) {
-        return false;
-    }
-
-    initialized = true;
-
-    // Apply persisted trackball settings (requires LVGL lock for cursor manipulation)
-    auto tbSettings = tt::settings::trackball::loadOrGetDefault();
-    if (tt::lvgl::lock(100)) {
-        trackball::setMode(tbSettings.trackballMode == tt::settings::trackball::TrackballMode::Pointer
-            ? trackball::Mode::Pointer
-            : trackball::Mode::Encoder);
-        trackball::setEncoderSensitivity(tbSettings.encoderSensitivity);
-        trackball::setPointerSensitivity(tbSettings.pointerSensitivity);
-        trackball::setEnabled(tbSettings.trackballEnabled);
-        tt::lvgl::unlock();
-    } else {
-        LOG_W(TAG, "Failed to acquire LVGL lock for trackball settings");
-    }
-
-    return true;
-}
-
-bool TrackballDevice::stop() {
-    if (initialized) {
-        // LVGL will handle indev cleanup
-        trackball::deinit();
-        indev = nullptr;
-        initialized = false;
-    }
-    return true;
-}

Devices/lilygo-tdeck/Source/devices/TrackballDevice.h

@@ -1,21 +0,0 @@
-#pragma once
-
-#include <tactility/hal/Device.h>
-#include <lvgl.h>
-
-class TrackballDevice : public tt::hal::Device {
-public:
-    tt::hal::Device::Type getType() const override { return tt::hal::Device::Type::Other; }
-    std::string getName() const override { return "Trackball"; }
-    std::string getDescription() const override { return "5-way GPIO trackball navigation"; }
-    
-    bool start();
-    bool stop();
-    bool isAttached() const { return initialized; }
-    
-    lv_indev_t* getLvglIndev() const { return indev; }
-    
-private:
-    lv_indev_t* indev = nullptr;
-    bool initialized = false;
-};

Devices/lilygo-tdeck/Source/drivers/tdeck_trackball.h

@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <tactility/drivers/gpio.h>
+#include <tactility/error.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+struct Device;
+struct DeviceType;
+
+struct TdeckTrackballConfig {
+    struct GpioPinSpec pin_right;
+    struct GpioPinSpec pin_up;
+    struct GpioPinSpec pin_left;
+    struct GpioPinSpec pin_down;
+    struct GpioPinSpec pin_click;
+};
+
+/**
+ * @brief API for the T-Deck 5-way trackball driver.
+ * Reports raw, unscaled movement: sensitivity and mode (encoder vs. pointer) are UI concerns
+ * layered on top by the consumer, not something this driver knows about.
+ */
+struct TdeckTrackballApi {
+    /**
+     * @brief Reads the accumulated movement since the last read, then resets it to zero.
+     * @param[in] device the trackball device
+     * @param[out] out_dx horizontal movement (right positive), in raw pulses
+     * @param[out] out_dy vertical movement (down positive), in raw pulses
+     * @retval ERROR_NONE when the operation was successful
+     */
+    error_t (*read_delta)(struct Device* device, int32_t* out_dx, int32_t* out_dy);
+
+    /**
+     * @brief Gets whether the click button is currently pressed.
+     * @param[in] device the trackball device
+     * @param[out] out_pressed true when pressed
+     * @retval ERROR_NONE when the operation was successful
+     */
+    error_t (*get_button_pressed)(struct Device* device, bool* out_pressed);
+};
+
+/**
+ * @brief Reads the accumulated movement using the specified trackball device.
+ */
+error_t tdeck_trackball_read_delta(struct Device* device, int32_t* out_dx, int32_t* out_dy);
+
+/**
+ * @brief Gets whether the click button is currently pressed on the specified trackball device.
+ */
+error_t tdeck_trackball_get_button_pressed(struct Device* device, bool* out_pressed);
+
+extern const struct DeviceType TDECK_TRACKBALL_TYPE;
+
+#ifdef __cplusplus
+}
+#endif

Devices/lilygo-tdeck/Source/module.cpp

@@ -9,9 +9,11 @@
 #include <Tactility/hal/Configuration.h>
 #include <Tactility/hal/gps/GpsConfiguration.h>
 #include <Tactility/kernel/Kernel.h>
+#include <Tactility/lvgl/LvglSync.h>
 #include <Tactility/service/gps/GpsService.h>
+#include <Tactility/settings/TrackballSettings.h>
 
-#include "devices/TrackballDevice.h"
+#include <Trackball/Trackball.h>
 
 #include <driver/gpio.h>
 
@@ -26,6 +28,7 @@ extern "C" {
 
 extern Driver tdeck_keyboard_driver;
 extern Driver tdeck_keyboard_backlight_driver;
+extern Driver tdeck_trackball_driver;
 
 static bool power_on() {
     gpio_config_t device_power_signal_config = {
@@ -66,16 +69,22 @@ void subscribe_events() {
         }
     });
 
+    // The kernel trackball device is already started by kernel_init(); this just registers it as an
+    // LVGL input device and applies persisted settings, both of which require LVGL to be up first.
     tt::kernel::subscribeSystemEvent(tt::kernel::SystemEvent::BootSplash, [](tt::kernel::SystemEvent event) {
-        auto trackball = tt::hal::findDevice("Trackball");
+        auto tbSettings = tt::settings::trackball::loadOrGetDefault();
-        if (trackball != nullptr) {
+        if (tt::lvgl::lock(100)) {
-            LOG_I(TAG, "%s starting", trackball->getName().c_str());
+            if (trackball::init() != nullptr) {
-            auto tbDevice = std::static_pointer_cast<TrackballDevice>(trackball);
+                trackball::setMode(tbSettings.trackballMode == tt::settings::trackball::TrackballMode::Pointer
-            if (tbDevice->start()) {
+                    ? trackball::Mode::Pointer
-                LOG_I(TAG, "%s started", trackball->getName().c_str());
+                    : trackball::Mode::Encoder);
-            } else {
+                trackball::setEncoderSensitivity(tbSettings.encoderSensitivity);
-                LOG_E(TAG, "%s start failed", trackball->getName().c_str());
+                trackball::setPointerSensitivity(tbSettings.pointerSensitivity);
+                trackball::setEnabled(tbSettings.trackballEnabled);
             }
+            tt::lvgl::unlock();
+        } else {
+            LOG_W(TAG, "Failed to acquire LVGL lock for trackball settings");
         }
     });
 }
@@ -97,6 +106,11 @@ static error_t start() {
         return ERROR_RESOURCE;
     }
 
+    if (driver_construct_add(&tdeck_trackball_driver) != ERROR_NONE) {
+        LOG_E(TAG, "Failed to register trackball driver");
+        return ERROR_RESOURCE;
+    }
+
     subscribe_events();
 
     return ERROR_NONE;
@@ -112,6 +126,10 @@ static error_t stop() {
         LOG_E(TAG, "Failed to unregister keyboard backlight driver");
         return ERROR_RESOURCE;
     }
+    if (driver_remove_destruct(&tdeck_trackball_driver) != ERROR_NONE) {
+        LOG_E(TAG, "Failed to unregister trackball driver");
+        return ERROR_RESOURCE;
+    }
     return ERROR_NONE;
 }
 

Devices/lilygo-tdeck/Source/tdeck_trackball.cpp

@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: Apache-2.0
+#include <drivers/tdeck_trackball.h>
+
+#include <tactility/check.h>
+#include <tactility/device.h>
+#include <tactility/driver.h>
+#include <tactility/drivers/gpio_controller.h>
+#include <tactility/drivers/gpio_descriptor.h>
+#include <tactility/log.h>
+
+#include <atomic>
+#include <new>
+
+#define TAG "tdeck_trackball"
+#define GET_CONFIG(device) (static_cast<const TdeckTrackballConfig*>((device)->config))
+#define GET_INTERNAL(device) (static_cast<TdeckTrackballInternal*>(device_get_driver_data(device)))
+
+struct TdeckTrackballInternal {
+    GpioDescriptor* pin_right = nullptr;
+    GpioDescriptor* pin_up = nullptr;
+    GpioDescriptor* pin_left = nullptr;
+    GpioDescriptor* pin_down = nullptr;
+    GpioDescriptor* pin_click = nullptr;
+
+    std::atomic<int32_t> dx {0};
+    std::atomic<int32_t> dy {0};
+    std::atomic<bool> button_pressed {false};
+};
+
+// region ISR callbacks
+
+static void on_right(void* arg) {
+    static_cast<TdeckTrackballInternal*>(arg)->dx.fetch_add(1, std::memory_order_relaxed);
+}
+
+static void on_left(void* arg) {
+    static_cast<TdeckTrackballInternal*>(arg)->dx.fetch_sub(1, std::memory_order_relaxed);
+}
+
+static void on_down(void* arg) {
+    static_cast<TdeckTrackballInternal*>(arg)->dy.fetch_add(1, std::memory_order_relaxed);
+}
+
+static void on_up(void* arg) {
+    static_cast<TdeckTrackballInternal*>(arg)->dy.fetch_sub(1, std::memory_order_relaxed);
+}
+
+static void on_click(void* arg) {
+    auto* internal = static_cast<TdeckTrackballInternal*>(arg);
+    bool high = true;
+    gpio_descriptor_get_level(internal->pin_click, &high);
+    // Active low: pressed when level is low
+    internal->button_pressed.store(!high, std::memory_order_relaxed);
+}
+
+// endregion
+
+// region Pin acquisition
+
+static error_t acquire_pin(const GpioPinSpec& spec, GpioInterruptType interrupt_type, void (*callback)(void*), void* arg, GpioDescriptor** out_descriptor) {
+    auto* descriptor = gpio_descriptor_acquire(spec.gpio_controller, spec.pin, GPIO_OWNER_GPIO);
+    if (descriptor == nullptr) {
+        return ERROR_RESOURCE;
+    }
+
+    gpio_flags_t flags = GPIO_FLAG_DIRECTION_INPUT | GPIO_FLAG_PULL_UP;
+    flags = GPIO_FLAG_INTERRUPT_TO_OPTIONS(flags, interrupt_type);
+
+    error_t error = gpio_descriptor_set_flags(descriptor, flags);
+    if (error == ERROR_NONE) {
+        error = gpio_descriptor_add_callback(descriptor, callback, arg);
+    }
+    if (error == ERROR_NONE) {
+        error = gpio_descriptor_enable_interrupt(descriptor);
+    }
+
+    if (error != ERROR_NONE) {
+        gpio_descriptor_remove_callback(descriptor);
+        gpio_descriptor_release(descriptor);
+        return error;
+    }
+
+    *out_descriptor = descriptor;
+    return ERROR_NONE;
+}
+
+static void release_pin(GpioDescriptor*& descriptor) {
+    if (descriptor == nullptr) {
+        return;
+    }
+    gpio_descriptor_disable_interrupt(descriptor);
+    gpio_descriptor_remove_callback(descriptor);
+    gpio_descriptor_release(descriptor);
+    descriptor = nullptr;
+}
+
+static void release_all_pins(TdeckTrackballInternal* internal) {
+    release_pin(internal->pin_right);
+    release_pin(internal->pin_up);
+    release_pin(internal->pin_left);
+    release_pin(internal->pin_down);
+    release_pin(internal->pin_click);
+}
+
+// endregion
+
+extern "C" {
+
+static error_t read_delta(Device* device, int32_t* out_dx, int32_t* out_dy) {
+    auto* internal = GET_INTERNAL(device);
+    *out_dx = internal->dx.exchange(0, std::memory_order_relaxed);
+    *out_dy = internal->dy.exchange(0, std::memory_order_relaxed);
+    return ERROR_NONE;
+}
+
+static error_t get_button_pressed(Device* device, bool* out_pressed) {
+    *out_pressed = GET_INTERNAL(device)->button_pressed.load(std::memory_order_relaxed);
+    return ERROR_NONE;
+}
+
+error_t tdeck_trackball_read_delta(Device* device, int32_t* out_dx, int32_t* out_dy) {
+    return read_delta(device, out_dx, out_dy);
+}
+
+error_t tdeck_trackball_get_button_pressed(Device* device, bool* out_pressed) {
+    return get_button_pressed(device, out_pressed);
+}
+
+static error_t start(Device* device) {
+    LOG_I(TAG, "start %s", device->name);
+    auto* config = GET_CONFIG(device);
+
+    auto* internal = new(std::nothrow) TdeckTrackballInternal();
+    if (internal == nullptr) {
+        return ERROR_OUT_OF_MEMORY;
+    }
+
+    error_t error = acquire_pin(config->pin_right, GPIO_INTERRUPT_NEG_EDGE, on_right, internal, &internal->pin_right);
+    if (error == ERROR_NONE) {
+        error = acquire_pin(config->pin_up, GPIO_INTERRUPT_NEG_EDGE, on_up, internal, &internal->pin_up);
+    }
+    if (error == ERROR_NONE) {
+        error = acquire_pin(config->pin_left, GPIO_INTERRUPT_NEG_EDGE, on_left, internal, &internal->pin_left);
+    }
+    if (error == ERROR_NONE) {
+        error = acquire_pin(config->pin_down, GPIO_INTERRUPT_NEG_EDGE, on_down, internal, &internal->pin_down);
+    }
+    if (error == ERROR_NONE) {
+        error = acquire_pin(config->pin_click, GPIO_INTERRUPT_ANY_EDGE, on_click, internal, &internal->pin_click);
+    }
+
+    if (error != ERROR_NONE) {
+        LOG_E(TAG, "Failed to acquire trackball pins: %s", error_to_string(error));
+        release_all_pins(internal);
+        delete internal;
+        return error;
+    }
+
+    // Read the click pin's initial level now that the descriptor is acquired.
+    on_click(internal);
+
+    device_set_driver_data(device, internal);
+    return ERROR_NONE;
+}
+
+static error_t stop(Device* device) {
+    LOG_I(TAG, "stop %s", device->name);
+    auto* internal = GET_INTERNAL(device);
+    release_all_pins(internal);
+    device_set_driver_data(device, nullptr);
+    delete internal;
+    return ERROR_NONE;
+}
+
+static constexpr TdeckTrackballApi TDECK_TRACKBALL_API = {
+    .read_delta = read_delta,
+    .get_button_pressed = get_button_pressed,
+};
+
+const struct DeviceType TDECK_TRACKBALL_TYPE {
+    .name = "tdeck-trackball"
+};
+
+extern Module lilygo_tdeck_module;
+
+Driver tdeck_trackball_driver = {
+    .name = "tdeck_trackball",
+    .compatible = (const char*[]) { "lilygo,tdeck-trackball", nullptr },
+    .start_device = start,
+    .stop_device = stop,
+    .api = &TDECK_TRACKBALL_API,
+    .device_type = &TDECK_TRACKBALL_TYPE,
+    .owner = &lilygo_tdeck_module,
+    .internal = nullptr
+};
+
+}

Devices/lilygo-tdeck/bindings/lilygo,tdeck-trackball.yaml

@@ -0,0 +1,25 @@
+description: LilyGO T-Deck 5-way GPIO trackball (4 directions + click button)
+
+compatible: "lilygo,tdeck-trackball"
+
+properties:
+  pin-right:
+    type: phandles
+    required: true
+    description: Right-direction GPIO pin
+  pin-up:
+    type: phandles
+    required: true
+    description: Up-direction GPIO pin
+  pin-left:
+    type: phandles
+    required: true
+    description: Left-direction GPIO pin
+  pin-down:
+    type: phandles
+    required: true
+    description: Down-direction GPIO pin
+  pin-click:
+    type: phandles
+    required: true
+    description: Click button GPIO pin

Devices/lilygo-tdeck/lilygo,tdeck.dts

@@ -18,6 +18,7 @@
 #include <bindings/st7789.h>
 #include <bindings/tdeck_keyboard.h>
 #include <bindings/tdeck_keyboard_backlight.h>
+#include <bindings/tdeck_trackball.h>
 
 // Reference: https://wiki.lilygo.cc/get_started/en/Wearable/T-Deck-Plus/T-Deck-Plus.html#Pin-Overview
 / {
@@ -53,6 +54,15 @@
 		gpio-count = <49>;
 	};
 
+	trackball {
+		compatible = "lilygo,tdeck-trackball";
+		pin-right = <&gpio0 2 GPIO_FLAG_NONE>;
+		pin-up = <&gpio0 3 GPIO_FLAG_NONE>;
+		pin-left = <&gpio0 1 GPIO_FLAG_NONE>;
+		pin-down = <&gpio0 15 GPIO_FLAG_NONE>;
+		pin-click = <&gpio0 0 GPIO_FLAG_NONE>;
+	};
+
 	i2c_internal: i2c0 {
 		compatible = "espressif,esp32-i2c";
 		port = <I2C_NUM_0>;