Add LilyGO T-Deck Max (e-paper) base board support (#552)

Devices/lilygo-tdeck-max/Source/devices/TdeckmaxKeyboard.h

@@ -0,0 +1,69 @@
+#pragma once
+
+#include <Tactility/hal/keyboard/KeyboardDevice.h>
+#include <Tactility/Timer.h>
+
+#include <Tca8418.h>
+#include <driver/gpio.h>
+#include <driver/ledc.h>
+#include <freertos/queue.h>
+
+// QWERTY keyboard for the LilyGO T-Deck (Pro) Max.
+//
+// The keyboard is a TCA8418 4x10 matrix scanner on the shared I2C bus at 0x34.
+// The keyboard reset line is wired through the XL9555 IO expander (P11), so it
+// must be released before this device is started (see Configuration.cpp).
+//
+// Pins, address and keymap are taken from Xinyuan-LilyGO/T-Deck-MAX:
+// examples/factory/peri_keypad.cpp and lib/TDeckMaxBoard/src/TDeckMaxBoard.h.
+class TdeckmaxKeyboard final : public tt::hal::keyboard::KeyboardDevice {
+
+    lv_indev_t* kbHandle = nullptr;
+    gpio_num_t backlightPin = GPIO_NUM_NC;
+    ledc_timer_t backlightTimer;
+    ledc_channel_t backlightChannel;
+    bool backlightOkay = false;
+    int backlightImpulseDuty = 0;
+    QueueHandle_t queue = nullptr;
+    // LVGL only registers a key on a RELEASED->PRESSED edge, so readCallback
+    // alternates press/release per queued key; this tracks the pending release.
+    uint32_t lastKey = 0;
+    bool lastKeyNeedsRelease = false;
+
+    std::shared_ptr<Tca8418> keypad;
+    std::unique_ptr<tt::Timer> inputTimer;
+    std::unique_ptr<tt::Timer> backlightImpulseTimer;
+
+    bool shiftPressed = false;
+    bool symPressed = false;
+    bool capToggle = false;
+    bool capToggleArmed = true;
+
+    bool initBacklight(gpio_num_t pin, uint32_t frequencyHz, ledc_timer_t timer, ledc_channel_t channel);
+    void processKeyboard();
+    void processBacklightImpulse();
+
+    static void readCallback(lv_indev_t* indev, lv_indev_data_t* data);
+
+public:
+
+    explicit TdeckmaxKeyboard(const std::shared_ptr<Tca8418>& tca) : keypad(tca) {
+        queue = xQueueCreate(20, sizeof(char));
+    }
+
+    ~TdeckmaxKeyboard() override {
+        vQueueDelete(queue);
+    }
+
+    std::string getName() const override { return "T-Deck Max Keyboard"; }
+    std::string getDescription() const override { return "T-Deck Max TCA8418 I2C matrix keyboard"; }
+
+    bool startLvgl(lv_display_t* display) override;
+    bool stopLvgl() override;
+
+    bool isAttached() const override;
+    lv_indev_t* getLvglIndev() override { return kbHandle; }
+
+    bool setBacklightDuty(uint8_t duty);
+    void makeBacklightImpulse();
+};