Add the freefall detection of the sensor together with a threshold and
time parameter. A freefall event is detected if the measuring signal
falls below the threshold.
Introduce a freefall threshold stored in regmap cache, and a freefall
time, having the scaled time value stored as a member variable in the
state instance.
Signed-off-by: Lothar Rubusch <l.rubusch@xxxxxxxxx>
---
drivers/iio/accel/adxl345_core.c | 122 +++++++++++++++++++++++++++++++
1 file changed, 122 insertions(+)
diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index 10cd81dd08bb..7f842e7f371a 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -79,6 +79,7 @@ struct adxl345_state {
u32 tap_duration_us;
u32 tap_latent_us;
u32 tap_window_us;
+ u32 ff_time_ms;
__le16 fifo_buf[ADXL345_DIRS * ADXL345_FIFO_SIZE + 1] __aligned(IIO_DMA_MINALIGN);
};
@@ -98,6 +99,14 @@ static struct iio_event_spec adxl345_events[] = {
BIT(IIO_EV_INFO_RESET_TIMEOUT) |
BIT(IIO_EV_INFO_TAP2_MIN_DELAY),
},
+ {
+ /* free fall */
+ .type = IIO_EV_TYPE_MAG,
+ .dir = IIO_EV_DIR_FALLING,
+ .mask_shared_by_type = BIT(IIO_EV_INFO_ENABLE) |
+ BIT(IIO_EV_INFO_VALUE) |
+ BIT(IIO_EV_INFO_PERIOD),
+ },
};
#define ADXL345_CHANNEL(index, reg, axis) { \
@@ -345,6 +354,64 @@ static int adxl345_set_tap_latent(struct adxl345_state *st, u32 val_int,
return _adxl345_set_tap_time(st, ADXL345_TAP_TIME_LATENT, val_fract_us);
}
+/* freefall */
+
+static int adxl345_is_ff_en(struct adxl345_state *st, bool *en)
+{
+ int ret;
+ unsigned int regval;
+
+ ret = regmap_read(st->regmap, ADXL345_REG_INT_ENABLE, ®val);
+ if (ret)
+ return ret;
+
+ *en = FIELD_GET(ADXL345_INT_FREE_FALL, regval) > 0;
+
+ return 0;
+}
+
+static int adxl345_set_ff_en(struct adxl345_state *st, bool cmd_en)
+{
+ unsigned int regval, ff_threshold;
+ const unsigned int freefall_mask = 0x02;
+ bool en;
+ int ret;
+
+ ret = regmap_read(st->regmap, ADXL345_REG_THRESH_FF, &ff_threshold);
+ if (ret)
+ return ret;
+
+ en = cmd_en && ff_threshold > 0 && st->ff_time_ms > 0;
+
+ regval = en ? ADXL345_INT_FREE_FALL : 0x00;
+
+ return regmap_update_bits(st->regmap, ADXL345_REG_INT_ENABLE,
+ freefall_mask, regval);
+}
+
+static int adxl345_set_ff_time(struct adxl345_state *st, u32 val_int,
+ u32 val_fract_us)
+{
+ unsigned int regval;
+ int val_ms;
+
+ /*
+ * max value is 255 * 5000 us = 1.275000 seconds
+ *
+ * Note: the scaling is similar to the scaling in the ADXL380
+ */
+ if (1000000 * val_int + val_fract_us > 1275000)
+ return -EINVAL;
+
+ val_ms = val_int * 1000 + DIV_ROUND_UP(val_fract_us, 1000);
+ st->ff_time_ms = val_ms;
+
+ regval = DIV_ROUND_CLOSEST(val_ms, 5);
+
+ /* Values between 100ms and 350ms (0x14 to 0x46) are recommended. */
+ return regmap_write(st->regmap, ADXL345_REG_TIME_FF, min(regval, 0xff));
+}
+
static int adxl345_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
@@ -471,6 +538,11 @@ static int adxl345_read_event_config(struct iio_dev *indio_dev,
default:
return -EINVAL;
}
+ case IIO_EV_TYPE_MAG:
+ ret = adxl345_is_ff_en(st, &int_en);
+ if (ret)
+ return ret;
+ return int_en;
default:
return -EINVAL;
}
@@ -510,6 +582,8 @@ static int adxl345_write_event_config(struct iio_dev *indio_dev,
default:
return -EINVAL;
}
+ case IIO_EV_TYPE_MAG:
+ return adxl345_set_ff_en(st, state);
default:
return -EINVAL;
}
@@ -524,6 +598,7 @@ static int adxl345_read_event_value(struct iio_dev *indio_dev,
{
struct adxl345_state *st = iio_priv(indio_dev);
unsigned int tap_threshold;
+ unsigned int ff_threshold;
int ret;
switch (type) {
@@ -554,6 +629,22 @@ static int adxl345_read_event_value(struct iio_dev *indio_dev,
default:
return -EINVAL;
}
+ case IIO_EV_TYPE_MAG:
+ switch (info) {
+ case IIO_EV_INFO_VALUE:
+ ret = regmap_read(st->regmap, ADXL345_REG_THRESH_FF,
+ &ff_threshold);
+ if (ret)
+ return ret;
+ *val = ff_threshold;
+ return IIO_VAL_INT;
+ case IIO_EV_INFO_PERIOD:
+ *val = st->ff_time_ms;
+ *val2 = 1000;
+ return IIO_VAL_FRACTIONAL;
+ default:
+ return -EINVAL;
+ }
default:
return -EINVAL;
}
@@ -594,6 +685,18 @@ static int adxl345_write_event_value(struct iio_dev *indio_dev,
break;
}
break;
+ case IIO_EV_TYPE_MAG:
+ switch (info) {
+ case IIO_EV_INFO_VALUE:
+ ret = regmap_write(st->regmap, ADXL345_REG_THRESH_FF, val);
+ break;
+ case IIO_EV_INFO_PERIOD:
+ ret = adxl345_set_ff_time(st, val, val2);
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ break;
default:
ret = -EINVAL;
break;
@@ -855,6 +958,17 @@ static int adxl345_push_event(struct iio_dev *indio_dev, int int_stat,
return ret;
}
+ if (FIELD_GET(ADXL345_INT_FREE_FALL, int_stat)) {
+ ret = iio_push_event(indio_dev,
+ IIO_MOD_EVENT_CODE(IIO_ACCEL, 0,
+ IIO_MOD_X_OR_Y_OR_Z,
+ IIO_EV_TYPE_MAG,
+ IIO_EV_DIR_FALLING),
+ ts);
+ if (ret)
+ return ret;
+ }
+
return -ENOENT;
}
@@ -954,6 +1068,7 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap,
ADXL345_DATA_FORMAT_FULL_RES |
ADXL345_DATA_FORMAT_SELF_TEST);
unsigned int tap_threshold;
+ unsigned int ff_threshold;
int ret;
indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
@@ -973,6 +1088,9 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap,
st->tap_window_us = 64; /* 64 [0x40] -> .080 */
st->tap_latent_us = 16; /* 16 [0x10] -> .020 */
+ ff_threshold = 8; /* 8 [0x08] */
+ st->ff_time_ms = 32; /* 32 [0x20] -> 0.16 */
+
indio_dev->name = st->info->name;
indio_dev->info = &adxl345_info;
indio_dev->modes = INDIO_DIRECT_MODE;
@@ -1049,6 +1167,10 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap,
if (ret)
return ret;
+ ret = regmap_write(st->regmap, ADXL345_REG_THRESH_FF, ff_threshold);
+ if (ret)
+ return ret;
+
/* FIFO_STREAM mode is going to be activated later */
ret = devm_iio_kfifo_buffer_setup(dev, indio_dev, &adxl345_buffer_ops);
if (ret)
--
2.39.5
