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sched/clock: support using CLOCKFD to call clock_adjtime

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This patch implements clock_adjtime() with CLOCKFD support, enabling
precise time and frequency adjustments for PTP clocks through the
standard POSIX clock API.

Key changes include:

1. New clock_adjtime() system call:
   - Added sched/clock/clock_adjtime.c implementation
   - Provides POSIX-compliant time adjustment interface
   - Supports both standard clocks and CLOCKFD-based dynamic clocks
   - Added CONFIG_CLOCK_ADJTIME Kconfig option

2. CLOCKFD support in clock_adjtime():
   - Detects CLOCKFD-encoded clockids via CLOCKFD_TO_FD() check
   - Extracts file descriptor and validates through fs_getfilep()
   - Issues PTP_CLOCK_ADJTIME ioctl to underlying PTP clock device
   - Returns clock status and adjustment results via struct timex

3. Enhanced struct timex support:
   - Extended include/sys/timex.h with additional ADJ_* flags
   - Added ADJ_OFFSET, ADJ_FREQUENCY, ADJ_MAXERROR, ADJ_ESTERROR
   - Added ADJ_STATUS, ADJ_TIMECONST, ADJ_TAI, ADJ_SETOFFSET
   - Added ADJ_MICRO, ADJ_NANO for time unit selection
   - Added STA_* status flags for clock state reporting

4. Clock operations supported:
   - ADJ_SETOFFSET: Apply time offset adjustment
   - ADJ_FREQUENCY: Adjust clock frequency (PPM)
   - ADJ_MAXERROR: Set maximum error estimate
   - ADJ_ESTERROR: Set estimated error
   - ADJ_STATUS: Modify clock status bits
   - ADJ_NANO: Use nanosecond resolution
   - ADJ_SETOFFSET: Set absolute time offset

5. API declarations:
   - Added clock_adjtime() prototype in include/nuttx/clock.h
   - Enabled by CONFIG_CLOCK_ADJTIME configuration
   - Compatible with Linux clock_adjtime() interface

Usage example:
  int fd = open("/dev/ptp0", O_RDWR);
  struct timex tx = {0};
  tx.modes = ADJ_FREQUENCY;
  tx.freq = 10000000;  /* Adjust frequency by 10 PPM */
  clock_adjtime(CLOCKFD(fd), &tx);
  close(fd);

This completes the PTP clock framework's POSIX clock API integration,
providing comprehensive time control capabilities for precision timing
applications including PTP synchronization daemons (ptp4l, timemaster).

Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
This commit is contained in:
dongjiuzhu1
2025-03-20 23:08:37 +08:00
committed by Alan C. Assis
parent 6802d3510b
commit 752a405f86
4 changed files with 142 additions and 1 deletions
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include/sys/timex.h
+31
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@@ -90,6 +90,37 @@ extern "C"
#define EXTERN extern
#endif
/****************************************************************************
* Name: clock_adjtime
*
* Description:
* Adjust the frequency and/or phase of a clock.
* This function allows the adjustment of the frequency and/or phase of a
* specified clock. It can be used to synchronize the clock with an
* external time source or to apply a frequency offset.
*
* Input Parameters:
* clk_id - The identifier of the clock to be adjusted. This is typically
* one of the predefined clock IDs such as CLOCK_REALTIME,
* CLOCK_MONOTONIC, or CLOCK_BOOTTIME.
*
* buf - A pointer to a `timex` structure that specifies the adjustment
* parameters. This structure includes fields for the frequency
* adjustment (`freq`), the maximum frequency error (`maxerror`),
* the estimated error (`esterror`), the phase offset (`offset`),
* and flags to indicate the type of adjustment (`status`).
*
* Returned Value:
* Return On success, the function returns 0. On error, it returns
* -1 and sets 'errno` to indicate the specific error that
* occurred.
*
****************************************************************************/
#ifdef CONFIG_CLOCK_ADJTIME
int clock_adjtime(clockid_t clk_id, FAR struct timex *buf);
#endif
#undef EXTERN
#if defined(__cplusplus)
}