Add mozc dial version.

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

mozc-dial/firmware/main/i2c_controller.cc

@@ -0,0 +1,47 @@
+// Copyright 2025 Google Inc.
+// Use of this source code is governed by an Apache License that can be found
+// in the LICENSE file.
+
+#include "i2c_controller.h"
+
+#include <algorithm>
+#include <vector>
+
+#include "hardware/gpio.h"
+
+static constexpr int kI2CSpeedInHz = 400 * 1000;
+
+I2CController::I2CController(i2c_inst_t* i2c, int8_t sda, int8_t scl)
+    : i2c_(i2c) {
+  hard_assert(i2c == i2c0 || i2c == i2c1);
+  gpio_init(sda);
+  gpio_init(scl);
+  gpio_set_function(sda, GPIO_FUNC_I2C);
+  gpio_set_function(scl, GPIO_FUNC_I2C);
+  gpio_pull_up(sda);
+  gpio_pull_up(scl);
+  i2c_init(i2c_, kI2CSpeedInHz);
+}
+
+bool I2CController::Read(uint8_t device_addr,
+                         uint8_t mem_addr,
+                         std::span<uint8_t> data) {
+  uint8_t addr[1] = {mem_addr};
+  int result = i2c_write_blocking(i2c_, device_addr, addr, 1, true);
+  if (result != 1) {
+    return false;
+  }
+  result = i2c_read_blocking(i2c_, device_addr, data.data(), data.size(), false);
+  return result == data.size();
+}
+
+bool I2CController::Write(uint8_t device_addr,
+                          uint8_t mem_addr,
+                          std::span<uint8_t> data) {
+  std::vector<uint8_t> buf;
+  buf.reserve(data.size() + 1);
+  buf.push_back(mem_addr);
+  buf.insert(buf.end(), data.begin(), data.end());
+  int rc = i2c_write_blocking(i2c_, device_addr, buf.data(), buf.size(), false);
+  return rc == buf.size();
+}