config: convert 'pi_proportional_exponent' to the new scheme.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>

config.c

@@ -98,6 +98,7 @@ struct config_item config_tab[] = {
 	GLOB_ITEM_INT("max_frequency", 900000000, 0, INT_MAX),
 	GLOB_ITEM_DBL("pi_integral_const", 0.0, 0.0, DBL_MAX),
 	GLOB_ITEM_DBL("pi_proportional_const", 0.0, 0.0, DBL_MAX),
+	GLOB_ITEM_DBL("pi_proportional_exponent", -0.3, -DBL_MAX, DBL_MAX),
 	GLOB_ITEM_DBL("pi_proportional_scale", 0.0, 0.0, DBL_MAX),
 	GLOB_ITEM_DBL("step_threshold", 0.0, 0.0, DBL_MAX),
 	GLOB_ITEM_INT("tx_timestamp_timeout", 1, 1, INT_MAX),
@@ -544,12 +545,6 @@ static enum parser_result parse_global_setting(const char *option,
 		cfg->dds.freq_est_interval = val;
 		pod->freq_est_interval = val;
 
-	} else if (!strcmp(option, "pi_proportional_exponent")) {
-		r = get_ranged_double(value, &df, -DBL_MAX, DBL_MAX);
-		if (r != PARSED_OK)
-			return r;
-		*cfg->pi_proportional_exponent = df;
-
 	} else if (!strcmp(option, "pi_proportional_norm_max")) {
 		r = get_ranged_double(value, &df, DBL_MIN, 1.0);
 		if (r != PARSED_OK)

config.h

@@ -69,7 +69,6 @@ struct config {
 	struct port_defaults pod;
 	enum servo_type clock_servo;
 
-	double *pi_proportional_exponent;
 	double *pi_proportional_norm_max;
 	double *pi_integral_scale;
 	double *pi_integral_exponent;

pi.c

@@ -36,7 +36,6 @@
 #define FREQ_EST_MARGIN 0.001
 
 /* These take their values from the configuration file. (see ptp4l.c) */
-double configured_pi_kp_exponent = -0.3;
 double configured_pi_kp_norm_max = 0.7;
 double configured_pi_ki_scale = 0.0;
 double configured_pi_ki_exponent = 0.4;
@@ -55,6 +54,7 @@ struct pi_servo {
 	double configured_pi_kp;
 	double configured_pi_ki;
 	double configured_pi_kp_scale;
+	double configured_pi_kp_exponent;
 };
 
 static void pi_destroy(struct servo *servo)
@@ -160,7 +160,7 @@ static void pi_sync_interval(struct servo *servo, double interval)
 {
 	struct pi_servo *s = container_of(servo, struct pi_servo, servo);
 
-	s->kp = s->configured_pi_kp_scale * pow(interval, configured_pi_kp_exponent);
+	s->kp = s->configured_pi_kp_scale * pow(interval, s->configured_pi_kp_exponent);
 	if (s->kp > configured_pi_kp_norm_max / interval)
 		s->kp = configured_pi_kp_norm_max / interval;
 
@@ -198,6 +198,8 @@ struct servo *pi_servo_create(struct config *cfg, int fadj, int sw_ts)
 	s->configured_pi_kp = config_get_double(cfg, NULL, "pi_proportional_const");
 	s->configured_pi_ki = config_get_double(cfg, NULL, "pi_integral_const");
 	s->configured_pi_kp_scale = config_get_double(cfg, NULL, "pi_proportional_scale");
+	s->configured_pi_kp_exponent =
+		config_get_double(cfg, NULL, "pi_proportional_exponent");
 
 	if (s->configured_pi_kp && s->configured_pi_ki) {
 		/* Use the constants as configured by the user without
@@ -205,7 +207,7 @@ struct servo *pi_servo_create(struct config *cfg, int fadj, int sw_ts)
 		   unstable. */
 		s->configured_pi_kp_scale = s->configured_pi_kp;
 		configured_pi_ki_scale = s->configured_pi_ki;
-		configured_pi_kp_exponent = 0.0;
+		s->configured_pi_kp_exponent = 0.0;
 		configured_pi_ki_exponent = 0.0;
 		configured_pi_kp_norm_max = MAX_KP_NORM_MAX;
 		configured_pi_ki_norm_max = MAX_KI_NORM_MAX;

pi.h

@@ -21,13 +21,6 @@
 
 #include "servo.h"
 
-/**
- * This variable determines the exponent in the formula used to set the
- * proportional constant of the PI controller from the sync interval.
- * kp = min(kp_scale * sync^kp_exponent, kp_norm_max / sync)
- */
-extern double configured_pi_kp_exponent;
-
 /**
  * This variable determines the normalized maximum in the formula used to set
  * the proportional constant of the PI controller from the sync interval.

ptp4l.c

@@ -103,7 +103,6 @@ static struct config cfg_settings = {
 	.transport = TRANS_UDP_IPV4,
 	.clock_servo = CLOCK_SERVO_PI,
 
-	.pi_proportional_exponent = &configured_pi_kp_exponent,
 	.pi_proportional_norm_max = &configured_pi_kp_norm_max,
 	.pi_integral_scale = &configured_pi_ki_scale,
 	.pi_integral_exponent = &configured_pi_ki_exponent,