rxts_calibrator: clean up

This cleans a little the calibrator code: we'll write to eeprom only when the measured value is different from the previous one. With this commit, code is also slightly smaller (28 bytes). Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

rxts_calibrator: clean up
This cleans a little the calibrator code: we'll write to eeprom only when the measured value is different from the previous one. With this commit, code is also slightly smaller (28 bytes). Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
c6b68c61 · Alessandro Rubini · Grzegorz Daniluk · d447f096 · c6b68c61
Commit c6b68c61 authored Aug 05, 2014 by Alessandro Rubini Committed by Grzegorz Daniluk Aug 18, 2014
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rxts_calibrator.c dev/rxts_calibrator.c +29 -27

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--- a/dev/rxts_calibrator.c
+++ b/dev/rxts_calibrator.c
@@ -208,43 +208,45 @@ int measure_t24p(uint32_t *value)
 	return rv;
 }

-/*SoftPLL must be locked prior calling this function*/
-static int calib_t24p_slave(uint32_t *value)
+/* Delays for master must have been calibrated while running as slave */
+static int calib_t24p_master(uint32_t *value)
 {
 	int rv;

-	rxts_calibration_start();
-	while (!(rv = rxts_calibration_update(value))) ;
-
-	if (rv < 0) {
-		pp_printf("Could not calibrate t24p, trying to read from EEPROM\n");
-		if(eeprom_phtrans(WRPC_FMC_I2C, FMC_EEPROM_ADR, value, 0) < 0) {
-			pp_printf("Something went wrong while writing EEPROM\n");
-			return -1;
-		}
-
-	}
-	else {
-		pp_printf("t24p value is %d ps, storing to EEPROM\n", *value);
-		if(eeprom_phtrans(WRPC_FMC_I2C, FMC_EEPROM_ADR, value, 1) < 0) {
-			pp_printf("Something went wrong while writing EEPROM\n");
-			return -1;
-		}
+	rv = eeprom_phtrans(WRPC_FMC_I2C, FMC_EEPROM_ADR, value, 0);
+	if(rv < 0) {
+		pp_printf("Error %d while reading EEPROM\n", rv);
+		return rv;
 	}
-
-	return 0;
+	pp_printf("t24p read from EEPROM: %d ps\n", *value);
+	return rv;
 }

-static int calib_t24p_master(uint32_t *value)
+
+/*SoftPLL must be locked prior calling this function*/
+static int calib_t24p_slave(uint32_t *value)
 {
 	int rv;
+	uint32_t prev;

-	rv = eeprom_phtrans(WRPC_FMC_I2C, FMC_EEPROM_ADR, value, 0);
-	if(rv < 0)
-		pp_printf("Something went wrong while reading from EEPROM: %d\n", rv);
-	else
-		pp_printf("t24p read from EEPROM: %d ps\n", *value);
+	rxts_calibration_start();
+	while (!(rv = rxts_calibration_update(value)))
+		/* FIXME: timeout */;
+	if (rv < 0) {
+		/* Fall back on master == eeprom-or-error */
+		return calib_t24p_master(value);
+	}

+	/*
+	 * Let's see if we have a matching value in EEPROM:
+	 * accept a 200ps difference, otherwise rewrite eeprom
+	 */
+	rv = eeprom_phtrans(WRPC_FMC_I2C, FMC_EEPROM_ADR, &prev, 0 /* rd */);
+	if (rv < 0 || (prev < *value - 200) || (prev > *value + 200)) {
+		rv = eeprom_phtrans(WRPC_FMC_I2C, FMC_EEPROM_ADR, value, 1);
+		pp_printf("Wrote new t24p value: %d ps (%s)\n", *value,
+			  rv < 0 ? "Failed" : "Success");
+	}
 	return rv;
 }