sys: clock: add sys_clock api and remove posix from iso c time

MAINTAINERS.yml

@@ -2556,7 +2556,6 @@ Utilities:
     - tests/unit/list/
     - tests/unit/intmath/
     - tests/unit/pot/
-    - tests/lib/time/
     - tests/lib/onoff/
     - tests/lib/sys_util/
     - tests/lib/sprintf/

doc/releases/release-notes-4.2.rst

@@ -239,6 +239,9 @@ New APIs and options
 
   * :c:func:`util_eq`
   * :c:func:`util_memeq`
+  * :c:func:`sys_clock_gettime`
+  * :c:func:`sys_clock_settime`
+  * :c:func:`sys_clock_nanosleep`
 
 * LoRaWAN
    * :c:func:`lorawan_request_link_check`

include/zephyr/posix/time.h

@@ -60,13 +60,14 @@ struct itimerspec {
 #include <errno.h>
 #include <zephyr/posix/posix_types.h>
 #include <zephyr/posix/signal.h>
+#include <zephyr/sys/clock.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 #ifndef CLOCK_REALTIME
-#define CLOCK_REALTIME 1
+#define CLOCK_REALTIME SYS_CLOCK_REALTIME
 #endif
 
 #ifndef CLOCK_PROCESS_CPUTIME_ID
@@ -78,11 +79,11 @@ extern "C" {
 #endif
 
 #ifndef CLOCK_MONOTONIC
-#define CLOCK_MONOTONIC 4
+#define CLOCK_MONOTONIC SYS_CLOCK_MONOTONIC
 #endif
 
 #ifndef TIMER_ABSTIME
-#define TIMER_ABSTIME 4
+#define TIMER_ABSTIME SYS_TIMER_ABSTIME
 #endif
 
 int clock_gettime(clockid_t clock_id, struct timespec *ts);

include/zephyr/sys/clock.h

@@ -0,0 +1,134 @@
+/*
+ * Copyright (c) 2025 Tenstorrent AI ULC
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ * @brief System clock APIs
+ *
+ * APIs for getting, setting, and sleeping with respect to system clocks.
+ */
+
+#ifndef ZEPHYR_INCLUDE_SYSCLOCK_H_
+#define ZEPHYR_INCLUDE_SYSCLOCK_H_
+
+#include <time.h>
+
+#include <zephyr/toolchain.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @addtogroup clock_apis
+ * @{
+ */
+
+/**
+ * @brief The real-time clock (i.e. "wall clock")
+ *
+ * This clock is used to measure time since the epoch (1970-01-01 00:00:00 UTC).
+ *
+ * It is not a steady clock; i.e. it may be adjusted for a number of reasons from initialization
+ * of a hardware real-time-clock, to network-time synchronization, to manual adjustment from the
+ * application.
+ */
+#define SYS_CLOCK_REALTIME 1
+
+/**
+ * @brief The monotonic clock
+ *
+ * This steady clock is used to measure time since the system booted. Time from this clock is
+ * always monotonically increasing.
+ */
+#define SYS_CLOCK_MONOTONIC 4
+
+/**
+ * @brief The flag used for specifying absolute timeouts
+ *
+ * This flag may be passed to @ref sys_clock_nanosleep to indicate the requested timeout is an
+ * absolute time with respect to the specified clock.
+ */
+#define SYS_TIMER_ABSTIME 4
+
+/**
+ * @brief Get the offset @ref SYS_CLOCK_REALTIME with respect to @ref SYS_CLOCK_MONOTONIC
+ *
+ * The "wall clock" (i.e. @ref SYS_CLOCK_REALTIME) depends on a base time that is set by the
+ * system. The base time may be updated for a number of reasons, such as initialization of a
+ * hardware real-time-clock (RTC), network time protocol (NTP) synchronization, or manual
+ * adjustment by the application.
+ *
+ * This function retrieves the current time offset, as a `timespec` object, for
+ * @ref SYS_CLOCK_REALTIME, with respect to @ref SYS_CLOCK_MONOTONIC, and writes it to the
+ * provided memory location pointed-to by @a tp.
+ *
+ * @note This function may assert if @a tp is NULL.
+ *
+ * @param tp Pointer to memory where time will be written.
+ */
+__syscall void sys_clock_getrtoffset(struct timespec *tp);
+
+/**
+ * @brief Get the current time from the specified clock
+ *
+ * @param clock_id The clock from which to query time.
+ * @param tp Pointer to memory where time will be written.
+ * @retval 0 on success.
+ * @retval -EINVAL when an invalid @a clock_id is specified.
+ */
+int sys_clock_gettime(int clock_id, struct timespec *tp);
+
+/**
+ * @brief Set the current time for the specified clock
+ *
+ * @param clock_id The clock for which the time should be set.
+ * @param tp Pointer to memory specifying the desired time.
+ * @retval 0 on success.
+ * @retval -EINVAL when an invalid @a clock_id is specified or when @a tp contains nanoseconds
+ * outside of the range `[0, 999999999]`.
+ */
+__syscall int sys_clock_settime(int clock_id, const struct timespec *tp);
+
+/**
+ * @brief Sleep for the specified amount of time with respect to the specified clock.
+ *
+ * This function will cause the calling thread to sleep either
+ * - until the absolute time specified by @a rqtp (if @a flags includes @ref SYS_TIMER_ABSTIME), or
+ * - until the relative time specified by @a rqtp (if @a flags does not include
+ *   @ref SYS_TIMER_ABSTIME).
+ *
+ * The accepted values for @a clock_id include
+ * - @ref SYS_CLOCK_REALTIME
+ * - @ref SYS_CLOCK_MONOTONIC
+ *
+ * If @a rmtp is not NULL, and the thread is awoken prior to the time specified by @a rqtp, then
+ * any remaining time will be written to @a rmtp. If the thread has slept for at least the time
+ * specified by @a rqtp, then @a rmtp will be set to zero.
+ *
+ * @param clock_id The clock to by which to sleep.
+ * @param flags Flags to modify the behavior of the sleep operation.
+ * @param rqtp Pointer to the requested time to sleep.
+ * @param rmtp Pointer to memory into which to copy the remaining time, if any.
+ *
+ * @retval 0 on success.
+ * @retval -EINVAL when an invalid @a clock_id, when @a rqtp contains nanoseconds outside of the
+ *         range `[0, 999999999]`, or when @a rqtp contains a negative value.
+ */
+__syscall int sys_clock_nanosleep(int clock_id, int flags, const struct timespec *rqtp,
+				  struct timespec *rmtp);
+
+/**
+ * @}
+ */
+
+#include <zephyr/syscalls/clock.h>
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

lib/libc/Kconfig

@@ -84,6 +84,7 @@ config MINIMAL_LIBC
 	imply COMMON_LIBC_MALLOC
 	imply COMMON_LIBC_CALLOC
 	imply COMMON_LIBC_REALLOCARRAY
+	imply COMMON_LIBC_TIME
 	help
 	  Build with minimal C library.
 
@@ -96,6 +97,7 @@ config PICOLIBC
 	select TC_PROVIDES_POSIX_C_LANG_SUPPORT_R
 	imply COMMON_LIBC_MALLOC
 	imply COMMON_LIBC_ABORT
+	imply COMMON_LIBC_TIME
 	depends on PICOLIBC_SUPPORTED
 	help
 	  Build with picolibc library. The picolibc library is built as
@@ -116,6 +118,7 @@ config NEWLIB_LIBC
 	imply POSIX_FILE_SYSTEM_ALIAS_FSTAT
 	imply POSIX_MULTI_PROCESS_ALIAS_GETPID
 	imply POSIX_SIGNALS_ALIAS_KILL
+	imply COMMON_LIBC_TIME
 	help
 	  Build with newlib library. The newlib library is expected to be
 	  part of the SDK in this case.
@@ -137,7 +140,7 @@ config IAR_LIBC
 	depends on IAR_LIBC_SUPPORTED
 	depends on "$(ZEPHYR_TOOLCHAIN_VARIANT)" = "iar"
 	select COMMON_LIBC_STRNLEN
-	select COMMON_LIBC_TIME if POSIX_TIMERS
+	select COMMON_LIBC_TIME
 	help
 	  Use the full IAR Compiler runtime libraries.
 	  A reduced Zephyr minimal libc will be used for library functionality

lib/libc/common/source/thrd/thrd.c

@@ -10,6 +10,7 @@
 #include <zephyr/kernel.h>
 #include <zephyr/posix/pthread.h>
 #include <zephyr/posix/sched.h>
+#include <zephyr/sys/clock.h>
 
 struct thrd_trampoline_arg {
 	thrd_start_t func;
@@ -44,7 +45,11 @@ thrd_t thrd_current(void)
 
 int thrd_sleep(const struct timespec *duration, struct timespec *remaining)
 {
-	return nanosleep(duration, remaining);
+	if (sys_clock_nanosleep(SYS_CLOCK_REALTIME, 0, duration, remaining) != 0) {
+		return thrd_error;
+	}
+
+	return thrd_success;
 }
 
 void thrd_yield(void)

lib/libc/common/source/time/time.c

@@ -1,22 +1,23 @@
 /*
  * Copyright (c) 2021 Golioth, Inc.
+ * Copyright (c) 2025 Tenstorrent AI ULC
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <errno.h>
 #include <time.h>
 
-/* clock_gettime() prototype */
-#include <zephyr/posix/time.h>
+#include <zephyr/sys/clock.h>
 
 time_t time(time_t *tloc)
 {
 	struct timespec ts;
 	int ret;
 
-	ret = clock_gettime(CLOCK_REALTIME, &ts);
+	ret = sys_clock_gettime(SYS_CLOCK_REALTIME, &ts);
 	if (ret < 0) {
-		/* errno is already set by clock_gettime */
+		errno = -ret;
 		return (time_t) -1;
 	}
 

lib/os/CMakeLists.txt

@@ -1,11 +1,13 @@
 # SPDX-License-Identifier: Apache-2.0
 
 zephyr_syscall_header(
+  ${ZEPHYR_BASE}/include/zephyr/sys/clock.h
   ${ZEPHYR_BASE}/include/zephyr/sys/mutex.h
 )
 
 zephyr_sources(
   cbprintf_packaged.c
+  clock.c
   printk.c
   sem.c
   thread_entry.c