Re: [PATCH v3 3/4] iio: accel: adxl345: Implement event scaling for ABI compliance

[David Lechner <dlechner@baylibre.com>]

On 2/8/26 9:05 AM, Taha Ed-Dafili wrote:
> The ADXL345 uses a fixed threshold resolution of 62.5 mg/LSB for
> event-related registers. Previously, the driver reported raw
> values without a scale factor.
> 
> Implement IIO_EV_INFO_SCALE for all event types to provide the
> conversion factor (0.612915 m/s^2) as required by the IIO ABI.
> 
> Suggested-by: Jonathan Cameron <jic23@kernel.org>
> Signed-off-by: Taha Ed-Dafili <0rayn.dev@gmail.com>
> ---
>  drivers/iio/accel/adxl345_core.c | 28 ++++++++++++++++++++++------
>  1 file changed, 22 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
> index 78e3f799ecc1..dfe3169ffc5f 100644
> --- a/drivers/iio/accel/adxl345_core.c
> +++ b/drivers/iio/accel/adxl345_core.c
> @@ -212,7 +212,8 @@ static const struct iio_event_spec adxl345_events[] = {
>  		.type = IIO_EV_TYPE_MAG,
>  		.dir = IIO_EV_DIR_RISING,
>  		.mask_shared_by_type =
> -			BIT(IIO_EV_INFO_ENABLE) |
> +			BIT(IIO_EV_INFO_ENABLE)	|
> +			BIT(IIO_EV_INFO_SCALE)	|
>  			BIT(IIO_EV_INFO_VALUE),

Would be nice to be consistent and put scale after value as the ones
at the end.

>  	},
>  	{
> @@ -221,6 +222,7 @@ static const struct iio_event_spec adxl345_events[] = {
>  		.dir = IIO_EV_DIR_RISING,
>  		.mask_shared_by_type =
>  			BIT(IIO_EV_INFO_ENABLE) |
> +			BIT(IIO_EV_INFO_SCALE)	|
>  			BIT(IIO_EV_INFO_VALUE),
>  	},
>  	{
> @@ -228,15 +230,19 @@ static const struct iio_event_spec adxl345_events[] = {
>  		.type = IIO_EV_TYPE_GESTURE,
>  		.dir = IIO_EV_DIR_SINGLETAP,
>  		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
> -		.mask_shared_by_type = BIT(IIO_EV_INFO_VALUE) |
> +		.mask_shared_by_type =
> +			BIT(IIO_EV_INFO_VALUE)	|
> +			BIT(IIO_EV_INFO_SCALE)	|

What is the units for gesture that we are scaling to?

>  			BIT(IIO_EV_INFO_TIMEOUT),
>  	},
>  	{
>  		/* double tap */
>  		.type = IIO_EV_TYPE_GESTURE,
>  		.dir = IIO_EV_DIR_DOUBLETAP,
> -		.mask_shared_by_type = BIT(IIO_EV_INFO_ENABLE) |
> -			BIT(IIO_EV_INFO_RESET_TIMEOUT) |
> +		.mask_shared_by_type =
> +			BIT(IIO_EV_INFO_ENABLE)		|
> +			BIT(IIO_EV_INFO_RESET_TIMEOUT)	|
> +			BIT(IIO_EV_INFO_SCALE)		|

There is no value here, so scale doesn't make sense (plus it is gesture
as above.

>  			BIT(IIO_EV_INFO_TAP2_MIN_DELAY),
>  	},
>  };
> @@ -274,7 +280,8 @@ static const struct iio_event_spec adxl345_fake_chan_events[] = {
>  		.dir = IIO_EV_DIR_FALLING,
>  		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
>  		.mask_shared_by_type =
> -			BIT(IIO_EV_INFO_VALUE) |
> +			BIT(IIO_EV_INFO_VALUE)	|
> +			BIT(IIO_EV_INFO_SCALE)	|
>  			BIT(IIO_EV_INFO_PERIOD),
>  	},
>  	{
> @@ -283,7 +290,8 @@ static const struct iio_event_spec adxl345_fake_chan_events[] = {
>  		.dir = IIO_EV_DIR_FALLING,
>  		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
>  		.mask_shared_by_type =
> -			BIT(IIO_EV_INFO_VALUE) |
> +			BIT(IIO_EV_INFO_VALUE)	|
> +			BIT(IIO_EV_INFO_SCALE)	|
>  			BIT(IIO_EV_INFO_PERIOD),
>  	},
>  };
> @@ -1367,6 +1375,14 @@ static int adxl345_read_event_value(struct iio_dev *indio_dev,
>  				return ret;
>  			*val = sign_extend32(tap_threshold, 7);
>  			return IIO_VAL_INT;
> +		case IIO_EV_INFO_SCALE:
> +			/*
> +			 * The event threshold LSB is fixed at 62.5 mg/LSB
> +			 * 0.0625 * 9.80665 = 0.612915625 m/s^2
> +			 */
> +			*val = 0;
> +			*val2 = 612915;
> +			return IIO_VAL_INT_PLUS_MICRO;
>  		case IIO_EV_INFO_TIMEOUT:
>  			*val = st->tap_duration_us;
>  			*val2 = MICRO;