blob: 7589f2ad1dae7de9fe04b5448b233fdda786db70 [file] [log] [blame]
/*
* 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, sip = 0, fifo_th_mask;
struct st_lsm6dsx_hw *hw = sensor->hw;
struct st_lsm6dsx_sensor *cur_sensor;
int i, err, data;
__le16 wdata;
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);
sip += cur_sensor->sip;
}
if (!sip)
return 0;
fifo_watermark = max_t(u16, fifo_watermark, sip);
fifo_watermark = (fifo_watermark / sip) * 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 count;
mutex_lock(&hw->fifo_lock);
count = st_lsm6dsx_read_fifo(hw);
mutex_unlock(&hw->fifo_lock);
return !count ? IRQ_NONE : IRQ_HANDLED;
}
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;
}