Re: [PATCH v2 1/4] iio: imu: inv_mpu6050: add WoM (Wake-on-Motion) sensor

[Jonathan Cameron <jic23@kernel.org>]

On Fri,  8 Mar 2024 15:10:20 +0000
inv.git-commit@tdk.com wrote:

> From: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
> 
> WoM is a threshold test on accel value comparing actual sample

Very short wrap on this message. Wrap at 75 chars for commit messages.

> with previous one. It maps best to roc rising event.
> Add support of a new WOM sensor and functions for handling the
> corresponding roc_rising event. The event value is in SI units.
> Ensure WOM is stopped and restarted at suspend-resume, handle
> usage with buffer data ready interrupt, and handle change in
> sampling rate impacting already set roc value.
> 
> Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Hi Jean-Baptiste

Some minor comments inline

Jonathan

> ---
>  drivers/iio/imu/inv_mpu6050/inv_mpu_core.c    | 293 +++++++++++++++++-
>  drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h     |  19 +-
>  drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c    |   6 +-
>  drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c |  14 +-
>  4 files changed, 319 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> index 0e94e5335e93..ad42be809f09 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> @@ -15,6 +15,7 @@

> +static u64 inv_mpu6050_convert_wom_to_roc(unsigned int threshold, unsigned int freq_div)
> +{
> +	/* 4mg per LSB converted in m/s² in micro (1000000) */
> +	const unsigned int convert = 4U * 9807U;
> +	u64 value;
> +
> +	value = threshold * convert;
> +	/* compute the differential by multiplying by the frequency */
> +	value = div_u64(value * INV_MPU6050_INTERNAL_FREQ_HZ, freq_div);

	return div_u64();


> +
> +	return value;
> +}
> +
> +static unsigned int inv_mpu6050_convert_roc_to_wom(u64 roc, unsigned int freq_div)
> +{
> +	/* 4mg per LSB converted in m/s² in micro (1000000) */
> +	const unsigned int convert = 4U * 9807U;
> +	u64 value;
> +	unsigned int threshold;
> +
> +	/* return 0 only if roc is 0 */
> +	if (roc == 0)
> +		return 0;
> +
> +	value = div_u64(roc * freq_div, convert * INV_MPU6050_INTERNAL_FREQ_HZ);
> +	/* limit value to 8 bits and prevent 0*/
> +	if (value == 0)
> +		threshold = 1;

	return min(255, max(1, value));

unless this open code flow is needed for later changes.


> +	else if (value > 255)
> +		threshold = 255;
> +	else
> +		threshold = value;
> +
> +	return threshold;
> +}
> +

...

> +static int inv_mpu6050_set_wom_threshold(struct inv_mpu6050_state *st, u64 value,
> +					 unsigned int freq_div)
> +{
> +	unsigned int threshold;
> +	int result;
> +
> +	/* convert roc to wom threshold and convert back to handle clipping */
> +	threshold = inv_mpu6050_convert_roc_to_wom(value, freq_div);
> +	value = inv_mpu6050_convert_wom_to_roc(threshold, freq_div);
> +
> +	dev_dbg(regmap_get_device(st->map), "wom_threshold: 0x%x\n", threshold);
> +
> +	switch (st->chip_type) {
> +	case INV_ICM20609:
> +	case INV_ICM20689:
> +	case INV_ICM20600:
> +	case INV_ICM20602:
> +	case INV_ICM20690:
> +		st->data[0] = threshold;
> +		st->data[1] = threshold;
> +		st->data[2] = threshold;
> +		result = regmap_bulk_write(st->map, INV_ICM20609_REG_ACCEL_WOM_X_THR,
> +					   st->data, 3);
> +		break;
> +	default:
> +		result = regmap_write(st->map, INV_MPU6500_REG_WOM_THRESHOLD, threshold);
> +		break;
> +	}
> +	if (!result)
> +		st->chip_config.roc_threshold = value;

	if (result)
		return result;

	st->chip_config.roc_threshold = value;

	return 0;

More code, but keeping all error handling out of line makes for easier code review.

> +
> +	return result;
> +}
> +

> +static int inv_mpu6050_write_event_config(struct iio_dev *indio_dev,
> +					  const struct iio_chan_spec *chan,
> +					  enum iio_event_type type,
> +					  enum iio_event_direction dir,
> +					  int state)
> +{
> +	struct inv_mpu6050_state *st = iio_priv(indio_dev);
> +	int enable;
> +	int result;
> +
> +	/* support only WoM (accel roc rising) event */
> +	if (chan->type != IIO_ACCEL || type != IIO_EV_TYPE_ROC || dir != IIO_EV_DIR_RISING)

Long line - consider a line break.  I don't think it will hurt readability
and I'd still prefer IIO mostly stays under 80 chars

> +		return -EINVAL;
> +
> +	enable = !!state;
> +
> +	mutex_lock(&st->lock);

At some point we should switch to automated unlocking.
	guard(mutex)(&st->lock);
as can do nice simple direct returns without the goto.


> +
> +	if (st->chip_config.wom_en == enable) {
> +		result = 0;
> +		goto exit_unlock;
> +	}
> +
> +	result = inv_mpu6050_enable_wom(st, enable);
> +
> +exit_unlock:
> +	mutex_unlock(&st->lock);
> +	return result;
> +}
> +
> +static int inv_mpu6050_read_event_value(struct iio_dev *indio_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 inv_mpu6050_state *st = iio_priv(indio_dev);
> +	u32 rem;
> +
> +	/* support only WoM (accel roc rising) event value */
> +	if (chan->type != IIO_ACCEL || type != IIO_EV_TYPE_ROC ||
> +			dir != IIO_EV_DIR_RISING || info != IIO_EV_INFO_VALUE)

Odd alignment.  dir should align with chan.

> +		return -EINVAL;
> +
> +	/* return value in micro */
> +	*val = div_u64_rem(st->chip_config.roc_threshold, 1000000U, &rem);
> +	*val2 = rem;
> +
> +	return IIO_VAL_INT_PLUS_MICRO;
> +}
> +
> +static int inv_mpu6050_write_event_value(struct iio_dev *indio_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 inv_mpu6050_state *st = iio_priv(indio_dev);
> +	struct device *pdev = regmap_get_device(st->map);
> +	u64 value;
> +	int result;
> +
> +	/* support only WoM (accel roc rising) event value */
> +	if (chan->type != IIO_ACCEL || type != IIO_EV_TYPE_ROC ||
> +			dir != IIO_EV_DIR_RISING || info != IIO_EV_INFO_VALUE)

As above, odd alignment.

> +		return -EINVAL;
> +
> +	if (val < 0 || val2 < 0)
> +		return -EINVAL;
> +
> +	mutex_lock(&st->lock);
> +
> +	result = pm_runtime_resume_and_get(pdev);
> +	if (result)
> +		goto exit_unlock;
> +
> +	value = (u64)val * 1000000ULL + (u64)val2;
> +	result = inv_mpu6050_set_wom_threshold(st, value, INV_MPU6050_FREQ_DIVIDER(st));
> +
> +	pm_runtime_mark_last_busy(pdev);
> +	pm_runtime_put_autosuspend(pdev);
> +
> +exit_unlock:
> +	mutex_unlock(&st->lock);
> +	return result;
> +}
> +
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
> index 5950e2419ebb..19adccf388cf 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
> @@ -88,11 +88,12 @@ enum inv_devices {
>  	INV_NUM_PARTS
>  };
>  
> -/* chip sensors mask: accelerometer, gyroscope, temperature, magnetometer */
> +/* chip sensors mask: accelerometer, gyroscope, temperature, magnetometer, WoM */
>  #define INV_MPU6050_SENSOR_ACCL		BIT(0)
>  #define INV_MPU6050_SENSOR_GYRO		BIT(1)
>  #define INV_MPU6050_SENSOR_TEMP		BIT(2)
>  #define INV_MPU6050_SENSOR_MAGN		BIT(3)
> +#define INV_MPU6050_SENSOR_WOM		BIT(4)
>  
>  /**
>   *  struct inv_mpu6050_chip_config - Cached chip configuration data.
> @@ -104,6 +105,7 @@ enum inv_devices {
>   *  @gyro_en:		gyro engine enabled
>   *  @temp_en:		temperature sensor enabled
>   *  @magn_en:		magn engine (i2c master) enabled
> + *  @wom_en:		Wake-on-Motion enabled
>   *  @accl_fifo_enable:	enable accel data output
>   *  @gyro_fifo_enable:	enable gyro data output
>   *  @temp_fifo_enable:	enable temp data output
> @@ -119,12 +121,14 @@ struct inv_mpu6050_chip_config {
>  	unsigned int gyro_en:1;
>  	unsigned int temp_en:1;
>  	unsigned int magn_en:1;
> +	unsigned int wom_en:1;
>  	unsigned int accl_fifo_enable:1;
>  	unsigned int gyro_fifo_enable:1;
>  	unsigned int temp_fifo_enable:1;
>  	unsigned int magn_fifo_enable:1;
>  	u8 divider;
>  	u8 user_ctrl;
> +	u64 roc_threshold;
No docs?
>  };
>