In the source for drivers/iio/accel/hid-sensor-accel-3d.c, the following code exists to assign a timestamp but fails to set ‘ret = 0’ after setting accel_state->timestamp.
/* Capture samples in local storage */
static int accel_3d_capture_sample(struct hid_sensor_hub_device *hsdev,
unsigned usage_id,
size_t raw_len, char *raw_data,
void *priv)
{
struct iio_dev *indio_dev = platform_get_drvdata(priv);
struct accel_3d_state *accel_state = iio_priv(indio_dev);
int offset;
int ret = -EINVAL;
switch (usage_id) {
case HID_USAGE_SENSOR_ACCEL_X_AXIS:
case HID_USAGE_SENSOR_ACCEL_Y_AXIS:
case HID_USAGE_SENSOR_ACCEL_Z_AXIS:
offset = usage_id - HID_USAGE_SENSOR_ACCEL_X_AXIS;
accel_state->accel_val[CHANNEL_SCAN_INDEX_X + offset] =
*(u32 *)raw_data;
ret = 0;
break;
case HID_USAGE_SENSOR_TIME_TIMESTAMP:
accel_state->timestamp =
hid_sensor_convert_timestamp(
&accel_state->common_attributes,
*(int64_t *)raw_data);
break;
default:
break;
}
return ret;
}
A similar construct exists in drivers/iio/gyro/hid-sensor-gyro-3d.c which sets ‘ret’:
case HID_USAGE_SENSOR_TIME_TIMESTAMP: // usec->nsec
gyro_state->timestamp = (*(int64_t *)raw_data)*1000;
ret = 0;
break;