Add OLED example project

.gitmodules

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+[submodule "examples/common_components/lvgl"]
+	path = examples/common_components/lvgl
+	url = git@github.com:lvgl/lvgl.git

examples/common_components/lvgl

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+Subproject commit ec9de515b36641be565d7bace5863ab631ce3b69

examples/wemos_lolin_oled/hello_world/CMakeLists.txt

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+# For more information about build system see
+# https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/build-system.html
+# The following five lines of boilerplate have to be in your project's
+# CMakeLists in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.5)
+
+set(EXTRA_COMPONENT_DIRS ../../common_components ../../..)
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(hello_world)

examples/wemos_lolin_oled/hello_world/main/CMakeLists.txt

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+idf_component_register(SRCS "hello_world.c"
+                    INCLUDE_DIRS ".")

examples/wemos_lolin_oled/hello_world/main/hello_world.c

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+/* Hello world on Wemos Lolin32 board
+ *
+ * This example code is in the Public Domain (or CC0 licensed, at your option.)
+ *
+ * Unless required by applicable law or agreed to in writing, this
+ * software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+ * CONDITIONS OF ANY KIND, either express or implied.
+ */
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "esp_freertos_hooks.h"
+#include "freertos/semphr.h"
+#include "esp_system.h"
+#include "driver/gpio.h"
+
+/* Littlevgl specific */
+#ifdef LV_LVGL_H_INCLUDE_SIMPLE
+#include "lvgl.h"
+#else
+#include "lvgl/lvgl.h"
+#endif
+
+#include "lvgl_helpers.h"
+
+/*********************
+ *      DEFINES
+ *********************/
+#define LV_TICK_PERIOD_MS 1
+
+/**********************
+ *  STATIC PROTOTYPES
+ **********************/
+static void lvgl_tick_inc(void *arg);
+static void guiTask(void *pvParameter);
+
+/**********************
+ *   APPLICATION MAIN
+ **********************/
+void app_main()
+{
+    xTaskCreatePinnedToCore(guiTask, "gui", 4096*2, NULL, 0, NULL, 1);
+}
+
+static void guiTask(void *pvParameter)
+{
+    (void) pvParameter;
+    lv_init();
+    lvgl_driver_init();
+
+    lv_color_t* buf1 = heap_caps_malloc(DISP_BUF_SIZE * sizeof(lv_color_t), MALLOC_CAP_DMA);
+    assert(buf1 != NULL);
+
+    static lv_disp_buf_t disp_buf;
+    lv_disp_buf_init(&disp_buf, buf1, NULL, DISP_BUF_SIZE * 8);
+
+    lv_disp_drv_t disp_drv;
+    lv_disp_drv_init(&disp_drv);
+    disp_drv.flush_cb = disp_driver_flush;
+    disp_drv.rounder_cb = disp_driver_rounder;
+    disp_drv.set_px_cb = disp_driver_set_px;
+    disp_drv.buffer = &disp_buf;
+    lv_disp_drv_register(&disp_drv);
+
+    /* Create and start a periodic timer interrupt to call lv_tick_inc */
+    const esp_timer_create_args_t periodic_timer_args = {
+        .callback = &lvgl_tick_inc,
+        .name = "lvgl_tick"
+    };
+    esp_timer_handle_t periodic_timer;
+    ESP_ERROR_CHECK(esp_timer_create(&periodic_timer_args, &periodic_timer));
+    ESP_ERROR_CHECK(esp_timer_start_periodic(periodic_timer, LV_TICK_PERIOD_MS * 1000));
+
+    /* Create a Hellow World label on the currently active screen */
+    lv_obj_t *scr = lv_disp_get_scr_act(NULL);
+    lv_obj_t *label1 =  lv_label_create(scr, NULL);
+    lv_label_set_text(label1, "Hello\nworld");
+
+    /* Align the Label to the center
+     * NULL means align on parent (which is the screen now)
+     * 0, 0 at the end means an x, y offset after alignment*/
+    lv_obj_align(label1, NULL, LV_ALIGN_CENTER, 0, 0);
+
+    while (1) {
+        vTaskDelay(pdMS_TO_TICKS(10));
+        lv_task_handler();
+    }
+    free(buf1);
+}
+
+static void lvgl_tick_inc(void *arg) {
+    (void) arg;
+    lv_tick_inc(LV_TICK_PERIOD_MS);
+}

examples/wemos_lolin_oled/hello_world/sdkconfig.defaults

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+CONFIG_LV_HOR_RES_MAX=128
+CONFIG_LV_VER_RES_MAX=64
+CONFIG_LV_COLOR_DEPTH_1=y
+CONFIG_LV_THEME_MONO=y
+
+CONFIG_LV_PREDEFINED_DISPLAY_WEMOS_LOLIN=y
+
+CONFIG_I2C_MANAGER_0_ENABLED=y
+CONFIG_I2C_MANAGER_0_SDA=5
+CONFIG_I2C_MANAGER_0_SCL=4
+CONFIG_I2C_MANAGER_0_FREQ_HZ=100000