src: Open up the ADXL375 self test range

Reading the datasheet more carefully, we discover that it mentions
that the self test magnitude can vary within a rather wide range.

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/drivers/ao_adxl375.c b/src/drivers/ao_adxl375.c
index 70bf92a5f1fb72e6a44d0f711de58623a711a222..4366e302fa0e9802cf2519623fb17e1beaec3128 100644 (file)
--- a/src/drivers/ao_adxl375.c
+++ b/src/drivers/ao_adxl375.c
@@ -102,11 +102,14 @@ struct ao_adxl375_total {
 
 #define AO_ADXL375_SELF_TEST_SAMPLES   10
 #define AO_ADXL375_SELF_TEST_SETTLE    4
+#define AO_ADXL375_SELF_TEST_DELAY     AO_MS_TO_TICKS(10)
 
 #define MIN_LSB_G      18.4
 #define MAX_LSB_G      22.6
-#define SELF_TEST_MIN_G        5.0
-#define SELF_TEST_MAX_G        6.8
+
+/* The self test value can vary within a rather wide range */
+#define SELF_TEST_MIN_G        4.0
+#define SELF_TEST_MAX_G        12.0
 
 #define MIN_SELF_TEST  ((int32_t) (MIN_LSB_G * SELF_TEST_MIN_G * AO_ADXL375_SELF_TEST_SAMPLES + 0.5))
 #define MAX_SELF_TEST  ((int32_t) (MAX_LSB_G * SELF_TEST_MAX_G * AO_ADXL375_SELF_TEST_SAMPLES + 0.5))
@@ -122,7 +125,7 @@ ao_adxl375_total_value(struct ao_adxl375_total *total, int samples)
                total->x += value.x;
                total->y += value.y;
                total->z += value.z;
-               ao_delay(AO_MS_TO_TICKS(10));
+               ao_delay(AO_ADXL375_SELF_TEST_DELAY);
        }
 }
 
@@ -174,6 +177,11 @@ ao_adxl375_setup(void)
                             (0 << AO_ADXL375_POWER_CTL_SLEEP) |
                             (AO_ADXL375_POWER_CTL_WAKEUP_8 << AO_ADXL375_POWER_CTL_WAKEUP));
 
+       /* Set to normal mode */
+
+       ao_adxl375_reg_write(AO_ADXL375_DATA_FORMAT,
+                            AO_ADXL375_DATA_FORMAT_SETTINGS(0));
+
        /* Perform self-test */
 
        struct ao_adxl375_total self_test_off, self_test_on;
@@ -208,13 +216,9 @@ ao_adxl375_setup(void)
        if (z_change < MIN_SELF_TEST)
                AO_SENSOR_ERROR(AO_DATA_ADXL375);
 
-       /* This check is commented out as maximum self test is unreliable
-
-          if (z_change > MAX_SELF_TEST)
+       if (z_change > MAX_SELF_TEST)
                AO_SENSOR_ERROR(AO_DATA_ADXL375);
 
-       */
-
        /* Discard some samples to let it settle down */
        ao_adxl375_total_value(&self_test_off, AO_ADXL375_SELF_TEST_SETTLE);
 }