/*
* STMicroelectronics st_lsm6dsx FIFO buffer library driver
*
* LSM6DS3/LSM6DS3H/LSM6DSL/LSM6DSM: 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/platform_data/st_sensors_pdata.h>
#include "st_lsm6dsx.h"
#define ST_LSM6DSX_REG_FIFO_THL_ADDR 0x06
#define ST_LSM6DSX_REG_FIFO_THH_ADDR 0x07
#define ST_LSM6DSX_FIFO_TH_MASK GENMASK(11, 0)
#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_REG_FIFO_DIFFL_ADDR 0x3a
#define ST_LSM6DSX_FIFO_DIFF_MASK GENMASK(11, 0)
#define ST_LSM6DSX_FIFO_EMPTY_MASK BIT(12)
#define ST_LSM6DSX_REG_FIFO_OUTL_ADDR 0x3e
#define ST_LSM6DSX_MAX_FIFO_ODR_VAL 0x08
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)
{
struct st_lsm6dsx_sensor *sensor;
u16 max_odr, min_odr, sip = 0;
int err, 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;
}
dec_reg = &hw->settings->decimator[sensor->id];
if (dec_reg->addr) {
err = st_lsm6dsx_write_with_mask(hw, dec_reg->addr,
dec_reg->mask, data);
if (err < 0)
return err;
}
sip += sensor->sip;
}
hw->sip = sip;
return 0;
}
int st_lsm6dsx_set_fifo_mode(struct st_lsm6dsx_hw *hw,
enum st_lsm6dsx_fifo_mode fifo_mode)
{
int err;
err = st_lsm6dsx_write_with_mask(hw, ST_LSM6DSX_REG_FIFO_MODE_ADDR,
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 st_lsm6dsx_write_with_mask(hw, ST_LSM6DSX_REG_FIFO_MODE_ADDR,
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;
struct st_lsm6dsx_hw *hw = sensor->hw;
struct st_lsm6dsx_sensor *cur_sensor;
__le16 wdata;
int i, err;
u8 data;
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 * ST_LSM6DSX_SAMPLE_DEPTH;
mutex_lock(&hw->lock);
err = hw->tf->read(hw->dev, ST_LSM6DSX_REG_FIFO_THH_ADDR,
sizeof(data), &data);
if (err < 0)
goto out;
fifo_watermark = ((data << 8) & ~ST_LSM6DSX_FIFO_TH_MASK) |
(fifo_watermark & ST_LSM6DSX_FIFO_TH_MASK);
wdata = cpu_to_le16(fifo_watermark);
err = hw->tf->write(hw->dev, ST_LSM6DSX_REG_FIFO_THL_ADDR,
sizeof(wdata), (u8 *)&wdata);
out:
mutex_unlock(&hw->lock);
return err < 0 ? err : 0;
}
/**
* st_lsm6dsx_read_fifo() - LSM6DS3-LSM6DS3H-LSM6DSL-LSM6DSM read FIFO 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;
int err, acc_sip, gyro_sip, read_len, samples, offset;
struct st_lsm6dsx_sensor *acc_sensor, *gyro_sensor;
s64 acc_ts, acc_delta_ts, gyro_ts, gyro_delta_ts;
u8 iio_buff[ALIGN(ST_LSM6DSX_SAMPLE_SIZE, sizeof(s64)) + sizeof(s64)];
u8 buff[pattern_len];
__le16 fifo_status;
err = hw->tf->read(hw->dev, ST_LSM6DSX_REG_FIFO_DIFFL_ADDR,
sizeof(fifo_status), (u8 *)&fifo_status);
if (err < 0)
return err;
if (fifo_status & cpu_to_le16(ST_LSM6DSX_FIFO_EMPTY_MASK))
return 0;
fifo_len = (le16_to_cpu(fifo_status) & ST_LSM6DSX_FIFO_DIFF_MASK) *
ST_LSM6DSX_CHAN_SIZE;
samples = fifo_len / ST_LSM6DSX_SAMPLE_SIZE;
fifo_len = (fifo_len / pattern_len) * pattern_len;
/*
* compute delta timestamp between two consecutive samples
* in order to estimate queueing time of data generated
* by the sensor
*/
acc_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_ACC]);
acc_ts = acc_sensor->ts - acc_sensor->delta_ts;
acc_delta_ts = div_s64(acc_sensor->delta_ts * acc_sensor->decimator,
samples);
gyro_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_GYRO]);
gyro_ts = gyro_sensor->ts - gyro_sensor->delta_ts;
gyro_delta_ts = div_s64(gyro_sensor->delta_ts * gyro_sensor->decimator,
samples);
for (read_len = 0; read_len < fifo_len; read_len += pattern_len) {
err = hw->tf->read(hw->dev, ST_LSM6DSX_REG_FIFO_OUTL_ADDR,
sizeof(buff), buff);
if (err < 0)
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), 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, Gx, Gy, Gz
*/
gyro_sip = gyro_sensor->sip;
acc_sip = acc_sensor->sip;
offset = 0;
while (acc_sip > 0 || gyro_sip > 0) {
if (gyro_sip-- > 0) {
memcpy(iio_buff, &buff[offset],
ST_LSM6DSX_SAMPLE_SIZE);
iio_push_to_buffers_with_timestamp(
hw->iio_devs[ST_LSM6DSX_ID_GYRO],
iio_buff, gyro_ts);
offset += ST_LSM6DSX_SAMPLE_SIZE;
gyro_ts += gyro_delta_ts;
}
if (acc_sip-- > 0) {
memcpy(iio_buff, &buff[offset],
ST_LSM6DSX_SAMPLE_SIZE);
iio_push_to_buffers_with_timestamp(
hw->iio_devs[ST_LSM6DSX_ID_ACC],
iio_buff, acc_ts);
offset += ST_LSM6DSX_SAMPLE_SIZE;
acc_ts += acc_delta_ts;
}
}
}
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;
if (hw->fifo_mode != ST_LSM6DSX_FIFO_BYPASS) {
err = st_lsm6dsx_flush_fifo(hw);
if (err < 0)
return err;
}
if (enable) {
err = st_lsm6dsx_sensor_enable(sensor);
if (err < 0)
return err;
} else {
err = st_lsm6dsx_sensor_disable(sensor);
if (err < 0)
return err;
}
err = st_lsm6dsx_set_fifo_odr(sensor, enable);
if (err < 0)
return err;
err = st_lsm6dsx_update_decimators(hw);
if (err < 0)
return err;
err = st_lsm6dsx_update_watermark(sensor, sensor->watermark);
if (err < 0)
return err;
if (hw->enable_mask) {
err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_CONT);
if (err < 0)
return err;
/*
* store enable buffer timestamp as reference to compute
* first delta timestamp
*/
sensor->ts = iio_get_time_ns(iio_dev);
}
return 0;
}
static irqreturn_t st_lsm6dsx_handler_irq(int irq, void *private)
{
struct st_lsm6dsx_hw *hw = private;
struct st_lsm6dsx_sensor *sensor;
int i;
if (!hw->sip)
return IRQ_NONE;
for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
sensor = iio_priv(hw->iio_devs[i]);
if (sensor->sip > 0) {
s64 timestamp;
timestamp = iio_get_time_ns(hw->iio_devs[i]);
sensor->delta_ts = timestamp - sensor->ts;
sensor->ts = timestamp;
}
}
return IRQ_WAKE_THREAD;
}
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 = st_lsm6dsx_write_with_mask(hw, ST_LSM6DSX_REG_HLACTIVE_ADDR,
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 = st_lsm6dsx_write_with_mask(hw, ST_LSM6DSX_REG_PP_OD_ADDR,
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;
}
