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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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ec74ae9fd3
Add a timestamping mechanism for buffer that provides accurate event timestamps when using watermark. This mechanism estimates device internal clock by comparing FIFO interrupts delta time and device elapsed time computed by parsing FIFO data. Take interrupt timestamp in hard irq handler and add IIO device specific timestamp structures in device private allocation. Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
85 lines
2.3 KiB
C
85 lines
2.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Copyright (C) 2020 Invensense, Inc.
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*/
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#ifndef INV_ICM42600_TIMESTAMP_H_
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#define INV_ICM42600_TIMESTAMP_H_
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#include <linux/kernel.h>
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struct inv_icm42600_state;
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/**
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* struct inv_icm42600_timestamp_interval - timestamps interval
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* @lo: interval lower bound
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* @up: interval upper bound
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*/
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struct inv_icm42600_timestamp_interval {
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int64_t lo;
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int64_t up;
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};
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/**
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* struct inv_icm42600_timestamp_acc - accumulator for computing an estimation
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* @val: current estimation of the value, the mean of all values
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* @idx: current index of the next free place in values table
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* @values: table of all measured values, use for computing the mean
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*/
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struct inv_icm42600_timestamp_acc {
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uint32_t val;
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size_t idx;
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uint32_t values[32];
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};
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/**
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* struct inv_icm42600_timestamp - timestamp management states
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* @it: interrupts interval timestamps
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* @timestamp: store last timestamp for computing next data timestamp
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* @mult: current internal period multiplier
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* @new_mult: new set internal period multiplier (not yet effective)
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* @period: measured current period of the sensor
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* @chip_period: accumulator for computing internal chip period
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*/
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struct inv_icm42600_timestamp {
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struct inv_icm42600_timestamp_interval it;
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int64_t timestamp;
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uint32_t mult;
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uint32_t new_mult;
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uint32_t period;
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struct inv_icm42600_timestamp_acc chip_period;
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};
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void inv_icm42600_timestamp_init(struct inv_icm42600_timestamp *ts,
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uint32_t period);
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int inv_icm42600_timestamp_setup(struct inv_icm42600_state *st);
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int inv_icm42600_timestamp_update_odr(struct inv_icm42600_timestamp *ts,
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uint32_t period, bool fifo);
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void inv_icm42600_timestamp_interrupt(struct inv_icm42600_timestamp *ts,
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uint32_t fifo_period, size_t fifo_nb,
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size_t sensor_nb, int64_t timestamp);
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static inline int64_t
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inv_icm42600_timestamp_pop(struct inv_icm42600_timestamp *ts)
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{
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ts->timestamp += ts->period;
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return ts->timestamp;
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}
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void inv_icm42600_timestamp_apply_odr(struct inv_icm42600_timestamp *ts,
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uint32_t fifo_period, size_t fifo_nb,
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unsigned int fifo_no);
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static inline void
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inv_icm42600_timestamp_reset(struct inv_icm42600_timestamp *ts)
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{
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const struct inv_icm42600_timestamp_interval interval_init = {0LL, 0LL};
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ts->it = interval_init;
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ts->timestamp = 0;
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}
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#endif
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