From 64d817e3625ec0c165678697a1f7b235d4de0520 Mon Sep 17 00:00:00 2001
From: Shaun Reed <shaunrd0@gmail.com>
Date: Sat, 15 Feb 2025 17:44:58 -0500
Subject: [PATCH] Move I2C into header file.

---
 esp/cpp/07_lcd-panel/main/display.cpp    | 22 +------------
 esp/cpp/07_lcd-panel/main/display.h      | 12 -------
 esp/cpp/07_lcd-panel/main/i2c.h          | 41 ++++++++++++++++++++++++
 esp/cpp/07_lcd-panel/main/main.cpp       |  2 +-
 esp/cpp/07_lcd-panel/main/panel_device.h |  7 ++--
 esp/cpp/07_lcd-panel/main/ssd1306.cpp    |  2 --
 6 files changed, 45 insertions(+), 41 deletions(-)
 create mode 100644 esp/cpp/07_lcd-panel/main/i2c.h

diff --git a/esp/cpp/07_lcd-panel/main/display.cpp b/esp/cpp/07_lcd-panel/main/display.cpp
index fcd9313..b0f5a5d 100644
--- a/esp/cpp/07_lcd-panel/main/display.cpp
+++ b/esp/cpp/07_lcd-panel/main/display.cpp
@@ -10,7 +10,6 @@
 #include <esp_timer.h>
 #include <lv_init.h>
 #include <display/lv_display.h>
-#include <driver/i2c_master.h>
 #include <mutex>
 
 // LVGL library is not thread-safe, this example calls LVGL APIs from tasks.
@@ -165,25 +164,6 @@ void Display::lvgl_increase_tick(void *)
   }
 }
 
-I2C::I2C(gpio_num_t sda, gpio_num_t scl) :
-    i2c_bus_(nullptr),
-    bus_config_(
-        (i2c_master_bus_config_t) {
-            .i2c_port = I2C_BUS_PORT,
-            .sda_io_num = sda,
-            .scl_io_num = scl,
-            .clk_source = I2C_CLK_SRC_DEFAULT,
-            .glitch_ignore_cnt = 7,
-            .flags {
-                .enable_internal_pullup = true,
-            },
-        }
-    )
-{
-  ESP_LOGI(TAG, "Initialize I2C bus");
-  ESP_ERROR_CHECK(i2c_new_master_bus(&bus_config_, &i2c_bus_));
-}
-
 Panel::Panel(IPanelDevice *device) :
     device_(device),
     io_handle_(nullptr),
@@ -191,7 +171,7 @@ Panel::Panel(IPanelDevice *device) :
     // According to SSD1306 datasheet
     panel_config_(
         (esp_lcd_panel_dev_config_t) {
-            .reset_gpio_num = device_->reset_gpio_num_,
+            .reset_gpio_num = PIN_RST,
             .bits_per_pixel = 1,
             // .vendor_config should be set in IPanelDevice::init_panel override
         }
diff --git a/esp/cpp/07_lcd-panel/main/display.h b/esp/cpp/07_lcd-panel/main/display.h
index 701a127..f587322 100644
--- a/esp/cpp/07_lcd-panel/main/display.h
+++ b/esp/cpp/07_lcd-panel/main/display.h
@@ -15,22 +15,10 @@
 
 #include "panel_device.h"
 
-#define I2C_BUS_PORT  0
 #define LVGL_TICK_PERIOD_MS    5
 #define LVGL_TASK_STACK_SIZE   (4 * 1024)
 #define LVGL_TASK_PRIORITY     2
 
-struct I2C {
-  I2C(gpio_num_t sda, gpio_num_t scl);
-
-  ~I2C() = default;
-
-  i2c_master_bus_handle_t i2c_bus_;
-
-private:
-  i2c_master_bus_config_t bus_config_;
-};
-
 struct ScopedLock {
   explicit ScopedLock() { _lock_acquire(&lock_); }
 
diff --git a/esp/cpp/07_lcd-panel/main/i2c.h b/esp/cpp/07_lcd-panel/main/i2c.h
new file mode 100644
index 0000000..ce7b2d2
--- /dev/null
+++ b/esp/cpp/07_lcd-panel/main/i2c.h
@@ -0,0 +1,41 @@
+#ifndef I2C_H
+#define I2C_H
+
+#define I2C_BUS_PORT  0
+
+#include <driver/i2c_master.h>
+#include "soc/gpio_num.h"
+
+static const char *TAG = "lcd-panel";
+
+struct I2C {
+  I2C(gpio_num_t sda, gpio_num_t scl, int rst = -1) :
+      i2c_bus_(nullptr),
+      rst_num_(rst),
+      bus_config_(
+          (i2c_master_bus_config_t) {
+              .i2c_port = I2C_BUS_PORT,
+              .sda_io_num = sda,
+              .scl_io_num = scl,
+              .clk_source = I2C_CLK_SRC_DEFAULT,
+              .glitch_ignore_cnt = 7,
+              .flags {
+                  .enable_internal_pullup = true,
+              },
+          }
+      )
+  {
+    ESP_LOGI(TAG, "Initialize I2C bus");
+    ESP_ERROR_CHECK(i2c_new_master_bus(&bus_config_, &i2c_bus_));
+  }
+
+  ~I2C() = default;
+
+  i2c_master_bus_handle_t i2c_bus_;
+
+  int rst_num_;
+private:
+  i2c_master_bus_config_t bus_config_;
+};
+
+#endif //I2C_H
diff --git a/esp/cpp/07_lcd-panel/main/main.cpp b/esp/cpp/07_lcd-panel/main/main.cpp
index ff916a2..7136de2 100644
--- a/esp/cpp/07_lcd-panel/main/main.cpp
+++ b/esp/cpp/07_lcd-panel/main/main.cpp
@@ -8,7 +8,7 @@
 
 // TODO: Can this be static since there can only be one initialization?
 // TODO: Store RST in I2C and retrieve within SSD instead of the #define
-I2C i2c(PIN_SDA, PIN_SCL);
+I2C i2c(PIN_SDA, PIN_SCL, PIN_RST);
 
 void setup()
 {
diff --git a/esp/cpp/07_lcd-panel/main/panel_device.h b/esp/cpp/07_lcd-panel/main/panel_device.h
index 7d41021..a6c1319 100644
--- a/esp/cpp/07_lcd-panel/main/panel_device.h
+++ b/esp/cpp/07_lcd-panel/main/panel_device.h
@@ -9,16 +9,14 @@
 #include <esp_log.h>
 #include "display/lv_display.h"
 
-#define LVGL_PALETTE_SIZE      8
+#include "i2c.h"
 
-static const char *TAG = "lcd-panel";
+#define LVGL_PALETTE_SIZE      8
 
 class IPanelDevice {
 public:
   explicit IPanelDevice(i2c_master_bus_handle_t i2c,
-                        int reset_gpio_num,
                         esp_lcd_panel_io_i2c_config_t io_config) :
-      reset_gpio_num_(reset_gpio_num),
       i2c_bus_(i2c),
       io_config_(io_config) { }
 
@@ -47,7 +45,6 @@ public:
 
   int32_t width_;
   int32_t height_;
-  int reset_gpio_num_;
 
   // LVGL reserves 2x4 bytes in the buffer to be used as a palette.
   size_t lv_buf_size_;
diff --git a/esp/cpp/07_lcd-panel/main/ssd1306.cpp b/esp/cpp/07_lcd-panel/main/ssd1306.cpp
index 081f80f..d10bcff 100644
--- a/esp/cpp/07_lcd-panel/main/ssd1306.cpp
+++ b/esp/cpp/07_lcd-panel/main/ssd1306.cpp
@@ -9,7 +9,6 @@ SSD1306::SSD1306(i2c_master_bus_handle_t i2c,
                  int width,
                  int height) :
     IPanelDevice(i2c,
-                 PIN_RST,
                  (esp_lcd_panel_io_i2c_config_t) {
                      .dev_addr = I2C_HW_ADDR,
                      .control_phase_bytes = 1,
@@ -23,7 +22,6 @@ SSD1306::SSD1306(i2c_master_bus_handle_t i2c,
 {
   this->width_ = width;
   this->height_ = height;
-  this->reset_gpio_num_ = PIN_RST;
   this->lv_buf_size_ = width_ * height_ / 8 + LVGL_PALETTE_SIZE;
 }