[PATCH v2 9/9] iio: imu: st_lsm6dsx: add tap event detection

Francesco Lavra
2025-11-20T08:26:29Z

In order to allow sensors to advertise tap event capability and report tap
events, define a new struct iio_event_spec array that includes a tap event
spec, and a new struct iio_chan_spec array that references the new
iio_event_spec array; for the LSM6DSV chip family, use the new
iio_chan_spec array and define an event source for tap events.
Tested on LSMDSV16X.

Signed-off-by: Francesco Lavra <flavra@baylibre.com>
---
drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h | 1 +
drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 55 +++++++++++++++++++-
2 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
index 3b90261e6bb1..5d820f2a0bce 100644
--- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
+++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
@@ -245,6 +245,7 @@ struct st_lsm6dsx_shub_settings {

enum st_lsm6dsx_event_id {
ST_LSM6DSX_EVENT_WAKEUP,
+ ST_LSM6DSX_EVENT_TAP,
ST_LSM6DSX_EVENT_MAX
};

diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
index 562544636f36..55cd63643c52 100644
--- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
+++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
@@ -105,6 +105,21 @@ static const struct iio_event_spec st_lsm6dsx_ev_motion[] = {
},
};

+static const struct iio_event_spec st_lsm6dsx_ev_motion_tap[] = {
+ {
+ .type = IIO_EV_TYPE_THRESH,
+ .dir = IIO_EV_DIR_EITHER,
+ .mask_separate = BIT(IIO_EV_INFO_VALUE) |
+ BIT(IIO_EV_INFO_ENABLE),
+ },
+ {
+ .type = IIO_EV_TYPE_GESTURE,
+ .dir = IIO_EV_DIR_SINGLETAP,
+ .mask_separate = BIT(IIO_EV_INFO_VALUE) |
+ BIT(IIO_EV_INFO_ENABLE),
+ },
+};
+
static const struct iio_chan_spec st_lsm6dsx_acc_channels[] = {
ST_LSM6DSX_CHANNEL_ACC(0x28, IIO_MOD_X, 0, st_lsm6dsx_ev_motion),
ST_LSM6DSX_CHANNEL_ACC(0x2a, IIO_MOD_Y, 1, st_lsm6dsx_ev_motion),
@@ -119,6 +134,13 @@ static const struct iio_chan_spec st_lsm6ds0_acc_channels[] = {
IIO_CHAN_SOFT_TIMESTAMP(3),
};

+static const struct iio_chan_spec st_lsm6dsx_acc_tap_channels[] = {
+ ST_LSM6DSX_CHANNEL_ACC(0x28, IIO_MOD_X, 0, st_lsm6dsx_ev_motion_tap),
+ ST_LSM6DSX_CHANNEL_ACC(0x2a, IIO_MOD_Y, 1, st_lsm6dsx_ev_motion_tap),
+ ST_LSM6DSX_CHANNEL_ACC(0x2c, IIO_MOD_Z, 2, st_lsm6dsx_ev_motion_tap),
+ IIO_CHAN_SOFT_TIMESTAMP(3),
+};
+
static const struct iio_chan_spec st_lsm6dsx_gyro_channels[] = {
ST_LSM6DSX_CHANNEL(IIO_ANGL_VEL, 0x22, IIO_MOD_X, 0),
ST_LSM6DSX_CHANNEL(IIO_ANGL_VEL, 0x24, IIO_MOD_Y, 1),
@@ -1250,8 +1272,8 @@ static const struct st_lsm6dsx_settings st_lsm6dsx_sensor_settings[] = {
},
.channels = {
[ST_LSM6DSX_ID_ACC] = {
- .chan = st_lsm6dsx_acc_channels,
- .len = ARRAY_SIZE(st_lsm6dsx_acc_channels),
+ .chan = st_lsm6dsx_acc_tap_channels,
+ .len = ARRAY_SIZE(st_lsm6dsx_acc_tap_channels),
},
[ST_LSM6DSX_ID_GYRO] = {
.chan = st_lsm6dsx_gyro_channels,
@@ -1426,6 +1448,30 @@ static const struct st_lsm6dsx_settings st_lsm6dsx_sensor_settings[] = {
.status_y_mask = BIT(1),
.status_x_mask = BIT(2),
},
+ [ST_LSM6DSX_EVENT_TAP] = {
+ .x_value = {
+ .addr = 0x57,
+ .mask = GENMASK(4, 0),
+ },
+ .y_value = {
+ .addr = 0x58,
+ .mask = GENMASK(4, 0),
+ },
+ .z_value = {
+ .addr = 0x59,
+ .mask = GENMASK(4, 0),
+ },
+ .enable_mask = BIT(6),
+ .enable_axis_reg = 0x56,
+ .enable_x_mask = BIT(3),
+ .enable_y_mask = BIT(2),
+ .enable_z_mask = BIT(1),
+ .status_reg = 0x46,
+ .status_mask = BIT(5),
+ .status_x_mask = BIT(2),
+ .status_y_mask = BIT(1),
+ .status_z_mask = BIT(0),
+ },
},
},
},
@@ -1939,6 +1985,8 @@ st_lsm6dsx_get_event_id(enum iio_event_type type)
switch (type) {
case IIO_EV_TYPE_THRESH:
return ST_LSM6DSX_EVENT_WAKEUP;
+ case IIO_EV_TYPE_GESTURE:
+ return ST_LSM6DSX_EVENT_TAP;
default:
return ST_LSM6DSX_EVENT_MAX;
}
@@ -2606,6 +2654,9 @@ static bool st_lsm6dsx_report_motion_event(struct st_lsm6dsx_hw *hw)
events_found = st_lsm6dsx_report_events(hw, ST_LSM6DSX_EVENT_WAKEUP,
IIO_EV_TYPE_THRESH,
IIO_EV_DIR_EITHER);
+ events_found |= st_lsm6dsx_report_events(hw, ST_LSM6DSX_EVENT_TAP,
+ IIO_EV_TYPE_GESTURE,
+ IIO_EV_DIR_SINGLETAP);

return events_found;
}
--
2.39.5