Initial Support for RP2040 platform (#3284)

Co-authored-by: Paulus Schoutsen <balloob@gmail.com>

platformio.ini

@@ -146,6 +146,24 @@ build_flags =
     -DUSE_ESP32_FRAMEWORK_ESP_IDF
 extra_scripts = post:esphome/components/esp32/post_build.py.script
 
+; These are common settings for the RP2040 using Arduino.
+[common:rp2040-arduino]
+extends = common:arduino
+board_build.core = earlephilhower
+board_build.filesystem_size = 0.5m
+
+platform = https://github.com/maxgerhardt/platform-raspberrypi.git
+platform_packages =
+    earlephilhower/framework-arduinopico @ ~1.20400.0
+
+framework = arduino
+lib_deps =
+    ${common:arduino.lib_deps}
+build_flags =
+    ${common:arduino.build_flags}
+    -DUSE_RP2040
+    -DUSE_RP2040_FRAMEWORK_ARDUINO
+
 ; All the actual environments are defined below.
 [env:esp8266-arduino]
 extends = common:esp8266-arduino
@@ -222,3 +240,10 @@ board_build.esp-idf.sdkconfig_path = .temp/sdkconfig-esp32s2-idf-tidy
 build_flags =
     ${common:esp32-idf.build_flags}
     ${flags:clangtidy.build_flags}
+
+[env:rp2040-pico-arduino]
+extends = common:rp2040-arduino
+board = pico
+build_flags =
+    ${common:rp2040-arduino.build_flags}
+    ${flags:runtime.build_flags}