2 files changed, 13 insertions, 0 deletions
diff --git a/shared-bindings/microcontroller/Pin.c b/shared-bindings/microcontroller/Pin.c
index 765e602e5..d5b971ae5 100644
--- a/shared-bindings/microcontroller/Pin.c
+++ b/shared-bindings/microcontroller/Pin.c
@@ -101,6 +101,18 @@ mcu_pin_obj_t *validate_obj_is_free_pin(mp_obj_t obj) {
     return pin;
 }
 
+// Validate every element in the list to be a free pin.
+void validate_list_is_free_pins(qstr what, mcu_pin_obj_t **pins_out, mp_int_t max_pins, mp_obj_t seq, uint8_t *count_out) {
+    mp_int_t len = MP_OBJ_SMALL_INT_VALUE(mp_obj_len(seq));
+    if (len > max_pins) {
+        mp_raise_ValueError_varg(translate("At most %d %q may be specified (not %d)"), max_pins, what, len);
+    }
+    *count_out = len;
+    for (mp_int_t i=0; i<len; i++) {
+        pins_out[i] = validate_obj_is_free_pin(mp_obj_subscr(seq, MP_OBJ_NEW_SMALL_INT(i), MP_OBJ_SENTINEL));
+    }
+}
+
 // Validate that the obj is a free pin or None. Return an mcu_pin_obj_t* or NULL, correspondingly.
 mcu_pin_obj_t *validate_obj_is_free_pin_or_none(mp_obj_t obj) {
     if (obj == mp_const_none) {
diff --git a/shared-bindings/microcontroller/Pin.h b/shared-bindings/microcontroller/Pin.h
index bb5256b55..f6659db7d 100644
--- a/shared-bindings/microcontroller/Pin.h
+++ b/shared-bindings/microcontroller/Pin.h
@@ -37,6 +37,7 @@ mcu_pin_obj_t *validate_obj_is_pin(mp_obj_t obj);
 mcu_pin_obj_t *validate_obj_is_pin_or_none(mp_obj_t obj);
 mcu_pin_obj_t *validate_obj_is_free_pin(mp_obj_t obj);
 mcu_pin_obj_t *validate_obj_is_free_pin_or_none(mp_obj_t obj);
+void validate_list_is_free_pins(qstr what, mcu_pin_obj_t **pins_out, mp_int_t max_pins, mp_obj_t seq, uint8_t *count_out);
 
 void assert_pin_free(const mcu_pin_obj_t* pin);