Re: [PATCH 4/6] iio: accel: bma220: add low-g event detection

[Jonathan Cameron <jic23@kernel.org>]

On Tue, 14 Oct 2025 19:43:00 +0300
Petre Rodan <petre.rodan@subdimension.ro> wrote:

> Add support for low-g detection.
> 
> Signed-off-by: Petre Rodan <petre.rodan@subdimension.ro>
Just a follow on related units of _period attributes.

> ---
>  drivers/iio/accel/bma220_core.c | 101 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 101 insertions(+)
> 
> diff --git a/drivers/iio/accel/bma220_core.c b/drivers/iio/accel/bma220_core.c
> index c4bebf3e5548..daff22ec1f2d 100644
> --- a/drivers/iio/accel/bma220_core.c
> +++ b/drivers/iio/accel/bma220_core.c
> @@ -119,6 +119,14 @@ static const struct iio_event_spec bma220_events[] = {
>  		.mask_shared_by_type = BIT(IIO_EV_INFO_VALUE) |
>  				       BIT(IIO_EV_INFO_PERIOD),
>  	},
> +	{
> +		.type = IIO_EV_TYPE_THRESH,
> +		.dir = IIO_EV_DIR_FALLING,
> +		.mask_shared_by_type = BIT(IIO_EV_INFO_ENABLE) |
> +				       BIT(IIO_EV_INFO_VALUE) |
> +				       BIT(IIO_EV_INFO_PERIOD) |
> +				       BIT(IIO_EV_INFO_HYSTERESIS),
> +	},
>  };
>  
>  #define BMA220_ACCEL_CHANNEL(index, reg, axis) {			\
> @@ -509,6 +517,7 @@ static int bma220_read_event_config(struct iio_dev *indio_dev,

> @@ -602,6 +634,37 @@ static int bma220_read_event_value(struct iio_dev *indio_dev,
>  		default:
>  			return -EINVAL;
>  		}
> +	case IIO_EV_TYPE_THRESH:
> +		switch (dir) {
> +		case IIO_EV_DIR_FALLING:
> +			switch (info) {
> +			case IIO_EV_INFO_VALUE:
> +				ret = regmap_read(data->regmap, BMA220_REG_CONF1,
> +						  &reg_val);
> +				if (ret)
> +					return ret;
> +				*val = FIELD_GET(BMA220_LOW_TH_MSK, reg_val);
> +				return IIO_VAL_INT;
> +			case IIO_EV_INFO_PERIOD:
> +				ret = regmap_read(data->regmap, BMA220_REG_CONF2,
> +						  &reg_val);
> +				if (ret)
> +					return ret;
> +				*val = FIELD_GET(BMA220_LOW_DUR_MSK, reg_val);
As in previous. Seems very unlikely period is in second here, given that would be far too long
to make sense!  See the ABI docs.  Looks to be samples which means
you need to deal with variable sampling frequencies as part of this
calculation.

> +				return IIO_VAL_INT;
>