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https://github.com/RIOT-OS/RIOT.git
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2d81738cb9
- Previously the pulse counter used GCC's built-in functions for atomic memory
access. This PR changes this to use C11 atomics instead:
- Use of C11 atomics instead of atomic build-in functions makes the code
more portable and readable.
- Previously pulse_counter_reset() did not use an atomic function, so that
resets would be racy. (E.g. on the 8-bit AVR platform an 16-bit store is
not atomic, unless special care (like using C11 atomics) is taken.)
97 lines
2.2 KiB
C
97 lines
2.2 KiB
C
/*
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* Copyright (C) 2017 UC Berkeley
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @defgroup drivers_pulse_counter Pulse counter
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* @ingroup drivers_sensors
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* @ingroup drivers_saul
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*
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* @brief GPIO based pulse counting driver
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*
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* This driver provides @ref drivers_saul capabilities.
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* @{
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*
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* @file
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* @brief Driver for the pulse counter
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*
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* @author Hyung-Sin Kim <hs.kim@cs.berkeley.edu>
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*/
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#ifndef PULSE_COUNTER_H
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#define PULSE_COUNTER_H
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#include <stdint.h>
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#ifdef __cplusplus
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#include "c11_atomics_compat.hpp"
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#else
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#include <stdatomic.h>
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#endif
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#include "periph/gpio.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @brief Parameters needed for device initialization
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*/
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typedef struct {
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gpio_t gpio; /**< GPIO pin that sensor is connected to */
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gpio_flank_t gpio_flank; /**< GPIO flank option */
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} pulse_counter_params_t;
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/**
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* @brief Device descriptor for a pulse counter device
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*/
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typedef struct {
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atomic_uint_least16_t pulse_count; /**< pulse counter */
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} pulse_counter_t;
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/**
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* @brief Initialize a pulse counter device
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*
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* @param[out] dev device descriptor
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* @param[in] params configuration parameters
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*
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* @return 0 on success
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* @return -1 on error
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*/
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int pulse_counter_init(pulse_counter_t *dev, const pulse_counter_params_t *params);
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/**
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* @brief Read and reset pulse counter value
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*
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* @param[out] dev device descriptor of sensor
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*
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* @return Accumulated pulse counts
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*/
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int16_t pulse_counter_read_with_reset(pulse_counter_t *dev);
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/**
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* @brief Read pulse counter value
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*
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* @param[in] dev device descriptor of sensor
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*
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* @return Accumulated pulse counts
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*/
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int16_t pulse_counter_read_without_reset(pulse_counter_t *dev);
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/**
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* @brief Reset pulse counter value
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*
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* @param[out] dev device descriptor of sensor
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*/
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void pulse_counter_reset(pulse_counter_t *dev);
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#ifdef __cplusplus
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}
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#endif
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#endif /* PULSE_COUNTER_H */
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/** @} */
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