Split driver-y things into a separate component

CMakeLists.txt

@@ -1,16 +1,25 @@
 # 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 3.8)
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 include($ENV{ADF_PATH}/CMakeLists.txt)
+
+# Build only the subset of components that we actually depend on.
+set(COMPONENTS "")
+
+# External dependencies
 list(APPEND EXTRA_COMPONENT_DIRS "lib/result")
 list(APPEND EXTRA_COMPONENT_DIRS "lib/lvgl")
 
+# Project components
+list(APPEND EXTRA_COMPONENT_DIRS "src/")
+
 include($ENV{IDF_PATH}/tools/cmake/project.cmake)
 project(gay-ipod-fw)
 
+# Extra build flags that should apply to the entire build. This should mostly
+# just be used to setting flags that our external dependencies requires.
+# Otherwise, prefer adding per-component build flags to keep things neat.
 idf_build_set_property(COMPILE_OPTIONS "-DRESULT_DISABLE_EXCEPTIONS -DLV_CONF_INCLUDE_SIMPLE" APPEND)

main/CMakeLists.txt

@@ -1,5 +0,0 @@
-idf_component_register(
-  SRCS "gay-ipod-fw.cpp" "dac.cpp" "gpio-expander.cpp" "battery.cpp" "storage.cpp"
-  "i2c.cpp" "playback.cpp" "display.cpp" "display-init.cpp" 
-  INCLUDE_DIRS "."
-  REQUIRES "esp_adc_cal" "fatfs" "audio_pipeline" "audio_stream" "result" "lvgl")

src/drivers/CMakeLists.txt

@@ -0,0 +1,5 @@
+idf_component_register(
+  SRCS "dac.cpp" "gpio-expander.cpp" "battery.cpp" "storage.cpp" "i2c.cpp"
+  "playback.cpp" "display.cpp" "display-init.cpp" 
+  INCLUDE_DIRS "include"
+  REQUIRES "esp_adc_cal" "fatfs" "audio_pipeline" "audio_stream" "result" "lvgl")

src/main/CMakeLists.txt

@@ -0,0 +1,3 @@
+idf_component_register(
+  SRCS "main.cpp"
+  REQUIRES "drivers")