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conf: add option to set maximum slew rate

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With the generic driver, the maxslewrate directive sets the maximum
frequency offset that the driver is allowed to use to slew the time. By
default, it's set to 83333.333 (1/12). This is identical to what Linux
fast slewing used to use.
This commit is contained in:
Miroslav Lichvar
2014-05-21 16:23:30 +02:00
parent 3e1dc801b0
commit 9cf78b974a
4 changed files with 44 additions and 9 deletions
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17
sys_generic.c
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@@ -30,6 +30,7 @@
#include "sys_generic.h"
#include "conf.h"
#include "local.h"
#include "localp.h"
#include "logging.h"
@@ -52,6 +53,9 @@ static double max_freq;
in local time */
static double max_freq_change_delay;
/* Maximum allowed frequency offset relative to the base frequency */
static double max_corr_freq;
/* Amount of outstanding offset to process */
static double offset_register;
@@ -62,9 +66,6 @@ static double offset_register;
as set by drv_set_freq (not in ppm) */
static double slew_freq;
/* Maximum allowed slewing frequency */
#define MAX_SLEW_FREQ (1 / 12.0)
/* Time (raw) of last update of slewing frequency and offset */
static struct timeval slew_start;
@@ -129,10 +130,10 @@ update_slew(void)
/* Get frequency offset needed to slew the offset in the duration
and clamp it to the allowed maximum */
corr_freq = offset_register / duration;
if (corr_freq < -MAX_SLEW_FREQ)
corr_freq = -MAX_SLEW_FREQ;
else if (corr_freq > MAX_SLEW_FREQ)
corr_freq = MAX_SLEW_FREQ;
if (corr_freq < -max_corr_freq)
corr_freq = -max_corr_freq;
else if (corr_freq > max_corr_freq)
corr_freq = max_corr_freq;
/* Get the new real frequency and clamp it */
total_freq = base_freq + corr_freq * (1.0e6 - base_freq);
@@ -275,6 +276,8 @@ SYS_Generic_CompleteFreqDriver(double max_set_freq_ppm, double max_set_freq_dela
slew_freq = 0.0;
offset_register = 0.0;
max_corr_freq = CNF_GetMaxSlewRate() / 1.0e6;
lcl_RegisterSystemDrivers(read_frequency, set_frequency,
accrue_offset, sys_apply_step_offset ?
sys_apply_step_offset : apply_step_offset,