using Desired frequency offset from nominal frequency in
parts per billion(ppb) to adjust frequency
Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
This patch introduces the foundational PTP (Precision Time Protocol) clock
driver framework for NuttX, enabling precise time synchronization support
based on IEEE 1588 standard.
Key changes include:
1. New PTP clock driver infrastructure:
- Added drivers/timers/ptp_clock.c implementing upper-half driver
- Created include/nuttx/timers/ptp_clock.h with PTP clock interfaces
- Implemented upper/lower half driver architecture for hardware abstraction
2. Core functionality:
- Clock time get/set operations (gettime, settime)
- Frequency adjustment support (adjtime, adjfine)
- Phase adjustment capabilities
- System-device cross-timestamping for precise synchronization
3. IOCTL commands:
- PTP_CLOCK_SETTIME/GETTIME for time manipulation
- PTP_CLOCK_GETRES for resolution queries
- PTP_CLOCK_ADJTIME for time adjustment
- PTP_CLOCK_GETCAPS for capability queries
- PTP_SYS_OFFSET* for system offset measurements
4. Supporting structures:
- struct ptp_lowerhalf_s: lower-half driver interface
- struct ptp_clock_caps: clock capabilities descriptor
- struct ptp_sys_offset: system time offset measurement
- Added timex structures in include/sys/timex.h for ADJ_* operations
5. Build system integration:
- Added CONFIG_PTP_CLOCK Kconfig option
- Updated CMakeLists.txt and Make.defs
- Added PTPCLK debug macros in include/debug.h
This framework provides the base for PTP clock implementations, allowing
hardware-specific drivers to register and provide precise time services
through a standardized interface.
Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
