[PATCH AUTOSEL 5.6 05/79] iio: imu: st_lsm6dsx: fix read misalignment on untagged FIFO

Sasha Levin
2020-04-30T13:50:58Z

From: Lorenzo Bianconi <lorenzo@kernel.org>

[ Upstream commit 7762902c89c4c78d32ec562f1ada44d02039104b ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h | 2 ++
.../iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c | 23 +++++++++++++------
2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
index 9c3486a8134fd..b8ed6c900c457 100644
--- 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 bb899345f2bba..afd00daeefb2d 100644
--- 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++;
}
}

--
2.20.1