> Add event channels that controls the creation of motion events.
> 
> Signed-off-by: Sean Nyekjaer <sean@geanix.com>
> ---
>  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h      |   2 +
>  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 148 ++++++++++++++++++-
>  2 files changed, 144 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
> index a5e373680e9c..966cc6e91c7f 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
> @@ -155,6 +155,8 @@ struct st_lsm6dsx_hw {
>  	u8 enable_mask;
>  	u8 ts_sip;
>  	u8 sip;
> +	u8 event_threshold;
> +	bool enable_event;
>  
>  	u8 *buff;
>  
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> index b5d3fa354de7..351c46f01662 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> @@ -78,6 +78,17 @@
>  #define ST_LSM6DSX_REG_GYRO_OUT_Y_L_ADDR	0x24
>  #define ST_LSM6DSX_REG_GYRO_OUT_Z_L_ADDR	0x26
>  
> +#define ST_LSM6DSX_REG_TAP_CFG_ADDR		0x58
> +#define ST_LSM6DSX_REG_TAP_CFG_INT_EN_MASK	BIT(7)
> +#define ST_LSM6DSX_REG_TAP_CFG_INACT_EN_MASK	GENMASK(6, 5)
> +
> +#define ST_LSM6DSX_DEFAULT_WAKE_THRESH		0
> +#define ST_LSM6DSX_REG_WAKE_UP_THS_ADDR		0x5B
> +#define ST_LSM6DSX_REG_WAKE_UP_THS_THRES_MASK	GENMASK(5, 0)

Could you please verify this registermap is used for all supported devices?
(e.g. LSM6DS3 or LSM6DS3H)

> +
> +#define ST_LSM6DSX_REG_MD1_CFG_ADDR		0x5E
> +#define ST_LSM6DSX_REG_MD1_CFG_INT1_WU_MASK	BIT(5)
> +
>  #define ST_LSM6DSX_ACC_FS_2G_GAIN		IIO_G_TO_M_S_2(61)
>  #define ST_LSM6DSX_ACC_FS_4G_GAIN		IIO_G_TO_M_S_2(122)
>  #define ST_LSM6DSX_ACC_FS_8G_GAIN		IIO_G_TO_M_S_2(244)
> @@ -303,6 +314,13 @@ static const struct st_lsm6dsx_settings st_lsm6dsx_sensor_settings[] = {
>  	},
>  };
>  
> +static const struct iio_event_spec st_lsm6dsx_event = {
> +	.type = IIO_EV_TYPE_THRESH,
> +	.dir = IIO_EV_DIR_EITHER,
> +	.mask_separate = BIT(IIO_EV_INFO_VALUE) |
> +			 BIT(IIO_EV_INFO_ENABLE)
> +};
> +
>  #define ST_LSM6DSX_CHANNEL(chan_type, addr, mod, scan_idx)		\
>  {									\
>  	.type = chan_type,						\
> @@ -319,6 +337,8 @@ static const struct st_lsm6dsx_settings st_lsm6dsx_sensor_settings[] = {
>  		.storagebits = 16,					\
>  		.endianness = IIO_LE,					\
>  	},								\
> +	.event_spec = &st_lsm6dsx_event,				\
> +	.num_event_specs = 1,						\
>  }

ST_LSM6DSX_CHANNEL is used even for sensor-hub so I do not think you can use in
this way

>  
>  static const struct iio_chan_spec st_lsm6dsx_acc_channels[] = {
> @@ -435,6 +455,20 @@ static int st_lsm6dsx_set_odr(struct st_lsm6dsx_sensor *sensor, u16 odr)
>  				  ST_LSM6DSX_SHIFT_VAL(val, reg->mask));
>  }
>  
> +static int st_lsm6dsx_set_event_threshold(struct st_lsm6dsx_hw *hw, u8 threshold)
> +{
> +	int err = 0;
> +
> +	err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_WAKE_UP_THS_ADDR,
> +				 ST_LSM6DSX_REG_WAKE_UP_THS_THRES_MASK,
> +				 threshold);
> +
> +	if (!err)
> +		hw->event_threshold = threshold;
> +
> +	return err;

I think we can just move this configuration in st_lsm6dsx_write_event()

> +}
> +
>  int st_lsm6dsx_sensor_enable(struct st_lsm6dsx_sensor *sensor)
>  {
>  	int err;
> @@ -472,18 +506,21 @@ static int st_lsm6dsx_read_oneshot(struct st_lsm6dsx_sensor *sensor,
>  	int err, delay;
>  	__le16 data;
>  
> -	err = st_lsm6dsx_sensor_enable(sensor);
> -	if (err < 0)
> -		return err;
> +	if (!hw->enable_event) {
> +		err = st_lsm6dsx_sensor_enable(sensor);
> +		if (err < 0)
> +			return err;
>  
> -	delay = 1000000 / sensor->odr;
> -	usleep_range(delay, 2 * delay);
> +		delay = 1000000 / sensor->odr;
> +		usleep_range(delay, 2 * delay);
> +	}
>  
>  	err = regmap_bulk_read(hw->regmap, addr, &data, sizeof(data));
>  	if (err < 0)
>  		return err;
>  
> -	st_lsm6dsx_sensor_disable(sensor);
> +	if (!hw->enable_event)
> +		st_lsm6dsx_sensor_disable(sensor);
>  
>  	*val = (s16)le16_to_cpu(data);
>  
> @@ -556,6 +593,75 @@ static int st_lsm6dsx_write_raw(struct iio_dev *iio_dev,
>  	return err;
>  }
>  
> +static int st_lsm6dsx_read_event(struct iio_dev *iio_dev,
> +				   const struct iio_chan_spec *chan,
> +				   enum iio_event_type type,
> +				   enum iio_event_direction dir,
> +				   enum iio_event_info info,
> +				   int *val, int *val2)
> +{
> +	struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
> +
> +	*val2 = 0;
> +	*val = sensor->hw->event_threshold;
> +
> +	return IIO_VAL_INT;
> +}
> +
> +static int st_lsm6dsx_write_event(struct iio_dev *iio_dev,
> +				    const struct iio_chan_spec *chan,
> +				    enum iio_event_type type,
> +				    enum iio_event_direction dir,
> +				    enum iio_event_info info,
> +				    int val, int val2)
> +{
> +	struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
> +	struct st_lsm6dsx_hw *hw = sensor->hw;
> +
> +	if (!hw->enable_event)
> +		return -EBUSY;
> +
> +	if ((val < 0) || (val > 31))

unnecessary brackets

> +		return -EINVAL;
> +
> +	if (st_lsm6dsx_set_event_threshold(sensor->hw, val))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int st_lsm6dsx_read_event_config(struct iio_dev *iio_dev,
> +					  const struct iio_chan_spec *chan,
> +					  enum iio_event_type type,
> +					  enum iio_event_direction dir)
> +{
> +	struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
> +	struct st_lsm6dsx_hw *hw = sensor->hw;
> +
> +	return hw->enable_event;
> +}
> +
> +static int st_lsm6dsx_write_event_config(struct iio_dev *iio_dev,
> +					   const struct iio_chan_spec *chan,
> +					   enum iio_event_type type,
> +					   enum iio_event_direction dir,
> +					   int state)
> +{
> +	struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
> +	struct st_lsm6dsx_hw *hw = sensor->hw;
> +
> +	if (state && hw->enable_event)
> +		return 0;
> +
> +	hw->enable_event = state;
> +	if (state)
> +		st_lsm6dsx_sensor_enable(sensor);

please correct me if I am wrong but in this way we break normal operation (e.g.
if we are reading acc data from the FIFO). You need to check enabled_mask.
Moreover we should check event type

> +	else
> +		st_lsm6dsx_sensor_disable(sensor);
> +
> +	return 0;
> +}
> +
>  static int st_lsm6dsx_set_watermark(struct iio_dev *iio_dev, unsigned int val)
>  {
>  	struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
> @@ -632,6 +738,10 @@ static const struct iio_info st_lsm6dsx_acc_info = {
>  	.attrs = &st_lsm6dsx_acc_attribute_group,
>  	.read_raw = st_lsm6dsx_read_raw,
>  	.write_raw = st_lsm6dsx_write_raw,
> +	.read_event_value = st_lsm6dsx_read_event,
> +	.write_event_value = st_lsm6dsx_write_event,
> +	.read_event_config = st_lsm6dsx_read_event_config,
> +	.write_event_config = st_lsm6dsx_write_event_config,
>  	.hwfifo_set_watermark = st_lsm6dsx_set_watermark,
>  };
>  
> @@ -761,6 +871,8 @@ static int st_lsm6dsx_init_device(struct st_lsm6dsx_hw *hw)
>  	if (err < 0)
>  		return err;
>  
> +	st_lsm6dsx_set_event_threshold(hw, ST_LSM6DSX_DEFAULT_WAKE_THRESH);

we do not need this since default value is already 0

> +
>  	return st_lsm6dsx_init_hw_timer(hw);
>  }
>  
> @@ -811,6 +923,27 @@ static struct iio_dev *st_lsm6dsx_alloc_iiodev(struct st_lsm6dsx_hw *hw,
>  	return iio_dev;
>  }
>  
> +int st_lsm6dsx_event_setup(struct st_lsm6dsx_hw *hw)
> +{
> +	int err;
> +
> +	/* Enable inactivity function - low power ACC, GYRO powered-down */
> +	err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_TAP_CFG_ADDR,
> +				 ST_LSM6DSX_REG_TAP_CFG_INT_EN_MASK |
> +				 ST_LSM6DSX_REG_TAP_CFG_INACT_EN_MASK,
> +				 ST_LSM6DSX_REG_TAP_CFG_INT_EN_MASK |
> +				 ST_LSM6DSX_REG_TAP_CFG_INACT_EN_MASK);
> +	if (err < 0)
> +		return err;
> +
> +	/* Enable wakeup interrupt */
> +	err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_MD1_CFG_ADDR,
> +				 ST_LSM6DSX_REG_MD1_CFG_INT1_WU_MASK,
> +				 ST_LSM6DSX_REG_MD1_CFG_INT1_WU_MASK);
> +
> +	return err;
> +}
> +
>  static irqreturn_t st_lsm6dsx_handler_irq(int irq, void *private)
>  {
>  	struct st_lsm6dsx_hw *hw = private;
> @@ -932,6 +1065,9 @@ int st_lsm6dsx_probe(struct device *dev, int irq, int hw_id, const char *name,
>  		err = st_lsm6dsx_fifo_setup(hw);
>  		if (err < 0)
>  			return err;
> +		err = st_lsm6dsx_event_setup(hw);
> +		if (err < 0)
> +			return err;
>  	}
>  
>  	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
> -- 
> 2.22.0
>