include/linux/timex.h

28  *	Added defines for hybrid phase/frequency-lock loop.
32  *	defines for PPS phase-lock loop.
35  *	Revised status codes and structures for external clock and PPS
46  * 1995-08-13    Torsten Duwe
47  *      kernel PLL updated to 1994-12-13 specs (rfc-1589)
48  * 1997-08-30    Ulrich Windl
50  * 2004-08-12    Christoph Lameter
61  * syscall interface - used (mainly by NTP daemon)
62  * to discipline kernel clock oscillator
67 	long freq;		/* frequency offset (scaled ppm) */
70 	int status;		/* clock command/status */
72 	long precision;		/* clock precision (usec) (read only) */
73 	long tolerance;		/* clock frequency tolerance (ppm)
77 	long tick;		/* (modified) usecs between clock ticks */
79 	long ppsfreq;           /* pps frequency (scaled ppm) (ro) */
99 #define ADJ_FREQUENCY		0x0002	/* frequency offset */
102 #define ADJ_STATUS		0x0010	/* clock status */
112 #define ADJ_OFFSET_SINGLESHOT	0x0001	/* old-fashioned adjtime */
113 #define ADJ_OFFSET_READONLY	0x2000	/* read-only adjtime */
115 #define ADJ_OFFSET_SINGLESHOT	0x8001	/* old-fashioned adjtime */
116 #define ADJ_OFFSET_SS_READ	0xa001	/* read-only adjtime */
137 #define STA_FLL		0x0008	/* select frequency-lock mode (rw) */
141 #define STA_UNSYNC	0x0040	/* clock unsynchronized (rw) */
142 #define STA_FREQHOLD	0x0080	/* hold frequency (rw) */
149 #define STA_CLOCKERR	0x1000	/* clock hardware fault (ro) */
152 #define STA_CLK		0x8000	/* clock source (0 = A, 1 = B) (ro) */
154 /* read-only bits */
159  * Clock states (time_state)
161 #define TIME_OK		0	/* clock synchronized, no leap second */
166 #define TIME_ERROR	5	/* clock not synchronized */
178  * adjust the frequency correction for a given offset in PLL mode.
184  * convergence time, but making the clock more stable.
189  * https://lists.ntp.org/pipermail/hackers/2008-January/003487.html
194  * clock steering implementation is HZ independent.
198  * v2.6.19), with good clock stability.
202  * adjust the frequency correction for a given offset in FLL mode.
207 #define SHIFT_PLL	2	/* PLL frequency factor (shift) */
208 #define SHIFT_FLL	2	/* FLL frequency factor (shift) */
213  * time_tolerance variables, which represent the current frequency
214  * offset and maximum frequency tolerance.
216 #define SHIFT_USEC 16		/* frequency offset scale (shift) */
217 #define PPM_SCALE ((s64)NSEC_PER_USEC << (NTP_SCALE_SHIFT - SHIFT_USEC))
223 #define MAXFREQ 500000		/* max frequency error (ns/s) */
238  * phase-lock loop variables
240 extern int time_status;		/* clock synchronization status bits */
246  * ntp_synced - Returns 1 if the NTP status is not UNSYNC
258 	__x < 0 ? -(-__x >> __s) : __x >> __s;	\
276 /* The clock frequency of the i8253/i8254 PIT */