Add mozc dial version.

Co-authored-by: Takashi Toyoshima <toyoshim@google.com>
Co-authored-by: Shun Ikejima <ikejima@google.com>

mozc-dial/firmware/one_dial/one_dial.cc

@@ -0,0 +1,56 @@
+// Copyright 2025 Google Inc.
+// Use of this source code is governed by an Apache License that can be found
+// in the LICENSE file.
+
+#include <cstdint>
+#include <cstdio>
+#include <optional>
+
+#include "pico/stdlib.h"
+
+#include "../common/dial_controller.h"
+#include "../common/motor_controller.h"
+#include "../common/photo_sensor.h"
+#include "../common/usage_tables.h"
+#include "../common/usb_hid_keyboard.h"
+
+int main() {
+  // GPIO0 and 1 are used for stdout, and stdin by default.
+  stdio_init_all();
+
+  // GPIO17, 18, 19, and 20 are used for motor phase control.
+  MotorController motor_controller(MotorController::Mode::k1Motor);
+
+  // GPIO2, 3, 4, 5, 6, and 7 are used for 6bit photo sensing.
+  PhotoSensor photo_sensor(2, 3, 4, 5, 6, 7);
+
+  DialController dial_controller;
+
+  UsbHidKeyboard usb_hid_keyboard(
+      /*vendor_id=*/0x6666, /*product_id=*/0x2025,
+      /*version=*/0x0101, /*vendor_name=*/"Gboard DIY prototype",
+      /*product_name=*/"Gboard Dial version", /*version_name=*/"1 Dial");
+  usb_hid_keyboard.SetAutoKeyRelease(true);
+
+  while (true) {
+    dial_controller.Update(photo_sensor.Read());
+    if (dial_controller.IsBasePosition()) {
+      motor_controller.Stop(8);
+    } else {
+      motor_controller.Start(8);
+    }
+    // `decided_position` is std::nullopt while the dial is not moved at the
+    // base position, or moving. But once it returns to the base position from
+    // non-base positions, it will have a 1 or a larger value that indicates the
+    // position where the dial starts returning.
+    std::optional<uint8_t> decided_position =
+        dial_controller.PopDecidedPosition();
+    if (decided_position && *decided_position <= usage_tables::a.size()) {
+      // Adjust the index as it is 1-based.
+      uint8_t usage = usage_tables::a[*decided_position - 1];
+      if (usage) {
+        usb_hid_keyboard.PressByUsageId(usage);
+      }
+    }
+  }
+}