include/linux/timex.h

28  *	Added defines for hybrid phase/frequency-lock loop.
32  *	defines for PPS phase-lock loop.
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
58 #define ADJ_ADJTIME		0x8000	/* switch between adjtime/adjtimex modes */
59 #define ADJ_OFFSET_SINGLESHOT	0x0001	/* old-fashioned adjtime */
60 #define ADJ_OFFSET_READONLY	0x2000	/* read-only adjtime */
73  * when an interrupt takes places versus a high speed, fine-grained
91  * adjust the frequency correction for a given offset in PLL mode.
102  * https://lists.ntp.org/pipermail/hackers/2008-January/003487.html
105  * was appropriate for other Unix systems with HZ=100, and that
106  * SHIFT_PLL should be decreased as HZ increases. However, Linux's
107  * clock steering implementation is HZ independent.
115  * adjust the frequency correction for a given offset in FLL mode.
120 #define SHIFT_PLL	2	/* PLL frequency factor (shift) */
121 #define SHIFT_FLL	2	/* FLL frequency factor (shift) */
126  * time_tolerance variables, which represent the current frequency
127  * offset and maximum frequency tolerance.
129 #define SHIFT_USEC 16		/* frequency offset scale (shift) */
130 #define PPM_SCALE ((s64)NSEC_PER_USEC << (NTP_SCALE_SHIFT - SHIFT_USEC))
136 #define MAXFREQ 500000		/* max frequency error (ns/s) */
154 	__x < 0 ? -(-__x >> __s) : __x >> __s;	\
159 #define NTP_INTERVAL_FREQ  (HZ)
170 /* The clock frequency of the i8253/i8254 PIT */