split out lvgl task into its own component

src/main/CMakeLists.txt

@@ -1,5 +1,5 @@
 idf_component_register(
   SRCS "main.cpp" "app_console.cpp"
   INCLUDE_DIRS "."
-  REQUIRES "audio" "drivers" "dev_console" "drivers")
+  REQUIRES "audio" "drivers" "dev_console" "ui")
 target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})

src/main/main.cpp

@@ -6,8 +6,6 @@
 #include <cstdint>
 #include <memory>
 
-#include "core/lv_disp.h"
-#include "core/lv_obj_pos.h"
 #include "driver/gpio.h"
 #include "driver/i2c.h"
 #include "driver/sdspi_host.h"
@@ -16,17 +14,10 @@
 #include "esp_freertos_hooks.h"
 #include "esp_intr_alloc.h"
 #include "esp_log.h"
-#include "font/lv_font.h"
 #include "freertos/portmacro.h"
 #include "freertos/projdefs.h"
-#include "freertos/timers.h"
 #include "hal/gpio_types.h"
 #include "hal/spi_types.h"
-#include "lvgl/lvgl.h"
-#include "misc/lv_color.h"
-#include "misc/lv_style.h"
-#include "misc/lv_timer.h"
-#include "widgets/lv_label.h"
 
 #include "app_console.hpp"
 #include "audio_playback.hpp"
@@ -36,64 +27,13 @@
 #include "display_init.hpp"
 #include "gpio_expander.hpp"
 #include "i2c.hpp"
+#include "lvgl_task.hpp"
 #include "spi.hpp"
 #include "storage.hpp"
 #include "touchwheel.hpp"
 
 static const char* TAG = "MAIN";
 
-auto tick_hook(TimerHandle_t xTimer) -> void {
-  lv_tick_inc(1);
-}
-
-static const size_t kLvglStackSize = 8 * 1024;
-static StaticTask_t sLvglTaskBuffer = {};
-static StackType_t sLvglStack[kLvglStackSize] = {0};
-
-struct LvglArgs {
-  drivers::GpioExpander* gpio_expander;
-};
-
-extern "C" void lvgl_main(void* voidArgs) {
-  ESP_LOGI(TAG, "starting LVGL task");
-  LvglArgs* args = (LvglArgs*)voidArgs;
-  drivers::GpioExpander* gpio_expander = args->gpio_expander;
-
-  // Dispose of the args now that we've gotten everything out of them.
-  delete args;
-
-  ESP_LOGI(TAG, "init lvgl");
-  lv_init();
-
-  // LVGL has been initialised, so we can now start reporting ticks to it.
-  xTimerCreate("lv_tick", pdMS_TO_TICKS(1), pdTRUE, NULL, &tick_hook);
-
-  ESP_LOGI(TAG, "init display");
-  std::unique_ptr<drivers::Display> display =
-      drivers::Display::create(gpio_expander, drivers::displays::kST7735R);
-
-  lv_style_t style;
-  lv_style_init(&style);
-  lv_style_set_text_color(&style, LV_COLOR_MAKE(0xFF, 0, 0));
-  // TODO: find a nice bitmap font for this display size and density.
-  // lv_style_set_text_font(&style, &lv_font_montserrat_24);
-
-  auto label = lv_label_create(NULL);
-  lv_label_set_text(label, "COLOURS!!");
-  lv_obj_add_style(label, &style, 0);
-
-  lv_obj_center(label);
-  lv_scr_load(label);
-
-  while (1) {
-    lv_timer_handler();
-    vTaskDelay(pdMS_TO_TICKS(10));
-  }
-
-  // TODO: break from the loop to kill this task, so that we can do our RAII
-  // cleanup, unregister our tick callback and so on.
-}
-
 extern "C" void app_main(void) {
   ESP_LOGI(TAG, "Initialising peripherals");
 
@@ -129,11 +69,9 @@ extern "C" void app_main(void) {
   std::unique_ptr<drivers::TouchWheel> touchwheel =
       std::make_unique<drivers::TouchWheel>();
 
-  LvglArgs* lvglArgs = (LvglArgs*)calloc(1, sizeof(LvglArgs));
+  std::atomic<bool> lvgl_quit;
-  lvglArgs->gpio_expander = expander;
+  TaskHandle_t lvgl_task_handle;
-  xTaskCreateStaticPinnedToCore(&lvgl_main, "LVGL", kLvglStackSize,
+  ui::StartLvgl(expander, &lvgl_quit, &lvgl_task_handle);
-                                (void*)lvglArgs, 1, sLvglStack,
-                                &sLvglTaskBuffer, 1);
 
   std::unique_ptr<audio::AudioPlayback> playback;
   if (storage) {

src/ui/CMakeLists.txt

@@ -0,0 +1,5 @@
+idf_component_register(
+  SRCS "lvgl_task.cpp"
+  INCLUDE_DIRS "include"
+  REQUIRES "drivers")
+target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})

src/ui/include/lvgl_task.hpp

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <atomic>
+#include <cstdbool>
+
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "gpio_expander.hpp"
+
+namespace ui {
+
+auto StartLvgl(drivers::GpioExpander* gpios,
+               std::atomic<bool>* quit,
+               TaskHandle_t* handle) -> bool;
+
+}  // namespace ui

src/ui/lvgl_task.cpp

@@ -0,0 +1,111 @@
+#include "lvgl_task.hpp"
+
+#include <dirent.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#include <cstddef>
+#include <cstdint>
+#include <memory>
+
+#include "core/lv_disp.h"
+#include "core/lv_obj.h"
+#include "core/lv_obj_pos.h"
+#include "core/lv_obj_tree.h"
+#include "esp_log.h"
+#include "font/lv_font.h"
+#include "freertos/portmacro.h"
+#include "freertos/projdefs.h"
+#include "freertos/timers.h"
+#include "hal/gpio_types.h"
+#include "hal/spi_types.h"
+#include "lvgl/lvgl.h"
+#include "misc/lv_color.h"
+#include "misc/lv_style.h"
+#include "misc/lv_timer.h"
+#include "widgets/lv_label.h"
+
+#include "display.hpp"
+#include "display_init.hpp"
+#include "gpio_expander.hpp"
+
+namespace ui {
+
+static const char* kTag = "lv_task";
+
+auto tick_hook(TimerHandle_t xTimer) -> void {
+  lv_tick_inc(1);
+}
+
+struct LvglArgs {
+  drivers::GpioExpander* gpio_expander;
+  std::atomic<bool>* quit;
+};
+
+void LvglMain(void* voidArgs) {
+  LvglArgs* args = (LvglArgs*)voidArgs;
+  drivers::GpioExpander* gpio_expander = args->gpio_expander;
+  std::atomic<bool>* quit = args->quit;
+
+  // Dispose of the args now that we've gotten everything out of them.
+  delete args;
+
+  {
+    ESP_LOGI(kTag, "init lvgl");
+    lv_init();
+
+    // LVGL has been initialised, so we can now start reporting ticks to it.
+    TimerHandle_t tick_timer =
+        xTimerCreate("lv_tick", pdMS_TO_TICKS(1), pdTRUE, NULL, &tick_hook);
+
+    ESP_LOGI(kTag, "init display");
+    std::unique_ptr<drivers::Display> display =
+        drivers::Display::create(gpio_expander, drivers::displays::kST7735R);
+
+    lv_style_t style;
+    lv_style_init(&style);
+    lv_style_set_text_color(&style, LV_COLOR_MAKE(0xFF, 0, 0));
+    // TODO: find a nice bitmap font for this display size and density.
+    // lv_style_set_text_font(&style, &lv_font_montserrat_24);
+
+    auto label = lv_label_create(NULL);
+    lv_label_set_text(label, "COLOURS!!");
+    lv_obj_add_style(label, &style, 0);
+
+    lv_obj_center(label);
+    lv_scr_load(label);
+
+    while (!quit->load()) {
+      lv_timer_handler();
+      vTaskDelay(pdMS_TO_TICKS(10));
+    }
+
+    // TODO(robin? daniel?): De-init the UI stack here.
+    lv_obj_del(label);
+    lv_style_reset(&style);
+
+    xTimerDelete(tick_timer, portMAX_DELAY);
+
+    lv_deinit();
+  }
+
+  vTaskDelete(NULL);
+}
+
+static const size_t kLvglStackSize = 8 * 1024;
+static StaticTask_t sLvglTaskBuffer = {};
+static StackType_t sLvglStack[kLvglStackSize] = {0};
+
+auto StartLvgl(drivers::GpioExpander* gpios,
+               std::atomic<bool>* quit,
+               TaskHandle_t* handle) -> bool {
+  LvglArgs* args = new LvglArgs();
+  args->gpio_expander = gpios;
+  args->quit = quit;
+
+  return xTaskCreateStaticPinnedToCore(&LvglMain, "LVGL", kLvglStackSize,
+                                       reinterpret_cast<void*>(args), 1,
+                                       sLvglStack, &sLvglTaskBuffer, 1);
+}
+
+}  // namespace ui