sys/evtimer: introduce ZTIMER_MSEC as timer backend

Makefile.dep

@@ -737,10 +737,6 @@ ifneq (,$(filter phydat,$(USEMODULE)))
   USEMODULE += fmt
 endif
 
-ifneq (,$(filter evtimer,$(USEMODULE)))
-  USEMODULE += xtimer
-endif
-
 ifneq (,$(filter evtimer_mbox,$(USEMODULE)))
   USEMODULE += evtimer
   USEMODULE += core_mbox
@@ -1067,6 +1063,13 @@ ifneq (,$(filter ztimer% %ztimer,$(USEMODULE)))
   include $(RIOTBASE)/sys/ztimer/Makefile.dep
 endif
 
+# handle evtimer's deps. Needs to be done *after* ztimer
+ifneq (,$(filter evtimer,$(USEMODULE)))
+  ifeq (,$(filter evtimer_on_ztimer,$(USEMODULE)))
+    USEMODULE += xtimer
+  endif
+endif
+
 # handle xtimer's deps. Needs to be done *after* ztimer
 ifneq (,$(filter xtimer,$(USEMODULE)))
   ifeq (,$(filter ztimer_xtimer_compat,$(USEMODULE)))

makefiles/pseudomodules.inc.mk

@@ -21,6 +21,7 @@ PSEUDOMODULES += dhcpv6_%
 PSEUDOMODULES += ecc_%
 PSEUDOMODULES += event_%
 PSEUDOMODULES += evtimer_mbox
+PSEUDOMODULES += evtimer_on_ztimer
 PSEUDOMODULES += fmt_%
 PSEUDOMODULES += gnrc_dhcpv6_%
 PSEUDOMODULES += gnrc_ipv6_default

sys/evtimer/evtimer.c

@@ -24,7 +24,6 @@
 
 #include "div.h"
 #include "irq.h"
-#include "xtimer.h"
 
 #include "evtimer.h"
 
@@ -91,27 +90,57 @@ static void _del_event_from_list(evtimer_t *evtimer, evtimer_event_t *event)
     }
 }
 
-static void _set_timer(xtimer_t *timer, uint32_t offset_ms)
+static void _set_timer(evtimer_t *evtimer)
 {
-    uint64_t offset_us = (uint64_t)offset_ms * US_PER_MS;
+    evtimer_event_t *next_event = evtimer->events;
+
+#if IS_USED(MODULE_EVTIMER_ON_ZTIMER)
+    evtimer->base = ztimer_now(ZTIMER_MSEC);
+
+    DEBUG("evtimer: now=%" PRIu32 " ms setting ztimer to %" PRIu32 " ms\n",
+          evtimer->base, next_event->offset);
+
+    ztimer_set(ZTIMER_MSEC, &evtimer->timer, next_event->offset);
+#else
+    uint64_t offset_us = (uint64_t)next_event->offset * US_PER_MS;
 
     DEBUG("evtimer: now=%" PRIu32 " us setting xtimer to %" PRIu32 ":%" PRIu32 " us\n",
           xtimer_now_usec(), (uint32_t)(offset_us >> 32), (uint32_t)(offset_us));
 
-    xtimer_set64(timer, offset_us);
+    xtimer_set64(&evtimer->timer, offset_us);
+#endif
 }
 
 static void _update_timer(evtimer_t *evtimer)
 {
     if (evtimer->events) {
-        evtimer_event_t *event = evtimer->events;
+        _set_timer(evtimer);
-        _set_timer(&evtimer->timer, event->offset);
     }
     else {
+#if IS_USED(MODULE_EVTIMER_ON_ZTIMER)
+        ztimer_remove(ZTIMER_MSEC, &evtimer->timer);
+#else
         xtimer_remove(&evtimer->timer);
+#endif
     }
 }
 
+#if IS_USED(MODULE_EVTIMER_ON_ZTIMER)
+static void _update_head_offset(evtimer_t *evtimer)
+{
+    if (evtimer->events) {
+        evtimer_event_t *event = evtimer->events;
+        uint32_t now = ztimer_now(ZTIMER_MSEC);
+        uint32_t elapsed = now - evtimer->base;
+        if (elapsed > event->offset) {
+            event->offset = 0;
+        } else {
+            event->offset -= elapsed;
+        }
+        evtimer->base = now;
+    }
+}
+#else /* IS_USED(MODULE_EVTIMER_ON_ZTIMER) */
 static uint32_t _get_offset(xtimer_t *timer)
 {
     uint64_t left = xtimer_left_usec(timer);
@@ -127,6 +156,7 @@ static void _update_head_offset(evtimer_t *evtimer)
         DEBUG("evtimer: _update_head_offset(): new head offset %" PRIu32 "\n", event->offset);
     }
 }
+#endif /* !IS_USED(MODULE_EVTIMER_ON_ZTIMER) */
 
 void evtimer_add(evtimer_t *evtimer, evtimer_event_t *event)
 {
@@ -137,7 +167,7 @@ void evtimer_add(evtimer_t *evtimer, evtimer_event_t *event)
     _update_head_offset(evtimer);
     _add_event_to_list(evtimer, event);
     if (evtimer->events == event) {
-        _set_timer(&evtimer->timer, event->offset);
+        _set_timer(evtimer);
     }
     irq_restore(state);
     if (sched_context_switch_request) {

sys/include/evtimer.h

@@ -44,8 +44,14 @@
 #define EVTIMER_H
 
 #include <stdint.h>
+#include "kernel_defines.h"
 
+#if IS_USED(MODULE_EVTIMER_ON_ZTIMER)
+#include "ztimer.h"
+#else
 #include "xtimer.h"
+#endif
+
 #include "timex.h"
 
 #ifdef __cplusplus
@@ -69,7 +75,12 @@ typedef void(*evtimer_callback_t)(evtimer_event_t* event);
  * @brief   Event timer
  */
 typedef struct {
+#if IS_USED(MODULE_EVTIMER_ON_ZTIMER)
+    ztimer_t timer;                 /**< Timer */
+    uint32_t base;                  /**< Absolute time the first event is built on */
+#else
     xtimer_t timer;                 /**< Timer */
+#endif
     evtimer_callback_t callback;    /**< Handler function for this evtimer's
                                          event type */
     evtimer_event_t *events;        /**< Event queue */
@@ -111,7 +122,11 @@ void evtimer_print(const evtimer_t *evtimer);
  */
 static inline uint32_t evtimer_now_msec(void)
 {
+#if IS_USED(MODULE_EVTIMER_ON_ZTIMER)
+    return ztimer_now(ZTIMER_MSEC);
+#else
     return xtimer_now_usec64() / US_PER_MS;
+#endif
 }
 
 /**
@@ -119,7 +134,11 @@ static inline uint32_t evtimer_now_msec(void)
  */
 static inline uint32_t evtimer_now_min(void)
 {
+#if IS_USED(MODULE_EVTIMER_ON_ZTIMER)
+    return ztimer_now(ZTIMER_MSEC) / (MS_PER_SEC * SEC_PER_MIN);
+#else
     return xtimer_now_usec64() / (US_PER_SEC * SEC_PER_MIN);
+#endif
 }
 
 #ifdef __cplusplus

sys/ztimer/Makefile.dep

@@ -30,6 +30,9 @@ ifneq (,$(filter ztimer_periph_timer,$(USEMODULE)))
       USEMODULE += xtimer_on_ztimer
     endif
   endif
+  ifneq (,$(filter evtimer,$(USEMODULE)))
+    USEMODULE += evtimer_on_ztimer
+  endif
 endif
 
 # make xtimer use ztimer_usec as low level timer
@@ -37,6 +40,12 @@ ifneq (,$(filter xtimer_on_ztimer,$(USEMODULE)))
   USEMODULE += ztimer_usec
 endif
 
+# make evtimer use ztimer_msec as low level timer
+ifneq (,$(filter evtimer_on_ztimer,$(USEMODULE)))
+  USEMODULE += ztimer_msec
+  USEMODULE += ztimer_now64
+endif
+
 # "ztimer_xtimer_compat" is a wrapper of the xtimer API on ztimer_used
 # (it is currently incomplete). Unless doing testing, use "xtimer_on_ztimer".
 ifneq (,$(filter ztimer_xtimer_compat,$(USEMODULE)))