qmk_firmware/keyboards/massdrop/ctrl/rules.mk

# project specific files
SRC += config_led.c

#For platform and packs
ARM_ATSAM = SAMD51J18A
MCU = cortex-m4

# Build Options
#   comment out to disable the options.
#
BOOTMAGIC_ENABLE = no       # Enable Bootmagic Lite
MOUSEKEY_ENABLE = no        # Mouse keys
EXTRAKEY_ENABLE = yes       # Audio control and System control
CONSOLE_ENABLE = no         # Console for debug
COMMAND_ENABLE = no         # Commands for debug and configuration
# Do not enable SLEEP_LED_ENABLE. it uses the same timer as BACKLIGHT_ENABLE
SLEEP_LED_ENABLE = no       # Breathing sleep LED during USB suspend
# if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
NKRO_ENABLE = yes           # USB Nkey Rollover
BACKLIGHT_ENABLE = no       # Enable keyboard backlight functionality on B7 by default
RGBLIGHT_ENABLE = no        # Enable keyboard RGB underglow
UNICODE_ENABLE = no         # Unicode
BLUETOOTH_ENABLE = no       # Enable Bluetooth with the Adafruit EZ-Key HID
AUDIO_ENABLE = no           # Audio output on port C6
VIRTSER_ENABLE = no         # USB Serial Driver
RAW_ENABLE = no             # Raw device
AUTO_SHIFT_ENABLE = no      # Auto Shift

# Custom RGB matrix handling
RGB_MATRIX_ENABLE = yes
RGB_MATRIX_DRIVER = custom