src/mainboard/google/brya/variants/brya4es/Makefile.inc - coreboot - Gitiles

 bootblock-y += gpio.c
 romstage-y += gpio.c
 ramstage-$(CONFIG_FW_CONFIG) += fw_config.c
 ramstage-$(CONFIG_FW_CONFIG) += variant.c
 ramstage-y += gpio.c
 ramstage-y += ramstage.c
	bootblock-y += gpio.c
	romstage-y += gpio.c
	ramstage-$(CONFIG_FW_CONFIG) += fw_config.c
	ramstage-$(CONFIG_FW_CONFIG) += variant.c
	ramstage-y += gpio.c
	ramstage-y += ramstage.c