// 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 * Denis Ciocca */ #include #include #include #include #include #include #include #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; } 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; } /* * 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; u8 gyro_buff[ST_LSM6DSX_IIO_BUFF_SIZE]; u8 acc_buff[ST_LSM6DSX_IIO_BUFF_SIZE]; u8 ext_buff[ST_LSM6DSX_IIO_BUFF_SIZE]; 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(gyro_buff, &hw->buff[offset], ST_LSM6DSX_SAMPLE_SIZE); offset += ST_LSM6DSX_SAMPLE_SIZE; } 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 && !(sip % ext_sensor->decimator)) { memcpy(ext_buff, &hw->buff[offset], ST_LSM6DSX_SAMPLE_SIZE); offset += ST_LSM6DSX_SAMPLE_SIZE; } 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], gyro_buff, 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], acc_buff, 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], ext_buff, 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; u8 iio_buff[ST_LSM6DSX_IIO_BUFF_SIZE], 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) { /* reset hw ts counter */ err = st_lsm6dsx_reset_hw_ts(hw); if (err < 0) goto out; err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_CONT); 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; }