From ef7a027cf0d2363a965a1f714341e49d83b21132 Mon Sep 17 00:00:00 2001
From: Shaun Reed <shaunrd0@gmail.com>
Date: Fri, 14 Feb 2025 16:48:04 -0500
Subject: [PATCH] Factor out I2C.

---
 esp/cpp/07_lcd-panel/main/display.cpp | 46 ++++++++++++---------------
 esp/cpp/07_lcd-panel/main/display.h   | 21 +++++++-----
 esp/cpp/07_lcd-panel/main/main.cpp    |  6 ++--
 3 files changed, 38 insertions(+), 35 deletions(-)

diff --git a/esp/cpp/07_lcd-panel/main/display.cpp b/esp/cpp/07_lcd-panel/main/display.cpp
index 383e463..ab50384 100644
--- a/esp/cpp/07_lcd-panel/main/display.cpp
+++ b/esp/cpp/07_lcd-panel/main/display.cpp
@@ -17,13 +17,22 @@ uint8_t Display::oled_buffer_[LCD_H_RES * LCD_V_RES / 8];
 // We must use a mutex to protect it.
 _lock_t ScopedLock::lock_;
 
-Display::Display() :
+Display::Display(const I2C &i2c) :
     io_handle_(nullptr),
     panel_handle_(nullptr),
-    i2c_bus_(nullptr),
     buf_(nullptr)
 {
-  init_i2c();
+  ESP_LOGI(TAG, "Install panel IO");
+  esp_lcd_panel_io_i2c_config_t io_config = {
+      .dev_addr = I2C_HW_ADDR,
+      .control_phase_bytes = 1,               // According to SSD1306 datasheet
+      .dc_bit_offset = 6,                     // According to SSD1306 datasheet
+      .lcd_cmd_bits = LCD_CMD_BITS,           // According to SSD1306 datasheet
+      .lcd_param_bits = LCD_CMD_BITS,         // According to SSD1306 datasheet
+      .scl_speed_hz = LCD_PIXEL_CLOCK_HZ,
+  };
+  ESP_ERROR_CHECK(
+      esp_lcd_new_panel_io_i2c(i2c.i2c_bus_, &io_config, &io_handle_));
 
   ESP_LOGI(TAG, "Install SSD1306 panel driver");
   ssd1306_config_ = {
@@ -158,7 +167,15 @@ void Display::lvgl_port_task(void *arg)
   }
 }
 
-void Display::init_i2c()
+//SSD1306::SSD1306() {
+//
+//}
+//void *SSD1306::vendor_config()
+//{
+//  return &ssd1306_config_;
+//}
+
+I2C::I2C() : i2c_bus_(nullptr)
 {
   ESP_LOGI(TAG, "Initialize I2C bus");
   i2c_master_bus_config_t bus_config = {
@@ -172,25 +189,4 @@ void Display::init_i2c()
       },
   };
   ESP_ERROR_CHECK(i2c_new_master_bus(&bus_config, &i2c_bus_));
-
-  ESP_LOGI(TAG, "Install panel IO");
-  esp_lcd_panel_io_i2c_config_t io_config = {
-      .dev_addr = I2C_HW_ADDR,
-      .control_phase_bytes = 1,               // According to SSD1306 datasheet
-      .dc_bit_offset = 6,                     // According to SSD1306 datasheet
-      .lcd_cmd_bits = LCD_CMD_BITS,           // According to SSD1306 datasheet
-      .lcd_param_bits = LCD_CMD_BITS,         // According to SSD1306 datasheet
-      .scl_speed_hz = LCD_PIXEL_CLOCK_HZ,
-  };
-  ESP_ERROR_CHECK(esp_lcd_new_panel_io_i2c(i2c_bus_, &io_config, &io_handle_));
 }
-
-//SSD1306::SSD1306() {
-//
-//}
-//void *SSD1306::vendor_config()
-//{
-//  return &ssd1306_config_;
-//}
-
-
diff --git a/esp/cpp/07_lcd-panel/main/display.h b/esp/cpp/07_lcd-panel/main/display.h
index e16e50b..983708f 100644
--- a/esp/cpp/07_lcd-panel/main/display.h
+++ b/esp/cpp/07_lcd-panel/main/display.h
@@ -34,6 +34,14 @@ static const char *TAG = "lcd-panel";
 #define PIN_SCL                GPIO_NUM_22
 #define PIN_RST                -1
 
+struct I2C {
+  I2C();
+
+  ~I2C() = default;
+
+  i2c_master_bus_handle_t i2c_bus_;
+};
+
 struct ScopedLock {
   explicit ScopedLock() { _lock_acquire(&lock_); }
 
@@ -46,11 +54,10 @@ struct ScopedLock {
 
 class Display {
 public:
-  Display();
+  explicit Display(const I2C &i2c);
 
   ~Display() = default;
 
-
   [[nodiscard]] inline const lv_display_t *get() const { return display_; }
 
   [[nodiscard]] inline lv_display_t *get() { return display_; }
@@ -73,6 +80,7 @@ public:
 
   // For LV_COLOR_FORMAT_I1 we need an extra buffer to hold the converted data.
   static uint8_t oled_buffer_[LCD_H_RES * LCD_V_RES / 8];
+
 protected:
   esp_lcd_panel_io_handle_t io_handle_;
 
@@ -82,17 +90,14 @@ protected:
 
   esp_lcd_panel_ssd1306_config_t ssd1306_config_;
 
-  i2c_master_bus_handle_t  i2c_bus_;
-
 private:
-  void init_i2c();
-
 //  virtual void *vendor_config() = 0;
 
   lv_display_t *display_;
 
-  void * vendor_config_;
-  void * buf_;
+  void *vendor_config_;
+
+  void *buf_;
 };
 
 //class SSD1306 : public Display {
diff --git a/esp/cpp/07_lcd-panel/main/main.cpp b/esp/cpp/07_lcd-panel/main/main.cpp
index cb81458..1df6c26 100644
--- a/esp/cpp/07_lcd-panel/main/main.cpp
+++ b/esp/cpp/07_lcd-panel/main/main.cpp
@@ -3,11 +3,13 @@
 #include "esp_log.h"
 #include "lvgl.h"
 
+I2C i2c;
+
 void setup()
 {
-  Display d;
+  Display d(i2c);
 
-  // UI function
+  // UI function scope.
   {
     // Lock the mutex due to the LVGL APIs are not thread-safe
     ScopedLock lock;