/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Copyright (C) 2020 Invensense, Inc.
 */

#ifndef INV_SENSORS_TIMESTAMP_H_
#define INV_SENSORS_TIMESTAMP_H_

/**
 * struct inv_sensors_timestamp_chip - chip internal properties
 * @clock_period:       internal clock period in ns
 * @jitter:             acceptable jitter in per-mille
 * @init_period:        chip initial period at reset in ns
 */
struct inv_sensors_timestamp_chip {
        uint32_t clock_period;
        uint32_t jitter;
        uint32_t init_period;
};

/**
 * struct inv_sensors_timestamp_interval - timestamps interval
 * @lo: interval lower bound
 * @up: interval upper bound
 */
struct inv_sensors_timestamp_interval {
        int64_t lo;
        int64_t up;
};

/**
 * struct inv_sensors_timestamp_acc - accumulator for computing an estimation
 * @val:        current estimation of the value, the mean of all values
 * @idx:        current index of the next free place in values table
 * @values:     table of all measured values, use for computing the mean
 */
struct inv_sensors_timestamp_acc {
        uint32_t val;
        size_t idx;
        uint32_t values[32];
};

/**
 * struct inv_sensors_timestamp - timestamp management states
 * @chip:               chip internal characteristics
 * @min_period:         minimal acceptable clock period
 * @max_period:         maximal acceptable clock period
 * @it:                 interrupts interval timestamps
 * @timestamp:          store last timestamp for computing next data timestamp
 * @mult:               current internal period multiplier
 * @new_mult:           new set internal period multiplier (not yet effective)
 * @period:             measured current period of the sensor
 * @chip_period:        accumulator for computing internal chip period
 */
struct inv_sensors_timestamp {
        struct inv_sensors_timestamp_chip chip;
        uint32_t min_period;
        uint32_t max_period;
        struct inv_sensors_timestamp_interval it;
        int64_t timestamp;
        uint32_t mult;
        uint32_t new_mult;
        uint32_t period;
        struct inv_sensors_timestamp_acc chip_period;
};

void inv_sensors_timestamp_init(struct inv_sensors_timestamp *ts,
                                const struct inv_sensors_timestamp_chip *chip);

int inv_sensors_timestamp_update_odr(struct inv_sensors_timestamp *ts,
                                     uint32_t period, bool fifo);

void inv_sensors_timestamp_interrupt(struct inv_sensors_timestamp *ts,
                                     size_t sample_nb, int64_t timestamp);

static inline int64_t inv_sensors_timestamp_pop(struct inv_sensors_timestamp *ts)
{
        ts->timestamp += ts->period;
        return ts->timestamp;
}

void inv_sensors_timestamp_apply_odr(struct inv_sensors_timestamp *ts,
                                     uint32_t fifo_period, size_t fifo_nb,
                                     unsigned int fifo_no);

static inline void inv_sensors_timestamp_reset(struct inv_sensors_timestamp *ts)
{
        const struct inv_sensors_timestamp_interval interval_init = {0LL, 0LL};

        ts->it = interval_init;
        ts->timestamp = 0;
}

#endif