Re: [PATCH v7 08/11] iio: accel: adxl345: add activity event feature

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 21 Apr 2025 22:06:38 +0000
Lothar Rubusch <l.rubusch@gmail.com> wrote:

> Make the sensor detect and issue interrupts at activity. Activity
> events are configured by a threshold stored in regmap cache. Initialize
> the activity threshold register to a reasonable default value in probe.
> The value is taken from the older ADXL345 input driver, to provide a
> similar behavior. Reset the activity/inactivity direction enabling
> register in probe. Reset and initialization shall bring the sensor in a
> defined initial state to prevent dangling settings when warm restarting
> the sensor.
> 
> Activity, ODR configuration together with the range setting prepare the
> activity/inactivity hystersesis setup, implemented in a follow up patch.
> 
> Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
> ---
>  drivers/iio/accel/adxl345_core.c | 217 ++++++++++++++++++++++++++++++-
>  1 file changed, 214 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
> index 80b5b8402ced..680981609d83 100644
> --- a/drivers/iio/accel/adxl345_core.c
> +++ b/drivers/iio/accel/adxl345_core.c
> @@ -36,11 +36,16 @@
>  #define ADXL345_REG_TAP_AXIS_MSK	GENMASK(2, 0)
>  #define ADXL345_REG_TAP_SUPPRESS_MSK	BIT(3)
>  #define ADXL345_REG_TAP_SUPPRESS	BIT(3)
> +#define ADXL345_REG_ACT_AXIS_MSK	GENMASK(6, 4)
>  
>  #define ADXL345_TAP_Z_EN		BIT(0)
>  #define ADXL345_TAP_Y_EN		BIT(1)
>  #define ADXL345_TAP_X_EN		BIT(2)
>  
> +#define ADXL345_ACT_Z_EN		BIT(4)
> +#define ADXL345_ACT_Y_EN		BIT(5)
> +#define ADXL345_ACT_X_EN		BIT(6)
> +
>  /* single/double tap */
>  enum adxl345_tap_type {
>  	ADXL345_SINGLE_TAP,
> @@ -64,6 +69,19 @@ static const unsigned int adxl345_tap_time_reg[] = {
>  	[ADXL345_TAP_TIME_DUR] = ADXL345_REG_DUR,
>  };
>  
> +/* activity/inactivity */
> +enum adxl345_activity_type {
> +	ADXL345_ACTIVITY,
> +};
> +
> +static const unsigned int adxl345_act_int_reg[] = {
> +	[ADXL345_ACTIVITY] = ADXL345_INT_ACTIVITY,
> +};
> +
> +static const unsigned int adxl345_act_thresh_reg[] = {
> +	[ADXL345_ACTIVITY] = ADXL345_REG_THRESH_ACT,
> +};
> +
>  enum adxl345_odr {
>  	ADXL345_ODR_0P10HZ = 0,
>  	ADXL345_ODR_0P20HZ,
> @@ -154,6 +172,13 @@ struct adxl345_state {
>  };
>  
>  static struct iio_event_spec adxl345_events[] = {
> +	{
> +		/* activity */
> +		.type = IIO_EV_TYPE_THRESH,

Is this a threshold, or a magnitude? I'd expect an activity detector
to be magnitude as it doesn't care which way up the sensor is.

> +		.dir = IIO_EV_DIR_RISING,
> +		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
> +		.mask_shared_by_type = BIT(IIO_EV_INFO_VALUE),
> +	},
>  	{
>  		/* single tap */
>  		.type = IIO_EV_TYPE_GESTURE,
> @@ -265,6 +290,99 @@ static int adxl345_set_measure_en(struct adxl345_state *st, bool en)
>  	return regmap_write(st->regmap, ADXL345_REG_POWER_CTL, val);
>  }
>
Jonathan