mirror of
https://github.com/espressif/esp-idf.git
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Ondrej Kosta
63 lines
2.2 KiB
C
63 lines
2.2 KiB
C
/*
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* SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#pragma once
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#include <time.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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* Minimal subset of <sys/timex.h> for clock_adjtime() support.
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* Original struct timex and ADJ_* constants by David L. Mills (1993).
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*
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* Only the modes, offset, and freq fields are implemented.
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* freq uses ppb (parts per billion) units instead of Linux's scaled ppm.
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*/
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#define ADJ_OFFSET 0x0001 /* time offset; microseconds by default, nanoseconds with ADJ_NANO */
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#define ADJ_FREQUENCY 0x0002 /* frequency offset in ppb (parts per billion) */
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#define ADJ_MICRO 0x1000 /* select microsecond resolution */
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#define ADJ_NANO 0x2000 /* select nanosecond resolution */
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#define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime (offset in microseconds)*/
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#define ADJ_OFFSET_SS_READ 0xa001 /* read-only adjtime (remaining offset in microseconds) */
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struct timex {
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int modes; /*!< Mode selector (ADJ_OFFSET, ADJ_FREQUENCY, etc.) */
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long offset; /*!< Time offset: microseconds by default, nanoseconds when ADJ_NANO is set */
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long freq; /*!< Frequency offset in ppb (parts per billion) */
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};
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/**
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* @brief Adjust a clock identified by clk_id
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*
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* Uses struct timex.modes to select which fields to apply:
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* - ADJ_OFFSET: gradually slew by buf->offset
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* - ADJ_FREQUENCY: set frequency trim to buf->freq ppb
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* - ADJ_OFFSET_SINGLESHOT: old-style adjtime(), buf->offset
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* - ADJ_OFFSET_SS_READ: read remaining adjtime() correction into buf->offset
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*
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* buf->offset uses microseconds by default. Set ADJ_NANO in modes to use
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* nanoseconds instead. ADJ_MICRO may be used to explicitly select the default.
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*
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* ADJ_OFFSET and ADJ_FREQUENCY are mutually exclusive; do not OR them together.
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*
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* @param clk_id Clock identifier (CLOCK_REALTIME, or a custom registered clock)
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* @param buf Pointer to struct timex with modes and values to apply.
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* On return, buf->offset may be updated (e.g. ADJ_OFFSET_SS_READ).
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*
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* @return
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* - 0: Success
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* - -1: Failure (errno is set)
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*/
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int clock_adjtime(clockid_t clk_id, struct timex *buf);
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#ifdef __cplusplus
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}
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#endif
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