rp2: Rework board variant support to require mpconfigvariant file.

Following how the board variants now work in the esp32 port.

Signed-off-by: Damien George <damien@micropython.org>

ports/rp2/CMakeLists.txt

@@ -38,10 +38,22 @@ if(NOT EXISTS ${MICROPY_BOARD_DIR}/mpconfigboard.cmake)
     message(FATAL_ERROR "Invalid MICROPY_BOARD specified: ${MICROPY_BOARD}")
 endif()
 
+# If a board variant is specified, check that it exists.
+if(MICROPY_BOARD_VARIANT)
+    if(NOT EXISTS ${MICROPY_BOARD_DIR}/mpconfigvariant_${MICROPY_BOARD_VARIANT}.cmake)
+        message(FATAL_ERROR "Invalid MICROPY_BOARD_VARIANT specified: ${MICROPY_BOARD_VARIANT}")
+    endif()
+endif()
+
 set(MICROPY_USER_FROZEN_MANIFEST ${MICROPY_FROZEN_MANIFEST})
 
 # Include board config, it may override MICROPY_FROZEN_MANIFEST
 include(${MICROPY_BOARD_DIR}/mpconfigboard.cmake)
+if(NOT MICROPY_BOARD_VARIANT)
+    include(${MICROPY_BOARD_DIR}/mpconfigvariant.cmake OPTIONAL)
+else()
+    include(${MICROPY_BOARD_DIR}/mpconfigvariant_${MICROPY_BOARD_VARIANT}.cmake)
+endif()
 
 # Set the PICO_BOARD if it's not already set (allow a board to override it).
 if(NOT PICO_BOARD)

ports/rp2/boards/WEACTSTUDIO/mpconfigboard.cmake

@@ -6,19 +6,3 @@ list(APPEND PICO_BOARD_HEADER_DIRS ${MICROPY_BOARD_DIR})
 
 # Freeze board.py
 set(MICROPY_FROZEN_MANIFEST ${MICROPY_BOARD_DIR}/manifest.py)
-
-# Select the 16MB variant as the default
-set(PICO_BOARD "weactstudio_16MiB")
-
-# Provide different variants for the downloads page
-if(MICROPY_BOARD_VARIANT STREQUAL "FLASH_2M")
-    set(PICO_BOARD "weactstudio_2MiB")
-endif()
-
-if(MICROPY_BOARD_VARIANT STREQUAL "FLASH_4M")
-    set(PICO_BOARD "weactstudio_4MiB")
-endif()
-
-if(MICROPY_BOARD_VARIANT STREQUAL "FLASH_8M")
-    set(PICO_BOARD "weactstudio_8MiB")
-endif()

ports/rp2/boards/WEACTSTUDIO/mpconfigvariant.cmake

@@ -0,0 +1 @@
+set(PICO_BOARD "weactstudio_16MiB")

ports/rp2/boards/WEACTSTUDIO/mpconfigvariant_FLASH_2M.cmake

@@ -0,0 +1 @@
+set(PICO_BOARD "weactstudio_2MiB")

ports/rp2/boards/WEACTSTUDIO/mpconfigvariant_FLASH_4M.cmake

@@ -0,0 +1 @@
+set(PICO_BOARD "weactstudio_4MiB")

ports/rp2/boards/WEACTSTUDIO/mpconfigvariant_FLASH_8M.cmake

@@ -0,0 +1 @@
+set(PICO_BOARD "weactstudio_8MiB")