diff --git a/unix/modtime.c b/unix/modtime.c
index 2b6372d3a0..33cf1cdab8 100644
--- a/unix/modtime.c
+++ b/unix/modtime.c
@@ -77,22 +77,6 @@ STATIC mp_obj_t mod_time_time(void) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_time_time_obj, mod_time_time);
 
-STATIC mp_obj_t mod_time_ticks_us(void) {
-    struct timeval tv;
-    gettimeofday(&tv, NULL);
-    mp_uint_t us = tv.tv_sec * 1000000 + tv.tv_usec;
-    return MP_OBJ_NEW_SMALL_INT(us & MP_SMALL_INT_POSITIVE_MASK);
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_time_ticks_us_obj, mod_time_ticks_us);
-
-STATIC mp_obj_t mod_time_ticks_ms(void) {
-    struct timeval tv;
-    gettimeofday(&tv, NULL);
-    mp_uint_t ms = tv.tv_sec * 1000 + tv.tv_usec / 1000;
-    return MP_OBJ_NEW_SMALL_INT(ms & MP_SMALL_INT_POSITIVE_MASK);
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_time_ticks_ms_obj, mod_time_ticks_ms);
-
 // Note: this is deprecated since CPy3.3, but pystone still uses it.
 STATIC mp_obj_t mod_time_clock(void) {
 #if MICROPY_PY_BUILTINS_FLOAT
@@ -143,22 +127,6 @@ STATIC mp_obj_t mod_time_sleep(mp_obj_t arg) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_time_sleep_obj, mod_time_sleep);
 
-STATIC mp_obj_t mod_time_sleep_ms(mp_obj_t arg) {
-    MP_THREAD_GIL_EXIT();
-    usleep(mp_obj_get_int(arg) * 1000);
-    MP_THREAD_GIL_ENTER();
-    return mp_const_none;
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_time_sleep_ms_obj, mod_time_sleep_ms);
-
-STATIC mp_obj_t mod_time_sleep_us(mp_obj_t arg) {
-    MP_THREAD_GIL_EXIT();
-    usleep(mp_obj_get_int(arg));
-    MP_THREAD_GIL_ENTER();
-    return mp_const_none;
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_time_sleep_us_obj, mod_time_sleep_us);
-
 STATIC mp_obj_t mod_time_strftime(size_t n_args, const mp_obj_t *args) {
     time_t t;
     if (n_args == 1) {
@@ -179,11 +147,11 @@ STATIC const mp_rom_map_elem_t mp_module_time_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_utime) },
     { MP_ROM_QSTR(MP_QSTR_clock), MP_ROM_PTR(&mod_time_clock_obj) },
     { MP_ROM_QSTR(MP_QSTR_sleep), MP_ROM_PTR(&mod_time_sleep_obj) },
-    { MP_ROM_QSTR(MP_QSTR_sleep_ms), MP_ROM_PTR(&mod_time_sleep_ms_obj) },
-    { MP_ROM_QSTR(MP_QSTR_sleep_us), MP_ROM_PTR(&mod_time_sleep_us_obj) },
+    { MP_ROM_QSTR(MP_QSTR_sleep_ms), MP_ROM_PTR(&mp_utime_sleep_ms_obj) },
+    { MP_ROM_QSTR(MP_QSTR_sleep_us), MP_ROM_PTR(&mp_utime_sleep_us_obj) },
     { MP_ROM_QSTR(MP_QSTR_time), MP_ROM_PTR(&mod_time_time_obj) },
-    { MP_ROM_QSTR(MP_QSTR_ticks_ms), MP_ROM_PTR(&mod_time_ticks_ms_obj) },
-    { MP_ROM_QSTR(MP_QSTR_ticks_us), MP_ROM_PTR(&mod_time_ticks_us_obj) },
+    { MP_ROM_QSTR(MP_QSTR_ticks_ms), MP_ROM_PTR(&mp_utime_ticks_ms_obj) },
+    { MP_ROM_QSTR(MP_QSTR_ticks_us), MP_ROM_PTR(&mp_utime_ticks_us_obj) },
     { MP_ROM_QSTR(MP_QSTR_ticks_diff), MP_ROM_PTR(&mp_utime_ticks_diff_obj) },
     { MP_ROM_QSTR(MP_QSTR_strftime), MP_ROM_PTR(&mod_time_strftime_obj) },
 };