[PATCH v9 01/11] iio: accel: adxl345: apply scale factor to tap threshold

From: Lothar Rubusch
Date: Tue Jun 10 2025 - 18:00:07 EST


The threshold for tap detection was still not scaled. The datasheet sets
a scale factor of 62.5mg/LSB. Remove commit about not scaled threshold
for tap detection, and apply scaling to it.

Signed-off-by: Lothar Rubusch <l.rubusch@xxxxxxxxx>
---
drivers/iio/accel/adxl345_core.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index 7c093c0241de..d80efb68d113 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -697,17 +697,15 @@ static int adxl345_read_event_value(struct iio_dev *indio_dev,
switch (info) {
case IIO_EV_INFO_VALUE:
/*
- * The scale factor would be 62.5mg/LSB (i.e. 0xFF = 16g) but
- * not applied here. In context of this general purpose sensor,
- * what imports is rather signal intensity than the absolute
- * measured g value.
+ * Scale factor is 62.5mg/LSB i.e. 0xff = 16g
*/
ret = regmap_read(st->regmap, ADXL345_REG_THRESH_TAP,
&tap_threshold);
if (ret)
return ret;
- *val = sign_extend32(tap_threshold, 7);
- return IIO_VAL_INT;
+ *val = 62500 * sign_extend32(tap_threshold, 7);
+ *val2 = MICRO;
+ return IIO_VAL_FRACTIONAL;
case IIO_EV_INFO_TIMEOUT:
*val = st->tap_duration_us;
*val2 = 1000000;
@@ -746,6 +744,7 @@ static int adxl345_write_event_value(struct iio_dev *indio_dev,
case IIO_EV_TYPE_GESTURE:
switch (info) {
case IIO_EV_INFO_VALUE:
+ val = DIV_ROUND_CLOSEST(val * MICRO + val2, 62500);
ret = regmap_write(st->regmap, ADXL345_REG_THRESH_TAP,
min(val, 0xFF));
if (ret)
--
2.39.5