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/* Copyright 2019 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef __CROS_EC_STILLNESS_DETECTOR_H
#define __CROS_EC_STILLNESS_DETECTOR_H
#include "common.h"
#include "math_util.h"
#include "stdbool.h"
#include <stdint.h>
struct still_det {
/** Variance threshold for the stillness confidence score. [units]^2 */
fp_t var_threshold;
/** The minimum window duration to consider a still sample. */
uint32_t min_batch_window;
/** The maximum window duration to consider a still sample. */
uint32_t max_batch_window;
/**
* The minimum number of samples in a window to consider a still sample.
*/
uint16_t min_batch_size;
/** The timestamp of the first sample in the current batch. */
uint32_t window_start_time;
/** The number of samples in the current batch. */
uint16_t num_samples;
/** Accumulators used for calculating stillness. */
fp_t acc_x, acc_y, acc_z, acc_xx, acc_yy, acc_zz, mean_x, mean_y,
mean_z;
};
#define STILL_DET(VAR_THRES, MIN_BATCH_WIN, MAX_BATCH_WIN, MIN_BATCH_SIZE) \
((struct still_det){ \
.var_threshold = VAR_THRES, \
.min_batch_window = MIN_BATCH_WIN, \
.max_batch_window = MAX_BATCH_WIN, \
.min_batch_size = MIN_BATCH_SIZE, \
.window_start_time = 0, \
.acc_x = 0.0f, \
.acc_y = 0.0f, \
.acc_z = 0.0f, \
.acc_xx = 0.0f, \
.acc_yy = 0.0f, \
.acc_zz = 0.0f, \
.mean_x = 0.0f, \
.mean_y = 0.0f, \
.mean_z = 0.0f, \
})
/**
* Update a stillness detector with a new sample.
*
* @param sample_time The timestamp of the sample to add.
* @param x The x component of the sample to add.
* @param y The y component of the sample to add.
* @param z The z component of the sample to add.
* @return True if the sample triggered a complete batch and mean_* are now
* valid.
*/
bool still_det_update(struct still_det *still_det, uint32_t sample_time, fp_t x,
fp_t y, fp_t z);
#endif /* __CROS_EC_STILLNESS_DETECTOR_H */
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