diff options
Diffstat (limited to 'drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c')
| -rw-r--r-- | drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c | 585 |
1 files changed, 585 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..4d89de0be --- /dev/null +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c @@ -0,0 +1,585 @@ +/* + * STMicroelectronics st_lsm6dsx FIFO buffer library driver + * + * LSM6DS3/LSM6DS3H/LSM6DSL/LSM6DSM/ISM330DLC: 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. + * 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> + * + * Licensed under the GPL-2. + */ +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/irq.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_HLACTIVE_ADDR 0x12 +#define ST_LSM6DSX_REG_HLACTIVE_MASK BIT(5) +#define ST_LSM6DSX_REG_PP_OD_ADDR 0x12 +#define ST_LSM6DSX_REG_PP_OD_MASK BIT(4) +#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_TS_RESET_ADDR 0x42 + +#define ST_LSM6DSX_MAX_FIFO_ODR_VAL 0x08 + +#define ST_LSM6DSX_TS_SENSITIVITY 25000UL /* 25us */ +#define ST_LSM6DSX_TS_RESET_VAL 0xaa + +struct st_lsm6dsx_decimator_entry { + u8 decimator; + u8 val; +}; + +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(u8 val) +{ + const int max_size = ARRAY_SIZE(st_lsm6dsx_decimator_table); + int i; + + for (i = 0; i < max_size; i++) + if (st_lsm6dsx_decimator_table[i].decimator == val) + break; + + return i == max_size ? 0 : st_lsm6dsx_decimator_table[i].val; +} + +static void st_lsm6dsx_get_max_min_odr(struct st_lsm6dsx_hw *hw, + u16 *max_odr, u16 *min_odr) +{ + struct st_lsm6dsx_sensor *sensor; + int i; + + *max_odr = 0, *min_odr = ~0; + for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) { + sensor = iio_priv(hw->iio_devs[i]); + + if (!(hw->enable_mask & BIT(sensor->id))) + continue; + + *max_odr = max_t(u16, *max_odr, sensor->odr); + *min_odr = min_t(u16, *min_odr, sensor->odr); + } +} + +static int st_lsm6dsx_update_decimators(struct st_lsm6dsx_hw *hw) +{ + u16 max_odr, min_odr, sip = 0, ts_sip = 0; + const struct st_lsm6dsx_reg *ts_dec_reg; + struct st_lsm6dsx_sensor *sensor; + 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; + + sensor = iio_priv(hw->iio_devs[i]); + /* update fifo decimators and sample in pattern */ + if (hw->enable_mask & BIT(sensor->id)) { + sensor->sip = sensor->odr / min_odr; + sensor->decimator = max_odr / sensor->odr; + data = st_lsm6dsx_get_decimator_val(sensor->decimator); + } else { + sensor->sip = 0; + sensor->decimator = 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 = regmap_update_bits(hw->regmap, 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 = regmap_update_bits(hw->regmap, 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) +{ + int err; + + err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_FIFO_MODE_ADDR, + ST_LSM6DSX_FIFO_MODE_MASK, + FIELD_PREP(ST_LSM6DSX_FIFO_MODE_MASK, + fifo_mode)); + if (err < 0) + return err; + + hw->fifo_mode = fifo_mode; + + return 0; +} + +static int st_lsm6dsx_set_fifo_odr(struct st_lsm6dsx_sensor *sensor, + bool enable) +{ + struct st_lsm6dsx_hw *hw = sensor->hw; + u8 data; + + data = hw->enable_mask ? ST_LSM6DSX_MAX_FIFO_ODR_VAL : 0; + return regmap_update_bits(hw->regmap, 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++) { + 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; + + err = regmap_read(hw->regmap, hw->settings->fifo_ops.fifo_th.addr + 1, + &data); + if (err < 0) + return err; + + 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); + return regmap_bulk_write(hw->regmap, + hw->settings->fifo_ops.fifo_th.addr, + &wdata, sizeof(wdata)); +} + +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 = regmap_write(hw->regmap, 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++) { + 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 in order to avoid + * a kmalloc for each bus access + */ +static inline int st_lsm6dsx_read_block(struct st_lsm6dsx_hw *hw, u8 *data, + unsigned int data_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, + ST_LSM6DSX_MAX_WORD_LEN); + err = regmap_bulk_read(hw->regmap, + ST_LSM6DSX_REG_FIFO_OUTL_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 + */ +static int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw) +{ + u16 fifo_len, pattern_len = hw->sip * ST_LSM6DSX_SAMPLE_SIZE; + u16 fifo_diff_mask = hw->settings->fifo_ops.fifo_diff.mask; + int err, acc_sip, gyro_sip, ts_sip, read_len, offset; + struct st_lsm6dsx_sensor *acc_sensor, *gyro_sensor; + u8 gyro_buff[ST_LSM6DSX_IIO_BUFF_SIZE]; + u8 acc_buff[ST_LSM6DSX_IIO_BUFF_SIZE]; + bool reset_ts = false; + __le16 fifo_status; + s64 ts = 0; + + err = regmap_bulk_read(hw->regmap, + 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]); + + for (read_len = 0; read_len < fifo_len; read_len += pattern_len) { + err = st_lsm6dsx_read_block(hw, hw->buff, pattern_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, .. + */ + gyro_sip = gyro_sensor->sip; + acc_sip = acc_sensor->sip; + ts_sip = hw->ts_sip; + offset = 0; + + while (acc_sip > 0 || gyro_sip > 0) { + if (gyro_sip > 0) { + memcpy(gyro_buff, &hw->buff[offset], + ST_LSM6DSX_SAMPLE_SIZE); + offset += ST_LSM6DSX_SAMPLE_SIZE; + } + if (acc_sip > 0) { + memcpy(acc_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 *= ST_LSM6DSX_TS_SENSITIVITY; + + offset += ST_LSM6DSX_SAMPLE_SIZE; + } + + if (gyro_sip-- > 0) + iio_push_to_buffers_with_timestamp( + hw->iio_devs[ST_LSM6DSX_ID_GYRO], + gyro_buff, gyro_sensor->ts_ref + ts); + if (acc_sip-- > 0) + iio_push_to_buffers_with_timestamp( + hw->iio_devs[ST_LSM6DSX_ID_ACC], + acc_buff, acc_sensor->ts_ref + ts); + } + } + + 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; +} + +int st_lsm6dsx_flush_fifo(struct st_lsm6dsx_hw *hw) +{ + int err; + + mutex_lock(&hw->fifo_lock); + + st_lsm6dsx_read_fifo(hw); + err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_BYPASS); + + mutex_unlock(&hw->fifo_lock); + + return err; +} + +static int st_lsm6dsx_update_fifo(struct iio_dev *iio_dev, bool enable) +{ + struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev); + struct st_lsm6dsx_hw *hw = sensor->hw; + int err; + + mutex_lock(&hw->conf_lock); + + if (hw->fifo_mode != ST_LSM6DSX_FIFO_BYPASS) { + err = st_lsm6dsx_flush_fifo(hw); + if (err < 0) + goto out; + } + + if (enable) { + err = st_lsm6dsx_sensor_enable(sensor); + if (err < 0) + goto out; + } else { + err = st_lsm6dsx_sensor_disable(sensor); + 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 (hw->enable_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); + } + +out: + mutex_unlock(&hw->conf_lock); + + return err; +} + +static irqreturn_t st_lsm6dsx_handler_irq(int irq, void *private) +{ + struct st_lsm6dsx_hw *hw = private; + + return hw->sip > 0 ? IRQ_WAKE_THREAD : IRQ_NONE; +} + +static irqreturn_t st_lsm6dsx_handler_thread(int irq, void *private) +{ + struct st_lsm6dsx_hw *hw = private; + int fifo_len = 0, len; + + /* + * If we are using edge IRQs, new samples can arrive while + * processing current interrupt since there are no hw + * guarantees the irq line stays "low" long enough to properly + * detect the new interrupt. In this case the new sample will + * be missed. + * Polling FIFO status register allow us to read new + * samples even if the interrupt arrives while processing + * previous data and the timeslot where the line is "low" is + * too short to be properly detected. + */ + do { + mutex_lock(&hw->fifo_lock); + len = st_lsm6dsx_read_fifo(hw); + mutex_unlock(&hw->fifo_lock); + + if (len > 0) + fifo_len += len; + } while (len > 0); + + return fifo_len ? IRQ_HANDLED : IRQ_NONE; +} + +static int st_lsm6dsx_buffer_preenable(struct iio_dev *iio_dev) +{ + return st_lsm6dsx_update_fifo(iio_dev, true); +} + +static int st_lsm6dsx_buffer_postdisable(struct iio_dev *iio_dev) +{ + return st_lsm6dsx_update_fifo(iio_dev, 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 device_node *np = hw->dev->of_node; + struct st_sensors_platform_data *pdata; + struct iio_buffer *buffer; + unsigned long irq_type; + bool irq_active_low; + int i, err; + + irq_type = irqd_get_trigger_type(irq_get_irq_data(hw->irq)); + + switch (irq_type) { + case IRQF_TRIGGER_HIGH: + case IRQF_TRIGGER_RISING: + irq_active_low = false; + break; + case IRQF_TRIGGER_LOW: + case IRQF_TRIGGER_FALLING: + irq_active_low = true; + break; + default: + dev_info(hw->dev, "mode %lx unsupported\n", irq_type); + return -EINVAL; + } + + err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_HLACTIVE_ADDR, + ST_LSM6DSX_REG_HLACTIVE_MASK, + FIELD_PREP(ST_LSM6DSX_REG_HLACTIVE_MASK, + irq_active_low)); + if (err < 0) + return err; + + pdata = (struct st_sensors_platform_data *)hw->dev->platform_data; + if ((np && of_property_read_bool(np, "drive-open-drain")) || + (pdata && pdata->open_drain)) { + err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_PP_OD_ADDR, + ST_LSM6DSX_REG_PP_OD_MASK, + FIELD_PREP(ST_LSM6DSX_REG_PP_OD_MASK, + 1)); + if (err < 0) + return err; + + irq_type |= IRQF_SHARED; + } + + err = devm_request_threaded_irq(hw->dev, hw->irq, + st_lsm6dsx_handler_irq, + st_lsm6dsx_handler_thread, + irq_type | IRQF_ONESHOT, + "lsm6dsx", hw); + if (err) { + dev_err(hw->dev, "failed to request trigger irq %d\n", + hw->irq); + return err; + } + + for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) { + 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; +} |