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>
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