iio: imu: st_lsm6dsx: fix read misalignment on untagged FIFO

st_lsm6dsx suffers of a read misalignment on untagged FIFO when
all 3 supported sensors (accel, gyro and ext device) are running
at different ODRs (the use-case is reported in the LSM6DSM Application
Note at pag 100).
Fix the issue taking into account decimation factor reading the FIFO
pattern.

Fixes: e485e2a2cfd6 ("iio: imu: st_lsm6dsx: enable sensor-hub support for lsm6dsm")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
index f2113a6..e9e756b 100644 (file)
--- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
+++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
@@ -337,6 +337,7 @@ enum st_lsm6dsx_fifo_mode {
  * @gain: Configured sensor sensitivity.
  * @odr: Output data rate of the sensor [Hz].
  * @watermark: Sensor watermark level.
+ * @decimator: Sensor decimation factor.
  * @sip: Number of samples in a given pattern.
  * @ts_ref: Sensor timestamp reference for hw one.
  * @ext_info: Sensor settings if it is connected to i2c controller
@@ -350,6 +351,7 @@ struct st_lsm6dsx_sensor {
        u32 odr;
 
        u16 watermark;
+       u8 decimator;
        u8 sip;
        s64 ts_ref;
 

diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
index bb89934..afd00da 100644 (file)
--- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
+++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
@@ -93,6 +93,7 @@ st_lsm6dsx_get_decimator_val(struct st_lsm6dsx_sensor *sensor, u32 max_odr)
                        break;
        }
 
+       sensor->decimator = decimator;
        return i == max_size ? 0 : st_lsm6dsx_decimator_table[i].val;
 }
 
@@ -337,7 +338,7 @@ static inline int st_lsm6dsx_read_block(struct st_lsm6dsx_hw *hw, u8 addr,
 int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw)
 {
        struct st_lsm6dsx_sensor *acc_sensor, *gyro_sensor, *ext_sensor = NULL;
-       int err, acc_sip, gyro_sip, ts_sip, ext_sip, read_len, offset;
+       int err, sip, acc_sip, gyro_sip, ts_sip, ext_sip, read_len, offset;
        u16 fifo_len, pattern_len = hw->sip * ST_LSM6DSX_SAMPLE_SIZE;
        u16 fifo_diff_mask = hw->settings->fifo_ops.fifo_diff.mask;
        u8 gyro_buff[ST_LSM6DSX_IIO_BUFF_SIZE];
@@ -399,19 +400,20 @@ int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw)
                acc_sip = acc_sensor->sip;
                ts_sip = hw->ts_sip;
                offset = 0;
+               sip = 0;
 
                while (acc_sip > 0 || gyro_sip > 0 || ext_sip > 0) {
-                       if (gyro_sip > 0) {
+                       if (gyro_sip > 0 && !(sip % gyro_sensor->decimator)) {
                                memcpy(gyro_buff, &hw->buff[offset],
                                       ST_LSM6DSX_SAMPLE_SIZE);
                                offset += ST_LSM6DSX_SAMPLE_SIZE;
                        }
-                       if (acc_sip > 0) {
+                       if (acc_sip > 0 && !(sip % acc_sensor->decimator)) {
                                memcpy(acc_buff, &hw->buff[offset],
                                       ST_LSM6DSX_SAMPLE_SIZE);
                                offset += ST_LSM6DSX_SAMPLE_SIZE;
                        }
-                       if (ext_sip > 0) {
+                       if (ext_sip > 0 && !(sip % ext_sensor->decimator)) {
                                memcpy(ext_buff, &hw->buff[offset],
                                       ST_LSM6DSX_SAMPLE_SIZE);
                                offset += ST_LSM6DSX_SAMPLE_SIZE;
@@ -441,18 +443,25 @@ int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw)
                                offset += ST_LSM6DSX_SAMPLE_SIZE;
                        }
 
-                       if (gyro_sip-- > 0)
+                       if (gyro_sip > 0 && !(sip % gyro_sensor->decimator)) {
                                iio_push_to_buffers_with_timestamp(
                                        hw->iio_devs[ST_LSM6DSX_ID_GYRO],
                                        gyro_buff, gyro_sensor->ts_ref + ts);
-                       if (acc_sip-- > 0)
+                               gyro_sip--;
+                       }
+                       if (acc_sip > 0 && !(sip % acc_sensor->decimator)) {
                                iio_push_to_buffers_with_timestamp(
                                        hw->iio_devs[ST_LSM6DSX_ID_ACC],
                                        acc_buff, acc_sensor->ts_ref + ts);
-                       if (ext_sip-- > 0)
+                               acc_sip--;
+                       }
+                       if (ext_sip > 0 && !(sip % ext_sensor->decimator)) {
                                iio_push_to_buffers_with_timestamp(
                                        hw->iio_devs[ST_LSM6DSX_ID_EXT0],
                                        ext_buff, ext_sensor->ts_ref + ts);
+                               ext_sip--;
+                       }
+                       sip++;
                }
        }