diff --git a/src/atsam/spi.c b/src/atsam/spi.c
index b6e7a1a3..cb186425 100644
--- a/src/atsam/spi.c
+++ b/src/atsam/spi.c
@@ -31,28 +31,28 @@ struct spi_info {
 DECL_ENUMERATION("spi_bus", "spi0", 0);
 DECL_ENUMERATION_RANGE("spi_bus", "usart0", 1, 3);
 DECL_CONSTANT_STR("BUS_PINS_spi0", "PA25,PA26,PA27");
-DECL_CONSTANT_STR("BUS_PINS_usart0", "PA10,PA11,PA17");
-DECL_CONSTANT_STR("BUS_PINS_usart1", "PA12,PA13,PA16");
-DECL_CONSTANT_STR("BUS_PINS_usart2", "PB21,PB20,PB24");
+DECL_CONSTANT_STR("BUS_PINS_usart0@spi_bus", "[_],PA10,PA11,PA17");
+DECL_CONSTANT_STR("BUS_PINS_usart1@spi_bus", "[_],PA12,PA13,PA16");
+DECL_CONSTANT_STR("BUS_PINS_usart2@spi_bus", "[_],PB21,PB20,PB24");
 #elif CONFIG_MACH_SAM4S
 DECL_ENUMERATION("spi_bus", "spi", 0);
 DECL_ENUMERATION_RANGE("spi_bus", "usart0", 1, 2);
 DECL_CONSTANT_STR("BUS_PINS_spi", "PA12,PA13,PA14");
-DECL_CONSTANT_STR("BUS_PINS_usart0", "PA5,PA6,PA2");
-DECL_CONSTANT_STR("BUS_PINS_usart1", "PA21,PA22,PA23");
+DECL_CONSTANT_STR("BUS_PINS_usart0@spi_bus", "[_],PA5,PA6,PA2");
+DECL_CONSTANT_STR("BUS_PINS_usart1@spi_bus", "[_],PA21,PA22,PA23");
 #elif CONFIG_MACH_SAM4E
 DECL_ENUMERATION("spi_bus", "spi", 0);
 DECL_ENUMERATION_RANGE("spi_bus", "usart0", 1, 2);
 DECL_CONSTANT_STR("BUS_PINS_spi", "PA12,PA13,PA14");
-DECL_CONSTANT_STR("BUS_PINS_usart0", "PB0,PB1,PB13");
-DECL_CONSTANT_STR("BUS_PINS_usart1", "PA21,PA22,PA23");
+DECL_CONSTANT_STR("BUS_PINS_usart0@spi_bus", "[_],PB0,PB1,PB13");
+DECL_CONSTANT_STR("BUS_PINS_usart1@spi_bus", "[_],PA21,PA22,PA23");
 #elif CONFIG_MACH_SAME70
 DECL_ENUMERATION_RANGE("spi_bus", "spi0", 0, 2);
 DECL_ENUMERATION_RANGE("spi_bus", "usart0", 2, 3);
 DECL_CONSTANT_STR("BUS_PINS_spi0", "PD20,PD21,PD22");
-DECL_CONSTANT_STR("BUS_PINS_usart0", "PB0,PB1,PB13");
-DECL_CONSTANT_STR("BUS_PINS_usart1", "PA21,PB4,PA23");
-DECL_CONSTANT_STR("BUS_PINS_usart2", "PD15,PD16,PD17");
+DECL_CONSTANT_STR("BUS_PINS_usart0@spi_bus", "[_],PB0,PB1,PB13");
+DECL_CONSTANT_STR("BUS_PINS_usart1@spi_bus", "[_],PA21,PB4,PA23");
+DECL_CONSTANT_STR("BUS_PINS_usart2@spi_bus", "[_],PD15,PD16,PD17");
 #endif
 
 static const struct spi_info spi_bus[] = {