sys/ztimer: add auto_adjust module

boards/arduino-uno/include/board.h

@@ -19,6 +19,16 @@
 #ifndef BOARD_H
 #define BOARD_H
 
+/**
+ * @name    ztimer configuration values
+ *
+ * @note    Overrides arduino-atmega defaults
+ * @{
+ */
+#define CONFIG_ZTIMER_USEC_ADJUST_SET     (128)
+#define CONFIG_ZTIMER_USEC_ADJUST_SLEEP   (116)
+/** @} */
+
 #include "board_common.h"
 
 #ifdef __cplusplus

boards/atmega256rfr2-xpro/include/board.h

@@ -46,8 +46,8 @@ extern "C" {
  * @name    ztimer configuration values
  * @{
  */
-#define CONFIG_ZTIMER_USEC_ADJUST_SET     (128)
-#define CONFIG_ZTIMER_USEC_ADJUST_SLEEP   (128)
+#define CONFIG_ZTIMER_USEC_ADJUST_SET     (132)
+#define CONFIG_ZTIMER_USEC_ADJUST_SLEEP   (120)
 /** @} */
 
 /**

boards/common/arduino-atmega/include/board_common.h

@@ -113,8 +113,12 @@ extern "C" {
 #define CONFIG_ZTIMER_USEC_DEV      (TIMER_DEV(0))
 #define CONFIG_ZTIMER_USEC_FREQ     (250000LU)
 #define CONFIG_ZTIMER_USEC_WIDTH    (16)
-#define CONFIG_ZTIMER_USEC_ADJUST_SET     (124)
-#define CONFIG_ZTIMER_USEC_ADJUST_SLEEP   (120)
+#ifndef CONFIG_ZTIMER_USEC_ADJUST_SET
+#define CONFIG_ZTIMER_USEC_ADJUST_SET     (128)
+#endif
+#ifndef CONFIG_ZTIMER_USEC_ADJUST_SLEEP
+#define CONFIG_ZTIMER_USEC_ADJUST_SLEEP   (116)
+#endif
 /** @} */
 
 /**

dist/tools/doccheck/exclude_patterns

@@ -14707,3 +14707,5 @@ drivers/ft5x06/include/ft5x06_constants\.h:[0-9]+: warning: Member FT5X06_G_MODE
 drivers/ft5x06/include/ft5x06_constants\.h:[0-9]+: warning: Member FT5X06_G_MODE_INTERRUPT_POLLING \(macro definition\) of file ft5x06_constants\.h is not documented\.
 drivers/ft5x06/include/ft5x06_constants\.h:[0-9]+: warning: Member FT5X06_G_MODE_INTERRUPT_TRIGGER \(macro definition\) of file ft5x06_constants\.h is not documented\.
 drivers/ft5x06/include/ft5x06_params\.h:[0-9]+: warning: Member FT5X06_PARAM_TYPE \(macro definition\) of file ft5x06_params\.h is not documented\.
+boards/arduino\-uno/include/board\.h:[0-9]+: warning: Member CONFIG_ZTIMER_USEC_ADJUST_SET \(macro definition\) of file board\.h is not documented\.
+boards/arduino\-uno/include/board\.h:[0-9]+: warning: Member CONFIG_ZTIMER_USEC_ADJUST_SLEEP \(macro definition\) of file board\.h is not documented\.

makefiles/default_modules.deps.mk

@@ -6,6 +6,10 @@ ifneq (,$(filter auto_init_ztimer,$(USEMODULE)))
   USEMODULE += ztimer_init
 endif
 
+ifneq (,$(filter ztimer_auto_adjust,$(USEMODULE)))
+  USEMODULE += ztimer_overhead
+endif
+
 ifneq (,$(filter auto_init_saul,$(USEMODULE)))
   USEMODULE += saul_init_devs
 endif

makefiles/pseudomodules.inc.mk

@@ -258,6 +258,20 @@ PSEUDOMODULES += ztimer
 PSEUDOMODULES += ztimer_%
 PSEUDOMODULES += ztimer64_%
 
+## @defgroup pseudomodule_ztimer_auto_adjust ztimer_auto_adjust
+## @brief A module to set on init ztimer->adjust_sleep/adjust_set values
+##
+## When this module is active, then on init if no CONFIG_ZTIMER_USEC_ADJUST_%
+## values are set for the BOARD correction values adjust_sleep and adjust_set
+## will be calculated in set for the required clocks.
+##
+## Note that some BOARDs clocks require a startup time to get accuarate values,
+## a configurable @ref CONFIG_ZTIMER_AUTO_ADJUST_SETTLE value can be set for this.
+##
+## Alternatively CONFIG_ZTIMER_USEC_ADJUST_% values can be set in the BOARDs
+## configuration header board.h. These can be found out by running tests/ztimer_overhead
+PSEUDOMODULES += ztimer_auto_adjust
+
 # ztimer's main module is called "ztimer_core"
 NO_PSEUDOMODULES += ztimer_core
 NO_PSEUDOMODULES += netdev_ieee802154_submac

sys/include/ztimer/config.h

@@ -136,6 +136,41 @@ extern "C" {
 #  endif
 #endif
 
+/**
+ * @brief   An offset for ZTIMER_USEC allowing to compensate for the offset
+ *          of @ref ztimer_set(). It can be measured with @ref ztimer_overhead_set()
+ *
+ *          This value should be configured in the board.h.
+ *
+ */
+#ifndef CONFIG_ZTIMER_USEC_ADJUST_SET
+#define CONFIG_ZTIMER_USEC_ADJUST_SET     0
+#endif
+
+/**
+ * @brief   An offset for ZTIMER_USEC allowing to compentsate for the offset
+ *          of @ref ztimer_sleep().
+ *
+ * @note    As internally @ref ztimer_sleep() uses @ref ztimer_set()
+ *          @ref CONFIG_ZTIMER_USEC_ADJUST_SET should be tuned before.
+ *
+ *          This value should be configured in the board.h.
+ */
+#ifndef CONFIG_ZTIMER_USEC_ADJUST_SLEEP
+#define CONFIG_ZTIMER_USEC_ADJUST_SLEEP   0
+#endif
+
+/**
+ * @brief   Some MCUs clocks need some warm-up time during which timing is
+ *          inaccurate. This can be a hindrance when using the @ref
+ *          pseudomodule_ztimer_auto_adjust module.
+ *
+ * @warning This value will increase the boards start-up time
+ */
+#ifndef CONFIG_ZTIMER_AUTO_ADJUST_SETTLE
+#define CONFIG_ZTIMER_AUTO_ADJUST_SETTLE    0
+#endif
+
 #ifdef __cplusplus
 }
 #endif

sys/include/ztimer/overhead.h

@@ -31,17 +31,28 @@ extern "C" {
 #endif
 
 /**
- * @brief   Measure ztimer overhead
+ * @brief   Measure overhead for ztimer_set()
  *
- * This function can be used to measure the overhead incurred by ztimer.
+ * This function can be used to measure the overhead incurred by ztimer_set().
  * It will configure a callback to trigger after @p base ticks, then return the
  * number of ticks that have passed, minus @p base.
  *
  * @param[in]   clock   ztimer clock to operate on
  * @param[in]   base    base interval to use
  * @return  (time from ztimer_set() until callback) - base
  */
-int32_t ztimer_overhead(ztimer_clock_t *clock, uint32_t base);
+int32_t ztimer_overhead_set(ztimer_clock_t *clock, uint32_t base);
+
+/**
+ * @brief   Measure overhead for ztimer_sleep()
+ *
+ * This function can be used to measure the overhead incurred by ztimer_sleep().
+ *
+ * @param[in]   clock   ztimer clock to operate on
+ * @param[in]   base    base interval to use
+ * @return  (time(ztimer_sleep(base))) - base
+ */
+int32_t ztimer_overhead_sleep(ztimer_clock_t *clock, uint32_t base);
 
 #endif /* ZTIMER_OVERHEAD_H */
 /** @} */

sys/ztimer/Kconfig

@@ -183,6 +183,10 @@ config MODULE_AUTO_INIT_ZTIMER
     select MODULE_ZTIMER_INIT
     default y
 
+config MODULE_ZTIMER_AUTO_ADJUST
+    bool "Auto adjust ztimer set and sleep values"
+    select MODULE_ZTIMER_OVERHEAD
+
 config MODULE_ZTIMER_NOW64
     bool "Use a 64-bits result for ztimer_now()"
 

sys/ztimer/init.c

@@ -43,6 +43,7 @@
 #include "ztimer/convert_frac.h"
 #include "ztimer/convert_shift.h"
 #include "ztimer/convert_muldiv64.h"
+#include "ztimer/overhead.h"
 #include "ztimer/periph_timer.h"
 #include "ztimer/periph_rtt.h"
 #include "ztimer/periph_rtc.h"
@@ -212,6 +213,29 @@ ztimer_clock_t *const ZTIMER_SEC = &_ztimer_convert_frac_sec.super.super;
 #  endif
 #endif
 
+#if IS_USED(MODULE_ZTIMER_USEC)
+#ifndef CONFIG_ZTIMER_AUTO_ADJUST_BASE_ITVL
+#define CONFIG_ZTIMER_AUTO_ADJUST_BASE_ITVL     1000
+#endif
+#ifndef CONFIG_ZTIMER_AUTO_ADJUST_ITER
+#define CONFIG_ZTIMER_AUTO_ADJUST_ITER          100
+#endif
+
+static void _ztimer_usec_overhead(unsigned samples, unsigned base, uint16_t *adjust_value,
+                                  int32_t (*overhead_fn)(ztimer_clock_t *clock, uint32_t base))
+{
+    int32_t min = INT32_MAX;
+
+    for (unsigned i = 0; i < samples; i++) {
+        int32_t overhead = overhead_fn(ZTIMER_USEC, base);
+        if (overhead < min) {
+            min = overhead;
+        }
+    }
+    *adjust_value = min;
+}
+#endif
+
 void ztimer_init(void)
 {
 /* Step 4: initialize used ztimer-periphery */
@@ -266,16 +290,42 @@ void ztimer_init(void)
 #  else
     LOG_DEBUG("ztimer_init(): ZTIMER_USEC without conversion\n");
 #  endif
-#  ifdef CONFIG_ZTIMER_USEC_ADJUST_SET
-    LOG_DEBUG("ztimer_init(): ZTIMER_USEC setting adjust_set value to %i\n",
-              CONFIG_ZTIMER_USEC_ADJUST_SET );
-    ZTIMER_USEC->adjust_set = CONFIG_ZTIMER_USEC_ADJUST_SET;
-#  endif
-#  ifdef CONFIG_ZTIMER_USEC_ADJUST_SLEEP
-    LOG_DEBUG("ztimer_init(): ZTIMER_USEC setting adjust_sleep value to %i\n",
-              CONFIG_ZTIMER_USEC_ADJUST_SLEEP );
-    ZTIMER_USEC->adjust_sleep = CONFIG_ZTIMER_USEC_ADJUST_SLEEP;
-#  endif
+
+    /* warm-up time if set and needed */
+    if (IS_USED(MODULE_ZTIMER_AUTO_ADJUST) &&
+        !(CONFIG_ZTIMER_USEC_ADJUST_SET && CONFIG_ZTIMER_USEC_ADJUST_SLEEP)) {
+        if (CONFIG_ZTIMER_AUTO_ADJUST_SETTLE) {
+            ztimer_sleep(ZTIMER_USEC, CONFIG_ZTIMER_AUTO_ADJUST_SETTLE);
+        }
+    }
+
+    /* calculate or set 'adjust_set' */
+    if (CONFIG_ZTIMER_USEC_ADJUST_SET) {
+        ZTIMER_USEC->adjust_set = CONFIG_ZTIMER_USEC_ADJUST_SET;
+    }
+    else if (IS_USED(MODULE_ZTIMER_AUTO_ADJUST)) {
+        _ztimer_usec_overhead(CONFIG_ZTIMER_AUTO_ADJUST_ITER, CONFIG_ZTIMER_AUTO_ADJUST_BASE_ITVL,
+                              &ZTIMER_USEC->adjust_set, ztimer_overhead_set);
+    }
+    if (ZTIMER_USEC->adjust_set) {
+        LOG_DEBUG("ztimer_init(): ZTIMER_USEC setting adjust_set value to %i\n",
+                  ZTIMER_USEC->adjust_set);
+    }
+
+    /* calculate or set 'adjust_sleep' */
+    if (CONFIG_ZTIMER_USEC_ADJUST_SLEEP) {
+        ZTIMER_USEC->adjust_sleep = CONFIG_ZTIMER_USEC_ADJUST_SLEEP;
+    }
+    else if (IS_USED(MODULE_ZTIMER_AUTO_ADJUST)) {
+        _ztimer_usec_overhead(CONFIG_ZTIMER_AUTO_ADJUST_ITER,
+                              CONFIG_ZTIMER_AUTO_ADJUST_BASE_ITVL, &ZTIMER_USEC->adjust_sleep,
+                              ztimer_overhead_sleep);
+    }
+
+    if (ZTIMER_USEC->adjust_sleep) {
+        LOG_DEBUG("ztimer_init(): ZTIMER_USEC setting adjust_sleep value to %i\n",
+                  ZTIMER_USEC->adjust_sleep);
+    }
 #endif
 
 #if MODULE_ZTIMER_MSEC

sys/ztimer/overhead.c

@@ -35,7 +35,7 @@ static void _callback(void *arg)
     *callback_arg->val = ztimer_now(callback_arg->clock);
 }
 
-int32_t ztimer_overhead(ztimer_clock_t *clock, uint32_t base)
+int32_t ztimer_overhead_set(ztimer_clock_t *clock, uint32_t base)
 {
     volatile uint32_t after = 0;
     uint32_t pre;
@@ -48,3 +48,13 @@ int32_t ztimer_overhead(ztimer_clock_t *clock, uint32_t base)
     while (!after) {}
     return after - pre - base;
 }
+
+int32_t ztimer_overhead_sleep(ztimer_clock_t *clock, uint32_t base)
+{
+    uint32_t pre = ztimer_now(clock);
+
+    ztimer_sleep(clock, base);
+    uint32_t after = ztimer_now(clock);
+
+    return after - pre - base;
+}

tests/ztimer_overhead/Makefile

@@ -1,6 +1,9 @@
 DEVELHELP ?= 0
+
 include ../Makefile.tests_common
 
-USEMODULE += ztimer_overhead ztimer_usec
+USEMODULE += ztimer_auto_adjust
+USEMODULE += ztimer_overhead
+USEMODULE += ztimer_usec
 
 include $(RIOTBASE)/Makefile.include

tests/ztimer_overhead/README.md

@@ -3,5 +3,22 @@
 This test application sets up a ztimer_periph at 1MHz, then measures 1024
 times how much overhead ztimer adds.
 
-It uses the "ztimer_overhead()" function. See it's documentation for more
+It uses the "ztimer_overhead_set()" function. See it's documentation for more
 information.
+
+It then sets `adjust_set` parameter and sleeps 1024 times and measure how
+much overhead ztimer_sleep adds.
+
+It uses the "ztimer_overhead_sleep()" function. See it's documentation for more
+information.
+
+At the end of the test `adjust_set` and `adjust_sleep` values are printed
+that can be set for the target `BOARD` in `board.h`.
+
+e.g for dwm1001:
+
+```shell
+ZTIMER_USEC adjust params for dwm1001:
+    CONFIG_ZTIMER_USEC_ADJUST_SET    6
+    CONFIG_ZTIMER_USEC_ADJUST_SLEEP  21
+```

tests/ztimer_overhead/app.config.test

@@ -3,3 +3,4 @@
 CONFIG_MODULE_ZTIMER=y
 CONFIG_ZTIMER_USEC=y
 CONFIG_MODULE_ZTIMER_OVERHEAD=y
+CONFIG_MODULE_ZTIMER_AUTO_ADJUST=y

tests/ztimer_overhead/main.c

@@ -23,26 +23,25 @@
 #include <stdlib.h>
 #include <inttypes.h>
 
+#include "board.h"
 #include "ztimer.h"
 #include "ztimer/overhead.h"
 
 #define BASE    1000
 #define SAMPLES 1024
 
-int main(void)
+static int32_t _ztimer_usec_overhead(unsigned samples, unsigned base,
+                                     int32_t (*overhead_fn)(ztimer_clock_t *clock, uint32_t base))
 {
     uint32_t total = 0;
 
     int32_t min = INT32_MAX;
     int32_t max = INT32_MIN;
 
-    /* unset configured adjustment */
-    /* ZTIMER_USEC->adjust_set = 0; */
-    printf("ZTIMER_USEC->adjust_set = %" PRIu16 "\n", ZTIMER_USEC->adjust_set);
+    unsigned n = samples;
 
-    unsigned n = SAMPLES;
     while (n--) {
-        int32_t overhead = ztimer_overhead(ZTIMER_USEC, BASE);
+        int32_t overhead = overhead_fn(ZTIMER_USEC, base);
         total += labs(overhead);
         if (overhead < min) {
             min = overhead;
@@ -55,5 +54,26 @@ int main(void)
     printf("min=%" PRIi32 " max=%" PRIi32 " avg_diff=%" PRIi32 "\n", min, max,
            (total / SAMPLES));
 
+    return min;
+}
+
+int main(void)
+{
+    /* unset configured adjustment */
+    printf("ZTIMER_USEC auto_adjust params:\n");
+    printf("    ZTIMER_USEC->adjust_set = %" PRIu16 "\n", ZTIMER_USEC->adjust_set);
+    ZTIMER_USEC->adjust_set = 0;
+    printf("    ZTIMER_USEC->adjust_sleep = %" PRIu16 "\n", ZTIMER_USEC->adjust_sleep);
+    ZTIMER_USEC->adjust_sleep = 0;
+    printf("ZTIMER_USEC auto_adjust params cleared\n");
+
+    printf("zitmer_overhead_set...\n");
+    ZTIMER_USEC->adjust_set = _ztimer_usec_overhead(SAMPLES, BASE, ztimer_overhead_set);
+    printf("zitmer_overhead_sleep...\n");
+    ZTIMER_USEC->adjust_sleep = _ztimer_usec_overhead(SAMPLES, BASE, ztimer_overhead_sleep);
+    printf("ZTIMER_USEC adjust params for %s:\n", RIOT_BOARD);
+    printf("    CONFIG_ZTIMER_USEC_ADJUST_SET    %" PRIi16 "\n", ZTIMER_USEC->adjust_set);
+    printf("    CONFIG_ZTIMER_USEC_ADJUST_SLEEP  %" PRIi16 "\n", ZTIMER_USEC->adjust_sleep);
+
     return 0;
 }