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Diffstat (limited to 'drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c')
-rw-r--r--drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c759
1 files changed, 759 insertions, 0 deletions
diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
new file mode 100644
index 000000000..12ed0a2e5
--- /dev/null
+++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
@@ -0,0 +1,759 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * STMicroelectronics st_lsm6dsx FIFO buffer library driver
+ *
+ * LSM6DS3/LSM6DS3H/LSM6DSL/LSM6DSM/ISM330DLC/LSM6DS3TR-C:
+ * The FIFO buffer can be configured to store data from gyroscope and
+ * accelerometer. Samples are queued without any tag according to a
+ * specific pattern based on 'FIFO data sets' (6 bytes each):
+ * - 1st data set is reserved for gyroscope data
+ * - 2nd data set is reserved for accelerometer data
+ * The FIFO pattern changes depending on the ODRs and decimation factors
+ * assigned to the FIFO data sets. The first sequence of data stored in FIFO
+ * buffer contains the data of all the enabled FIFO data sets
+ * (e.g. Gx, Gy, Gz, Ax, Ay, Az), then data are repeated depending on the
+ * value of the decimation factor and ODR set for each FIFO data set.
+ *
+ * LSM6DSO/LSM6DSOX/ASM330LHH/LSM6DSR/LSM6DSRX/ISM330DHCX:
+ * The FIFO buffer can be configured to store data from gyroscope and
+ * accelerometer. Each sample is queued with a tag (1B) indicating data
+ * source (gyroscope, accelerometer, hw timer).
+ *
+ * FIFO supported modes:
+ * - BYPASS: FIFO disabled
+ * - CONTINUOUS: FIFO enabled. When the buffer is full, the FIFO index
+ * restarts from the beginning and the oldest sample is overwritten
+ *
+ * Copyright 2016 STMicroelectronics Inc.
+ *
+ * Lorenzo Bianconi <lorenzo.bianconi@st.com>
+ * Denis Ciocca <denis.ciocca@st.com>
+ */
+#include <linux/module.h>
+#include <linux/iio/kfifo_buf.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/regmap.h>
+#include <linux/bitfield.h>
+
+#include <linux/platform_data/st_sensors_pdata.h>
+
+#include "st_lsm6dsx.h"
+
+#define ST_LSM6DSX_REG_FIFO_MODE_ADDR 0x0a
+#define ST_LSM6DSX_FIFO_MODE_MASK GENMASK(2, 0)
+#define ST_LSM6DSX_FIFO_ODR_MASK GENMASK(6, 3)
+#define ST_LSM6DSX_FIFO_EMPTY_MASK BIT(12)
+#define ST_LSM6DSX_REG_FIFO_OUTL_ADDR 0x3e
+#define ST_LSM6DSX_REG_FIFO_OUT_TAG_ADDR 0x78
+#define ST_LSM6DSX_REG_TS_RESET_ADDR 0x42
+
+#define ST_LSM6DSX_MAX_FIFO_ODR_VAL 0x08
+
+#define ST_LSM6DSX_TS_RESET_VAL 0xaa
+
+struct st_lsm6dsx_decimator_entry {
+ u8 decimator;
+ u8 val;
+};
+
+enum st_lsm6dsx_fifo_tag {
+ ST_LSM6DSX_GYRO_TAG = 0x01,
+ ST_LSM6DSX_ACC_TAG = 0x02,
+ ST_LSM6DSX_TS_TAG = 0x04,
+ ST_LSM6DSX_EXT0_TAG = 0x0f,
+ ST_LSM6DSX_EXT1_TAG = 0x10,
+ ST_LSM6DSX_EXT2_TAG = 0x11,
+};
+
+static const
+struct st_lsm6dsx_decimator_entry st_lsm6dsx_decimator_table[] = {
+ { 0, 0x0 },
+ { 1, 0x1 },
+ { 2, 0x2 },
+ { 3, 0x3 },
+ { 4, 0x4 },
+ { 8, 0x5 },
+ { 16, 0x6 },
+ { 32, 0x7 },
+};
+
+static int
+st_lsm6dsx_get_decimator_val(struct st_lsm6dsx_sensor *sensor, u32 max_odr)
+{
+ const int max_size = ARRAY_SIZE(st_lsm6dsx_decimator_table);
+ u32 decimator = max_odr / sensor->odr;
+ int i;
+
+ if (decimator > 1)
+ decimator = round_down(decimator, 2);
+
+ for (i = 0; i < max_size; i++) {
+ if (st_lsm6dsx_decimator_table[i].decimator == decimator)
+ break;
+ }
+
+ sensor->decimator = decimator;
+ return i == max_size ? 0 : st_lsm6dsx_decimator_table[i].val;
+}
+
+static void st_lsm6dsx_get_max_min_odr(struct st_lsm6dsx_hw *hw,
+ u32 *max_odr, u32 *min_odr)
+{
+ struct st_lsm6dsx_sensor *sensor;
+ int i;
+
+ *max_odr = 0, *min_odr = ~0;
+ for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
+ if (!hw->iio_devs[i])
+ continue;
+
+ sensor = iio_priv(hw->iio_devs[i]);
+
+ if (!(hw->enable_mask & BIT(sensor->id)))
+ continue;
+
+ *max_odr = max_t(u32, *max_odr, sensor->odr);
+ *min_odr = min_t(u32, *min_odr, sensor->odr);
+ }
+}
+
+static u8 st_lsm6dsx_get_sip(struct st_lsm6dsx_sensor *sensor, u32 min_odr)
+{
+ u8 sip = sensor->odr / min_odr;
+
+ return sip > 1 ? round_down(sip, 2) : sip;
+}
+
+static int st_lsm6dsx_update_decimators(struct st_lsm6dsx_hw *hw)
+{
+ const struct st_lsm6dsx_reg *ts_dec_reg;
+ struct st_lsm6dsx_sensor *sensor;
+ u16 sip = 0, ts_sip = 0;
+ u32 max_odr, min_odr;
+ int err = 0, i;
+ u8 data;
+
+ st_lsm6dsx_get_max_min_odr(hw, &max_odr, &min_odr);
+
+ for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
+ const struct st_lsm6dsx_reg *dec_reg;
+
+ if (!hw->iio_devs[i])
+ continue;
+
+ sensor = iio_priv(hw->iio_devs[i]);
+ /* update fifo decimators and sample in pattern */
+ if (hw->enable_mask & BIT(sensor->id)) {
+ sensor->sip = st_lsm6dsx_get_sip(sensor, min_odr);
+ data = st_lsm6dsx_get_decimator_val(sensor, max_odr);
+ } else {
+ sensor->sip = 0;
+ data = 0;
+ }
+ ts_sip = max_t(u16, ts_sip, sensor->sip);
+
+ dec_reg = &hw->settings->decimator[sensor->id];
+ if (dec_reg->addr) {
+ int val = ST_LSM6DSX_SHIFT_VAL(data, dec_reg->mask);
+
+ err = st_lsm6dsx_update_bits_locked(hw, dec_reg->addr,
+ dec_reg->mask,
+ val);
+ if (err < 0)
+ return err;
+ }
+ sip += sensor->sip;
+ }
+ hw->sip = sip + ts_sip;
+ hw->ts_sip = ts_sip;
+
+ /*
+ * update hw ts decimator if necessary. Decimator for hw timestamp
+ * is always 1 or 0 in order to have a ts sample for each data
+ * sample in FIFO
+ */
+ ts_dec_reg = &hw->settings->ts_settings.decimator;
+ if (ts_dec_reg->addr) {
+ int val, ts_dec = !!hw->ts_sip;
+
+ val = ST_LSM6DSX_SHIFT_VAL(ts_dec, ts_dec_reg->mask);
+ err = st_lsm6dsx_update_bits_locked(hw, ts_dec_reg->addr,
+ ts_dec_reg->mask, val);
+ }
+ return err;
+}
+
+static int st_lsm6dsx_set_fifo_mode(struct st_lsm6dsx_hw *hw,
+ enum st_lsm6dsx_fifo_mode fifo_mode)
+{
+ unsigned int data;
+
+ data = FIELD_PREP(ST_LSM6DSX_FIFO_MODE_MASK, fifo_mode);
+ return st_lsm6dsx_update_bits_locked(hw, ST_LSM6DSX_REG_FIFO_MODE_ADDR,
+ ST_LSM6DSX_FIFO_MODE_MASK, data);
+}
+
+static int st_lsm6dsx_set_fifo_odr(struct st_lsm6dsx_sensor *sensor,
+ bool enable)
+{
+ struct st_lsm6dsx_hw *hw = sensor->hw;
+ const struct st_lsm6dsx_reg *batch_reg;
+ u8 data;
+
+ batch_reg = &hw->settings->batch[sensor->id];
+ if (batch_reg->addr) {
+ int val;
+
+ if (enable) {
+ int err;
+
+ err = st_lsm6dsx_check_odr(sensor, sensor->odr,
+ &data);
+ if (err < 0)
+ return err;
+ } else {
+ data = 0;
+ }
+ val = ST_LSM6DSX_SHIFT_VAL(data, batch_reg->mask);
+ return st_lsm6dsx_update_bits_locked(hw, batch_reg->addr,
+ batch_reg->mask, val);
+ } else {
+ data = hw->enable_mask ? ST_LSM6DSX_MAX_FIFO_ODR_VAL : 0;
+ return st_lsm6dsx_update_bits_locked(hw,
+ ST_LSM6DSX_REG_FIFO_MODE_ADDR,
+ ST_LSM6DSX_FIFO_ODR_MASK,
+ FIELD_PREP(ST_LSM6DSX_FIFO_ODR_MASK,
+ data));
+ }
+}
+
+int st_lsm6dsx_update_watermark(struct st_lsm6dsx_sensor *sensor, u16 watermark)
+{
+ u16 fifo_watermark = ~0, cur_watermark, fifo_th_mask;
+ struct st_lsm6dsx_hw *hw = sensor->hw;
+ struct st_lsm6dsx_sensor *cur_sensor;
+ int i, err, data;
+ __le16 wdata;
+
+ if (!hw->sip)
+ return 0;
+
+ for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
+ if (!hw->iio_devs[i])
+ continue;
+
+ cur_sensor = iio_priv(hw->iio_devs[i]);
+
+ if (!(hw->enable_mask & BIT(cur_sensor->id)))
+ continue;
+
+ cur_watermark = (cur_sensor == sensor) ? watermark
+ : cur_sensor->watermark;
+
+ fifo_watermark = min_t(u16, fifo_watermark, cur_watermark);
+ }
+
+ fifo_watermark = max_t(u16, fifo_watermark, hw->sip);
+ fifo_watermark = (fifo_watermark / hw->sip) * hw->sip;
+ fifo_watermark = fifo_watermark * hw->settings->fifo_ops.th_wl;
+
+ mutex_lock(&hw->page_lock);
+ err = regmap_read(hw->regmap, hw->settings->fifo_ops.fifo_th.addr + 1,
+ &data);
+ if (err < 0)
+ goto out;
+
+ fifo_th_mask = hw->settings->fifo_ops.fifo_th.mask;
+ fifo_watermark = ((data << 8) & ~fifo_th_mask) |
+ (fifo_watermark & fifo_th_mask);
+
+ wdata = cpu_to_le16(fifo_watermark);
+ err = regmap_bulk_write(hw->regmap,
+ hw->settings->fifo_ops.fifo_th.addr,
+ &wdata, sizeof(wdata));
+out:
+ mutex_unlock(&hw->page_lock);
+ return err;
+}
+
+static int st_lsm6dsx_reset_hw_ts(struct st_lsm6dsx_hw *hw)
+{
+ struct st_lsm6dsx_sensor *sensor;
+ int i, err;
+
+ /* reset hw ts counter */
+ err = st_lsm6dsx_write_locked(hw, ST_LSM6DSX_REG_TS_RESET_ADDR,
+ ST_LSM6DSX_TS_RESET_VAL);
+ if (err < 0)
+ return err;
+
+ for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
+ if (!hw->iio_devs[i])
+ continue;
+
+ sensor = iio_priv(hw->iio_devs[i]);
+ /*
+ * store enable buffer timestamp as reference for
+ * hw timestamp
+ */
+ sensor->ts_ref = iio_get_time_ns(hw->iio_devs[i]);
+ }
+ return 0;
+}
+
+int st_lsm6dsx_resume_fifo(struct st_lsm6dsx_hw *hw)
+{
+ int err;
+
+ /* reset hw ts counter */
+ err = st_lsm6dsx_reset_hw_ts(hw);
+ if (err < 0)
+ return err;
+
+ return st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_CONT);
+}
+
+/*
+ * Set max bulk read to ST_LSM6DSX_MAX_WORD_LEN/ST_LSM6DSX_MAX_TAGGED_WORD_LEN
+ * in order to avoid a kmalloc for each bus access
+ */
+static inline int st_lsm6dsx_read_block(struct st_lsm6dsx_hw *hw, u8 addr,
+ u8 *data, unsigned int data_len,
+ unsigned int max_word_len)
+{
+ unsigned int word_len, read_len = 0;
+ int err;
+
+ while (read_len < data_len) {
+ word_len = min_t(unsigned int, data_len - read_len,
+ max_word_len);
+ err = st_lsm6dsx_read_locked(hw, addr, data + read_len,
+ word_len);
+ if (err < 0)
+ return err;
+ read_len += word_len;
+ }
+ return 0;
+}
+
+#define ST_LSM6DSX_IIO_BUFF_SIZE (ALIGN(ST_LSM6DSX_SAMPLE_SIZE, \
+ sizeof(s64)) + sizeof(s64))
+/**
+ * st_lsm6dsx_read_fifo() - hw FIFO read routine
+ * @hw: Pointer to instance of struct st_lsm6dsx_hw.
+ *
+ * Read samples from the hw FIFO and push them to IIO buffers.
+ *
+ * Return: Number of bytes read from the FIFO
+ */
+int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw)
+{
+ struct st_lsm6dsx_sensor *acc_sensor, *gyro_sensor, *ext_sensor = NULL;
+ 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;
+ bool reset_ts = false;
+ __le16 fifo_status;
+ s64 ts = 0;
+
+ err = st_lsm6dsx_read_locked(hw,
+ hw->settings->fifo_ops.fifo_diff.addr,
+ &fifo_status, sizeof(fifo_status));
+ if (err < 0) {
+ dev_err(hw->dev, "failed to read fifo status (err=%d)\n",
+ err);
+ return err;
+ }
+
+ if (fifo_status & cpu_to_le16(ST_LSM6DSX_FIFO_EMPTY_MASK))
+ return 0;
+
+ fifo_len = (le16_to_cpu(fifo_status) & fifo_diff_mask) *
+ ST_LSM6DSX_CHAN_SIZE;
+ fifo_len = (fifo_len / pattern_len) * pattern_len;
+
+ acc_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_ACC]);
+ gyro_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_GYRO]);
+ if (hw->iio_devs[ST_LSM6DSX_ID_EXT0])
+ ext_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_EXT0]);
+
+ for (read_len = 0; read_len < fifo_len; read_len += pattern_len) {
+ err = st_lsm6dsx_read_block(hw, ST_LSM6DSX_REG_FIFO_OUTL_ADDR,
+ hw->buff, pattern_len,
+ ST_LSM6DSX_MAX_WORD_LEN);
+ if (err < 0) {
+ dev_err(hw->dev,
+ "failed to read pattern from fifo (err=%d)\n",
+ err);
+ return err;
+ }
+
+ /*
+ * Data are written to the FIFO with a specific pattern
+ * depending on the configured ODRs. The first sequence of data
+ * stored in FIFO contains the data of all enabled sensors
+ * (e.g. Gx, Gy, Gz, Ax, Ay, Az, Ts), then data are repeated
+ * depending on the value of the decimation factor set for each
+ * sensor.
+ *
+ * Supposing the FIFO is storing data from gyroscope and
+ * accelerometer at different ODRs:
+ * - gyroscope ODR = 208Hz, accelerometer ODR = 104Hz
+ * Since the gyroscope ODR is twice the accelerometer one, the
+ * following pattern is repeated every 9 samples:
+ * - Gx, Gy, Gz, Ax, Ay, Az, Ts, Gx, Gy, Gz, Ts, Gx, ..
+ */
+ ext_sip = ext_sensor ? ext_sensor->sip : 0;
+ gyro_sip = gyro_sensor->sip;
+ 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 && !(sip % gyro_sensor->decimator)) {
+ memcpy(hw->scan[ST_LSM6DSX_ID_GYRO].channels,
+ &hw->buff[offset],
+ sizeof(hw->scan[ST_LSM6DSX_ID_GYRO].channels));
+ offset += sizeof(hw->scan[ST_LSM6DSX_ID_GYRO].channels);
+ }
+ if (acc_sip > 0 && !(sip % acc_sensor->decimator)) {
+ memcpy(hw->scan[ST_LSM6DSX_ID_ACC].channels,
+ &hw->buff[offset],
+ sizeof(hw->scan[ST_LSM6DSX_ID_ACC].channels));
+ offset += sizeof(hw->scan[ST_LSM6DSX_ID_ACC].channels);
+ }
+ if (ext_sip > 0 && !(sip % ext_sensor->decimator)) {
+ memcpy(hw->scan[ST_LSM6DSX_ID_EXT0].channels,
+ &hw->buff[offset],
+ sizeof(hw->scan[ST_LSM6DSX_ID_EXT0].channels));
+ offset += sizeof(hw->scan[ST_LSM6DSX_ID_EXT0].channels);
+ }
+
+ if (ts_sip-- > 0) {
+ u8 data[ST_LSM6DSX_SAMPLE_SIZE];
+
+ memcpy(data, &hw->buff[offset], sizeof(data));
+ /*
+ * hw timestamp is 3B long and it is stored
+ * in FIFO using 6B as 4th FIFO data set
+ * according to this schema:
+ * B0 = ts[15:8], B1 = ts[23:16], B3 = ts[7:0]
+ */
+ ts = data[1] << 16 | data[0] << 8 | data[3];
+ /*
+ * check if hw timestamp engine is going to
+ * reset (the sensor generates an interrupt
+ * to signal the hw timestamp will reset in
+ * 1.638s)
+ */
+ if (!reset_ts && ts >= 0xff0000)
+ reset_ts = true;
+ ts *= hw->ts_gain;
+
+ offset += ST_LSM6DSX_SAMPLE_SIZE;
+ }
+
+ if (gyro_sip > 0 && !(sip % gyro_sensor->decimator)) {
+ iio_push_to_buffers_with_timestamp(
+ hw->iio_devs[ST_LSM6DSX_ID_GYRO],
+ &hw->scan[ST_LSM6DSX_ID_GYRO],
+ gyro_sensor->ts_ref + ts);
+ gyro_sip--;
+ }
+ if (acc_sip > 0 && !(sip % acc_sensor->decimator)) {
+ iio_push_to_buffers_with_timestamp(
+ hw->iio_devs[ST_LSM6DSX_ID_ACC],
+ &hw->scan[ST_LSM6DSX_ID_ACC],
+ acc_sensor->ts_ref + ts);
+ acc_sip--;
+ }
+ if (ext_sip > 0 && !(sip % ext_sensor->decimator)) {
+ iio_push_to_buffers_with_timestamp(
+ hw->iio_devs[ST_LSM6DSX_ID_EXT0],
+ &hw->scan[ST_LSM6DSX_ID_EXT0],
+ ext_sensor->ts_ref + ts);
+ ext_sip--;
+ }
+ sip++;
+ }
+ }
+
+ if (unlikely(reset_ts)) {
+ err = st_lsm6dsx_reset_hw_ts(hw);
+ if (err < 0) {
+ dev_err(hw->dev, "failed to reset hw ts (err=%d)\n",
+ err);
+ return err;
+ }
+ }
+ return read_len;
+}
+
+#define ST_LSM6DSX_INVALID_SAMPLE 0x7ffd
+static int
+st_lsm6dsx_push_tagged_data(struct st_lsm6dsx_hw *hw, u8 tag,
+ u8 *data, s64 ts)
+{
+ s16 val = le16_to_cpu(*(__le16 *)data);
+ struct st_lsm6dsx_sensor *sensor;
+ struct iio_dev *iio_dev;
+
+ /* invalid sample during bootstrap phase */
+ if (val >= ST_LSM6DSX_INVALID_SAMPLE)
+ return -EINVAL;
+
+ /*
+ * EXT_TAG are managed in FIFO fashion so ST_LSM6DSX_EXT0_TAG
+ * corresponds to the first enabled channel, ST_LSM6DSX_EXT1_TAG
+ * to the second one and ST_LSM6DSX_EXT2_TAG to the last enabled
+ * channel
+ */
+ switch (tag) {
+ case ST_LSM6DSX_GYRO_TAG:
+ iio_dev = hw->iio_devs[ST_LSM6DSX_ID_GYRO];
+ break;
+ case ST_LSM6DSX_ACC_TAG:
+ iio_dev = hw->iio_devs[ST_LSM6DSX_ID_ACC];
+ break;
+ case ST_LSM6DSX_EXT0_TAG:
+ if (hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT0))
+ iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT0];
+ else if (hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT1))
+ iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT1];
+ else
+ iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT2];
+ break;
+ case ST_LSM6DSX_EXT1_TAG:
+ if ((hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT0)) &&
+ (hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT1)))
+ iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT1];
+ else
+ iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT2];
+ break;
+ case ST_LSM6DSX_EXT2_TAG:
+ iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT2];
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ sensor = iio_priv(iio_dev);
+ iio_push_to_buffers_with_timestamp(iio_dev, data,
+ ts + sensor->ts_ref);
+
+ return 0;
+}
+
+/**
+ * st_lsm6dsx_read_tagged_fifo() - tagged hw FIFO read routine
+ * @hw: Pointer to instance of struct st_lsm6dsx_hw.
+ *
+ * Read samples from the hw FIFO and push them to IIO buffers.
+ *
+ * Return: Number of bytes read from the FIFO
+ */
+int st_lsm6dsx_read_tagged_fifo(struct st_lsm6dsx_hw *hw)
+{
+ u16 pattern_len = hw->sip * ST_LSM6DSX_TAGGED_SAMPLE_SIZE;
+ u16 fifo_len, fifo_diff_mask;
+ /*
+ * Alignment needed as this can ultimately be passed to a
+ * call to iio_push_to_buffers_with_timestamp() which
+ * must be passed a buffer that is aligned to 8 bytes so
+ * as to allow insertion of a naturally aligned timestamp.
+ */
+ u8 iio_buff[ST_LSM6DSX_IIO_BUFF_SIZE] __aligned(8);
+ u8 tag;
+ bool reset_ts = false;
+ int i, err, read_len;
+ __le16 fifo_status;
+ s64 ts = 0;
+
+ err = st_lsm6dsx_read_locked(hw,
+ hw->settings->fifo_ops.fifo_diff.addr,
+ &fifo_status, sizeof(fifo_status));
+ if (err < 0) {
+ dev_err(hw->dev, "failed to read fifo status (err=%d)\n",
+ err);
+ return err;
+ }
+
+ fifo_diff_mask = hw->settings->fifo_ops.fifo_diff.mask;
+ fifo_len = (le16_to_cpu(fifo_status) & fifo_diff_mask) *
+ ST_LSM6DSX_TAGGED_SAMPLE_SIZE;
+ if (!fifo_len)
+ return 0;
+
+ for (read_len = 0; read_len < fifo_len; read_len += pattern_len) {
+ err = st_lsm6dsx_read_block(hw,
+ ST_LSM6DSX_REG_FIFO_OUT_TAG_ADDR,
+ hw->buff, pattern_len,
+ ST_LSM6DSX_MAX_TAGGED_WORD_LEN);
+ if (err < 0) {
+ dev_err(hw->dev,
+ "failed to read pattern from fifo (err=%d)\n",
+ err);
+ return err;
+ }
+
+ for (i = 0; i < pattern_len;
+ i += ST_LSM6DSX_TAGGED_SAMPLE_SIZE) {
+ memcpy(iio_buff, &hw->buff[i + ST_LSM6DSX_TAG_SIZE],
+ ST_LSM6DSX_SAMPLE_SIZE);
+
+ tag = hw->buff[i] >> 3;
+ if (tag == ST_LSM6DSX_TS_TAG) {
+ /*
+ * hw timestamp is 4B long and it is stored
+ * in FIFO according to this schema:
+ * B0 = ts[7:0], B1 = ts[15:8], B2 = ts[23:16],
+ * B3 = ts[31:24]
+ */
+ ts = le32_to_cpu(*((__le32 *)iio_buff));
+ /*
+ * check if hw timestamp engine is going to
+ * reset (the sensor generates an interrupt
+ * to signal the hw timestamp will reset in
+ * 1.638s)
+ */
+ if (!reset_ts && ts >= 0xffff0000)
+ reset_ts = true;
+ ts *= hw->ts_gain;
+ } else {
+ st_lsm6dsx_push_tagged_data(hw, tag, iio_buff,
+ ts);
+ }
+ }
+ }
+
+ if (unlikely(reset_ts)) {
+ err = st_lsm6dsx_reset_hw_ts(hw);
+ if (err < 0)
+ return err;
+ }
+ return read_len;
+}
+
+int st_lsm6dsx_flush_fifo(struct st_lsm6dsx_hw *hw)
+{
+ int err;
+
+ if (!hw->settings->fifo_ops.read_fifo)
+ return -ENOTSUPP;
+
+ mutex_lock(&hw->fifo_lock);
+
+ hw->settings->fifo_ops.read_fifo(hw);
+ err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_BYPASS);
+
+ mutex_unlock(&hw->fifo_lock);
+
+ return err;
+}
+
+int st_lsm6dsx_update_fifo(struct st_lsm6dsx_sensor *sensor, bool enable)
+{
+ struct st_lsm6dsx_hw *hw = sensor->hw;
+ u8 fifo_mask;
+ int err;
+
+ mutex_lock(&hw->conf_lock);
+
+ if (enable)
+ fifo_mask = hw->fifo_mask | BIT(sensor->id);
+ else
+ fifo_mask = hw->fifo_mask & ~BIT(sensor->id);
+
+ if (hw->fifo_mask) {
+ err = st_lsm6dsx_flush_fifo(hw);
+ if (err < 0)
+ goto out;
+ }
+
+ if (sensor->id == ST_LSM6DSX_ID_EXT0 ||
+ sensor->id == ST_LSM6DSX_ID_EXT1 ||
+ sensor->id == ST_LSM6DSX_ID_EXT2) {
+ err = st_lsm6dsx_shub_set_enable(sensor, enable);
+ if (err < 0)
+ goto out;
+ } else {
+ err = st_lsm6dsx_sensor_set_enable(sensor, enable);
+ if (err < 0)
+ goto out;
+ }
+
+ err = st_lsm6dsx_set_fifo_odr(sensor, enable);
+ if (err < 0)
+ goto out;
+
+ err = st_lsm6dsx_update_decimators(hw);
+ if (err < 0)
+ goto out;
+
+ err = st_lsm6dsx_update_watermark(sensor, sensor->watermark);
+ if (err < 0)
+ goto out;
+
+ if (fifo_mask) {
+ err = st_lsm6dsx_resume_fifo(hw);
+ if (err < 0)
+ goto out;
+ }
+
+ hw->fifo_mask = fifo_mask;
+
+out:
+ mutex_unlock(&hw->conf_lock);
+
+ return err;
+}
+
+static int st_lsm6dsx_buffer_preenable(struct iio_dev *iio_dev)
+{
+ struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
+ struct st_lsm6dsx_hw *hw = sensor->hw;
+
+ if (!hw->settings->fifo_ops.update_fifo)
+ return -ENOTSUPP;
+
+ return hw->settings->fifo_ops.update_fifo(sensor, true);
+}
+
+static int st_lsm6dsx_buffer_postdisable(struct iio_dev *iio_dev)
+{
+ struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
+ struct st_lsm6dsx_hw *hw = sensor->hw;
+
+ if (!hw->settings->fifo_ops.update_fifo)
+ return -ENOTSUPP;
+
+ return hw->settings->fifo_ops.update_fifo(sensor, false);
+}
+
+static const struct iio_buffer_setup_ops st_lsm6dsx_buffer_ops = {
+ .preenable = st_lsm6dsx_buffer_preenable,
+ .postdisable = st_lsm6dsx_buffer_postdisable,
+};
+
+int st_lsm6dsx_fifo_setup(struct st_lsm6dsx_hw *hw)
+{
+ struct iio_buffer *buffer;
+ int i;
+
+ for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
+ if (!hw->iio_devs[i])
+ continue;
+
+ buffer = devm_iio_kfifo_allocate(hw->dev);
+ if (!buffer)
+ return -ENOMEM;
+
+ iio_device_attach_buffer(hw->iio_devs[i], buffer);
+ hw->iio_devs[i]->modes |= INDIO_BUFFER_SOFTWARE;
+ hw->iio_devs[i]->setup_ops = &st_lsm6dsx_buffer_ops;
+ }
+
+ return 0;
+}