Re: [PATCH v4 3/4] iio: accel: adxl345: Implement event scaling for ABI compliance

[David Lechner]

On 2/21/26 8:12 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.
> 
> Consequently, remove the obsolete comment in adxl345_read_event_value()
> which stated that the scale factor is not applied.
> 
> Add explicit write rejection for IIO_EV_INFO_SCALE in
> adxl345_write_event_value() returning -EINVAL.
> 
> Suggested-by: Jonathan Cameron <jic23@xxxxxxxxxx>
> Signed-off-by: Taha Ed-Dafili <0rayn.dev@xxxxxxxxx>
> ---
>  drivers/iio/accel/adxl345_core.c | 37 ++++++++++++++++++++++----------
>  1 file changed, 26 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
> index 78e3f799ecc1..eac4ab052fa2 100644
> --- a/drivers/iio/accel/adxl345_core.c
> +++ b/drivers/iio/accel/adxl345_core.c
> @@ -213,7 +213,8 @@ 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_VALUE),
> +			BIT(IIO_EV_INFO_VALUE)	|
> +			BIT(IIO_EV_INFO_SCALE),
>  	},
>  	{
>  		/* activity, ac bit set */
> @@ -221,22 +222,27 @@ 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_VALUE),
> +			BIT(IIO_EV_INFO_VALUE)	|
> +			BIT(IIO_EV_INFO_SCALE),
>  	},
>  	{
>  		/* single tap */
>  		.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)	|
>  			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_SCALE)		|

I still question this one. Why do we have a IIO_EV_INFO_SCALE with no
IIO_EV_INFO_VALUE?

The docs say:

| in_accel_gesture_doubletap_scale | Double tap gesture threshold scale. |

But there is no attribute labeled "Double tap gesture threshold" that it
could be referring to.


> +			BIT(IIO_EV_INFO_RESET_TIMEOUT)  |
>  			BIT(IIO_EV_INFO_TAP2_MIN_DELAY),
>  	},
>  };ret = adxl345_write_mag_value(st, dir, info,