iio: imu: st_lsm6dsx: add support to LSM6DSO

Add support to STM LSM6DSO 6-axis (acc + gyro) Mems sensor
https://www.st.com/resource/en/datasheet/lsm6dso.pdf

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 138 insertions, 6 deletions

diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
index ab0eec2bc70e..61f2c5777295 100644
--- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
+++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
@@ -12,6 +12,11 @@
  * 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: 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
@@ -46,6 +51,7 @@
 #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
@@ -58,6 +64,12 @@ struct st_lsm6dsx_decimator_entry {
 	u8 val;
 };
 
+enum st_lsm6dsx_fifo_tag {
+	ST_LSM6DSX_GYRO_TAG = 0x01,
+	ST_LSM6DSX_ACC_TAG = 0x02,
+	ST_LSM6DSX_TS_TAG = 0x04,
+};
+
 static const
 struct st_lsm6dsx_decimator_entry st_lsm6dsx_decimator_table[] = {
 	{  0, 0x0 },
@@ -177,12 +189,34 @@ 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;
 
-	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));
+	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 regmap_update_bits(hw->regmap, batch_reg->addr,
+					  batch_reg->mask, val);
+	} else {
+		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)
@@ -251,8 +285,8 @@ static int st_lsm6dsx_reset_hw_ts(struct st_lsm6dsx_hw *hw)
 }
 
 /*
- * Set max bulk read to ST_LSM6DSX_MAX_WORD_LEN in order to avoid
- * a kmalloc for each bus access
+ * 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,
@@ -403,6 +437,104 @@ int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw)
 	return read_len;
 }
 
+/**
+ * st_lsm6dsx_read_tagged_fifo() - LSM6DSO 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
+ */
+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;
+	struct st_lsm6dsx_sensor *acc_sensor, *gyro_sensor;
+	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 = 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;
+	}
+
+	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;
+
+	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,
+					    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;
+			switch (tag) {
+			case 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 *= ST_LSM6DSX_TS_SENSITIVITY;
+				break;
+			case ST_LSM6DSX_GYRO_TAG:
+				iio_push_to_buffers_with_timestamp(
+					hw->iio_devs[ST_LSM6DSX_ID_GYRO],
+					iio_buff, gyro_sensor->ts_ref + ts);
+				break;
+			case ST_LSM6DSX_ACC_TAG:
+				iio_push_to_buffers_with_timestamp(
+					hw->iio_devs[ST_LSM6DSX_ID_ACC],
+					iio_buff, acc_sensor->ts_ref + ts);
+				break;
+			default:
+				break;
+			}
+		}
+	}
+
+	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;